US5998759A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Laser processing
Assignee: Electro Scientific Industries Inc
•
Filing: 1996-12-24
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Granted: 1999-12-07
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Expires: 2016-12-24
Abstract
Abstract A controlled, switched laser system for vaporizing a target structure on a substrate includes a diode-pumped, solid-state laser for producing a laser output, a controllable switch for controlling the on/off state and power level of the laser, and a wavelength shifter. The wavelength shifter shifts the wavelength of the laser output from a conventional wavelength to a wavelength beyond the absorption edge of the substrate but shorter than 1.2 μm in order to obtain a decrease in absorption of the laser output by the substrate due to the shift in the wavelength of the laser output. The wavelength shifter is removably insertable into the switched laser system so as to enable the switched laser system to operate at the conventional wavelength and at the wavelength beyond the absorption edge of the substrate. Heating of the substrate and hence damage to the substrate is limited due to the wavelength being beyond the absorption edge of the substrate. Good depth of focus of the laser beam output is maintained relative to spot size of the laser beam output due to the wavelength being less than about 1.2 μm.
Inventors
- 👤 Donald V. Smart
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:49
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/067; H10W20/068; B; B23; B23K; B23K26/00; B23K26/02; B23K26/06; B23K26/062; B23K26/0622; B23K26/08; B23K26/082; B23K26/083; B23K26/0853; B23K26/36; B23K26/361; B23K26/40; B23K2101/00; B23K2101/36; B23K2101/40; B23K2103/00; B23K2103/30; B23K2103/42; B23K2103/50
Claims Analysis
Total Claims: 50
Claim 1
Independent Claim
167 words
A method of vaporizing and removing a target link structure on a silicon substrate, comprising the steps of: providing a controlled, switched laser system comprising a diode-pumped, solid-state laser assembly and a controllable switch for controlling the on/off state and power level of the laser assembly; producing a laser beam output having an output pulse width less than about 8 nanoseconds at an operating repetition rate of about 5 kilohertz or higher, and a wavelength beyond the absorption edge of the silicon substrate but shorter than 1.2 μm in order to obtain low absorption of the laser beam output by the silicon substrate; and directing the laser beam output at the target link structure on the silicon substrate to vaporize and remove the target link structure; whereby heating of the silicon substrate and hence damage to the silicon substrate is limited due to the output pulse width being less than about 8 nanoseconds and due to the wavelength remaining beyond the absorption edge of the silicon substrate.
Claim 2
Independent Claim
167 words
A method of vaporizing and removing a target link structure on a silicon substrate, comprising the steps of: providing a controlled, switched laser system comprising a diode-pumped, solid-state laser assembly and a controllable switch for controlling the on/off state and power level of the laser assembly; producing a laser beam output having an output pulse width less than about 8 nanoseconds at an operating repetition rate of about 5 kilohertz or higher, and a wavelength beyond the absorption edge of the silicon substrate but shorter than 1.2 μm in order to obtain low absorption of the laser beam output by the silicon substrate; and directing the laser beam output at the target link structure on the silicon substrate to vaporize and remove the target link structure; whereby heating of the silicon substrate and hence damage to the silicon substrate is limited due to the output pulse width being less than about 8 nanoseconds and due to the wavelength remaining beyond the absorption edge of the silicon substrate.
Claim 3
Dependent Claim
32 words
The method of claim 1 wherein the output pulse width of the laser beam output is less than about 5 nanoseconds at an operating repetition rate of about 5 kilohertz or higher.
Claim 4
Dependent Claim
32 words
The method of claim 2 wherein the output pulse width of the laser beam output is less than about 4 nanoseconds at an operating repetition rate of about 5 kilohertz or higher.
Claim 5
Dependent Claim
32 words
The method of claim 3 wherein the output pulse width of the laser beam output is less than about 4 nanoseconds at an operating repetition rate of about 8 kilohertz or higher.
Claim 6
Dependent Claim
32 words
The method of claim 2 wherein the output pulse width of the laser beam output is less than about 5 nanoseconds at an operating repetition rate of about 10 kilohertz or higher.
Claim 7
Dependent Claim
25 words
The method of claim 1 wherein the output pulse has a peak beam power sufficiently high to evaporate a metal link in a high-density memory.
Claim 8
Dependent Claim
14 words
The method of claim 1 wherein the laser assembly comprises a neodymium vanadate laser.
Claim 9
Dependent Claim
13 words
The method of claim 1 wherein the laser assembly comprises a neodymium:YLF laser.
Claim 10
Dependent Claim
13 words
The method of claim 1 wherein the laser assembly comprises a neodymium:YAG laser.
Claim 11
Dependent Claim
23 words
The method of claim 1 wherein the laser assembly comprises a laser having a cavity length optimized for limiting the output pulse width.
