Laminated glass article with low compaction and method for forming the same

• US 10,562,272 B2
• Filed: 12/07/2015
• Issued: 02/18/2020
• Est. Priority Date: 12/08/2014
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Kiczenski, Timothy James, Koseba, Samuel John, Venkataraman, Natesan
• Primary Examiner(s): Franklin, Jodi C
• Application Number:
  US15/534,192
• Publication Number:
  US 20170361574A1
• Time in Patent Office: 1,534 Days
• CPC Class Codes: B32B 17/06 comprising glass as the main or only constituent of a layer, next to another layer of a specific material
• CPC Class Codes: B32B 2250/03 3 layers
• CPC Class Codes: C03B 17/02 Forming molten glass coated with coloured layers; Forming molten glass of different compositions or layers; Forming molten glass comprising reinforcements or inserts
• CPC Class Codes: C03B 17/064 by the overflow downdraw fusion process; Isopipes therefor
• CPC Class Codes: C03B 17/067 combined with thermal conditioning of the sheets
• CPC Class Codes: C03B 25/08 of glass sheets
• CPC Class Codes: C03B 25/12 of glass sheets
• CPC Class Codes: C03B 32/00 Thermal after-treatment of glass products not provided for in groups C03B19/00 , C03B25/00 - C03B31/00 or C03B37/00, e.g. crystallisation, eliminating gas inclusions or other impurities; Hot-pressing vitrified, non-porous, shaped glass products
• CPC Class Codes: H01L 21/02422 Non-crystalline insulating materials, e.g. glass, polymers
• CPC Class Codes: H01L 21/02488 Insulating materials
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium

Abstract

A strengthened glass article (100), such as a substrate for a p-Si based transistors, includes first and second glass cladding layers (104, 106) and a glass core layer (102) disposed therebetween. A coefficient of thermal expansion [CTE] of each cladding layer (104, 106), which can be made of the same glass, is at least 1×10⁻⁷° C.⁻¹ less than that of the core layer (102). Each of the core and cladding layers has a strain point less than 700° C. A compaction of the glass article (100) is at most about 20 ppm [see FIG. 1]. A method includes forming a glass article and/or heating a glass article to a first temperature of at least about 400° C. The glass article has a glass core layer (102) and a glass cladding layer (104, 106) adjacent to the core layer. The glass article is maintained at a temperature within a range of from 400° C. to 600° C. for a holding period from 30 to 90 minutes and subsequently cooled to a temperature of at most 50° C. over a cooling period from 30 seconds to 5 minutes. The glass article (100) for heat strengthening may have been produced by the fusion overflow down draw process, e.g. as depicted in FIG. 3.

Claims

1. A strengthened glass article comprising:

a first glass cladding layer;

a second glass cladding layer; and

a glass core layer disposed between the first glass cladding layer and the second glass cladding layer;

wherein a coefficient of thermal expansion (CTE) of each of the first glass cladding layer and the second glass cladding layer is at least 1×

10⁷°

C.<sup>−

1</sup> less than a CTE of the glass core layer;

wherein each of the glass core layer and the glass cladding layer comprises a strain point of less than 650°

C.;

wherein each of the first glass cladding layer and the second glass cladding layer comprises a compressive stress of at least about 20 MPa; and

wherein a compaction of the glass article is at most about 20 ppm.

2. The glass article of claim 1, wherein at least one of the glass cladding layers is substantially free of BaO.

3. The glass article of claim 1, wherein at least one of the glass cladding layers comprises from about 60 mol % to about 70 mol % SiO₂, from about 6 mol % to about 18 mol % Al₂O₃, from about 6 mol % to about 21 mol % B₂O₃, from about 0.2 mol % to about 5 mol % MgO, and from about 8 mol % to about 12 mol % CaO.

4. The glass article of claim 1, wherein the glass cladding layer is substantially free of alkali metal.

5. The glass article of claim 1, wherein the glass cladding layer is substantially free of As₂O₃.

6. The glass article of claim 1, wherein the glass core layer comprises from about 50 mol % to about 80 mol % SiO₂, from about 5 mol % to about 20 mol % Al₂O₃, and from about 1 mol % to about 8 mol % MgO.

7. The glass article of claim 1, wherein the compaction of the glass article is at most about 3 ppm.

8. The glass article of claim 1, wherein the compaction of the glass article is at most about 1 ppm.

9. The glass article of claim 1, further comprising a poly-crystalline silicon (p-Si) electronic device formed on a surface of the glass article.

10. The glass article of claim 9, wherein the p-Si electronic device comprises a thin-film-transistor (TFT).

11. A display device comprising the glass article of claim 1.

12. A method comprising:

forming a glass article comprising a glass core layer and a glass cladding layer adjacent to the glass core layer;

maintaining the glass article within a hold temperature range from about 400°

C. to about 600°

C. for a holding period from about 30 minutes to about 90 minutes; and

cooling the glass article to a quench temperature of at most about 50°

C. over a cooling period from about 30 seconds to about 5 minutes subsequent to the maintaining step.

13. The method of claim 12, further comprising cooling the glass article to a cool temperature of about 200°

C. at a cooling rate from about 1°

C./minute to about 7°

C./minute subsequent to the maintaining step and prior to the cooling the glass article to the quench temperature step.

14. The method of claim 12, wherein the glass cladding layer comprises a first glass cladding layer and a second glass cladding layer, and the glass core layer is disposed between the first glass cladding layer and the second glass cladding layer.

15. The method of claim 12, further comprising forming a poly-crystalline silicon (p-Si) electronic device on a surface of the glass article.

16. The method of claim 12, wherein the forming the glass article comprises contacting the glass core layer in a viscous state with the glass cladding layer in a viscous state using an overflow distributor.

21. The method of claim 12, wherein subsequent to the cooling step, a compaction of the glass article is at most about 20 ppm.

23. A glass article made by the method of claim 12.

17. A method comprising:

heating a glass article to a first temperature of at least about 400°

C., the glass article comprising a glass core layer and a glass cladding layer adjacent to the glass core layer;

maintaining the glass article within a temperature range from about 400°

C. to about 600°

C. for a holding period from about 30 minutes to about 90 minutes; and

cooling the glass article to a second temperature of at most about 50°

C. over a cooling period from about 30 seconds to about 5 minutes subsequent to the maintaining step.

18. The method of claim 17, further comprising cooling the glass article to an intermediate temperature of about 200°

C. at a cooling rate from about 1°

C./minute to about 7°

C./minute subsequent to the maintaining step and prior to the cooling the glass article to the second temperature step.

19. The method of claim 17, wherein the glass cladding layer comprises a first glass cladding layer and a second glass cladding layer, and the glass core layer is disposed between the first glass cladding layer and the second glass cladding layer.

20. The method of claim 17, further comprising forming a poly-crystalline silicon (p-Si) electronic device on a surface of the glass article.

22. The method of claim 17, wherein subsequent to the cooling step, a compaction of the glass article is at most about 20 ppm.