Glass sealing with transparent materials having transient absorption properties

• US 9,666,763 B2
• Filed: 03/15/2013
• Issued: 05/30/2017
• Est. Priority Date: 11/30/2012
• Status: Expired due to Fees

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Logunov, Stephan Lvovich, Quesada, Mark Alejandro
• Primary Examiner(s): Lee, Cheung
• Assistant Examiner(s): Smith, Stephen C
• Application Number:
  US13/841,391
• Publication Number:
  US 20140151742A1
• Time in Patent Office: 1,537 Days
• Field of Search: 501 15- 44, 257794, 257E23118, 438426-432
• CPC Class Codes: B29C 65/1635 at least passing through one of the parts to be joined, i.e. laser transmission welding
• CPC Class Codes: B29C 65/1638 focusing the laser beam on the interface
• CPC Class Codes: C03C 27/06 Joining glass to glass by processes other than fusing fusing C03B23/20; units for use as elements for closing wall or like openings and comprising two or more parallel glass panes in spaced relationship, the panes being permanently secured together E06B3/66
• CPC Class Codes: C03C 3/247 containing fluorine and phosphorus
• CPC Class Codes: C03C 4/085 for ultraviolet absorbing glass
• CPC Class Codes: C03C 8/24 Fusion seal compositions being frit compositions having non-frit additions, i.e. for use as seals between dissimilar materials, e.g. glass and metal; Glass solders
• CPC Class Codes: C08K 2003/023 Silicon
• CPC Class Codes: H01L 21/02348 treatment by exposure to UV light
• CPC Class Codes: H01L 31/048 Encapsulation of modules
• CPC Class Codes: H01L 33/483 Containers
• CPC Class Codes: H01S 5/0216 using an intermediate compound, e.g. a glue or solder
• CPC Class Codes: H10K 50/8426 Peripheral sealing arrangements, e.g. adhesives, sealants

Abstract

Transparent glass-to-glass hermetic seals are formed by providing a low melting temperature sealing glass along a sealing interface between two glass substrates and irradiating the interface with laser radiation. Absorption by the sealing glass and induced transient absorption by the glass substrates along the sealing interface causes localized heating and melting of both the sealing glass layer and the substrate materials, which results in the formation of a glass-to-glass weld. Due to the transient absorption by the substrate material, the sealed region is transparent upon cooling.

Claims

1. A method of protecting a workpiece comprising:

forming a low T_g glass sealing layer over a major surface of a first substrate;

arranging a workpiece to be protected between the first substrate and a second substrate where the sealing layer is in contact with the second substrate;

locally heating the glass sealing layer with laser radiation to a sealing temperature sufficient to melt the sealing layer; and

inducing transient absorption of the laser radiation by the first substrate to melt at least a portion of the first substrate and form a glass seal between the first and second substrates,

wherein the first substrate is a glass substrate having (a) an absorption of the laser radiation that is less than 15% at room temperature and (b) an induced transient absorption of the laser radiation that is greater than 15% at the sealing temperature.

2. The method according to claim 1, wherein the laser radiation is translated to define a sealing interface.

3. The method according to claim 1, wherein the laser radiation comprises UV radiation.

4. The method according to claim 1, wherein a pulse-width of the laser radiation is from 1 to 10 nanoseconds and a repetition rate of the laser radiation is at least 1 kHz.

5. The method according to claim 1, wherein the low T_g glass comprises:

20-100 mol % SnO;

0-50 mol % SnF₂; and

0-30 mol % P₂O₅ or B₂O₃.

6. The method according to claim 1, wherein a thickness of the low T_g glass sealing layer ranges from about 100 nm to 10 microns.

7. The method according to claim 1, wherein absorption of the laser radiation by the low T_g glass sealing layer at room temperature is at least 15%.

8. The method according to claim 1, wherein the second substrate comprises a glass substrate having (a) an absorption of the laser radiation that is less than 15% at room temperature and (b) an induced transient absorption of the laser radiation that is greater than 15% at the sealing temperature.

9. The method according to claim 1, wherein the sealing temperature is greater than 400°

C.

