METHOD OF BONDING SEMICONDUCTOR SUBSTRATE AND MEMS DEVICE

• US 20120306032A1
• Filed: 12/11/2009
• Published: 12/06/2012
• Est. Priority Date: 12/11/2009
• Status: Active Grant

• Current Assignee: Pioneer Corporation, Pioneer Micro Technology Corporation (Pioneer Corporation)
• Original Assignee: Pioneer Corporation, Pioneer Micro Technology Corporation (Pioneer Corporation)
• Inventors: Noda, Naoki, Yokouchi, Toshio, Ishimori, Masahiro
• Granted Patent: US 8,592,285 B2
• Time in Patent Office: Days
• US Class Current: 257/417
• CPC Class Codes: B23K 20/023 Thermo-compression bonding
• CPC Class Codes: B23K 20/16 with interposition of special material to facilitate connection of the parts, e.g. material for absorbing or producing gas
• CPC Class Codes: B23K 20/233 without ferrous layer
• CPC Class Codes: B23K 2101/40 Semiconductor devices
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81C 1/00269 Bonding of solid lids or wafers to the substrate
• CPC Class Codes: B81C 2203/0118 Bonding a wafer on the substrate, i.e. where the cap consists of another wafer
• CPC Class Codes: B81C 2203/019 characterised by the material or arrangement of seals between parts
• CPC Class Codes: B81C 2203/035 Soldering

Abstract

Disclosed is a method for bonding semiconductor substrates, wherein an eutectic alloy does run off the bonding surfaces during the eutectic bonding. Also disclosed is an MEMS device which is obtained by bonding semiconductor substrates by this method. Specifically, a substrate (11) and a substrate (21) are eutectically bonded with each other by pressing and heating the substrate (11) and the substrate (21), while interposing an aluminum-containing layer (31) and a germanium layer (32) between a bonding part (30a) of the substrate (11) and a bonding part (30b) of the substrate (21) in such a manner that the aluminum-containing layer (31) and the germanium layer (32) overlap each other, with an outer edge (32a) of the germanium layer (32) being inwardly set back from the an outer edge (31a) of the aluminum-containing layer (31).

Claims

1. A method of bonding a semiconductor substrate in which a first semiconductor substrate is bonded with a second semiconductor substrate by eutectic bonding with pressurization and heating, an aluminum containing layer primarily made of aluminum and a germanium layer in a polymer state being interposed between a bonding surface of the first semiconductor substrate and a bonding surface of the second semiconductor substrate, the method comprising a step of:

receding an outer end of the germanium layer inward with respect to an outer end of the aluminum containing layer as to the aluminum containing layer and the germanium layer in the polymer state.

2. The method of bonding a semiconductor substrate according to claim 1, wherein heating temperature and heating time of the pressurization and heating is controlled for alloying the germanium layer and the aluminum containing layer by eutectic bonding except an outer end portion of the aluminum containing layer.

3. The method of bonding a semiconductor substrate according to claim 1, wherein the aluminum containing layer and the germanium layer are film-formed on either the first semiconductor substrate or the second semiconductor substrate.

4. The method of bonding a semiconductor substrate according to claim 3, wherein the aluminum containing layer is film-formed in a ring shape in planar view as having predetermined width, and the germanium layer has one or more strip layer sections film-formed in a ring shape in planar view on the aluminum containing layer.

5. The method of bonding a semiconductor substrate according to claim 3, wherein the aluminum containing layer is film-formed in a ring shape in planar view as having predetermined width, and the germanium layer has a strip layer section film-formed in a ring shape in planar view and a plurality of branch layer sections branched from the strip layer section on the aluminum containing layer.

6. The method of bonding a semiconductor substrate according to claim 3, wherein the aluminum containing layer and the germanium layer are film-formed on the second semiconductor substrate and a pit is formed in the bonding surface of the first semiconductor substrate, in which a eutectic alloy generated by the pressurization and heating fills.

7. A MEMS device bonded by the method of bonding a semiconductor substrate according to claim 1, wherein the first semiconductor substrate has a MEMS structure formed to be engraved at the bonding surface side thereof, and the second semiconductor substrate has an integrated circuit formed at the bonding surface side to control the MEMS structure.

8. The MEMS device according to claim 7, wherein the MEMS device is either one of an acceleration sensor, an angular velocity sensor, an infrared ray sensor, a pressure sensor, a magnetic sensor and a sonic sensor.

9. The method of bonding a semiconductor substrate according to claim 2, wherein the aluminum containing layer and the germanium layer are film-formed on either the first semiconductor substrate or the second semiconductor substrate.

10. The method of bonding a semiconductor substrate according to claim 9, wherein the aluminum containing layer is film-formed in a ring shape in planar view as having predetermined width, and the germanium layer has one or more strip layer sections film-formed in a ring shape in planar view on the aluminum containing layer.

11. The method of bonding a semiconductor substrate according to claim 9, wherein the aluminum containing layer is film-formed in a ring shape in planar view as having predetermined width, and the germanium layer has a strip layer section film-formed in a ring shape in planar view and a plurality of branch layer sections branched from the strip layer section on the aluminum containing layer.

12. The method of bonding a semiconductor substrate according to claim 9, wherein the aluminum containing layer and the germanium layer are film-formed on the second semiconductor substrate and a pit is formed in the bonding surface of the first semiconductor substrate, in which a eutectic alloy generated by the pressurization and heating fills.

13. The method of bonding a semiconductor substrate according to claim 4, wherein the aluminum containing layer and the germanium layer are film-formed on the second semiconductor substrate and a pit is formed in the bonding surface of the first semiconductor substrate, in which a eutectic alloy generated by the pressurization and heating fills.

14. The method of bonding a semiconductor substrate according to claim 5, wherein the aluminum containing layer and the germanium layer are film-formed on the second semiconductor substrate and a pit is formed in the bonding surface of the first semiconductor substrate, in which a eutectic alloy generated by the pressurization and heating fills.