Methods for making metallization structures for semiconductor device interconnects

• US 6,955,979 B2
• Filed: 03/29/2002
• Issued: 10/18/2005
• Est. Priority Date: 09/01/1999
• Status: Expired due to Fees

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Akram, Salman
• Primary Examiner(s): Pham, Long
• Assistant Examiner(s): Ha, Nathan W.
• Application Number:
  US10/112,928
• Publication Number:
  US 20020106879A1
• Time in Patent Office: 1,299 Days
• Field of Search: 438/597, 438/687, 257/691, 257/777, 257/758
• US Class Current: 438/597
• CPC Class Codes: H01L 21/76844 Bottomless liners
• CPC Class Codes: H01L 21/7685 the layer covering a conductive structure H01L21/76849 takes precedence
• CPC Class Codes: H01L 21/76852 the layer also covering the sidewalls of the conductive structure

Abstract

The present invention provides a metallization structure for semiconductor device interconnects such as a conductive line, including a substrate with a substantially planar upper surface, foundation metal layer disposed on a portion of the substrate upper surface, primary conducting metal layer overlying the foundation metal layer, and metal spacer on the sidewalls of the primary conducting metal layer and the foundation metal layer. The present invention also provides a metallization structure including a substrate with a foundation metal layer disposed thereon, a dielectric layer with an aperture therethrough being disposed on the substrate, where the bottom of the aperture exposes the foundation metal layer of the substrate, and a metal spacer on the sidewall of the aperture and a line or plug of a primary conducting metal fill the remaining portion of the aperture. The present invention also includes methods for making the metallization structures.

Claims

1. A method for making a metallization structure comprising:

forming a substrate comprising at least one metal layer on a surface thereof, a first layer of the at least one metal layer comprising titanium;

forming a dielectric layer over the at least one metal layer;

forming an aperture through the dielectric layer to expose a surface of the at least one metal layer;

forming a conducting layer in the aperture such that at least a bottom surface of the conducting layer contacts a portion of the at least one metal layer;

forming at least one upper metal layer overlying the dielectric layer and the conducting layer in the aperture, a first upper metal layer of the at least one upper metal layer comprising titanium;

removing portions of the at least one upper metal layer overlying the dielectric layer, removing the dielectric layer, and removing portions of the at least one metal layer surrounding the conducting layer to form a multilayer metal structure having at least one sidewall; and

forming a titanium spacer flanking the at least one sidewall of the multilayer metal structure.

2. The method of claim 1, wherein the at least one metal layer comprises the titanium layer and further including forming a second metal layer between the titanium layer and the substrate, the second metal layer comprising TiN, TiW, WN, or TaN.

3. The method of claim 1, further comprising forming the at least one metal layer by vapor deposition.

4. The method of claim 1, further comprising forming the at least one metal layer by CVD, PVD or PECVD.

5. The method of claim 1, further comprising forming the conducting layer by vapor deposition.

6. The method of claim 5, further comprising forming the conducting layer by CVD, PVD or PECVD.

7. The method of claim 1, further comprising forming the dielectric layer of silicon oxide.

8. The method of claim 1, further comprising forming the titanium spacer by vapor deposition of a metal layer over the multilayer metal structure and directional etching of the vapor-deposited metal layer.

9. The method of claim 1, further comprising forming the at least one upper metal layer as a plurality of upper metal layers.

10. The method of claim 1, further comprising forming the at least one upper metal layer by vapor deposition.

11. The method of claim 10, wherein the vapor deposition is effected by CVD, PVD or PECVD.

12. The method of claim 1, further comprising removing the dielectric layer by using a hydrofluoric acid wet etch solution or an oxide dry etch process.

13. The method of claim 1, further comprising removing the portions of the at least one metal layer by directional etching.

14. A method for making a metallization structure comprising:

forming a substrate comprising a first layer of Ti, Ta, W, Co or Mo or alloys or compounds thereof, including TaN or TiN on a surface thereof,

forming a dielectric layer over the first layer;

forming an aperture having at least one sidewall through the dielectric layer to expose a surface of the first layer;

forming a metal spacer completely flanking the at least one sidewall of the aperture and contacting the first layer; and

forming a conductive layer in a remaining portion of the aperture such that at least a bottom surface of the conductive layer contacts a portion of the first layer.

15. The method of claim 14, further comprising forming the first layer of titanium or titanium nitride.

16. The method of claim 14, further comprising forming the first layer by vapor deposition.

17. The method of claim 14, further comprising forming the conductive layer by vapor deposition.

18. The method of claim 14, further comprising forming the first layer and the metal spacer of the same metal.

19. The method of claim 14, further comprising forming the metal spacer by vapor deposition and directional etching.

20. The method of claim 14, further comprising forming the metal spacer of at least one layer of Ti, Ta, W, Co or Mo, or alloys or compounds thereof, including TaN or TiN.

