Method of making semiconductor device

• US 8,785,231 B2
• Filed: 01/24/2013
• Issued: 07/22/2014
• Est. Priority Date: 12/23/2008
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Sugiura, Kazuhiko, Fujii, Tetsuo, Yokura, Hisanori
• Primary Examiner(s): Kraig, William F
• Assistant Examiner(s): Ahmad, Khaja
• Application Number:
  US13/748,734
• Publication Number:
  US 20130178008A1
• Time in Patent Office: 544 Days
• Field of Search: 257/254, 257/415, 257/433, 257/678, 257/704, 257/710, 257/779, 257/E23.18, 257/E23.193, 257/E21.5, 257/E23.181, 257/E29.324, 257/414, 257/684, 438/50, 438/118, 438/121, 438124-125, 438/127, 438/48, 438/49, 438/51, 438/106
• US Class Current: 438/51
• CPC Class Codes: B81B 2207/095 through the lid
• CPC Class Codes: B81C 1/00134 comprising flexible or deformable structures manufacture of MEMS devices for specific applications, see relevant places, e.g. gyroscopes G01C19/5719, pressure sensors G01L9/0042, accelerometers G01P15/0802, acoustic transducers or diaphragms therefor H04R31/00
• CPC Class Codes: B81C 1/00269 Bonding of solid lids or wafers to the substrate
• CPC Class Codes: B81C 1/00301 Connecting electric signal lines from the MEMS device with external electrical signal lines, e.g. through vias
• CPC Class Codes: H01L 2224/48463 the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
• CPC Class Codes: H01L 2924/14 Integrated circuits
• CPC Class Codes: H01L 2924/19041 being a capacitor
• CPC Class Codes: H01L 2924/30105 Capacitance

Abstract

A semiconductor device includes a sensor portion, a cap portion, and an ion-implanted layer. The sensor portion has a sensor structure at a surface portion of a surface. The cap portion has first and second surfaces opposite to each other and includes a through electrode. The surface of the sensor portion is joined to the first surface of the cap portion such that the sensor structure is sealed between the sensor portion and the cap portion. The ion-implanted layer is located on the second surface of the cap portion. The through electrode extends from the first surface to the second surface and is exposed through the ion-implanted layer.

Claims

1. A method of making a semiconductor device comprising:

preparing a sensor wafer having one side and including a plurality of sensor portions, each sensor portion having one surface on the one side of the sensor wafer and including a sensor structure at a surface portion of the surface;

preparing a cap wafer having a front side and a back side opposite to the front side, the cap wafer including a plurality of cap portions, each cap portion having a cover surface on the front side of the cap wafer and a second surface on the back side of the cap wafer;

forming a wiring layer on the cover surface of the cap portion;

forming a cover insulation layer on the first surface of the cap portion to cover the wiring layer on an upper surface and side surfaces;

forming a trench on the first surface of the cap portion;

forming a trench wall insulation layer on a wall of the trench;

forming a buried electrode on the trench wall insulation layer;

joining the one side of the sensor wafer to the front side of the cap wafer together with the wiring layer facing the sensor structure through the cover insulation layer, the buried electrode of the cap portion electrically connecting to a contact region of the sensor structure of the sensor portion and sealing the sensor structure between the sensor portion and the cap portion;

removing the back side of the cap wafer until the trench and the buried electrode are exposed to a new surface of the back side of the cap wafer and forming a through hole and a through electrode extending from the first surface to the second surface of the cap portion; and

dividing a joined body of the sensor wafer and the cap wafer into a plurality of semiconductor devices in the form of chips after the forming of the through electrode.

2. The method according to claim 1, wherein

the removing the back side of the cap wafer until the buried electrode is exposed to the new surface of the back side of the cap wafer includes:

forming an ion-implanted layer in the cap wafer by implanting a plurality of ions into the back side of the cap wafer, the ion-implanted layer being located at a depth equal to or greater than a bottom of the trench measured from the back side of the cap wafer;

thermally treating the joined body of the sensor wafer and the cap wafer after the forming of the ion-implanted layer; and

separating the back side of the cap wafer with respect to the ion-implanted layer as a cleavage surface, so that the buried electrode is exposed to the new surface of the back side of the cap wafer.