Claim 12
Dependent Claim
17 words
The method of claim 1 wherein the target structure comprises a metal link in a high-density memory.
Claim 13
Dependent Claim
25 words
The method of claim 1 wherein the second target structure comprises a link formed of a material selected from the group of polysilicide and polysilicon.
Claim 14
Dependent Claim
10 words
The method of claim 1 wherein the substrate comprises silicon.
Claim 15
Independent Claim
183 words
A method of vaporizing and removing a target link structure on a silicon substrate, comprising the steps of: providing a controlled, switched laser system comprising a diode-pumped, solid-state laser and a controllable switch for controlling the on/off state and power level of the laser; producing a laser output having an output pulse width less than about 8 nanoseconds at an operating repetition rate of about 5 kilohertz or higher; shifting the wavelength of the laser output from a wavelength that is not beyond the absorption edge of the silicon substrate to a wavelength beyond the absorption edge of the silicon substrate but shorter than 1.2 μm in order to obtain a decrease in absorption of the laser output by the silicon substrate due to the shift in the wavelength of the laser output, whereby heating of the silicon substrate and hence damage to the silicon substrate is limited due to the wavelength remaining beyond the absorption edge of the silicon substrate; and directing the laser output at the target link structure on the silicon substrate to vaporize and remove the target link structure.
Claim 16
Independent Claim
183 words
A method of vaporizing and removing a target link structure on a silicon substrate, comprising the steps of: providing a controlled, switched laser system comprising a diode-pumped, solid-state laser and a controllable switch for controlling the on/off state and power level of the laser; producing a laser output having an output pulse width less than about 8 nanoseconds at an operating repetition rate of about 5 kilohertz or higher; shifting the wavelength of the laser output from a wavelength that is not beyond the absorption edge of the silicon substrate to a wavelength beyond the absorption edge of the silicon substrate but shorter than 1.2 μm in order to obtain a decrease in absorption of the laser output by the silicon substrate due to the shift in the wavelength of the laser output, whereby heating of the silicon substrate and hence damage to the silicon substrate is limited due to the wavelength remaining beyond the absorption edge of the silicon substrate; and directing the laser output at the target link structure on the silicon substrate to vaporize and remove the target link structure.
Claim 17
Dependent Claim
24 words
The method of claim 14 wherein the laser is a tunable fosterite laser and the wavelength shifter is a tuner incorporated into the laser.
Claim 18
Dependent Claim
15 words
The laser-system of claim 14 wherein the wavelength shifter is not part of the laser.
Claim 19
Dependent Claim
62 words
The method of claim 14 further comprising the step of removably inserting the wavelength shifter into the controlled, switched laser system so as to enable the switched laser system to operate at the wavelength that is not beyond the absorption edge of the silicon substrate and at the wavelength beyond the absorption edge of the silicon substrate but shorter than 1.2 μm.
Claim 20
Dependent Claim
22 words
The method of claim 14 wherein the wavelength that is not beyond the absorption edge of the substrate is about 1.047 μm.
Claim 21
Dependent Claim
22 words
The method of claim 14 wherein the wavelength that is not beyond the absorption edge of the substrate is about 1.064 μm.
Claim 22
Dependent Claim
31 words
The method of claim 19 wherein the output pulse width of the laser output is less than about 4 nanoseconds at an operating repetition rate of about 8 kilohertz or higher.
Claim 23
Dependent Claim
31 words
The method of claim 19 wherein the output pulse width of the laser output is less than about 5 nanoseconds at an operating repetition rate of about 10 kilohertz or higher.
Claim 24
Dependent Claim
13 words
The method of claim 14 wherein the wavelength shifter is a Raman shifter.
Claim 25
Dependent Claim
25 words
The method of claim 14 wherein the output pulse has a peak beam power sufficiently high to evaporate a metal link in a high-density memory.
Claim 26
Independent Claim
198 words
A method of vaporizing and removing a target link structure on a silicon substrate, comprising the steps of: providing a controlled, switched laser system comprising a diode-pumped, solid-state laser assembly and a controllable switch for controlling the on/off state and power level of the laser assembly; producing a laser beam output having an output pulse width less than about 8 nanoseconds at an operating repetition rate of about 5 kilohertz or higher, and a wavelength beyond the absorption edge of the silicon substrate but shorter than 1.2 μm in order to obtain low absorption of the laser beam output by the silicon substrate; and directing the laser beam output at the target link structure on the silicon substrate to vaporize and removing the target link structure; whereby heating of the silicon substrate and hence damage to the silicon substrate is limited due to the output pulse width being less than about 8 nanoseconds and due to the wavelength remaining beyond the absorption edge of the silicon substrate, and whereby good depth of focus of the laser beam output is maintained relative to spot size of the laser beam output due to the wavelength being less than 1.2 μm.