21. The method of claim 14, further comprising forming the metal spacer of titanium or titanium nitride.

22. The method of claim 14, further comprising forming at least one upper metal layer on the conductive layer.

23. The method of claim 22, further comprising forming the at least one upper metal layer on the conductive layer from Ti, Ta, W, Co or Mo or alloys or compounds thereof, including TaN or TiN.

24. The method of claim 22, further comprising forming the at least one upper metal layer as a plurality of upper metal layers.

25. The method of claim 22, further comprising forming the at least one upper metal layer of titanium or titanium nitride.

26. The method of claim 22, further comprising forming the at least one upper metal layer by vapor deposition.

27. The method of claim 14, further comprising removing the dielectric layer and portions of the first layer not underlying the aperture.

28. The method of claim 27, further comprising removing the dielectric layer by using a hydrofluoric acid wet etch solution or an oxide dry etch process.

29. The method of claim 28, further comprising removing the portions of the first layer by directional etching.

30. A method for making a metallization structure comprising:

forming a first metal layer of TiN, TiW, WN, or TaN on a substrate;

forming a second metal layer of Ti, Ta, W, Co or Mo or alloys or compounds thereof, including TaN or TiN over the first metal layer;

forming a dielectric layer over the second metal layer;

forming an aperture having at least one sidewall through the dielectric layer to expose a surface of the second metal layer;

forming a metal spacer completely flanking the at least one sidewall of the aperture and contacting the second metal layer; and

forming a conductive layer in a remaining portion of the aperture such that at least a bottom surface of the conductive layer contacts a portion of the second metal layer.

31. The method of claim 30, further comprising forming the first metal layer of titanium or titanium nitride.

32. The method of claim 30, further comprising forming the first metal layer by vapor deposition.

33. The method of claim 30, further comprising forming the conductive layer by vapor deposition.

34. The method of claim 30, further comprising forming the first metal layer and the metal spacer of the same metal.

35. The method of claim 30, further comprising forming the metal spacer by vapor deposition and directional etching.

36. The method of claim 30, further comprising forming the metal spacer of at least one layer of Ti, Ta, W, Co or Mo, or alloys or compounds thereof, including TaN or TiN.

37. The method of claim 30, further comprising forming the metal spacer of titanium or titanium nitride.

38. The method of claim 30, further comprising forming at least one upper metal layer on the conductive layer.

39. The method of claim 38, further comprising forming the at least one upper metal layer on the conductive layer from Ti, Ta, W, Co or Mo or alloys or compounds thereof including TaN or TiN.

40. The method of claim 38, further comprising forming the at least one upper metal layer as a plurality of upper metal layers.

41. The method of claim 38, further comprising forming the at least one upper metal layer of titanium or titanium nitride.

42. The method of claim 38, further comprising forming the at least one upper metal layer by vapor deposition.

43. The method of claim 30, further comprising removing the dielectric layer and portions of the second metal layer and first metal layer not underlying the aperture.

44. The method of claim 43, further comprising removing the dielectric layer by using a hydrofluoric acid wet etch solution or an oxide dry etch process.

45. The method of claim 43, further comprising removing the portions of the first metal layer and second metal layer by directional etching.

46. A method for making a metallization structure comprising:

forming a first metal layer of titanium or titanium nitride over a substrate;

forming a dielectric layer over the first metal layer;

forming an aperture having at least one sidewall through the dielectric layer to expose a surface of the first metal layer;

forming a metal spacer completely flanking the at least one sidewall of the aperture and contacting the first metal layer; and

forming a conductive layer in a remaining portion of the aperture such that at least a bottom surface of the conductive layer contacts a portion of the first metal layer.

47. The method of claim 46, further comprising forming the first metal layer by vapor deposition.

48. The method of claim 46, further comprising forming the conductive layer by vapor deposition.

49. The method of claim 46, further comprising forming the first metal layer and the metal spacer of the same metal.

50. The method of claim 46, further comprising forming the metal spacer by vapor deposition and directional etching.

51. The method of claim 46, further comprising forming the metal spacer of at least one layer of Ti, Ta, W, Co or Mo, or alloys or compounds thereof, including TaN or TiN.

