# US 2014/0150716 A1 · Melt fixture including thermal shields having a stepped configuration

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- Number: US 2014/0150716 A1
- Document ID: US20140150716A1
- Status: Published application
- Kind: A1
- Application number: 14/176,437
- Filed: 2014-02-10
- Published: 2014-06-05
- Earliest claimed: 2004-04-08
- Assignees: Saint-Gobain Ceramics & Plastics, Inc.
- Applicants: Saint-Gobain Ceramics & Plastics, Inc.
- Inventors: John Walter Locher; Stephen Anthony Zanella; Ralph Lampson MacLean, JR.; Herbert Ellsworth Bates
- Web page: https://patentgrep.com/patent/US20140150716A1

## CPC

- C30B 15/30: Mechanisms for rotating or moving either the melt or the crystal (flotation methods C30B15/28)
- C30B 15/34: Edge-defined film-fed crystal-growth using dies or slits
- C30B 29/20: Aluminium oxides
- Y10T 117/1044: including means forming a flat shape [e.g., ribbon]
- Y10T 428/2495: Thickness [relative or absolute]
- Y10T 428/26: Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
- 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

Various single crystals are disclosed including sapphire. The single crystals have desirable geometric properties, including a width not less than about 15 cm and the thickness is not less than about 0.5 cm. The single crystal may also have other features, such as a maximum thickness variation, and as-formed crystals may have a generally symmetrical neck portion, particularly related to the transition from the neck to the main body of the crystal. Methods and for forming such crystals and an apparatus for carrying out the methods are disclosed as well.

## Claims

### Claim 1

A melt fixture comprising:
a crucible;
a die open to and extending along a length of the crucible; and
a plurality of thermal shields overlying the crucible and adjacent to the die, the thermal shields having a stepped configuration.

### Claim 2 (depends on 1)

The melt fixture of claim 1, wherein thermal shields include a first shield set positioned along a first lateral side of the die, and a second shield set positioned along an opposite, second lateral side the die.

### Claim 3 (depends on 2)

The melt fixture of claim 2, wherein each of the first and second shield sets is generally symmetrical about a vertical central axis corresponding to midpoint of the die.

### Claim 4 (depends on 1)

The melt fixture of claim 1, further comprising an afterheater disposed above the die and configured to receive an as-formed crystal sheet, wherein the afterheater has a lower compartment and an upper compartment separated from each other by an isolation structure.

### Claim 5 (depends on 1)

The melt fixture of claim 1, wherein thermal shields are substantially parallel to one another.

### Claim 6 (depends on 5)

The melt fixture of claim 5, further comprising shield pins to hold the thermal shields in place.

### Claim 7 (depends on 1)

The melt fixture of claim 1, wherein the thermal shields provide a static temperature gradient along the die.

### Claim 8 (depends on 7)

The melt fixture of claim 7, wherein the thermal shields provide a temperature profile along the length of the die such that the temperature profile has a maximum temperature at about a midpoint of the die.

### Claim 9 (depends on 1)

The melt fixture of claim 1, wherein the die has an opening with a length that is not less than about 28 cm.

### Claim 10 (depends on 9)

The melt fixture of claim 9, wherein the opening of the die has a width that is not less than about 0.5 cm.

### Claim 11 (depends on 10)

The melt fixture of claim 10, wherein the length of the opening is not less than about 30 cm.

### Claim 12 (depends on 1)

The melt fixture of claim 1, further comprising an afterheater having a lower compartment and an upper compartment separated from each other by an isolation structure.

### Claim 13 (depends on 12)

The method of claim 12, wherein the isolation structure comprises isolation doors, between the lower compartment and the upper compartment.