Claim 27
Independent Claim
198 words
A method of vaporizing and removing a target link structure on a silicon substrate, comprising the steps of: providing a controlled, switched laser system comprising a diode-pumped, solid-state laser assembly and a controllable switch for controlling the on/off state and power level of the laser assembly; producing a laser beam output having an output pulse width less than about 8 nanoseconds at an operating repetition rate of about 5 kilohertz or higher, and a wavelength beyond the absorption edge of the silicon substrate but shorter than 1.2 μm in order to obtain low absorption of the laser beam output by the silicon substrate; and directing the laser beam output at the target link structure on the silicon substrate to vaporize and removing the target link structure; whereby heating of the silicon substrate and hence damage to the silicon substrate is limited due to the output pulse width being less than about 8 nanoseconds and due to the wavelength remaining beyond the absorption edge of the silicon substrate, and whereby good depth of focus of the laser beam output is maintained relative to spot size of the laser beam output due to the wavelength being less than 1.2 μm.
Claim 28
Dependent Claim
25 words
The method of claim 24 wherein the output pulse has a peak beam power sufficiently high to evaporate a metal link in a high-density memory.
Claim 29
Dependent Claim
32 words
The method of claim 24 wherein the laser beam output has a spot size and depth of field sufficient for processing of target structures on a substrate having a substantially non-flat surface.
Claim 30
Dependent Claim
49 words
The method of claim 26 wherein the laser beam output has a spot size and depth of field sufficient for processing of target structures on a wafer having approximately an 8-inch diameter, a thickness of less than about 300 μm, and a substantial variation in flatness over its surface.
Claim 31
Dependent Claim
20 words
The method of claim 24 wherein the target structure vaporized by the laser beam output is about 1 μm wide.
Claim 32
Dependent Claim
20 words
The method of claim 24 wherein the target structure vaporized by the laser beam output is about 1/3 μm thick.
Claim 33
Dependent Claim
17 words
The method of claim 24 wherein the target structure comprises a metal link in a high-density memory.
Claim 34
Independent Claim
269 words
A method of vaporizing and removing target link structures on substrates, comprising the steps of: providing a controlled, switched laser system comprising a diode-pumped, solid-state laser and a controllable switch for controlling the on/off state and power level of the laser; producing a laser output having an output pulse width less than about 8 nanoseconds at an operating repetition rate of about 5 kilohertz or higher; directing the laser output at a first target link structure on a first, silicon substrate to vaporize and remove the first target link structure, the laser output remaining at a wavelength beyond the absorption edge of the first, silicon substrate but shorter than 1.2 μm in order to obtain low absorption of the laser output by the first, silicon substrate, whereby heating of the first, silicon substrate and hence damage to the first, silicon substrate is limited due to the wavelength remaining beyond the absorption edge of the first, silicon substrate, the laser output being focused by optics of the laser; shifting the wavelength of the laser output from the wavelength beyond the absorption edge of the first, silicon substrate to a wavelength that is not beyond the absorption edge of the first, silicon substrate; and directing the laser output at a second target link structure on a second substrate to vaporize and remove the second target link structure, the laser output being at the wavelength that is not beyond the absorption edge of the first, silicon substrate, the laser output being focused by the optics previously used to focus the laser output onto the first, silicon substrate, without modification of the optics.
Claim 35
Independent Claim
269 words
A method of vaporizing and removing target link structures on substrates, comprising the steps of: providing a controlled, switched laser system comprising a diode-pumped, solid-state laser and a controllable switch for controlling the on/off state and power level of the laser; producing a laser output having an output pulse width less than about 8 nanoseconds at an operating repetition rate of about 5 kilohertz or higher; directing the laser output at a first target link structure on a first, silicon substrate to vaporize and remove the first target link structure, the laser output remaining at a wavelength beyond the absorption edge of the first, silicon substrate but shorter than 1.2 μm in order to obtain low absorption of the laser output by the first, silicon substrate, whereby heating of the first, silicon substrate and hence damage to the first, silicon substrate is limited due to the wavelength remaining beyond the absorption edge of the first, silicon substrate, the laser output being focused by optics of the laser; shifting the wavelength of the laser output from the wavelength beyond the absorption edge of the first, silicon substrate to a wavelength that is not beyond the absorption edge of the first, silicon substrate; and directing the laser output at a second target link structure on a second substrate to vaporize and remove the second target link structure, the laser output being at the wavelength that is not beyond the absorption edge of the first, silicon substrate, the laser output being focused by the optics previously used to focus the laser output onto the first, silicon substrate, without modification of the optics.
Claim 36
Dependent Claim
22 words
The method of claim 31 wherein the wavelength that is not beyond the absorption edge of the substrate is about 1.064 μm.