52. The method of claim 46, further comprising forming the metal spacer of titanium or titanium nitride.

53. The method of claim 46, further comprising forming at least one upper metal layer on the conductive layer.

54. The method of claim 53, further comprising forming the at least one upper metal layer on the conductive layer from Ti, Ta, W, Co or Mo or alloys or compounds thereof, including TaN or TiN.

55. The method of claim 53, further comprising forming the at least one upper metal layer as a plurality of upper metal layers.

56. The method of claim 53, further comprising forming the at least one upper metal layer of titanium or titanium nitride.

57. The method of claim 53, further comprising forming the at least one upper metal layer by vapor deposition.

58. The method of claim 46, further comprising removing the dielectric layer and portions of the first metal layer not underlying the aperture.

59. The method of claim 58, further comprising removing the dielectric layer by using a hydrofluoric acid wet etch solution or an oxide dry etch process.

60. The method of claim 58, further comprising removing the portions of the first metal layer by directional etching.

61. A method for making a metallization structure comprising:

forming a metal layer over a substrate;

forming a dielectric layer over the metal layer;

forming an aperture having at least one sidewall through the dielectric layer to expose a surface of the metal layer;

forming a metal spacer including the same metal as the metal layer, the metal spacer completely flanking the at least one sidewall of the aperture and contacting the metal layer; and

forming a conductive layer in a remaining portion of the aperture such that at least a bottom surface of the conductive layer contacts a portion of the metal layer.

62. The method of claim 61, further comprising forming the metal layer by vapor deposition.

63. The method of claim 61, further comprising forming the conductive layer by vapor deposition.

64. The method of claim 61, further comprising forming the metal spacer by vapor deposition and directional etching.

65. The method of claim 61, further comprising forming at least one upper metal layer on the conductive layer.

66. The method of claim 65, further comprising forming the at least one upper metal layer on the conductive layer from Ti, Ta, W, Co or Mo or alloys or compounds thereof, including TaN or TiN.

67. The method of claim 65, further comprising forming the at least one upper metal layer as a plurality of upper metal layers.

68. The method of claim 65, further comprising forming the at least one upper metal layer of titanium or titanium nitride.

69. The method of claim 65, further comprising forming the at least one upper metal layer by vapor deposition.

70. The method of claim 61, further comprising removing the dielectric layer and portions of the metal layer not underlying the aperture.

71. The method of claim 70, further comprising removing the dielectric layer by using a hydrofluoric acid wet etch solution or an oxide dry etch process.

72. The method of claim 70, further comprising removing the portions of the metal layer by directional etching.

73. A method for making a metallization structure comprising:

forming at least one metal layer including Ti, Ta, W, Co or Mo or alloys or compounds thereof, including TaN or TiN over a substrate;

forming a dielectric layer over the at least one metal layer;

forming an aperture through the dielectric layer to expose a surface of the at least one metal layer;

forming a conducting layer in the aperture such that at least a bottom surface of the conducting layer contacts a portion of the at least one metal layer;

forming at least one upper metal layer overlying the dielectric layer and the conducting layer in the aperture;

removing portions of the at least one upper metal layer overlying the dielectric layer, removing the dielectric layer, and removing portions of the at least one metal layer surrounding the conducting layer to form a multilayer metal structure having at least one sidewall; and

forming a metal spacer flanking the at least one sidewall of the multilayer metal structure.

74. The method of claim 73, wherein the at least one metal layer comprises a first metal layer, and further including forming a second metal layer between the first metal layer and the substrate, the second metal layer comprising TiN, TiW, WN, or TaN.

75. The method of claim 73, further comprising forming the at least one metal layer of titanium or titanium nitride.

76. The method of claim 73, further comprising forming the at least one metal layer by vapor deposition.

77. The method of claim 73, further comprising forming the conducting layer by vapor deposition.

78. The method of claim 73, further comprising forming the at least one metal layer and the metal spacer of the same metal.

79. The method of claim 73, further comprising forming the metal spacer by vapor deposition of a metal layer over the multilayer metal structure and directional etching of the vapor-deposited metal layer.

80. The method of claim 73, further comprising forming the metal spacer of at least one layer of Ti, Ta, W, Co or Mo, or alloys thereof or compounds thereof, including TaN or TiN.

81. The method of claim 73, further comprising forming the metal spacer of titanium or titanium nitride.

82. The method of claim 73, further comprising forming the at least one upper metal layer overlying the dielectric layer from Ti, Ta, W, Co or Mo or an alloy or a compound of any thereof, including TaN or TiN.

83. The method of claim 73, further comprising forming the at least one upper metal layer as a plurality of upper metal layers.

84. The method of claim 73, further comprising forming the at least one upper metal layer of titanium or titanium nitride.