10. The method according to claim 1, wherein the first glass substrate is heated by thermal conduction.

11. The method according to claim 1, wherein the workpiece comprises quantum dots, a display, a light emitting diode, or an organic light emitting diode.

12. The method according to claim 1, wherein the glass seal forms a perimeter around the workpiece.

13. The method of claim 1, wherein the low T_g glass sealing layer is formed over substantially all of the major surface of the first substrate.

14. The method of claim 1, wherein the glass seal is optically transparent.

15. The method of claim 1, wherein the low T_g glass sealing layer is free of fillers.

16. The method of claim 1, wherein a thickness of the low T_g glass sealing layer ranges from 100 nm to 0.5 microns.

17. A method of sealing a device comprising the steps of:

forming a non-frit, low T_g glass sealing layer over a surface of a first substrate;

arranging a device to be sealed between the first substrate and a second substrate where the sealing layer is in contact with the second substrate and the device, thereby forming an interface between the first substrate, sealing layer and second substrate;

locally heating the interface using laser radiation to cause a local increase in temperature at the interface and to melt the sealing layer at the interface;

inducing transient absorption of the laser radiation in portions of the first substrate and second substrate adjacent the interface as a function of the local increase in temperature at the interface;

melting the portions of the first substrate and second substrate as a function of the induced transient absorption; and

sealing the device between the first and second substrates by the melted sealing layer and melted portions of the first and second substrates.

18. The method according to claim 17, wherein the sealing layer comprises:

20-100 mol % SnO;

0-50 mol % SnF₂; and

0-30 mol % P₂O₅ or B₂O₃.

19. The method according to claim 17, wherein a thickness of the sealing layer ranges from about 100 nm to about 10 microns.

20. The method according to claim 17, wherein the device comprises quantum dots, a display, a light emitting diode, or an organic light emitting diode.

21. The method according to claim 17, wherein the first and second substrates have different coefficients of thermal expansion.

22. The method of claim 17, wherein the non-frit, low T_g glass sealing layer is formed over substantially all of a major surface of the first substrate.

23. The method of claim 17, wherein the interface is locally heated to a sealing temperature and wherein at least one of the first or second glass substrates has (a) an absorption of the laser radiation that is less than 15% at room temperature and (b) an induced transient absorption of the laser radiation that is greater than 15% at the sealing temperature.

24. A method of protecting a workpiece comprising:

forming a non-frit, low T_g glass sealing layer over substantially all of a major surface of a first glass substrate;

arranging a workpiece to be protected between the first glass substrate and a second glass substrate where the sealing layer is in contact with the second glass substrate; and

locally heating the glass sealing layer and the glass substrates with laser radiation to a sealing temperature to melt the sealing layer and the glass substrates to form an optically transparent glass seal between the glass substrates,

wherein at least one of the first or second glass substrates has (a) an absorption of the laser radiation that is less than 15% at room temperature and (b) an induced transient absorption of the laser radiation that is greater than 15% at the sealing temperature, and

wherein the non-frit low T_g glass comprises;

35-50 mol % SnO;

30-40 mol % SnF₂;

15-25 mol % P₂O₅; and

1.5 to 3 mol % of a dopant oxide.

25. The method according to claim 24, wherein a thickness of the non-frit low T_g glass sealing layer ranges from about 100 nm to 10 microns.

26. The method according to claim 24, wherein the dopant oxide is selected from the group consisting of WO₃, CeO₂, Nb₂O₅, and combinations thereof.

27. A method of protecting a workpiece comprising:

forming a low T_g glass sealing layer over substantially all of a major surface of a first glass substrate;

arranging a workpiece to be protected between the first substrate and a second glass substrate where the sealing layer is in contact with the second glass substrate; and

locally heating the glass sealing layer and the glass substrates with laser radiation to a sealing temperature to melt the sealing layer and the glass substrates to form an optically transparent glass seal between the glass substrates,

wherein at least one of the first or second glass substrates has (a) an absorption of the laser radiation that is less than 15% at room temperature and (b) an induced transient absorption of the laser radiation that is greater than 15% at the sealing temperature.