Descriptor for identifying a defective die site and methods of formation

• US 6,889,902 B2
• Filed: 06/12/2002
• Issued: 05/10/2005
• Est. Priority Date: 08/30/2000
• Status: Expired due to Term

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Rumsey, Brad D.
• Primary Examiner(s): Lee, Michael G.
• Assistant Examiner(s): Kim, Ahshik
• Application Number:
  US10/170,508
• Publication Number:
  US 20020148897A1
• Time in Patent Office: 1,063 Days
• Field of Search: 235/454, 235/492, 235/494, 235/449, 235/575, 235/792, 257431-435, 257/678, 702/35, 438 14- 17
• US Class Current: 235/454
• CPC Class Codes: H01L 21/67282 Marking devices
• CPC Class Codes: H01L 21/67288 Monitoring of warpage, curvature, damage, defects or the like
• CPC Class Codes: H01L 2223/5442 comprising non digital, non alphanumeric information, e.g. symbols
• CPC Class Codes: H01L 2223/54473 for use after dicing
• 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 24/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• 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 2924/12042 LASER
• CPC Class Codes: H01L 2924/14 Integrated circuits

Abstract

The present invention relates to the marking and identification of defective die sites on a mounting substrate. A mounting substrate is provided which is inspected and tested for visual and electrical defects. Information relating to the functionality and/or various defects of one or more die sites is then encoded in the form of a designator placed on the substrate. The information encoded on the designator may then be read or scanned by, for example, computer-driven video equipment and used in a die-attach process to discriminately place semiconductor dice only on known good die sites. Embodiments of the designator include information encoded in the form of a bar code, a series of identifying marks, a strip of magnetic tape or a computerized map of a mounting substrate. Correlated data regarding die site functionality can then be electronically transferred to a die-bonding apparatus.

Claims

1. A method of assembling a semiconductor package comprising:

providing a substrate having at least one semiconductor die site;

inspecting the at least one semiconductor die site for defects;

forming a descriptor having information relating to the at least one semiconductor die site wherein forming a descriptor is accomplished by one of a group consisting of encoding information in the form of a computerized map of the substrate and forming a magnetic strip on a surface of the substrate; and

selecting between attaching a semiconductor die to the at least one semiconductor die site and not attaching a semiconductor die to the at least one semiconductor die site, responsive to the descriptor.

2. The method according to claim 1, wherein selecting between attaching a semiconductor die to the at least one semiconductor die site and not attaching a semiconductor die to the at least one semiconductor die site comprises:

transferring data from the computerized map of the substrate to a die attach apparatus; and

operating the die attach apparatus responsive to the data.

3. The method according to claim 1, wherein selecting between attaching a semiconductor die to the at least one semiconductor die site and not attaching a semiconductor die to the at least one semiconductor die site comprises:

reading data from the descriptor; and

evaluating the data for information relating to at least one defect associated with the at least one semiconductor die site.

4. The method according to claim 1, wherein the descriptor consists of machine readable information on a surface of the substrate wherein the machine readable information is formed by one of the group consisting of screen printing, photo-lithography and chemical vapor deposition.

5. The method according to claim 4, wherein encoding machine readable information on a surface of the substrate comprises forming marks in the surface of the substrate with optical energy.

6. The method according to claim 5, further comprising:

forcing air over the substrate while forming marks in the surface of the substrate with optical energy.

7. The method according to claim 5, further comprising:

coating a least part of the surface of the substrate with a material resistant to releasing volatile materials prior to forming marks in the surface of the substrate with optical energy.

8. The method according to claim 5, wherein forming marks in the surface of the substrate with optical energy comprises forming marks to a microscopic depth in the surface of the substrate with a low-powered laser.

9. The method according to claim 4, wherein encoding machine readable information on the surface of the substrate comprises forming the machine readable information as at least one mark selected from the group consisting of alphanumeric characters, symbols, colors, binary sequences and combinations thereof.

10. The method according to claim 1, wherein the at least one semiconductor die site comprises a plurality of semiconductor die sites, and further comprising:

reading the descriptor for a semiconductor die site defect percentage; and

discarding the substrate if the defect percentage exceeds a threshold percentage.