Machining of fusion-drawn glass laminate structures containing a photomachinable layer

• US 9,340,451 B2
• Filed: 03/13/2013
• Issued: 05/17/2016
• Est. Priority Date: 02/28/2013
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Boek, Heather Debra, Cook, Glen Bennett, Edwards, Victoria Ann, Weller, Mark Owen
• Primary Examiner(s): DEHGHAN, QUEENIE S
• Application Number:
  US13/798,479
• Publication Number:
  US 20140238078A1
• Time in Patent Office: 1,161 Days
• US Class Current: 1/1
• 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 2307/704 Crystalline
• CPC Class Codes: B32B 2457/00 Electrical equipment
• CPC Class Codes: B32B 3/266 characterised by an apertured layer, the apertures going through the whole thickness of the layer, e.g. expanded metal, perforated layer, slit layer regular cells B32B3/12
• 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: C03C 15/00 Surface treatment of glass, not in the form of fibres or filaments, by etching etching or surface-brightening compositions, in general C09K13/00
• CPC Class Codes: C03C 21/002 to perform ion-exchange between alkali ions C03C21/005 takes precedence
• CPC Class Codes: C03C 23/002 by ultraviolet light
• CPC Class Codes: C03C 23/007 by thermal treatment
• CPC Class Codes: C03C 3/091 containing aluminium
• CPC Class Codes: C03C 3/093 containing zinc or zirconium
• CPC Class Codes: C03C 3/095 containing rare earths
• CPC Class Codes: G03F 7/0043 Chalcogenides; Silicon, germanium, arsenic or derivatives thereof; Metals, oxides or alloys thereof G03F7/0044 takes precedence
• CPC Class Codes: G03F 7/0757 Macromolecular compounds containing Si-O, Si-C or Si-N bonds G03F7/0752 takes precedence
• CPC Class Codes: G03F 7/38 Treatment before imagewise removal, e.g. prebaking G03F7/265 takes precedence

Abstract

Methods for machining glass structures may be performed on fusion-drawn glass laminates having a core layer interposed between a first cladding layer and a second cladding layer. The core layer may be formed from a core glass composition having a core photosensitivity, the first cladding layer may be formed from a glass composition having a photosensitivity different from the core photosensitivity, and the second cladding layer may be formed from a glass composition having a photosensitivity different from the core photosensitivity. At least one of the core layer, the first cladding layer, and the second cladding layer is a photomachinable layer. The methods may include exposing a selected region of a photomachinable layer in the fusion-drawn laminate to ultraviolet radiation; heating the glass structure until the selected region crystallizes; and removing the crystallized material selectively from the photomachinable layer.

Claims

1. A method for machining a glass structure, wherein:

the glass structure comprises a fusion-drawn laminate of a core layer interposed between a first cladding layer and a second cladding layer;

the core layer is formed from a core glass composition having a nonzero core photosensitivity;

the first cladding layer is formed from a first-clad glass composition having a first-clad photosensitivity different from the core photosensitivity;

the second cladding layer is formed from a second-clad glass composition having a second-clad photosensitivity different from the core photosensitivity; and

at least one of the core layer, the first cladding layer, and the second cladding layer is a photomachinable layer,

the method comprising;

exposing at least one selected region of at least one photomachinable layer in the fusion-drawn laminate to ultraviolet radiation for a predetermined exposure time;

heating the glass structure until the at least one selected region forms a crystallized region of crystallized material in the photomachinable layer; and

removing the crystallized region selectively from the photomachinable layer.

2. The method of claim 1, wherein:

each of the core layer, the first cladding layer, and the second cladding layer are photomachinable layers; and

the first-clad photosensitivity and the second-clad photosensitivity are both greater than the core photosensitivity.

3. The method of claim 1, wherein:

a first plurality of selected regions of the first cladding layer and a second plurality of selected regions of the second cladding layer are exposed to the ultraviolet radiation; and

during the heating the first plurality of selected regions form crystallized regions in the first cladding layer and the second plurality of selected regions form crystallized regions in the second cladding layer.

4. The method of claim 3, wherein the exposing is conducted through at least one photomask having apertures that define the first plurality of selected regions, the second plurality of selected regions, or both.

5. The method of claim 4, further comprising:

exposing the glass structure to ultraviolet radiation a second time after heating the glass structure and before removing the crystallized region, such that a first portion of the core layer is shielded from the ultraviolet radiation by the crystallized region and a second portion of the core layer is not shielded from the ultraviolet radiation; and

heating the glass structure until the unshielded portion of the core layer crystallizes.

6. The method of claim 5, wherein the crystallized region is removed after exposing the glass structure to ultraviolet radiation the second time and before heating the glass structure until the unshielded portion of the core layer crystallizes.

7. The method of claim 4, wherein the first plurality of selected regions and the second plurality of selected regions are vertically aligned, the method further comprising removing portions of the core layer between the first plurality of selected regions and the second plurality of selected regions to form through-holes through the glass structure.

8. The method of claim 4, wherein removing the crystallized region forms hole structures in the first cladding layer, the second cladding layer, or both.

9. The method of claim 8, further comprising:

exposing the glass structure to ultraviolet radiation a second time after heating the glass structure and removing the crystallized region through a photomask having apertures that are aligned with the hole structures and are smaller than hole structures; and

heating the glass structure after the second exposure until at least a core crystallized region of the core layer crystallizes.

10. The method of claim 9, further comprising removing the core crystallized region to form at least one through-hole extending from hole structures on opposite sides of the glass structure.

11. The method of claim 8, further comprising etching surfaces of the first cladding layer, the second cladding layer, and the hole structures to form roughened cladding surfaces on the first cladding layer and the second cladding layer and roughened hole surfaces in the hole structures.

12. The method of claim 1, further comprising subjecting the glass structure to an ion-exchange process after the crystallized region is removed.

13. The method of claim 12, wherein subjecting the glass structure to the ion-exchange process comprises continuing the ion-exchange process at least until the first cladding layer and the second cladding layer are ion-exchanged through their entire thicknesses.

14. The method of claim 12, wherein subjecting the glass structure to the ion-exchange process comprises continuing the ion-exchange process at least until a contiguous ion-exchange layer is formed including portions of the first cladding layer, the second cladding layer, and the core layer.

15. The method of claim 14, further comprising breaking the glass structure at break lines formed in ion-exchanged regions of the core layer.

16. The method of claim 1, wherein the first-clad photosensitivity and the second-clad photosensitivity are both less than the core photosensitivity.

17. The method of claim 16, wherein the crystallized region forms in the core layer and not in the first cladding layer or the second cladding layer.

18. The method of claim 16, further comprising drilling through the first cladding layer, the second cladding layer, or both, to provide access for etchant to reach the crystallized region in the core layer.

19. The method of claim 1, wherein the first-clad photosensitivity and the second-clad photosensitivity are both zero;

and the first-clad glass composition and the second-clad glass composition are fast-etch glass compositions each having clad solubilities in an etchant at least 1.5 times a core solubility of the core glass composition in the etchant.

20. The method of claim 19, further comprising before exposing the photomachinable layer to the ultraviolet radiation:

applying a masking layer over at least a portion of the first cladding layer, the second cladding layer, or both; and

removing portions of the first cladding layer, the second cladding layer, or both, that are not covered by the masking layer.