DAMAGE-FREE SELF-LIMITING THROUGH-SUBSTRATE LASER ABLATION

• US 20170157712A1
• Filed: 02/18/2017
• Published: 06/08/2017
• Est. Priority Date: 11/07/2014
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Narayan, Chandrasekhar, Doany, Fuad E.
• Granted Patent: US 10,486,268 B2
• Time in Patent Office: Days
• CPC Class Codes: B23K 2103/42 Plastics B23K2103/16 takes precedence
• CPC Class Codes: B23K 2103/50 Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
• CPC Class Codes: B23K 26/0622 by shaping pulses
• CPC Class Codes: B23K 26/0652 comprising prisms
• CPC Class Codes: B23K 26/082 Scanning systems, i.e. devices involving movement of the laser beam relative to the laser head
• CPC Class Codes: B23K 26/0869 Devices involving movement of the laser head in at least one axial direction
• CPC Class Codes: B23K 26/18 using absorbing layers on the workpiece, e.g. for marking or protecting purposes
• CPC Class Codes: B23K 26/352 for surface treatment
• CPC Class Codes: B23K 26/402 involving non-metallic material, e.g. isolators
• 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 2255/24 Organic non-macromolecular coating
• CPC Class Codes: B32B 2307/40 having particular optical properties light or UV resistant B32B2307/71
• CPC Class Codes: B32B 2457/20 Displays, e.g. liquid crystal displays, plasma displays
• CPC Class Codes: B32B 38/10 Removing layers, or parts of layers, mechanically or chemically
• CPC Class Codes: B32B 43/006 Delaminating
• CPC Class Codes: B32B 7/06 permitting easy separation
• CPC Class Codes: C09J 2301/502 process for debonding adherents
• CPC Class Codes: C09J 2479/08 polyimide
• CPC Class Codes: C09J 5/00 Adhesive processes in general; Adhesive processes not provided for elsewhere, e.g. relating to primers
• CPC Class Codes: H01L 21/02002 Preparing wafers
• CPC Class Codes: H01L 21/268 : using electromagnetic radiation, e.g. laser radiation
• CPC Class Codes: H01L 21/6835 : using temporarily an auxiliary support
• CPC Class Codes: H01L 2221/68381 : Details of chemical or physical process used for separating the auxiliary support from a device or wafer
• CPC Class Codes: Y10T 156/1158 : Electromagnetic radiation applied to work for delamination [e.g., microwave, uv, ir, etc.]
• CPC Class Codes: Y10T 156/1917 : Electromagnetic radiation delaminating means [e.g., microwave, uv, ir, etc.]

Abstract

A first substrate, bonded to a second substrate by a material, is provided. The first substrate is transparent to at least some wavelengths of electromagnetic radiation. The first substrate is irradiated with the electromagnetic radiation to which the first substrate is transparent, such that the electromagnetic radiation impinges on the material causing a decomposition thereof at a location at an interface between the first substrate and the material. The decomposition results in, at the location, an interface of the first substrate and an atmosphere of the decomposition. The atmosphere of the decomposition has an optical property resulting in ceasing the decomposition of the material.

Claims

1-20. -20. (canceled)

21. A product comprising:

a first substrate that is transparent to at least a first wavelength of electromagnetic radiation;

a second substrate that is bonded to a bottom surface of the first substrate;

a material disposed between and bonding the second substrate and the first substrate; and

an atmosphere of decomposition that is formed in a portion of the material and interfaces said first substrate;

wherein the material has an optical property that causes transmission of electromagnetic radiation of the first wavelength from the first substrate into the material when the electromagnetic radiation of the first wavelength impinges on the material within a given range of angles, and the material decomposes to form the atmosphere of decomposition when exposed to the electromagnetic radiation of the first wavelength at an intensity greater than a given threshold that is a property of the material;

wherein the atmosphere of decomposition has an optical property that causes substantially total reflection of the electromagnetic radiation of the first wavelength when the electromagnetic radiation of the first wavelength impinges on the atmosphere of decomposition within at least a subset of the given range of angles;

wherein at least a portion of a top surface of the first substrate is angled relative to the bottom surface of the first substrate such that the electromagnetic radiation of the first wavelength, impinging on the top surface of the first substrate at a first angle, will impinge on the material at a second angle within the subset of the given range of angles.