85. The method of claim 73, further comprising forming the at least one upper metal layer by vapor deposition.

86. The method of claim 73, further comprising removing the dielectric layer by using a hydrofluoric acid wet etch solution or an oxide dry etch process.

87. The method of claim 73, further comprising removing the portions of the at least one metal layer by directional etching.

88. The method of claim 73, further comprising forming the conducting layer from at least one of aluminum and copper.

89. The method of claim 73, further comprising forming the at least one metal layer, metal spacer, and at least one upper metal layer of the same metal.

90. The method of claim 89, wherein the same metal is Ti.

91. A method for making a metallization structure comprising:

forming a first metal layer including Ti, Ta, W, Co or Mo or alloys or compounds thereof, including TaN or TiN over a substrate;

forming a second metal layer TiN, TiW, WN, or TaN between the first metal layer and the substrate;

forming a dielectric layer over the first metal layer;

forming an aperture through the dielectric layer to expose a surface of the first metal layer;

forming a conducting layer in the aperture such that at least a bottom surface of the conducting layer contacts a portion of the first metal layer;

forming at least one upper metal layer overlying the dielectric layer and the conducting layer in the aperture;

removing portions of the at least one upper metal layer overlying the dielectric layer, removing the dielectric layer, and removing portions of the first metal layer and second metal layer surrounding the conducting layer to form a multilayer metal structure having at least one sidewall; and

forming a metal spacer flanking the at least one sidewall of the multilayer metal structure.

92. The method of claim 91, further comprising forming the first metal layer of titanium or titanium nitride.

93. The method of claim 91, further comprising forming the first metal layer by vapor deposition.

94. The method of claim 91, further comprising forming the conducting layer by vapor deposition.

95. The method of claim 91, further comprising forming the first metal layer and the metal spacer of the same metal.

96. The method of claim 91, further comprising forming the metal spacer by vapor deposition of a metal layer over the multilayer metal structure and directional etching of the vapor-deposited metal layer.

97. The method of claim 91, further comprising forming the metal spacer of at least one layer of Ti, Ta, W, Co or Mo, or alloys thereof or compounds thereof, including TaN or TiN.

98. The method of claim 91, further comprising forming the metal spacer of titanium or titanium nitride.

99. The method of claim 91, further comprising forming the at least one upper metal layer overlying the dielectric layer from Ti, Ta, W, Co or Mo or an alloy or a compound of any thereof, including TaN or TiN.

100. The method of claim 99, further comprising forming the at least one upper metal layer as a plurality of upper metal layers.

101. The method of claim 91, further comprising forming the at least one upper metal layer of titanium or titanium nitride.

102. The method of claim 91, further comprising forming the at least one upper metal layer by vapor deposition.

103. The method of claim 91, further comprising removing the dielectric layer by using a hydrofluoric acid wet etch solution or an oxide dry etch process.

104. The method of claim 91, further comprising removing the portions of the first metal layer and second metal layer by directional etching.

105. The method of claim 91, further comprising forming the conducting layer from at least one of aluminum and copper.

106. The method of claim 91, further comprising forming the first metal layer, metal spacer, and at least one upper metal layer of the same metal.

107. The method of claim 106, wherein the same metal is Titanium.

108. A method for making a metallization structure comprising:

forming a first metal layer including titanium or titanium nitride over a substrate;

forming a dielectric layer over the first metal layer;

forming an aperture through the dielectric layer to expose a surface of the first metal layer;

forming a conducting layer in the aperture such that at least a bottom surface of the conducting layer contacts a portion of the first metal layer;

forming at least one upper metal layer overlying the dielectric layer and the conducting layer in the aperture;

removing portions of the at least one upper metal layer overlying the dielectric layer, removing the dielectric layer, and removing portions of the first metal layer surrounding the conducting layer to form a multilayer metal structure having at least one sidewall; and

forming a metal spacer flanking the at least one sidewall of the multilayer metal structure.

109. The method of claim 108, further comprising forming the first metal layer by vapor deposition.

110. The method of claim 108, further comprising forming the conducting layer by vapor deposition.

111. The method of claim 108, further comprising forming the first metal layer and the metal spacer of the same metal.

112. The method of claim 108, further comprising forming the metal spacer by vapor deposition of a metal layer over the multilayer metal structure and directional etching of the vapor-deposited metal layer.

113. The method of claim 108, further comprising forming the metal spacer of at least one layer of Ti, Ta, W, Co or Mo, or alloys thereof or compounds thereof, including TaN or TiN.

