Shower head of a wafer treatment apparatus having a gap controller

• US 20030010452A1
• Filed: 06/25/2002
• Published: 01/16/2003
• Est. Priority Date: 07/16/2001
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Park, Jong-Chul, Kwon, O-Ik, Jo, Hye-Jin, Kim, Dong-Hyun
• Granted Patent: US 6,872,258 B2
• Time in Patent Office: Days
• US Class Current: 156/345.33
• CPC Class Codes: C23C 16/45565 Shower nozzles
• CPC Class Codes: C23C 16/45589 Movable means, e.g. fans
• CPC Class Codes: H01L 21/67017 Apparatus for fluid treatment H01L21/67126, H01L21/6715 take precedence

Abstract

A shower head for adjusting distribution of a reactant gas in a process region of a semiconductor manufacturing reaction chamber, wherein a top plate has a gas port for introducing the reactant gas into the reaction chamber; a face plate, having through holes, disposed opposite the process region; a first baffle plate, having through holes, disposed between the top plate and the face plate and capable of moving up or down, wherein the first baffle plate has a top surface that defines a first gap for forming a first lateral flow passage; a second baffle plate, having through holes, disposed between the first baffle plate and the face plate and capable of moving up or down, wherein the second baffle plate has a top surface that defines a second gap for forming a second lateral flow passage; and a gap controller for determining widths of the first and second gaps.

Claims

1. A shower head for supplying a reactant gas to a process region within a reaction chamber during manufacture of a semiconductor device, the shower head comprising:

a top plate having a gas port for introducing the reactant gas supplied from an outside source into the reaction chamber;

a face plate disposed opposite the process region, the face plate having a plurality of through holes;

a first baffle plate, having a plurality of through holes, the first baffle plate disposed between the top plate and the face plate so that it is capable of moving up or down, the first baffle plate having a top surface that defines a first gap for forming a first lateral flow passage of the reactant gas;

a second baffle plate, having a plurality of through holes, the second baffle plate disposed between the first baffle plate and the face plate so that it is capable of moving up or down, the second baffle plate having a top surface that defines a second gap for forming a second lateral flow passage of the reactant gas between the first and second baffle plates; and

a gap controller for determining a width of the first gap and a width of the second gap.

2. The shower head as claimed in claim 1, wherein the plurality of through holes formed in the first baffle plate comprise:

a plurality of first through holes formed at a first position which is proximate to a central axis of the first baffle plate and spaced apart in a radial direction from the central axis by a first distance; and

a plurality of second through holes formed at a second position which is proximate to an edge of the first baffle plate and spaced apart in a radial direction from the central axis by a second distance greater than the first distance.

3. The shower head as claimed in claim 2, wherein the gap controller determines the position of the first baffle plate to decrease the width of the first gap so that the amount of the reactant gas flowing through the plurality of first through holes is greater than an amount of the reactant gas flowing through the plurality of second through holes.

4. The shower head as claimed in claim 2, wherein the gap controller determines the position of the first baffle plate to increase the width of the first gap so that the amount of the reactant gas flowing through the plurality of second through holes is increased.

5. The shower head as claimed in claim 1, wherein the gap controller determines the position of the second baffle plate to increase the width of the second gap so that the amount of the reactant gas flowing through the plurality of through holes formed in the second baffle plate is made uniform over the entire process region.

6. The shower head as claimed in claim 1, wherein the gap controller determines the position of the second baffle plate to decrease the width of the second gap so that the amount of the reactant gas flowing through the plurality of through holes formed in the second baffle plate is selectively made to vary depending on a position in the process region.

7. The shower head as claimed in claim 1, wherein the gap controller comprises:

a first spacer ring disposed on top of the first baffle plate for determining the width of the first gap; and

a second spacer ring disposed between the first and second baffle plates for determining the width of the second gap.

8. The shower head as claimed in claim 7, wherein the first spacer ring is disposed on a top edge of the first baffle plate, and the second spacer ring is disposed on a top edge of the second baffle plate.

