Laser cutting method

• US 8,108,998 B2
• Filed: 11/14/2005
• Issued: 02/07/2012
• Est. Priority Date: 11/26/2004
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Inada, Genji, Iri, Junichiro, Nishiwaki, Masayuki, Sugama, Sadayuki
• Primary Examiner(s): Heinrich, Samuel M
• Application Number:
  US11/273,730
• Publication Number:
  US 20060113287A1
• Time in Patent Office: 2,276 Days
• Field of Search: 21912167-12169, 219/121.72, 219/121.76, 219/121.77, 219/121.85, 438/460, 438/462, 438/463, 438/21, 298/901, 216/27, 257/E21.599
• US Class Current: 29/890.1
• CPC Class Codes: B23K 2101/40 Semiconductor devices
• CPC Class Codes: B23K 2103/50 Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
• 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 26/364 for making a groove or trench, e.g. for scribing a break initiation groove
• CPC Class Codes: B23K 26/38 by boring or cutting
• CPC Class Codes: B23K 26/40 taking account of the properties of the material involved
• CPC Class Codes: B23K 26/53 for modifying or reforming the material inside the workpiece, e.g. for producing break initiation cracks
• CPC Class Codes: Y10T 29/49401 Fluid pattern dispersing device making, e.g., ink jet

Abstract

At least one exemplary embodiment is directed to a laser cutting method where a laser beam is condensed at internal points inside a substrate forming processing regions, and where the laser is swept along a cutting line, where the cutting line is associated with a recess on the substrate and where the recess can be formed contemporaneously with the formation of the processing regions.

Claims

1. A method for splitting a workpiece on a wafer comprising:

irradiating a laser beam to the workpiece to form a recessed portion at a surface of the workpiece and condensing the laser beam at predetermined depth at a position away from the recessed portion in the workpiece to form an internal processing region including a condensing point having a depth;

splitting the workpiece by applying an external force to the workpiece to generate a crack along a first cutting line and second cutting line connecting the recessed portion with the internal processing region; and

applying etching to the wafer to form a supply port positioned beneath a nozzle layer, the nozzle layer being disposed between the first cutting line and the second cutting line.

2. The method according to claim 1, wherein the laser beam has a wavelength such that the laser beam passes through a laser beam receiving surface of the workpiece and enters the workpiece but does not exit from a back surface of the workpiece.

3. The method according to claim 1, wherein the predetermined depth is a condensing position of the laser beam that forms an internal processing region that is not connected via a crack to the recessed portion.

4. The method according to claim 1, wherein the internal processing region includes a plurality of processing regions formed inside the workpiece serially in a depth direction of the workpiece.

5. The method according to claim 1, wherein the internal region includes a plurality of processing regions formed inside the workpiece serially from a position a first predetermined distance from a front surface of the workpiece to a position a second predetermined distance to the front surface of the workpiece.

6. The method according to claim 1, further comprising:

applying a second external force to the workpiece to generate a crack connecting the recessed portion on the surface of the workpiece with the internal processing region, thereby substantially cutting the workpiece in a second direction, wherein the second direction intersects the first direction, and where the workpiece is separated into a number of subpieces, wherein a substantial number of subpieces are cut from the workpiece.

7. The method according to claim 6, wherein the first direction and the second direction are substantially orthogonal to each other.

8. The method according to claim 7, further comprising:

identifying subpieces not cut from the workpiece; and

applying a pressing force to the identified subpieces not cut from the workpiece, wherein the pressing force cuts the identified subpieces from the workpiece.

9. The method according to claim 7, wherein the external force and the second external force are applied to the surface of the workpiece opposite the surface having the recessed portion.

10. The method according to claim 1, wherein the workpiece is a silicon substrate of the wafer.