# US 8,785,235 B2 · Apparatus and method for producing solar cells

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- Number: US 8,785,235 B2
- Document ID: US8785235B2
- Status: Granted
- Kind: B2
- Application number: 13/486,079
- Filed: 2012-06-01
- Published: 2013-08-15
- Granted: 2014-07-22
- Earliest claimed: 2012-02-10
- Assignees: TSMC Solar Ltd.
- Applicants: Edward Teng; Ying-Chen Chao; Chih-Jen Yang; Kuo-Jui Hsiao
- Inventors: Edward Teng; Ying-Chen Chao; Chih-Jen Yang; Kuo-Jui Hsiao
- Web page: https://patentgrep.com/patent/US8785235B2

## CPC

- H10F 71/00: Manufacture or treatment of devices covered by this subclass (patterning processes to connect thin photovoltaic cells in integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/33; manufacture or treatment of encapsulations or containers for integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/80; manufacture or treatment of integrated devices, or assemblies of multiple devices, comprising at least one element in which radiation controls the flow of current H10F39/00)
- C23C 14/0623: {Sulfides, selenides or tellurides}
- C23C 14/185: {by cathodic sputtering}
- C23C 14/24: Vacuum evaporation
- C23C 14/3464: {using more than one target (C23C14/56 takes precedence)}
- C23C 14/505: {for rotation of the substrates}
- H10F 77/126: {comprising only Group I-III-VI chalcopyrite materials, e.g. CuInSe2, CuGaSe2 or CuInGaSe2 [CIGS]}
- H10F 77/128: {comprising only Group I-II-IV-VI kesterite materials, e.g. Cu2ZnSnSe4 or Cu2ZnSnS4}
- H10P 14/00: Formation of materials, e.g. in the shape of layers or pillars
- H10P 14/22: using physical deposition, e.g. vacuum deposition or sputtering
- H10P 72/04: {Apparatus for manufacture or treatment}
- H10P 72/0451: {Apparatus for manufacturing or treating in a plurality of work-stations}
- H10D 64/01342: {by deposition, e.g. evaporation, ALD or laser deposition (H10D64/01344 takes precedence)}
- Y02E 10/541: CuInSe2 material PV cells
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- 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)
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A method and apparatus for forming a solar cell. The apparatus includes a housing defining a vacuum chamber and a rotatable substrate apparatus configured to hold a plurality of substrates on a plurality of surfaces wherein each of the plurality of surfaces are disposed facing an interior surface of the vacuum chamber. A first sputtering source is configured to deposit a plurality of absorber layer atoms of a first type over at least a portion of a surface of each one of the plurality of substrates. An evaporation source is disposed in a first subchamber of the vacuum chamber and configured to deposit a plurality of absorber layer atoms of a second type over at least a portion of the surface of each one of the plurality of substrates. A first isolation source is configured to isolate the evaporation source from the first sputtering source.

## Claims

### Claim 1

An apparatus for forming a solar cell, comprising:
a housing defining a vacuum chamber;
a rotatable substrate apparatus configured to hold a plurality of substrates on a plurality of surfaces wherein each of the plurality of surfaces is disposed facing an interior surface of the vacuum chamber;
a first sputtering source configured to deposit a plurality of absorber layer atoms of a first type over at least a portion of a surface of each one of the plurality of substrates;
an evaporation source disposed in a first subchamber of the vacuum chamber and configured to deposit a plurality of absorber layer atoms of a second type over at least a portion of the surface of each one of the plurality of substrates; and
a first isolation source configured to isolate the evaporation source from the first sputtering source.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein the first isolation source comprises one or more of an isolation pump.

### Claim 3 (depends on 2)

The apparatus of claim 2, wherein the first isolation source comprises:
a vacuum pump disposed within the first subchamber to maintain the pressure in the first subchamber lower than the pressure in the vacuum chamber outside of the first subchamber.

### Claim 4 (depends on 1)

The apparatus of claim 1, further comprising:
a heater apparatus configured to heat the plurality of substrates, wherein the substrate apparatus is polygonally-shaped, and wherein the heater apparatus has a shape that is substantially conformal with the shape of the substrate apparatus.

### Claim 5 (depends on 1)

The apparatus of claim 1, further comprising:
a second sputtering source configured to deposit a plurality of absorber layer atoms of a third type over at least a portion of the surface of each one of the plurality of substrates.

### Claim 6 (depends on 5)

The apparatus of claim 5, wherein the first and second sputtering sources are disposed adjacent to each other within the vacuum chamber.