9. The shower head as claimed in claim 7, wherein the first spacer ring is composed of one or more annular rings.

10. The shower head as claimed in claim 7, wherein the second spacer ring is composed of one or more annular rings.

11. The shower head as claimed in claim 7, wherein at least one of the first and second spacer rings has an annular contact portion in which a plurality of sawtooth gears are formed.

12. The shower head as claimed in claim 11, wherein each of the plurality of sawtooth gears has a pitch corresponding to the length of an arc of a central angle 90°

.

13. The shower head as claimed in claim 7, wherein the height of each sawtooth gear of the annular contact portion is in the range of approximately 0.01-0.5 mm.

14. The shower head as claimed in claim 7, wherein the first spacer ring has an annular contact portion comprised of a plurality of sawtooth gears formed opposite the first baffle plate, and

wherein the first baffle plate includes a spacer ring coupler having a plurality of sawtooth gears formed opposite the first spacer ring to mesh with the plurality of sawtooth gears of the annular contact portion.

15. The shower head as claimed in claim 14, wherein each of the plurality of sawtooth gears of the spacer ring coupler has a pitch corresponding to the length of an arc of a central angle 90°

.

16. The shower head as claimed in claim 14, wherein the height of each sawtooth gear of the spacer ring coupler is in the range of approximately 0.01-0.5 mm.

17. The shower head as claimed in claim 7, wherein the second spacer ring has an annular contact portion comprised of a plurality of sawtooth gears formed opposite the second baffle plate, and

wherein the second baffle plate includes a spacer ring coupler having a plurality of sawtooth gears formed opposite the second spacer ring to mesh with the plurality of sawtooth gears of the annular contact portion.

18. The shower head as claimed in claim 17, wherein each of the plurality of sawtooth gears of the spacer ring coupler has a pitch corresponding to the length of an arc of a central angle 90°

.

19. The shower head as claimed in claim 17, wherein the height of each sawtooth gear of the spacer ring coupler is in the range of approximately 0.01-0.5 mm.

20. The shower head as claimed in claim 1, wherein the first baffle plate is comprised of a single disk-type element having a uniform thickness over the entire surface.

21. The shower head as claimed in claim 1, wherein the first baffle plate comprises:

a disk-like base plate having a plurality of through holes and a groove for providing a circular space at the center of a top surface thereof; and

a disk-like insert plate inserted to rotate about a central axis of the first baffle plate within the groove, the disk-like insert plate having a plurality of through holes in communication with selected ones of the plurality of through holes formed in the base plate.

22. The shower head as claimed in claim 21, wherein the plurality of through holes formed in the base plate comprise:

a plurality of first through holes formed at a first position that is proximate to the central axis of the first baffle plate and spaced apart in a radial direction from the central axis by a first distance less than a radius of the insert plate; and

a plurality of second through holes formed at a second position that is proximate to an edge of the base plate and spaced apart in a radial direction from the central axis by a second distance greater than the radius of the insert plate, and

wherein the plurality of first through holes are in communication with the plurality of through holes formed in the insert plate depending on rotational distance of the insert plate.

23. The shower head as claimed in claim 22, wherein, in order to change the opening ratio of the first through holes depending on the rotational distance of the insert plate, the plurality of through holes in the insert plate and the plurality of first through holes in the base plate are formed selectively only in some angular ranges with respect to the central axis of the first baffle plate.

24. The shower head as claimed in claim 1, further comprising a guide baffle plate disposed on the first baffle plate coaxially with respect to the first baffle plate, the guide baffle plate having an inlet for introducing the reactant gas supplied through the top plate and a plurality of outlets for flowing the reactant gas introduced through the inlet out into the first gap through a plurality of passages,

wherein the width of the first gap is defined by a bottom of the guide baffle plate and a top surface of the first baffle plate.

25. The shower head as claimed in claim 24, wherein the plurality of outlets formed in the guide baffle plate are formed at a position spaced apart in a radial direction from a central axis of the guide baffle plate by a predetermined distance.

