Method of Manufacturing a Semiconductor Device Including Removing a Reformed Layer

• US 8,703,517 B2
• Filed: 10/24/2011
• Issued: 04/22/2014
• Est. Priority Date: 10/29/2010
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Taya, Atsushi, Kanamori, Katsuhiko, Totokawa, Masashi
• Primary Examiner(s): Malsawma, Lex
• Assistant Examiner(s): ZHU, SHENG-BAI
• Application Number:
  US13/279,409
• Publication Number:
  US 20120107994A1
• Time in Patent Office: 911 Days
• Field of Search: 257/415, 257/254, 257/417, 257/414, 257/E21.002, 438/53, 438/50, 438/148
• US Class Current: 438/53
• CPC Class Codes: B23K 2103/50 Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
• CPC Class Codes: B23K 26/361 for deburring or mechanical trimming B23K26/351 takes precedence
• CPC Class Codes: B23K 26/40 taking account of the properties of the material involved
• CPC Class Codes: B23K 26/53 for modifying or reforming the material inside the workpiece, e.g. for producing break initiation cracks
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81C 1/00158 Diaphragms, membranes manufacture process for semi-permeable inorganic membranes B01D67/0039
• CPC Class Codes: B81C 1/00476 removing a sacrificial layer B81C1/00912 takes precedence
• CPC Class Codes: B81C 1/00595 Control etch selectivity
• CPC Class Codes: B81C 2201/0133 Wet etching
• CPC Class Codes: B81C 2201/0143 Focussed beam, i.e. laser, ion or e-beam
• CPC Class Codes: C30B 29/06 Silicon
• CPC Class Codes: C30B 33/04 using electric or magnetic fields or particle radiation
• CPC Class Codes: C30B 33/08 Etching
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: H01L 21/268 using electromagnetic radiation, e.g. laser radiation
• CPC Class Codes: H01L 21/30608 Anisotropic liquid etching H01L21/3063 takes precedence

Abstract

In a manufacturing method of a semiconductor device, a substrate including single crystalline silicon is prepared, a reformed layer that continuously extends is formed in the substrate, and the reformed layer is removed by etching. The forming the reformed layer includes polycrystallizing a portion of the single crystalline silicon by irradiating the substrate with a pulsed laser beam while moving a focal point of the laser beam in the substrate.

Claims

1. A manufacturing method of a semiconductor device comprising:

preparing a substrate including single crystalline silicon;

forming a reformed layer that continuously extends in the substrate, the forming the reformed layer including polycrystallizing a portion of the single crystalline silicon by irradiating the substrate with a pulsed laser beam while moving a focal point of the laser beam in the substrate; and

removing the reformed layer by wet etching,

wherein the semiconductor device includes a sensor having a diaphragm,

wherein the forming the reformed layer and the removing the reformed layer are applied to forming the diaphragm in the substrate,

wherein the forming the reformed layer includes forming the reformed layer along an interface between the diaphragm and a removal region under the diaphragm, and

wherein the removing the reformed layer includes hollowing out the removal region by removing the reformed layer by wet etching, the diaphragm thereby being exposed to the outside.

2. The manufacturing method according to claim 1,

wherein the pulsed laser beam has a wavelength within a range from 1000 nm to 1100 nm.

3. The manufacturing method according to claim 1,

wherein the pulsed laser beam has an average pulse energy of more than 2.5 μ

J.

4. The manufacturing method according to claim 3,

wherein the pulsed laser beam has the average pulse energy of 15 μ

J or less.

5. The manufacturing method according to claim 4,

wherein the pulsed laser beam has the average pulse energy within a range from 6.25 μ

J to 12.5 μ

J.

6. The manufacturing method according to claim 1,

wherein the forming the reformed layer includes moving the focal point of the laser beam in a direction parallel to a planar direction of the substrate at a planar pitch of 5 μ

m or less.

7. The manufacturing method according to claim 6,

wherein the planar pitch is within a range from 2 μ

m to 4 μ

m.

8. The manufacturing method according to claim 1,

wherein the forming the reformed layer includes moving the focal point of the laser beam in a direction vertical to a planar direction of the substrate at a vertical pitch of 5 μ

m or less.

9. The manufacturing method according to claim 8,

wherein the vertical pitch is within a range from 10 μ

m to 25 μ

m.

10. The manufacturing method according to claim 1,

wherein the reformed layer is removed by wet etching.

11. The manufacturing method according to claim 10,

wherein the diaphragm has a width of 600 μ

m or less in a planar direction of the substrate.

12. The manufacturing method according to claim 11,

wherein the diaphragm has the width of 350 μ

m or less.

13. The manufacturing method according to claim 1,

wherein the reformed layer is formed at a predetermined distance from the diaphragm to be formed along a direction parallel to a planar direction of the substrate, and

wherein the predetermined distance is within a range from 10 μ

m to 30 μ

m.

14. The manufacturing method according to claim 1,

wherein the substrate is a single crystalline silicon substrate.

15. The manufacturing method according to claim 1,

wherein the substrate is a silicon-on-insulator substrate in which a silicon oxide layer is buried in single crystalline silicon.