### Claim 7 (depends on 5)

The apparatus of claim 5, wherein the first and second sputtering sources are disposed on opposing sides of the vacuum chamber.

### Claim 8 (depends on 7)

The apparatus of claim 7, further comprising:
an isolation baffle disposed about the evaporation source.

### Claim 9 (depends on 8)

The apparatus of claim 8, further comprising:
a first isolation pump disposed between the evaporation source and the second sputtering source; and wherein the first isolation source comprises a second isolation pump disposed between the evaporation source and the first sputtering source.

### Claim 10 (depends on 5)

The apparatus of claim 5, further comprising:
a third sputtering source disposed in a second subchamber of the vacuum chamber and configured to deposit a buffer layer over the surface of each one of the plurality of substrates;
a second isolation source configured to isolate the evaporation source from the second sputtering source; and
a third isolation source configured to isolate the evaporation source from the third sputtering source.

### Claim 11 (depends on 5)

The apparatus of claim 5, wherein the first type comprises copper, the second type comprises selenium and the third type comprises indium.

### Claim 12 (depends on 11)

The apparatus of claim 11, wherein the first sputtering source is configured to deposit a plurality of absorber layer atoms of a first type and a fourth type over at least a portion of the surface of each one of the plurality of substrates, and wherein the fourth type is gallium.

### Claim 13 (depends on 1)

The apparatus of claim 1, further comprising a monitoring device to monitor a process parameter in the vacuum chamber.

### Claim 14 (depends on 1)

The apparatus of claim 1, further comprising a rotatable drum disposed within the vacuum chamber and coupled to a first surface of the vacuum chamber, the rotatable drum having a shape that is substantially conformal with the shape of the substrate apparatus.

### Claim 15 (depends on 1)

The apparatus of claim 1, wherein each of the plurality of surfaces of the substrate apparatus are disposed at a predetermined tilt angle relative to the interior surface of the vacuum chamber.

### Claim 16

A method of forming a solar cell, comprising:
disposing a plurality of substrates about a plurality of surfaces of a substrate apparatus that is operatively coupled to rotate within a vacuum chamber;
rotating the substrate apparatus;
forming an absorber monolayer over a surface of each one of the plurality of substrates, the step of forming comprising:
depositing a plurality of copper and gallium atoms over at least a portion of the surface of each one of the plurality of substrates using a first sputtering source;
depositing a plurality of selenium atoms over at least a portion of the surface using an evaporation source;
depositing a plurality of indium atoms over at least a portion of the surface of each one of the plurality of substrates using a second sputtering source; and
reacting the plurality of copper, gallium, and indium atoms with the plurality of selenium atoms to form the absorber monolayer; and
repeating the step of forming to form an absorber layer.

### Claim 17 (depends on 16)

The method of claim 16, further comprising a step of evacuating atoms from the vacuum chamber to prevent contamination of the first and second sputtering sources, wherein the evacuating comprises:
evacuating a plurality of selenium atoms from the vacuum chamber using a first isolation pump disposed between the evaporation source and the first sputtering source and a second isolation pump disposed between the evaporation source and the second sputtering source.

### Claim 18 (depends on 16)

The method of claim 16, further comprising:
depositing a buffer layer over the absorber layer of each one of the plurality of substrates using a third sputtering source disposed in a subchamber of the vacuum chamber.

### Claim 19 (depends on 16)

The method of claim 16, wherein each one of the formed monolayers of the absorber layer comprises a composition of 20 to 24% copper, 4 to 14% gallium, 10 to 24% indium and 49 to 53% selenium.

### Claim 20

An apparatus for forming a solar cell, comprising:
a housing defining a vacuum chamber;
a rotatable substrate apparatus configured to hold a plurality of substrates on a plurality of surfaces wherein each of the plurality of surfaces are disposed facing an interior surface of the vacuum chamber;
a first sputtering source configured to deposit a plurality of copper and gallium atoms over at least a portion of the surface of each one of the plurality of substrates;
an evaporation source disposed in a first subchamber of the vacuum chamber and configured to deposit a plurality of selenium atoms over at least a portion of the surface of each one of the plurality of substrates;
a second sputtering source configured to deposit a plurality of indium atoms over at least a portion of the surface of each one of the plurality of substrates;
a third sputtering source disposed in a second subchamber of the vacuum chamber and configured to deposit a buffer layer over the surface of each one of the plurality of substrates; and
an evacuation source configured to evacuate atoms from the vacuum chamber to prevent contamination of the first and second sputtering sources.