26. The shower head as claimed in claim 25, wherein the plurality of through holes comprise:

a plurality of first through holes formed at a first position which is proximate to a central axis of the first baffle plate and spaced apart in a radial direction from the central axis by a first distance; and

a plurality of second through holes formed at a second position which is proximate to an edge of the first baffle plate and spaced apart in a radial direction from the central axis by a second distance greater than the first distance, and

wherein the plurality of outlets formed in the guide baffle plate are formed at a position that is spaced apart in a radial direction from the central axis of the guide baffle plate by a third distance greater than the first distance and less than the second distance.

27. The shower head as claimed in claim 26, wherein a distance between each of the plurality of outlets and each of the plurality of first through holes is less than the distance between each of the plurality of outlets and each of the plurality of second through holes.

28. The shower head as claimed in claim 24, wherein the gap controller comprises:

a first spacer ring disposed between the guide baffle plate and the first baffle plate for determining the width of the first gap; and

a second spacer ring disposed between the first and second baffle plates for determining the width of the second gap.

29. The shower head as claimed in claim 28, wherein the first and second spacer rings, respectively, are composed of one or more annular rings.

30. The shower head as claimed in claim 28, wherein at least one of the first and second spacer rings has an annular contact portion in which a plurality of sawtooth gears are formed.

31. The shower head as claimed in claim 30, wherein each of the plurality of sawtooth gears has a pitch corresponding to the length of an arc of a central angle 90°

.

32. The shower head as claimed in claim 30, wherein the height of each sawtooth gear of the annular contact portion is in the range of approximately 0.01-0.5 mm.

33. The shower head as claimed in claim 28, wherein the first spacer ring has an annular contact portion comprised of a plurality of sawtooth gears formed opposite the first baffle plate, and

wherein the first baffle plate comprises a spacer ring coupler having a plurality of sawtooth gears formed opposite the first spacer ring to mesh with the plurality of sawtooth gears of the annular contact portion.

34. The shower head as claimed in claim 33, wherein each of the plurality of sawtooth gears of the spacer ring coupler has a pitch corresponding to the length of an arc of a central angle 90°

.

35. The shower head as claimed in claim 33, wherein the height of each sawtooth gear of the spacer ring coupler is in the range of approximately 0.01-0.5 mm.

36. The shower head as claimed in claim 28, wherein the second spacer ring has an annular contact portion comprised of a plurality of sawtooth gears formed opposite the second baffle plate, and

wherein the second baffle plate includes a spacer ring coupler having a plurality of sawtooth gears formed opposite the second spacer ring to mesh with the plurality of sawtooth gears of the annular contact portion.

37. The shower head as claimed in claim 36, wherein each of the plurality of sawtooth gears of the spacer ring coupler has a pitch corresponding to the length of an arc of a central angle 90°

.

38. The shower head as claimed in claim 36, wherein the height of each sawtooth gear of the spacer ring coupler is in the range of approximately 0.01-0.5 mm.

39. The shower head as claimed in claim 24, wherein the gap controller comprises:

a first driving shaft for selectively moving the guide baffle plate upwardly or downwardly in order to determine the width of the first gap; and

a second driving shaft for selectively moving the first baffle plate upwardly or downwardly in order to determine the width of the second gap.

40. The shower head as claimed in claim 39, wherein the first driving shaft is installed coaxially with the second driving shaft.

41. The shower head as claimed in claim 24, wherein the gap controller comprises:

an elevating mechanism for moving the first baffle plate upwardly or downwardly using a first stepping motor in order to determine the width of the second gap; and

a rotating mechanism for moving the guide baffle plate upwardly or downwardly by a gear drive using a second stepping motor in order to determine the width of the first gap, and

wherein the elevating mechanism is integrated with the rotating mechanism.

42. The shower head as claimed in claim 41, wherein the elevating mechanism comprises a shaft, which extends to pass through the guide baffle plate and the first baffle plate, and an outward flange disposed at one end of the shaft for moving the first baffle plate upwardly or downwardly to follow the upward or downward movement of the shaft, and

wherein the rotating mechanism includes the shaft which is rotatable by power transmitted from the second stepping motor, and an external screw formed on an outer circumference of the shaft where the guide baffle plate is combined, for raising or lowering the guide baffle plate according to the rotation of the shaft.

