Method and apparatus for indelibly marking articles during a manufacturing process

• US 4,255,851 A
• Filed: 12/06/1978
• Issued: 03/17/1981
• Est. Priority Date: 12/06/1978
• Status: Expired due to Term

• Current Assignee: AT&T Technologies Inc (Nokia Corporation)
• Original Assignee: Western Electric Co., Inc. (Nokia Corporation)
• Inventors: Fortuna, Joseph J.
• Primary Examiner(s): Larson, Lowell A.
• Application Number:
  US05/967,175
• Time in Patent Office: 832 Days
• Field of Search: 29/593, 29/626, 29/740, 29/827, 228/103, 219/68, 219/69 G, 219/383, 219/384
• US Class Current: 29/827
• CPC Class Codes: H01L 21/67282 Marking devices
• 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 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: Y10T 29/49004 including measuring or testing of device or component part
• CPC Class Codes: Y10T 29/49121 Beam lead frame or beam lead device
• CPC Class Codes: Y10T 29/53178 Chip component

Abstract

An indelible mark (26) is produced on an article of manufacture (17) for indicating a defective article. In the preferred embodiment a bonded lead frame assembly (17) which has a lead frame site (14, 15) with a semiconductor die (18) and cracked ceramic substrate (20) bonded thereto is indelibly marked by causing a spark to occur from an electrode (25) to the bonded lead frame assembly (17) in the vicinity of the lead frame site (14, 15) having a cracked substrate (20).

Claims

1. A method of indicating a defective site in a lead frame assembly having a plurality of components bonded thereto comprising the steps of:

(a) positioning a portion of the lead frame assembly which will be discarded in a later manufacturing process and which is in the region of the defective component into a spaced relationship with a charged spark electrode; and

(b) producing a spark between said electrode and the lead frame assembly for marking said portion of the lead frame.

2. A method as set forth in claim 1, wherein said spark produces an oxidation in the lead frame.

3. A method as set forth in claim 2, wherein said lead frame material comprises copper with an oxidizable coating thereon.

4. A method as set forth in claim 1, wherein said spark produces an indelible mark.

5. An automated assembly method for bonding ceramic substrates having semiconductor die attached thereto to a lead frame assembly and inspection of the bonded devices comprising the steps of:

(a) aligning a ceramic substrate with one of a plurality of lead frame sites of a lead frame assembly in a bonding machine;

(b) bonding the ceramic substrate to said one of a plurality of lead frame sites;

(c) ultrasonically testing the ceramic substrates for the occurrence of cracks in the ceramic during said bonding process;

(d) automatically storing said occurrence of said cracks for later marking of defective substrates;

(e) advancing the lead frame assembly into proximity with a lead frame marking electrode; and

(f) automatically discharging a spark from said electrode to a portion of the lead frame assembly in the vicinity of a lead frame site having a semiconductor die with a defective substrate attached thereto for indicating that a bonded semiconductor die has a defective substrate, said portion lying in a region of the lead frame assembly which will be discarded in a later manufacturing process.

6. The improvement as recited in claim 5, wherein the lead frame comprises nickel plated copper.