Method of making reference surface markings on semiconductor wafers by laser beam

• US 4,522,656 A
• Filed: 04/26/1984
• Issued: 06/11/1985
• Est. Priority Date: 07/07/1983
• Status: Expired due to Term

• Current Assignee: Lumonics Limited
• Original Assignee: Wacker-Chemitronic Gesellschaft Fur Elektronik-Grundstoffe MbH
• Inventors: Gerber, Hans-Adolf, Kuhn-Kuhnenfeld, Franz, Kramler, Josef
• Primary Examiner(s): Roy, Upendra
• Application Number:
  US06/604,301
• Time in Patent Office: 411 Days
• Field of Search: 148/1.5, 148/187, 29/574, 29/576 T, 427/53.1, 156/644
• US Class Current: 219/121.66
• CPC Class Codes: B41M 5/24 Ablative recording, e.g. by burning marks; Spark recording marking by high energetic means, e.g. by laser otherwise than burning or ablative removal B41M5/26; materials or methods for recording or reproduction by optical means G11B7/00
• CPC Class Codes: B44C 1/02 Pyrography
• CPC Class Codes: H01L 21/268 using electromagnetic radiation, e.g. laser radiation
• CPC Class Codes: H01L 2223/54406 comprising alphanumeric information
• CPC Class Codes: H01L 2223/54493 Peripheral marks on wafers, e.g. orientation flats, notches, lot number
• CPC Class Codes: H01L 23/544 Marks applied to semiconductor devices or parts, e.g. registration marks, alignment structures, wafer maps test patterns for characterising or monitoring manufacturing processes H01L22/00
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: Y10S 438/94 Laser ablative material removal

Abstract

A method for producing contrast rich, permanent and slag-free characterizations, particularly on polished semiconductor disks is described, in which the surface for generating the surface pattern is partially melted by laser radiation. According to the invention, a surface segment corresponding to 1.5 to 6.5 times the surface area of the desired surface pattern is irradiated, and the semiconductor material is caused to melt and partially vaporize only in the center thereof.

Claims

1. In a method for the characterization of semiconductor surfaces by means of surface patterns, which are each generated by melting and partial vaporization of a surface segment by means of a laser pulse, the improvement comprising the steps of:

irradiating by means of a laser pulse a surface segment of the semiconductor surface whose surface area corresponds to 1.5 to 6.5 times the surface area of the desired surface pattern; and

adjusting the energy of the laser pulse so that melting and partial vaporization of the semiconductor material takes place only in the center of said surface segment on a surface of the semiconductor material corresponding to the desired surface pattern.

2. The method of claim 1, wherein the irradiated semiconductor surfaces having an average roughness value, according to DIN 4768, of at most 0.4 μ

m.

3. The method of claim 1 wherein said irradiating and adjusting steps result in the generation of circular recesses as said surface patterns having a diameter ranging from 50 to 150 μ

m.

4. The method of claim 1, wherein said circular recesses each have, relative to the original semiconductor surface, a raised annular rim and a recessed center.

5. The method of claim 1, wherein said surface segment of said semiconductor material is melted and partially vaporized to a depth of from 1 to 5 μ

m.