22. A product comprising:

a first substrate that is transparent to at least a first wavelength of electromagnetic radiation;

a second substrate that is bonded to a bottom surface of the first substrate;

a material disposed between and bonding the second substrate and the first substrate;

an atmosphere of decomposition that is formed in a portion of the material and interfaces said first substrate; and

a prism that is optically coupled to the first substrate;

wherein the material has an optical property that causes transmission of the electromagnetic radiation of the first wavelength into the material when the electromagnetic radiation of the first wavelength impinges on the material within a given range of angles, and the material decomposes to form the atmosphere of decomposition when exposed to the electromagnetic radiation of the first wavelength at an intensity greater than a given threshold that is a property of the material;

wherein the atmosphere of decomposition has an optical property that causes substantially total reflection of the electromagnetic radiation of the first wavelength when the electromagnetic radiation of the first wavelength impinges on the atmosphere of decomposition within at least a subset of the given range of angles;

wherein the prism includes a surface that is angled at a first angle relative to the bottom surface of the first substrate such that the electromagnetic radiation of the first wavelength, impinging on the prism at an angle normal to the first angle, will impinge on the material at a second angle within the subset of the given range of angles.

23. The product as claimed in claim 22 further comprising an array of prisms optically coupled to the first substrate, wherein the array of prisms is index-matched to the first substrate.

24. The product as claimed in claim 23 wherein the array of prisms is disposed on the top surface of the first substrate.

25. The product as claimed in claim 23 wherein the array of prisms is integral with the first substrate.

26. An apparatus comprising:

a first substrate that is transparent to at least a first wavelength of electromagnetic radiation;

a second substrate that is bonded to a bottom surface of the first substrate;

a material disposed between and bonding the second substrate and the first substrate;

an atmosphere of decomposition that is formed in a portion of the material and interfaces said first substrate;

a prism that is optically coupled to the first substrate; and

a laser that is arranged to emit electromagnetic radiation of the first wavelength toward the first substrate at a chosen angle relative to the bottom surface of the first substrate;

wherein the material has an optical property that causes transmission of the electromagnetic radiation of the first wavelength into the material when the electromagnetic radiation of the first wavelength impinges on the material within a given range of angles, and the material decomposes to form the atmosphere of decomposition when exposed to the electromagnetic radiation of the first wavelength at an intensity greater than a given threshold that is a property of the material;

wherein the atmosphere of decomposition has an optical property that causes substantially total reflection of the electromagnetic radiation of the first wavelength when the electromagnetic radiation of the first wavelength impinges on the atmosphere of decomposition within at least a subset of the given range of angles;

wherein the prism is disposed at one of the top surface or the bottom surface of the first substrate, and includes a surface that is angled relative to the other of the top surface or the bottom surface of the first substrate such that refraction of the electromagnetic radiation of the first wavelength by the prism and the first substrate causes the electromagnetic radiation of the first wavelength to impinge on the atmosphere of decomposition at an angle within the subset of the given range of angles.

27. The product as claimed in claim 26 wherein the prism is one of an array of prisms optically coupled to the first substrate, wherein the array of prisms is index-matched to the first substrate.

28. The product as claimed in claim 26 wherein the prism is disposed at the top surface of the first substrate and the chosen angle is within the subset of the given range of angles.

29. The product as claimed in claim 27 wherein the prism is disposed at the bottom surface of the first substrate and the chosen angle is not within the given range of angles.

30. The product as claimed in claim 26 wherein the first substrate comprises at least one of a glass and a fused silica material transparent to at least one of visible and near-ultraviolet wavelengths of the electromagnetic radiation.

31. The product as claimed in claim 26 wherein the first substrate comprises a semiconductor wafer transparent to infrared wavelengths of the electromagnetic radiation.

32. The product as claimed in claim 26 wherein the material comprises a polyimide polymer.

33. The product as claimed in claim 26 wherein the second substrate comprises one of a semiconductor substrate and a glass substrate for a flat panel display.