43. The shower head as claimed in claim 42, wherein a circular space for housing the outward flange formed at the end of the shaft is formed at the central portion of the first baffle plate.

44. The shower head as claimed in claim 42, wherein a central hole, through which the shaft passes, is formed at a central portion of the guide baffle plate, and an internal thread for mating with the external thread of the screw of the shaft is formed on an inner wall of the central hole.

45. The shower head as claimed in claim 42, wherein an internal thread for mating with the external thread of the screw is formed in the guide baffle plate so that the guide baffle plate is moved upwardly or downwardly to follow the movement of the shaft when the shaft is moved up or down by the elevating mechanism in order to raise or lower the first baffle plate.

46. The shower head as claimed in claim 42, wherein a circular space for housing the outward flange without friction is formed in the first baffle plate so that the rotation of the outward range does not affect the first baffle plate when the shaft is rotated by the rotating mechanism in order to raise or lower the guide baffle plate.

47. The shower head as claimed in claim 42, further comprising a stopper for preventing the guide baffle plate from rotating when the shaft is rotated by the rotating mechanism.

48. The shower head as claimed in claim 1, further comprising a rotating mechanism connected to the first baffle plate so that the first baffle plate rotates with respect to the second baffle plate in a predetermined angular range,

wherein the first baffle plate contacts the second baffle plate so that selected ones of the plurality of through holes formed in the first baffle plate are in communication with selected ones of the plurality of through holes formed in the second baffle plate to thereby form align holes.

49. The shower head as claimed in claim 48, wherein the width of the second gap is effectively zero.

50. The shower head as claimed in claim 48, wherein the plurality of through holes formed in the first baffle plate are distributed to have different opening ratios depending on a radius from the central axis of the first baffle plate,

wherein the plurality of through holes formed in the second baffle plate are distributed to have different opening ratios depending on the distance by which the first baffle plate rotates about the central axis of the second baffle plate, and

wherein the rotating mechanism changes the rotational distance of the first baffle plate in order to change the opening position of the align holes.

51. The shower head of claim 50, wherein the first baffle plate is divided into a plurality of sectorial regions that extend in a radial direction from the central axis thereof, each sectorial region having a plurality of through holes formed only in a predetermined range spaced apart from the central axis by a selected radius.

52. The shower head of claim 50, wherein the second baffle plate is divided into a plurality of sectorial regions that extend in a radial direction from the central axis thereof, and the plurality of sectorial regions having the plurality of through holes are arranged at regular intervals.

53. The shower head of claim 48, wherein the gap controller comprises a driving shaft for simultaneously moving the first and second baffle plates upwardly or downwardly in order to determine the width of the first gap.

54. The shower head of claim 53, further comprising a guide baffle plate disposed on the first baffle plate coaxially with respect to the first baffle plate, the guide baffle plate having an inlet for introducing the reactant gas supplied through the top plate and a plurality of outlets for flowing the reactant gas that has been introduced through the inlet into the first gap through a plurality of passages,

wherein the width of the first gap is defined by a bottom of the guide baffle plate and a top surface of the first baffle plate.

55. The shower head of claim 54, wherein the plurality of outlets in the guide baffle plate are formed at a position spaced apart in a radial direction from a central axis of the guide baffle plate by a predetermined distance.

57. The shower head of claim 56, wherein each of the plurality of piezoelectric elements comprises:

a piezoelectric layer which vibrates in a thickness extensional mode according to the application of voltage, the piezoelectric layer having two main surfaces;

first and second electrode layers, each of which is formed on one of the two main surfaces of the piezoelectric layer; and

an insulating layer formed on the first electrode layer adjacent to the first baffle plate.

58. The shower head of claim 57, wherein the piezoelectric layer is formed of one selected from the group consisting of lead zirconate titanate (PZT), PbTiO₃, BaTiO₃, and poly vinylidene fluoride (PVDF) polymer.

