# US 9,437,473 B2 · Method for separating at least two substrates along a selected interface

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- Number: US 9,437,473 B2
- Document ID: US9437473B2
- Status: Granted
- Kind: B2
- Application number: 14/424,311
- Filed: 2013-09-04
- Published: 2015-08-06
- Granted: 2016-09-06
- Earliest claimed: 2012-09-07
- Assignees: Soitec
- Applicants: Soitec
- Inventors: Didier Landru; Christophe Figuet
- Web page: https://patentgrep.com/patent/US9437473B2

## CPC

- B32B 43/006: {Delaminating}
- H10P 72/0428: {Apparatus for mechanical treatment or grinding or cutting}
- H10P 72/74: {using temporarily an auxiliary support}
- H10P 90/1914: {using bonding}
- H10W 10/181: {Semiconductor-on-insulator [SOI] isolation regions, e.g. buried oxide regions of SOI wafers}
- H10P 72/7422: {used to protect an active side of a device or wafer}
- H10P 72/744: {Details of chemical or physical process used for separating the auxiliary support from a device or a wafer}
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A process for separating at least two substrates comprising at least two separation interfaces along one of the interfaces includes, before inserting a blade between the substrate, damaging at least one portion of a peripheral region of a chosen one of the interfaces, then inserting the blade and partially parting the substrates, and applying a fluid in a space between the parted substrates while the blade remains inserted therebetween, and decreasing a rupture energy of the chosen interface by stress corrosion involving breaking of siloxane bonds present at the interface.

## Claims

### Claim 1

A process for separating at least two substrates forming part of a structure comprising at least two separation interfaces extending parallel to main faces of the structure, along one interface selected from the at least two separation interfaces, at least one of the two substrates being intended to be used in electronics, optics, optoelectronics and/or photovoltaics, the separation of the at least two substrates being carried out by inserting a blade between the at least two substrates and applying a parting force, via the blade, and at least partially parting the at least two substrates, the method comprising:
before inserting the blade into an insertion region between the at least two substrates, damaging at least one portion of a peripheral region of the one interface in the insertion region such that a rupture energy in the at least one portion of the peripheral region is lower than a rupture energy of other interfaces of the at least two separation interfaces in the insertion region;
inserting the blade into the insertion region between the at least two substrates and applying a parting force, via the blade, and partially parting the at least two substrates along the one interface in the damaged region; and
applying a fluid in a space between the partially parted at least two substrates while the blade remains inserted therebetween and decreasing the rupture energy of the one interface by stress corrosion involving breaking of siloxane bonds present at the interface.

### Claim 2 (depends on 1)

The process of claim 1, wherein the peripheral region of the one interface is in the form of a ring.

### Claim 3 (depends on 1)

The process of claim 1, wherein the damaging of the at least one portion of the peripheral region of the one interface in the insertion region is performed prior to assembly of the two substrates to form the structure.

### Claim 4 (depends on 3)

The process of claim 3, wherein the damaging of the at least one portion of the peripheral region is performed by laser irradiation of the one interface.

### Claim 5 (depends on 3)

The process of claim 3, wherein the damaging of the at least one portion of the peripheral region is performed by chemical etching of the one interface.

### Claim 6 (depends on 1)

The process of claim 1, wherein the damaging of the at least one portion of the peripheral region of the one interface in the insertion region is performed after assembly of the two substrates to form the structure.

### Claim 7 (depends on 6)

The process of claim 6, wherein the damaging of the at least one portion of the peripheral region is performed by laser irradiation of the one interface.

### Claim 8 (depends on 6)

The process of claim 6, wherein the damaging of the at least one portion of the peripheral region is performed by chemical etching of the one interface.

### Claim 9 (depends on 1)

The process of claim 1, wherein the damaging of the at least one portion of the peripheral region is performed by laser irradiation of the one interface.

### Claim 10 (depends on 1)

The process of claim 1, wherein the damaging of the at least one portion of the peripheral region is performed by chemical etching of the one interface.

### Claim 11 (depends on 10)

The process of claim 10, wherein the chemical etching is carried out by applying hydrofluoric acid to the at least one portion of the peripheral region.

### Claim 12 (depends on 1)

The process of claim 1, wherein the structure comprises a semiconductor-on-insulator structure including a support substrate, a buried silicon oxide layer and a silicon layer, and wherein the one interface comprises an interface between the oxide layer and the silicon layer.

### Claim 13 (depends on 1)

The process of claim 1, wherein the rupture energy of each of the at least two separation interfaces is greater than 1 J/m2 before inserting the blade into an insertion region between the at least two substrates.

### Claim 14 (depends on 13)

The process of claim 13, wherein the rupture energy of each of the at least two separation interfaces is greater than 1.5 J/m2 before inserting the blade into an insertion region between the at least two substrates.

### Claim 15 (depends on 14)

The process of claim 14, wherein the rupture energy in the peripheral region of the one interface is less than or equal to 1 J/m2 at the time the blade is inserted into the insertion region between the at least two substrates.

### Claim 16 (depends on 1)

The process of claim 1, wherein the rupture energy in the peripheral region of the one interface is less than or equal to 1 J/m2 at the time the blade is inserted into the insertion region between the at least two substrates.

### Claim 17 (depends on 16)

The process of claim 16, wherein the rupture energy in a remainder of the one interface outside the peripheral region of the one interface is greater than or equal to 1 J/m2 at the time the blade is inserted into the insertion region between the at least two substrates.

### Claim 18 (depends on 17)

The process of claim 17, wherein the rupture energy in the remainder of the one interface outside the peripheral region of the one interface is greater than or equal to 1.5 J/m2 at the time the blade is inserted into the insertion region between the at least two substrates.

### Claim 19 (depends on 1)

The process of claim 1, wherein the one interface is an interface between silicon and silicon oxide.

### Claim 20 (depends on 1)

The process of claim 1, wherein the fluid applied in the space between the partially parted at least two substrates is selected from the group consisting of deionized water, ethanol, water vapor, aqueous ammonia and hydrazine.