# US 11,077,525 B2 · Method of processing a silicon carbide containing crystalline substrate, silicon carbide chip, and processing chamber

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- Number: US 11,077,525 B2
- Document ID: US11077525B2
- Status: Granted
- Kind: B2
- Application number: 16/374,265
- Filed: 2019-04-03
- Published: 2019-10-10
- Granted: 2021-08-03
- Earliest claimed: 2018-04-04
- Assignees: Infineon Technologies AG
- Applicants: Infineon Technologies AG
- Inventors: Michael Roesner; Markus Menath; Gudrun Stranzl
- Web page: https://patentgrep.com/patent/US11077525B2

## CPC

- B23K 26/362: Laser etching
- H10P 72/0462: {characterised by the construction of the processing chambers, e.g. modular processing chambers}
- B23K 26/0006: {taking account of the properties of the material involved (B23K26/32, B23K26/40 take precedence)}
- B23K 26/0624: {using ultrashort pulses, i.e. pulses of 1 ns or less}
- B23K 26/0661: {disposed on the workpiece}
- B23K 26/082: Scanning systems, i.e. devices involving movement of the laser beam relative to the laser head
- B23K 26/127: {in an enclosure}
- B23K 26/359: by providing a line or line pattern, e.g. a dotted break initiation line
- B23K 26/364: for making a groove or trench, e.g. for scribing a break initiation groove
- B23K 26/40: taking account of the properties of the material involved
- B23K 26/402: involving non-metallic material, e.g. isolators
- C30B 29/36: Carbides
- C30B 33/00: After-treatment of single crystals or homogeneous polycrystalline material with defined structure (C30B31/00 takes precedence)
- C30B 33/08: Etching
- H10D 62/8325: {Silicon carbide}
- H10P 50/242: {of Group IV materials}
- H10P 50/642: {Chemical etching}
- H10P 54/00: Cutting or separating of wafers, substrates or parts of devices
- H10P 72/0421: {for drying etching}
- H10P 72/0424: {using mainly spraying means, e.g. nozzles}
- H10P 72/7618: {characterised by a movable susceptor, stage or support, others than those only rotating on their own vertical axis, e.g. susceptors on a rotating carrousel}
- H10P 90/126: {by chemical etching}
- B23K 2101/34: Coated articles {; Surface treated articles}
- B23K 2101/40: Semiconductor devices
- B23K 2103/56: {being semiconducting}
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

A method of processing silicon carbide containing crystalline substrate is provided. The method includes pyrolyzing a surface of the silicon carbide containing crystalline substrate to produce a silicon and carbon containing debris layer over the silicon carbide containing crystalline substrate, and removing the silicon and carbon containing debris layer, wherein the pyrolyzing and the removing is repeated at least once.

## Claims

### Claim 1

A method of processing silicon carbide containing crystalline substrate, the method comprising:
pyrolyzing a surface of the silicon carbide containing crystalline substrate to produce a silicon and carbon containing debris layer over the silicon carbide containing crystalline substrate; and
removing the silicon and carbon containing debris layer,
wherein the pyrolyzing and the removing is repeated at least once.

### Claim 2 (depends on 1)

The method of claim 1, wherein the pyrolyzing comprises supplying energy to the surface.

### Claim 3 (depends on 2)

The method of claim 2, wherein the energy is supplied to the surface with an intensity in a range from about 1 J/cm2 to less than 10 J/cm2.

### Claim 4 (depends on 2)

The method of claim 2, wherein the energy is supplied to the surface using at least one energy supply device.

### Claim 5 (depends on 4)

The method of claim 4, wherein supplying energy to the surface comprises moving the at least one energy supply device relative to the silicon carbide containing crystalline substrate or vice-versa.

### Claim 6 (depends on 5)

The method of claim 5, wherein moving the at least one energy supply device comprises a combination of scanning and stepping the at least one energy supply device across the silicon carbide containing crystalline substrate, such that the pyrolyzed surface comprises one or more areas of pyrolyzed silicon carbide adjacent to unpyrolyzed areas of silicon carbide.

### Claim 7 (depends on 6)

The method of claim 6, wherein the silicon carbide containing crystalline substrate is a silicon carbide wafer comprising a plurality of chips, and wherein the one or more areas of pyrolyzed silicon carbide are located in predefined separation regions between the plurality of chips.

### Claim 8 (depends on 1)

The method of claim 1, wherein the repeating at least once comprises repeating the pyrolyzing and the removing until an opening formed in the silicon carbide containing crystalline substrate by the pyrolyzing and the removing extends completely through the silicon carbide containing crystalline substrate.