59. The shower head of claim 57, wherein the second electrode layer is constructed by the second baffle plate.

60. The shower head of claim 56, wherein the plurality of piezoelectric elements are formed at positions corresponding to those at which the plurality of through holes of the first baffle plate are formed.

61. The shower head of claim 56, wherein each of the plurality of piezoelectric elements controls the amount of the reactant gas flowing from the through holes of the first baffle plate into the gap using a thickness expansion rate of the piezoelectric element adjusted according to the level of voltage applied from the power supply unit.

62. The shower head of claim 56, wherein each of the plurality of piezoelectric elements selectively opens or closes the plurality of through holes using a thickness expansion rate of the piezoelectric element adjusted according to the level of voltage applied from the supply unit.

63. The shower head of claim 56, wherein the plurality of through holes of the first baffle plate are formed at a first position spaced apart from a central axis of the first baffle plate by a predetermined radius, and

wherein one of the plurality of piezoelectric elements includes an annular element formed at a position corresponding to the first position on the second baffle plate.

64. The shower head of claim 56, wherein the first and second baffle plates are formed of aluminum.

65. The shower head of claim 56, further comprising a guide baffle plate disposed on the first baffle plate coaxially with respect to the first baffle plate, the guide baffle plate having a bottom face opposing the first baffle plate,

wherein an upper gap for providing a lateral flow passage of the reactant gas is formed between the guide baffle plate and the first baffle plate, and

wherein the guide baffle plate has an inlet for introducing the reactant gas supplied through the top plate, and a plurality of outlets for flowing the reactant gas introduced through the inlet out into the upper gap through a plurality of passages.

66. The shower head of claim 65, wherein the plurality of outlets formed in the guide baffle plate are formed at a position spaced apart in a radial direction from a central axis of the guide baffle plate by a predetermined distance.

67. The shower head of claim 56, further comprising a third baffle plate disposed between the second baffle plate and the face baffle plate, the third baffle plate having a plurality of through holes.

68. The shower head of claim 67, wherein the third baffle plate is formed of high resistance material whose resistivity is sufficiently high to electrically stabilize the shower head.

69. The shower head of claim 68, wherein the third baffle plate is formed of silicon carbide (SiC).

56. A shower head for supplying a reactant gas to a process region within a reaction chamber, the shower head comprising:

a top plate having a gas port for introducing the reactant gas supplied from an outside source into the reaction chamber;

a face plate disposed opposite the process region, the face plate having a plurality of through holes;

a first baffle plate disposed between the top plate and the face plate, the first baffle plate having a plurality of through holes;

a second baffle plate, having a plurality of through holes, disposed between the first baffle plate and the face plate, the second baffle plate having a top surface that defines a gap for forming a lateral flow passage of the reactant gas between the first and second baffle plates;

a plurality of piezoelectric elements disposed on the second baffle plate for controlling the amount of the reactant gas through the gap; and

a power supply unit for applying voltage to each of the plurality of piezoelectric elements.

70. A shower head for supplying a reactant gas to a process region within a reaction chamber, the shower head comprising:

a first baffle plate having a plurality of first and second through holes in order to selectively adjust the amount of the reactant gas supplied from an outside source according to a radius from the central axis, wherein the plurality of first through holes are spaced apart from a central axis by a first radius and the plurality of second through holes are spaced apart from the central axis by a second radius;

a second baffle plate disposed below the first baffle plate so that a gap for providing a lateral flow passage is formed between the first and second baffle plates, the second baffle plate having a plurality of through holes; and

a gap controller for moving at least one of the first and second baffle plates in order to adjust the width of the gap.

71. The shower head of claim 70, wherein the gap controller comprises a spacer ring having a predetermined thickness disposed between the first and second baffle plates for determining the width of the gap.

72. The shower head of claim 71, wherein the spacer ring is formed on a top edge of the second baffle plate.

73. The shower head of claim 71, wherein the spacer ring is composed of one or more annular rings.

74. The shower head of claim 71, wherein the spacer ring has an annular contact portion in which a plurality of sawtooth gears are formed.