3. The method according to claim 1, wherein

the removing the back side of the cap wafer until the buried electrode is exposed to the new surface of the back side of the cap wafer includes:

mechanically polishing the back side of the cap wafer.

4. The method according to claim 1, wherein

the removing the back side of the cap wafer until the buried electrode is exposed to the ne surface of the back side of the cap wafer includes:

chemically polishing the back side of the cap wafer.

5. The method according to claim 1, wherein

the removing the back side of the cap wafer until the buried electrode is exposed to the new surface of the back side of the cap wafer includes:

etching the back side of the cap wafer,

6. The method according to claim 1, wherein the forming of the cover insulation layer includes forming a recess in the cover insulation layer at a position facing the wiring layer.

7. The method according to claim 6, wherein the sensor structure includes an oscillator,

8. The method according to claim 7, further comprising:

forming an under insulation layer on the first surface of the cap portion, wherein

the wiring layer is formed on the first surface of the cap portion on the under insulation layer,

9. A method of making a semiconductor device comprising steps of:

(A) preparing a sensor wafer having one side and including a plurality of sensor portions, each sensor portion having one surface on the one side of the sensor wafer and including a sensor structure at a surface portion of the surface;

(B) preparing a cap wafer having a front side and a back side opposite to the front side, the cap wafer including a plurality of cap portions, each cap portion having a first surface on the front side of the cap wafer and a second surface on the back side of the cap wafer;

(C) forming a wiring layer on the first surface of the cap portion;

(D) forming a cover insulation layer on the first surface of the cap portion and covering the wiring layer on an upper surface and side surfaces;

(E) forming a trench on the first surface of the cap portion;

(F) forming a trench wall insulation layer on a wall of the trench;

(G) forming a buried electrode on the trench wall insulation layer;

(H) joining the one side of the sensor wafer to the front side of the cap wafer together with interposing the cover insulation between the wiring layer and the sensor structure, electrically connecting the buried electrode of the cap portion to a contact region of the sensor structure of the sensor portion and sealing the sensor structure between the sensor portion and the cap portion;

(I) removing the backside of the cap wafer and exposing a new surface including the trench and the buried electrode and forming a through hole and a through electrode extending from the first surface to the second surface of the cap portion; and

(J) dividing a joined body of the sensor wafer and the cap wafer into a plurality of semiconductor devices in the form of chips after the forming of the through electrode.

10. The method according to claim 9, wherein step (I) includes:

forming an ion-implanted layer in the cap wafer by implanting a plurality of ions into the back side of the cap wafer, the ion-implanted layer being located at a depth equal to or greater than a bottom of the trench measured from the back side of the cap wafer;

thermally treating the joined body of the sensor wafer and the cap wafer after the forming of the ion-implanted layer; and

separating the back side of the cap wafer with respect to the ion-implanted layer as a cleavage surface and exposing the buried electrode at the new surface of the back side of the cap wafer,

11. The method according to claim 9, wherein step (I) includes mechanically polishing the back side of the cap wafer until the buried electrode is exposed to the new surface of the back side of the cap wafer.

12. The method according to claim 9, wherein step (I) includes polishing the back side of the cap wafer by chemical polishing until the buried electrode is exposed at the new surface of the back side of the cap wafer.

13. The method according to claim 9, wherein step (I) includes etching the back side of the cap wafer until the buried electrode is exposed at the new surface of the back side of the cap wafer.

14. The method according to claim 9, wherein step (D) includes forming a recess in the cover insulation layer at a position facing the wiring layer.

15. The method according to claim 14, wherein the sensor structure includes an oscillator.

16. The method according to claim 15, further comprising a step of forming an under insulation layer on the first surface of the cap portion, wherein the wiring layer is formed on the first surface of the cap portion on the second insulation layer.