# US 5,700,382 A · Method for fabricating a silicon semiconductor substrate having an integrated waveguide and an optical fiber coupled thereto

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- Number: US 5,700,382 A
- Document ID: US5700382A
- Status: Granted
- Kind: A
- Application number: 08/591,619
- Filed: 1996-04-01
- Granted: 1997-12-23
- Earliest claimed: 1993-07-27
- Assignees: Siemens Aktiengesellschaft
- Inventors: Armin Splett
- Web page: https://patentgrep.com/patent/US5700382A

## CPC

- G02B 6/3652: {the additional structures being prepositioning mounting areas, allowing only movement in one dimension, e.g. grooves, trenches or vias in the microbench surface, i.e. self aligning supporting carriers}
- G02B 6/30: for use between fibre and thin-film device
- H10P 50/642: {Chemical etching}
- H10P 50/644: {Anisotropic liquid etching (H10P50/61 takes precedence)}
- H10P 52/00: Grinding, lapping or polishing of wafers, substrates or parts of devices
- A61F 2005/0158: {with locking means}
- A61F 2005/0167: {adjustable}
- G02B 6/3692: {with surface micromachining involving etching, e.g. wet or dry etching steps (surface micromachining involving subtractive techniques B81C1/00055)}
- H01S 5/0202: {Cleaving}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C)
- H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL

## Abstract

A method for fabricating a silicon semiconductor substrate having an optical fiber coupled to an integrated waveguide by anisotropically etching a V-shaped groove aligned with the integrated waveguide into the substrate. The integrated waveguide is provided with a freely accessible end surface situated opposite the end of the V-shaped groove. The freely accessible end surface is formed by first producing a recess in the silicon semiconductor substrate. The recess is made by anisotropically etching a piece of the substrate from the surface opposite the surface bearing said V-shaped groove. The piece is bared down to a region surrounding said integrated waveguide but the piece remains connected to the waveguide by a V-shaped notch. Then pressure is exerted on the piece, causing it to break off at the V-shaped notch, thus forming the freely accessible end surface of the waveguide as a fracture surface. An optical fiber is inserted into the V-shaped groove and extended up to the freely accessible end surface.

## Claims

### Claim 1

A method for fabricating a silicon semiconductor substrate having an integrated waveguide and an optical fiber coupled thereto, comprising the steps of:
a) providing an integrated waveguide in a silicon semiconductor substrate;
b) anisotropically etching a V-shaped groove into said silicon semiconductor substrate aligned with said waveguide;
c) providing said integrated waveguide with a freely accessible end surface situated opposite the end of the V-shaped groove by producing a recess in the silicon semiconductor substrate, the formation of said recess comprising the steps of:
1) anisotropically etching a piece of the semiconductor substrate from the surface of said silicon semiconductor substrate opposite the surface beating said V-shaped groove, wherein said piece is bared down to a region surrounding said integrated waveguide, and wherein said piece remains connected to said waveguide by a V-shaped notch;
2) exerting pressure on said piece, causing it to break off at said V-shaped notch, forming said freely accessible end surface of said integrated waveguide as a fracture surface;
d) inserting an optical fiber into the V-shaped groove, said optical fiber extending up to said freely accessible end surface.

### Claim 2 (depends on 1)

The method of claim 1, wherein a mask is applied to the surface of said silicon semiconductor substrate opposite the surface bearing said V-shaped groove, said mask being used to separate out said piece of said silicon semiconductor substrate thereby forming said recess, said mask having a strip that is accessible to anisotropically acting etching medium in the region in which said freely accessible end surface is to be formed, said strip being shaped to enable said V-shaped notch to be formed during etching.

### Claim 3 (depends on 1)

The method of claim 1, wherein pressure is applied to said semiconductor substrate to separate said piece to form said recess by applying an oncoming flow of a liquid or a gas.

### Claim 4 (depends on 2)

The method of claim 2, wherein pressure is applied to said semiconductor substrate to separate said piece to form said recess by applying an oncoming flow of a liquid or a gas.