75. The shower head of claim 74, wherein each of the plurality of sawtooth gears has a pitch corresponding to the length of an arc of a central angle 90°

.

76. The shower head of claim 74, wherein the height of each sawtooth gear of the annular contact portion is in the range of approximately 0.01-0.5 mm.

77. The shower head of claim 74, wherein the annular contact portion of the spacer ring contacts a bottom surface of the first baffle plate, and

wherein a spacer ring coupler having a plurality of sawtooth gears formed to mesh with the plurality of sawtooth gears of the annular contact portion is formed on the edge of the bottom surface of the first baffle plate.

78. The shower head of claim 77, wherein the space ring coupler of the first baffle plate has a portion having a thickness less than a thickness of a bottom central portion of the first baffle plate.

79. The shower head of claim 74, wherein the annular contact portion of spacer ring contacts a top surface of the second baffle plate, and

wherein a spacer ring coupler having a plurality of sawtooth gears formed to mesh with the plurality of sawtooth gears of the annular contact portion is formed on the top surface of the second baffle plate.

80. The shower head of claim 79, wherein the spacer ring coupler of the second baffle plate has a portion having a thickness less than a thickness of a top central portion of the second baffle plate.

81. The shower head of claim 70, wherein the first baffle plate is comprised of a single disk-type element having a uniform thickness over the entire surface.

82. The shower head of claim 70, wherein the first baffle plate comprises:

a disk-like base plate having a central portion in which a groove for providing a circular space is formed, and a plurality of through holes for constructing some of the plurality of the first through holes at the central portion thereof; and

a disk-like insert plate inserted so that it can rotate about a central axis of the first baffle plate within the groove, the disk-like insert plate having a plurality of through holes that can communicate with the plurality of through holes formed at the central portion of base plate in order to form the first through holes.

83. The shower head of claim 82, wherein, in order to change the opening ratio of the first through holes depending on the rotational distance of the insert plate, the plurality of through holes in the insert plate and the plurality of through holes in the base plate are formed selectively only in some angular ranges with respect to the central axis of the first baffle plate.

84. The shower head of claim 70, wherein the gap controller comprises a driving shaft for selectively moving the first baffle plate upwardly or downwardly in order to determine the width of the gap.

85. The shower head of claim 70, wherein the first baffle plate contacts the second baffle plate so that some through holes selected among the plurality of first and second through holes formed in the first baffle plate communicate with selected ones of the plurality of through holes formed in the second baffle plate in order to form align holes, and

wherein the width of the gap is effectively zero.

86. The shower head of claim 85, further comprising a rotating mechanism connected to the first baffle plate so that the first baffle plate rotates with respect to the second baffle plate in a predetermined angular range.

87. The shower head of claim 86, wherein the plurality of through holes formed in the second baffle plate are distributed to have different opening ratios depending on the distance by which the first baffle plate rotates about the central axis of the second baffle plate, and

wherein the rotating mechanism changes the rotational angle of the first baffle plate in order to change the opening position of the align holes.

88. The shower head of claim 86, wherein the first baffle plate further has a plurality of third through holes formed in a third radius range greater than the second radius range,

wherein the first baffle plate is divided into a plurality of sectorial regions that extend in a radial direction from the central axis thereof, and

wherein the plurality of first, second, and third through holes are formed at different sectorial regions.

89. The shower head of claim 88, wherein the second baffle plate is divided into a plurality of sectorial regions that extend in a radial direction from the central axis thereof, and the plurality of sectorial regions having the plurality of through holes are arranged at regular intervals.

90. The shower head of claim 70, further comprising a face plate disposed opposite the process region, the face plate having a plurality of through holes.

91. The shower head of claim 90, further comprising a third baffle plate disposed between the second baffle plate and the face baffle plate, the third baffle plate having a plurality of through holes.

92. The shower head of claim 91, wherein the third baffle plate is formed of silicon carbide.

93. A shower head comprising:

a circular first baffle plate having a plurality of through holes;

a circular second baffle plate disposed below the first baffle plate with a gap having a predetermined width interposed between the first and second baffle plates, the second baffle plate having a plurality of through holes; and

a plurality of piezoelectric elements disposed between the first and second baffle plates for controlling the amount of a reactant gas flowing through the plurality of through holes formed in the first baffle plate.