114. The method of claim 108, further comprising forming the metal spacer of titanium or titanium nitride.

115. The method of claim 108, further comprising forming the at least one upper metal layer overlying the dielectric layer from Ti, Ta, W, Co or Mo or an alloy or a compound of any thereof, including TaN or TiN.

116. The method of claim 115, further comprising forming the at least one upper metal layer as a plurality of upper metal layers.

117. The method of claim 108, further comprising forming the at least one upper metal layer of titanium or titanium nitride.

118. The method of claim 108, further comprising forming the at least one upper metal layer by vapor deposition.

119. The method of claim 108, further comprising removing the dielectric layer by using a hydrofluoric acid wet etch solution or an oxide dry etch process.

120. The method of claim 108, further comprising removing the portions of the first metal layer and the at least one upper metal layer by directional etching.

121. The method of claim 108, further comprising forming the conducting layer from at least one of aluminum and copper.

122. The method of claim 108, further comprising forming the first metal layer, metal spacer, and at least one upper metal layer of the same metal.

123. The method of claim 122, wherein the same metal is Titanium.

124. A method for making a metallization structure comprising:

forming at least one metal layer on a substrate;

forming a dielectric layer over the at least one metal layer;

forming an aperture through the dielectric layer to expose a surface of the at least one metal layer;

forming a conducting layer in the aperture such that at least a bottom surface of the conducting layer contacts a portion of the at least one metal layer;

forming at least one upper metal layer overlying the dielectric layer and the conducting layer in the aperture;

removing portions of the at least one upper metal layer overlying the dielectric layer, removing the dielectric layer, and removing portions of the at least one metal layer surrounding the conducting layer to form a multilayer metal structure having at least one sidewall; and

forming a metal spacer of the same metal as the at least one metal layer, the metal spacer flanking the at least one sidewall of the multilayer metal structure.

125. The method of claim 124, further comprising forming the at least one metal layer by vapor deposition.

126. The method of claim 124, further comprising forming the conducting layer by vapor deposition.

127. The method of claim 124, further comprising forming the metal spacer by vapor deposition of a metal layer over the multilayer metal structure and directional etching of the vapor-deposited metal layer.

128. The method of claim 124, further comprising forming the at least one upper metal layer overlying the dielectric layer from Ti, Ta, W, Co or Mo or an alloy or a compound of any thereof, including TaN or TiN.

129. The method of claim 128, further comprising forming the at least one upper metal layer as a plurality of upper metal layers.

130. The method of claim 124, further comprising forming the at least one upper metal layer of titanium or titanium nitride.

131. The method of claim 124, further comprising forming the at least one upper metal layer by vapor deposition.

132. The method of claim 124, further comprising removing the dielectric layer by using a hydrofluoric acid wet etch solution or an oxide dry etch process.

133. The method of claim 124, further comprising removing the portions of the at least one metal layer by directional etching.

134. The method of claim 124, further comprising forming the conducting layer from at least one of aluminum and copper.

135. The method of claim 124, further comprising forming the at least one metal layer, metal spacer, and at least one upper metal layer of the same metal.

136. The method of claim 135, wherein the same metal is Titanium.

137. A method for making a metallization structure comprising:

forming a first metal layer over a substrate;

forming a dielectric layer over the first metal layer;

forming an aperture through the dielectric layer to expose a surface of the first metal layer;

forming a conducting layer in the aperture such that at least a bottom surface of the conducting layer contacts a portion of the first metal layer;

forming at least one upper metal layer overlying the dielectric layer and the conducting layer in the aperture;

removing portions of the at least one upper metal layer overlying the dielectric layer, removing the dielectric layer, and removing portions of the first metal layer surrounding the conducting layer to form a multilayer metal structure having at least one sidewall; and

forming a metal spacer flanking the at least one sidewall of the multilayer metal structure, the first metal layer, at least one upper metal and metal spacer comprising the same metal.

138. The method of claim 137, further comprising forming the first metal layer by vapor deposition.

139. The method of claim 137, further comprising forming the conducting layer by vapor deposition.

140. The method of claim 137, further comprising forming the metal spacer by vapor deposition of a metal layer over the multilayer metal structure and directional etching of the vapor-deposited metal layer.

141. The method of claim 137, further comprising forming the at least one upper metal layer as a plurality of upper metal layers.

142. The method of claim 137, further comprising forming the at least one upper metal layer by vapor deposition.

143. The method of claim 137, further comprising removing the dielectric layer by using a hydrofluoric acid wet etch solution or an oxide dry etch process.

144. The method of claim 137, further comprising removing the portions of the first metal layer by directional etching.

145. The method of claim 137, further comprising forming the conducting layer from at least one of aluminum and copper.