Claim 37
Dependent Claim
20 words
The method of claim 31 wherein the wavelength beyond the absorption edge of the substrate is shorter than 1.2 μm.
Claim 38
Dependent Claim
13 words
The method of claim 31 wherein the wavelength shifter is a Raman shifter.
Claim 39
Dependent Claim
25 words
The method of claim 31 wherein the output pulse has a peak beam power sufficiently high to evaporate a metal link in a high-density memory.
Claim 40
Dependent Claim
25 words
The method of claim 31 wherein the second target structure comprises a link formed of a material selected from the group of polysilicide and polysilicon.
Claim 41
Dependent Claim
14 words
The method of claim 31 wherein the first target structure comprises a metal link.
Claim 42
Independent Claim
304 words
A method of vaporizing and removing target link structures on substrates, comprising the steps of: providing a controlled, switched laser system comprising a diode-pumped, solid-state laser and a controllable switch for controlling the on/off state and power level of the laser; producing a laser output having an output pulse width less than about 8 nanoseconds at an operating repetition rate of about 5 kilohertz or higher; directing the laser output through a removably insertable wavelength shifter to a first target link structure on a first, silicon substrate to vaporize and remove the first target link structure, the laser output remaining at a wavelength beyond the absorption edge of the first, silicon substrate but shorter than 1.2 μm in order to obtain low absorption of the laser output by the first, silicon substrate while maintaining good depth of focus of the laser beam output relative to spot size of the laser beam output, the laser output at the wavelength beyond the absorption edge of the first, silicon substrate but shorter than 1.2 μm having an output pulse width less than about 8 nanoseconds at an operating repetition rate of about 5 kilohertz or higher, whereby heating of the first, silicon substrate and hence damage to the first, silicon substrate is limited due to the wavelength remaining beyond the absorption edge of the first, silicon substrate; removing the removably insertable wavelength shifter from the switched laser system, in order to shift the wavelength of the laser output from the wavelength beyond the absorption edge of the first, silicon substrate to a wavelength that is not beyond the absorption edge of the first, silicon substrate; and directing the laser output at a second target link structure on a second substrate to vaporize and remove the second target link structure, the laser output being at the conventional wavelength.
Claim 43
Independent Claim
304 words
A method of vaporizing and removing target link structures on substrates, comprising the steps of: providing a controlled, switched laser system comprising a diode-pumped, solid-state laser and a controllable switch for controlling the on/off state and power level of the laser; producing a laser output having an output pulse width less than about 8 nanoseconds at an operating repetition rate of about 5 kilohertz or higher; directing the laser output through a removably insertable wavelength shifter to a first target link structure on a first, silicon substrate to vaporize and remove the first target link structure, the laser output remaining at a wavelength beyond the absorption edge of the first, silicon substrate but shorter than 1.2 μm in order to obtain low absorption of the laser output by the first, silicon substrate while maintaining good depth of focus of the laser beam output relative to spot size of the laser beam output, the laser output at the wavelength beyond the absorption edge of the first, silicon substrate but shorter than 1.2 μm having an output pulse width less than about 8 nanoseconds at an operating repetition rate of about 5 kilohertz or higher, whereby heating of the first, silicon substrate and hence damage to the first, silicon substrate is limited due to the wavelength remaining beyond the absorption edge of the first, silicon substrate; removing the removably insertable wavelength shifter from the switched laser system, in order to shift the wavelength of the laser output from the wavelength beyond the absorption edge of the first, silicon substrate to a wavelength that is not beyond the absorption edge of the first, silicon substrate; and directing the laser output at a second target link structure on a second substrate to vaporize and remove the second target link structure, the laser output being at the conventional wavelength.
Claim 44
Dependent Claim
55 words
The method of claim 38 wherein the laser output has an output pulse width less than about 8 nanoseconds at an operating repetition rate of about 5 kilohertz or higher, whereby heating of the substrate and hence damage to the substrate is limited due to the output pulse width being less than about 8 nanoseconds.
Claim 45
Dependent Claim
13 words
The method of claim 38 wherein the laser is a neodymium vanadate laser.
Claim 46
Dependent Claim
12 words
The method of claim 38 wherein the laser is a neodymium:YLF laser.
Claim 47
Dependent Claim
12 words
The method of claim 38 wherein the laser is a neodymium:YAG laser.
Claim 48
Dependent Claim
19 words
The method of claim 38 wherein the laser has a cavity length optimized for limiting the output pulse width.
Claim 49
Dependent Claim
13 words
The method of claim 38 wherein the wavelength shifter is a Raman shifter.
Claim 50
Dependent Claim
25 words
The method of claim 38 wherein the output pulse has a peak beam power sufficiently high to evaporate a metal link in a high-density memory.
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