94. The shower head of claim 93, wherein the plurality of through holes formed in the first baffle plate comprises:

a plurality of first through holes formed at a position spaced apart from a central axis of the first baffle plate by a first radius;

a plurality of second through holes formed at a position spaced apart from the central axis of the first baffle plate by a second radius greater than the first radius; and

a plurality of third through holes formed at a position spaced apart from the central axis of the first baffle plate by a third radius greater than the second radius.

95. The shower head of claim 94, wherein the plurality of through holes formed in the second baffle plate comprises:

a fourth through hole formed at a position corresponding to a central axis of the second baffle plate;

a plurality of fifth through holes formed at a position spaced apart from a central axis of the second baffle plate by a fourth radius;

a plurality of sixth through holes formed at a position spaced apart from the central axis of the second baffle plate by a fifth radius greater than the fourth radius; and

a plurality of seventh through holes formed at a position spaced apart from the central axis of the second baffle plate by a sixth radius greater than the fifth radius.

96. The shower head of claim 93, wherein each of the plurality of piezoelectric elements is comprised of an annular element disposed on the second baffle plate.

97. The shower head of claim 93, wherein the plurality of piezoelectric elements are bonded to the second baffle plate.

98. The shower head of claim 94, wherein the plurality of piezoelectric elements comprise:

a first piezoelectric element disposed at a position on the second baffle plate corresponding to a position at which the plurality of first through holes of the first baffle plate are formed;

a second piezoelectric element disposed at a position on the second baffle plate corresponding to a position at which the plurality of second through holes of the first baffle plate are formed; and

a third piezoelectric element disposed at a position on the second baffle plate corresponding to a position at which the plurality of third through holes of the first baffle plate are formed.

99. The shower head of claim 93, further comprising a power supply unit for applying voltage to each of the plurality of piezoelectric elements.

100. The shower head of claim 98, further comprising a power supply unit for applying voltage to each of the first, second, and third piezoelectric elements,

wherein the power supply unit applies different levels of voltage to each of the first, second, and third piezoelectric elements.

101. The shower head of claim 98, further comprising a power supply unit for applying voltage to the first piezoelectric element,

wherein the first piezoelectric element has a thickness expansion rate that can be adjusted according to the level of voltage applied from the power supply unit in order to control a distance between the first through hole and the first piezoelectric element.

102. The shower head of claim 98, further comprising a power supply unit for applying voltage to the second piezoelectric element,

wherein the second piezoelectric element has a thickness expansion rate that can be adjusted according to the level of voltage applied from the power supply unit in order to control a distance between the plurality of second through holes and the second piezoelectric element.

103. The shower head of claim 98, further comprising a power supply unit for applying voltage to the third piezoelectric element,

wherein the third piezoelectric element has a thickness expansion rate that can be adjusted according to the level of voltage applied from the power supply unit in order to control a distance between the plurality of third through holes and the third piezoelectric element.

104. The shower head of claim 93, wherein the first and second baffle plates are formed of aluminum.

105. The shower head of claim 93, wherein each of the plurality of piezoelectric elements comprises:

a piezoelectric layer which vibrates in a thickness extensional mode according to the application of voltage, the piezoelectric layer having two main surfaces;

first and second electrode layers, each of which is formed on one of the two main surfaces of the piezoelectric layer; and

an insulating layer formed on the first electrode layer adjacent to the first baffle plate.

106. The shower head of claim 105, wherein the piezoelectric layer is formed of one selected from the group consisting of lead zirconate titanate (PZT), PbTiO₃, BaTiO₃, and poly vinylidene fluoride (PVDF) polymer.

107. The shower head of claim 105, wherein the second electrode layer is constructed by the second baffle plate.

108. The shower head of claim 107, wherein each of the plurality of piezoelectric element further comprises a bonding surface between the piezoelectric layer and the second baffle plate.