### Claim 9 (depends on 1)

The method of claim 1, wherein the pyrolyzing comprises irradiating the surface with laser light.

### Claim 10 (depends on 1)

The method of claim 1, wherein the pyrolyzing comprises micro-spark eroding the surface.

### Claim 11 (depends on 10)

The method of claim 10, wherein micro-spark eroding the surface comprises arranging at least one wire above the surface.

### Claim 12 (depends on 10)

The method of claim 10, wherein micro-spark eroding the surface comprises arranging a plurality of wires above the surface.

### Claim 13 (depends on 12)

The method of claim 12, wherein the plurality of wires are arranged as a grid.

### Claim 14 (depends on 12)

The method of claim 12, wherein the silicon carbide containing crystalline substrate is a silicon carbide wafer comprising a plurality of chips, and wherein the plurality of wires is arranged above predefined separation regions between the plurality of chips.

### Claim 15 (depends on 1)

The method of claim 1, wherein removing the silicon and carbon containing debris layer comprises etching with an etchant suitable for removing the silicon and carbon containing debris layer.

### Claim 16 (depends on 15)

The method of claim 15, wherein the etching comprises plasma etching or wet etching.

### Claim 17 (depends on 16)

The method of claim 16, wherein the etchant comprises Ar, O2, and SF6.

### Claim 18 (depends on 1)

The method of claim 1, wherein the silicon carbide containing crystalline substrate is a silicon carbide wafer comprising a plurality of chips, the wafer having a front side comprising active areas of the plurality of chips, and a back side opposite the front side.

### Claim 19 (depends on 18)

The method of claim 18, further comprising:
mounting the silicon carbide wafer on a carrier with the front side facing the carrier,
wherein pyrolyzing the surface and the removing the silicon and carbon containing debris layer are performed on the back side of the wafer.

### Claim 20 (depends on 18)

The method of claim 18, further comprising:
mounting the silicon carbide wafer on a carrier with the back side facing the carrier,
wherein pyrolyzing the surface and the removing the silicon and carbon containing debris layer are performed on the front side of the wafer.

### Claim 21 (depends on 1)

The method of claim 1, further comprising:
arranging a structured mask layer over the silicon carbide containing crystalline substrate, the structured mask layer being configured to mask at least one region of the silicon carbide containing crystalline substrate from an etchant used to remove the silicon and carbon containing debris layer.

### Claim 22 (depends on 21)

The method of claim 21, wherein arranging the structured mask layer comprises arranging an unstructured mask layer over the silicon carbide containing crystalline substrate and structuring the unstructured mask layer using a laser, wherein the laser is further used for the pyrolyzing of the surface.

### Claim 23 (depends on 1)

The method of claim 1, wherein pyrolyzing the surface and the removing the silicon and carbon containing debris layer are performed in a common process chamber.

### Claim 24 (depends on 1)

The method of claim 1, wherein the pyrolyzing is configured to produce the silicon and carbon containing debris layer with a thickness of between 1 μm and 10 μm.

### Claim 25

A processing chamber, comprising:
an energy supply device configured to pyrolyze a surface of a silicon carbide containing crystalline substrate to produce a silicon and carbon containing debris layer over the silicon carbide containing crystalline substrate; and
a removing device configured to remove the silicon and carbon containing debris layer,
wherein the processing chamber is further configured to repeat the pyrolyzing and the removing at least once.

### Claim 26 (depends on 25)

The processing chamber of claim 25, wherein the processing chamber is further configured to have the silicon carbide containing crystalline substrate remain in the processing chamber between the pyrolyzing and the removing.

### Claim 27 (depends on 25)

The processing chamber of claim 25, wherein the removing device is an etching device.

### Claim 28 (depends on 25)

The processing chamber of claim 25, wherein the energy supply device comprises at least one laser or a micro-spark erosion device.

### Claim 29 (depends on 25)

The processing chamber of claim 25, further comprising a moveable substrate support structure configured to move the silicon carbide containing crystalline substrate from a position for the pyrolyzing to a position for the etching and vice-versa.

### Claim 30 (depends on 29)

The processing chamber of claim 29, wherein the moveable substrate support structure is further configured to move the silicon carbide containing crystalline substrate during the pyrolyzing in order to scan the energy supply device across the silicon carbide containing crystalline substrate.

### Claim 31

A silicon carbide chip, comprising:
a first main surface;
a second main surface opposite the first main surface; and
a side surface connecting the first main surface and the second main surface,
wherein the side surface is essentially orthogonal to the first main surface and/or to the second main surface,
wherein at least a portion of the side surface has an undulating shape in a direction from the first main surface to the second main surface.