Method and system for high-speed, precise micromachining an array of devices

• US 7,871,903 B2
• Filed: 12/22/2009
• Issued: 01/18/2011
• Est. Priority Date: 03/27/2002
• Status: Expired due to Term

• Current Assignee: Electro Scientific Industries Incorporated (MKS Instruments Incorporated)
• Original Assignee: GSI Group Corporation (Novanta Inc.)
• Inventors: Chu, Yun Fee, Johnson, Shepard D., Erhmann, Jonathan S., Lento, Joseph V., Couch, Bruce L.
• Primary Examiner(s): Ghyka; Alexander G
• Application Number:
  US12/644,832
• Publication Number:
  US 20100140239A1
• Time in Patent Office: 392 Days
• Field of Search: 438/463, 438/460, 219/121.69
• US Class Current: 438/463
• CPC Class Codes: B23K 2101/38 Conductors
• CPC Class Codes: B23K 2103/50 Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
• CPC Class Codes: B23K 26/03 Observing, e.g. monitoring, the workpiece
• CPC Class Codes: B23K 26/032 using optical means
• CPC Class Codes: B23K 26/034 Observing the temperature of the workpiece
• CPC Class Codes: B23K 26/04 Automatically aligning, aiming or focusing the laser beam, e.g. using the back-scattered light
• CPC Class Codes: B23K 26/0622 by shaping pulses
• CPC Class Codes: B23K 26/064 by means of optical elements, e.g. lenses, mirrors or prisms
• CPC Class Codes: B23K 26/0665 by beam condensation on the workpiece, e.g. for focusing
• CPC Class Codes: B23K 26/073 Shaping the laser spot
• CPC Class Codes: B23K 26/0736 into an oval shape, e.g. elliptic shape
• 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 26/0823 Devices involving rotation of the workpiece
• CPC Class Codes: B23K 26/0853 Devices involving movement of the workpiece in at least in two axial directions, e.g. in a plane
• CPC Class Codes: B23K 26/351 for trimming or tuning of electrical components
• CPC Class Codes: B23K 26/361 for deburring or mechanical trimming B23K26/351 takes precedence
• CPC Class Codes: B23K 26/40 taking account of the properties of the material involved
• CPC Class Codes: H01C 17/242 by laser trimming by laser in general B23K26/351
• CPC Class Codes: H01L 27/016 Thin-film circuits
• CPC Class Codes: H01L 28/20 Resistors

Abstract

A method and system for high-speed, precise micromachining an array of devices are disclosed wherein improved process throughput and accuracy, such as resistor trimming accuracy, are provided. Beam scanning and deflection are both used to distribute beam spots to elements of an array of elements for selective processing. The deflection can be performed with a solid state deflector.

Claims

1. A method of precisely cutting selected substantially identical conductive circuit elements in an array of such elements arranged in at least one of one or more rows and one or more columns on a substrate, the cutting selectively removing material from the selected elements, the method comprising:

generating at least one pulsed laser output beam; and

irradiating the selected substantially identical conductive circuit elements with the pulsed laser output beam, the step of irradiating comprising;

positioning and focusing the laser output beam to produce calibrated, aligned and focused beams to each of a plurality of selected elements of the array, wherein the step of positioning comprises;

scanning the pulsed laser output beam in a scanning pattern over the array of elements; and

superimposing a distribution pattern on the scanning pattern by deflecting the pulsed laser output beam with at least one programmable deflector; and

,

wherein the pulsed laser beam impinges each selected array element with controlled energy and wherein the pulsed laser beam selectively and accurately cuts each selected array element.

2. The method of claim 1, comprising deflecting according to a programmed sequence of deflections.

3. The method of claim 1, wherein the scanning pattern comprises a substantially continuous scan over the elements and wherein the deflecting provides fast jumps between elements within the substantially continuous scan.

7. The method of claim 1, wherein the steps of deflecting and scanning are carried out with a multi-beam generator comprising the at least one solid-state deflector and an electromechanical scanner.

8. The method of claim 7, wherein the solid-state deflector is a 2D solid-state deflector.

9. The method of claim 7, wherein the electromechanical scanner is a 2D galvanometer based mirror scanner.

10. The method as claimed in claim 1, wherein deflecting comprises generating control signals and controlling a signal generator in response to the control signals to generate one on more frequencies corresponding with locations in the distribution pattern.

11. The method of claim 7, wherein the electromechanical scanner provides a linear scan with a stage driven apparatus.

12. The method of claim 11, wherein the electromechanical scanner comprises a deflection mirror and stage driven apparatus, wherein the deflection mirror provides stage motion compensation.

13. The method of claim 11, wherein the deflector provides fast jumps to thereby increase the effective linear scan rate.

14. The method of claim 1, further comprising orienting the distribution pattern into a selected orientation.

15. The method of claim 1, further comprising irradiating for a second time elements previously irradiated by a first laser beam.

16. The method of claim 1, further comprising determining a sequence of non-adjacent cuts based on an advantageous thermal management.

17. The method of claim 1, further comprising focusing multiple beams with a common scan lens.

18. The method of claim 1, wherein the elements are resistors.

19. The method of claim 1, wherein the elements are links.

4. A method of reducing a number of passes across a substrate in a laser micro-machining sequence of precisely cutting selected substantially identical conductive circuit elements in an array of such elements arranged in at least one of one or more rows and one or more columns on the substrate, the cutting selectively removing material from the selected elements, the method comprising:

forming a programmable distribution of multiple spots in a spot array, and

moving the spot array along a row or column to scan at least a portion of the substrate, and

processing conductive elements of the array by selective irradiation with the programmable distribution;

wherein forming a programmable distribution pattern comprises sequentially deflecting one or more beams to elements in multiple rows in first and second directions with a programmable acousto-optic deflector to jump across gaps between elements in a programmed sequence, whereby multiple rows are processed in a single pass and wherein a moving speed is increased by superimposing acousto-optic deflection and substrate scanning.

5. A method of precisely processing selected substantially identical conductive circuit elements in an array of such elements arranged in multiple rows and one or more columns on a substrate, the processing selectively removing material from the selected circuit elements, the method comprising:

moving the substrate along a row of conductive circuit elements;

generating at least one pulsed laser output beam; and

substantially irradiating sequentially with the pulsed laser output beam the selected substantially identical conductive circuit elements, the step of irradiating comprising;

deflecting and focusing the pulsed laser output beam to each of a plurality of selected elements of the array in a sequence to produce a distribution pattern of multiple focused beams to each of a plurality of selected elements of the array, the plurality of selected elements distributed along the multiple rows of the array, the step of deflecting comprising deflecting in 2 axes, thereby providing fast jumps across gaps between elements relative to the moving substrate;

wherein the steps of deflecting and focusing are carried out, at least in part, with at least one solid-state deflector and an objective lens and wherein at least one focused beam impinges each selected circuit element, and wherein the at least one laser pulse selectively and accurately cuts each selected circuit element.

6. The method of claim 5, wherein the distribution pattern is a programmable spot distribution comprising a multiple spots in a spot array, the programmable distribution formed with a programmable acousto-optic deflector, the distribution pattern comprising a sequence of deflections, the sequence including jumps across gaps between elements in a programmed sequence, whereby multiple rows are processed in a single pass and wherein a moving speed is increased by superimposing acousto-optic deflection and substrate scanning.