# US 2019/0169745 A1 · Wafer carrier having retention pockets with compound radii for chemical vapor deposition systems

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- Number: US 2019/0169745 A1
- Document ID: US20190169745A1
- Status: Published application
- Kind: A1
- Application number: 16/205,613
- Filed: 2018-11-30
- Published: 2019-06-06
- Earliest claimed: 2014-01-27
- Assignees: Veeco Instruments Inc.
- Applicants: Veeco Instruments Inc.
- Inventors: Sandeep Krishnan; Lukas Urban
- Web page: https://patentgrep.com/patent/US20190169745A1

## CPC

- C23C 16/4584: {the substrate being rotated}
- C23C 16/458: characterised by the method used for supporting substrates in the reaction chamber
- C30B 25/12: Substrate holders or susceptors
- Y10T 29/49: Method of mechanical manufacture
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- 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
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A wafer carrier for use in a chemical vapor deposition (CVD) system includes a plurality of wafer retention pockets, each having a peripheral wall surface surrounding a floor surface and defining a periphery of that wafer retention pocket. Each wafer retention pocket has a periphery with a shape defined by at least a first arc having a first radius of curvature situated around a first arc center and a second arc having a second radius of curvature situated around a second arc center. The second arc is different from the first arc, either by its radius of curvature, arc center, or both.

## Claims

### Claim 1

A wafer carrier for use in a system for growing epitaxial layers on one or more wafers by chemical vapor deposition (CVD), the wafer carrier comprising:
a body formed symmetrically about a central axis, and including a generally planar top surface that is perpendicular to the central axis;
a plurality of wafer retention pockets recessed in the body from the top surface, each of the wafer retention pockets including:
a floor surface generally parallel to the top surface; and
a peripheral wall surface surrounding the floor surface and defining a periphery of that wafer retention pocket,
wherein each wafer retention pocket has a pocket center situated along a corresponding wafer carrier radial axis that is perpendicular to the central axis; and
each wafer retention pocket has a periphery having a shape defined by at least a first arc having a first radius of curvature situated around a first arc center and a second arc having a second radius of curvature situated around a second arc center, wherein the second arc is different from the first arc by at least one of:
the first radius of curvature being different from the second radius of curvature; or
the first arc center being different from the second arc center.

### Claim 2

(canceled)

### Claim 3 (depends on 1)

The wafer carrier of claim 1, wherein in the periphery of each wafer retention pocket, the first arc and the second arc do not intersect.

### Claim 4 (depends on 1)

The wafer carrier of claim 1, wherein each wafer retention pocket has a proximal end and a distal end relative to the central axis, and in the periphery of each wafer retention pocket, the first arc is situated at the distal end and the second arc is situated at the proximal end;
wherein the first arc has a smaller radius of curvature than the second arc.

### Claim 5

(canceled)

### Claim 6 (depends on 1)

The wafer carrier of claim 1, wherein each wafer retention pocket has a proximal end and a distal end relative to the central axis, and in the periphery of each wafer retention pocket, the first arc is situated at the distal end and the second arc is situated at the proximal end;
wherein the first arc is situated symmetrically about the wafer carrier radial axis corresponding to the wafer retention pocket having the periphery defined by the first and the second arcs.

### Claim 7 (depends on 1)

The wafer carrier of claim 1, wherein each wafer retention pocket has a proximal end and a distal end relative to the central axis, and in the periphery of each wafer retention pocket, the first arc is situated at the distal end and the second arc is situated at the proximal end;
wherein the second arc is situated symmetrically about the wafer carrier radial axis corresponding to the wafer retention pocket having the periphery defined by the first and the second arcs.

### Claim 8 (depends on 1)

The wafer carrier of claim 1, wherein each wafer retention pocket has a proximal end and a distal end relative to the central axis, and in the periphery of each wafer retention pocket, the first arc is situated at the distal end and the second arc is situated at the proximal end;
wherein the first arc and the second arc are each situated symmetrically about the wafer carrier radial axis corresponding to the wafer retention pocket having the periphery defined by the first and the second arcs.

### Claim at position 9

9-11. (canceled)

### Claim 12 (depends on 1)

The wafer carrier of claim 1, wherein the shape of the periphery of each wafer retention pocket is further defined by at least one connecting portion that intersects with both the first arc and the second arc.

### Claim 13

(canceled)

### Claim 14 (depends on 1)

The wafer carrier of claim 1, further comprising:
a first wafer retention pocket and a second wafer retention pocket; and
wherein a ratio between a length of the first arc to a length of the second arc of a common wafer retention pocket is different among the first wafer retention pocket and the second wafer retention pocket.

### Claim 15 (depends on 1)

The wafer carrier of claim 1, further comprising:
a first wafer retention pocket and a second wafer retention pocket; and
wherein a ratio between a radius of curvature of the first arc to a radius of curvature of the second arc of a common wafer retention pocket is different among the first wafer retention pocket and the second wafer retention pocket.

### Claim 16 (depends on 1)

The wafer carrier of claim 1, wherein the periphery of each wafer retention pocket is constructed such that, when a wafer is situated in the wafer retention pocket during CVD processing, a gap between an outer edge of the wafer and the periphery of the wafer retention pocket is generally uniform in size around at least 50% of a circumference of the wafer.

### Claim 17 (depends on 1)

The wafer carrier of claim 1, wherein the periphery of each wafer retention pocket is constructed such that, when a wafer is situated in the wafer retention pocket during CVD processing, a gap between an outer edge of the wafer and the periphery of the wafer retention pocket is generally uniform in size around at least 75% of a circumference of the wafer.

### Claim 18

A method for constructing a wafer carrier for use in a system for growing epitaxial layers on one or more wafers by chemical vapor deposition (CVD), the method comprising:
forming a body symmetrically about a central axis to include a generally planar top surface that is perpendicular to the central axis;
forming a plurality of wafer retention pockets recessed in the body from the top surface, each of the wafer retention pockets including:
a floor surface generally parallel to the top surface; and
a peripheral wall surface surrounding the floor surface and defining a periphery of that wafer retention pocket,
wherein in forming the plurality of wafer retention pockets, each wafer retention pocket is formed to have a pocket center situated along a corresponding wafer carrier radial axis that is perpendicular to the central axis; and
each wafer retention pocket has a periphery having a shape defined by at least a first arc having a first radius of curvature situated around a first arc center and a second arc having a second radius of curvature situated around a second arc center, wherein the second arc is different from the first arc by at least one of:
the first radius of curvature being different from the second radius of curvature; or
the first arc center being different from the second arc center.