Multi-chip module with accessible test pads and test fixture

• US 6,094,056 A
• Filed: 03/05/1998
• Issued: 07/25/2000
• Est. Priority Date: 09/11/1996
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Eastman, Jed R., Bardsley, Thomas J.
• Primary Examiner(s): Nguyen, Vinh P.
• Application Number:
  US09/035,445
• Time in Patent Office: 873 Days
• Field of Search: 324/755, 324/765, 324/158.1, 324/761, 324/754, 439/482, 361/777, 361/774, 361/780, 174/260, 174/261
• US Class Current: 324/756.01
• CPC Class Codes: G01R 1/0408 Test fixtures or contact fields; Connectors or connecting adaptors; Test clips; Test sockets G01R1/067 takes precedence; mass production testing systems G01R31/59; testing of connections G01R31/66; for testing printed circuit boards G01R31/2808
• CPC Class Codes: G01R 31/2884 using dedicated test connectors, test elements or test circuits on the IC under test G01R31/2855 takes precedence
• CPC Class Codes: G01R 31/31712 Input or output aspects
• CPC Class Codes: G01R 31/31715 Testing of input or output circuits; test of circuitry between the I/C pins and the functional core, e.g. testing of input or output driver, receiver, buffer
• CPC Class Codes: G01R 31/318505 Test of Modular systems, e.g. Wafers, MCM's
• CPC Class Codes: G01R 31/318513 Test of Multi-Chip-Moduls
• CPC Class Codes: H01L 22/32 Additional lead-in metallisation on a device or substrate, e.g. additional pads or pad portions, lines in the scribe line, sacrificed conductors arrangements for conducting electric current to or from the solid state body in operation H01L23/48
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2924/15174 in different layers of the multilayer substrate
• CPC Class Codes: H01L 2924/15192 Resurf arrangement of the internal vias
• CPC Class Codes: H01L 2924/15312 being a pin array, e.g. PGA
• CPC Class Codes: H05K 7/1084 pin grid array package carriers

Abstract

A test fixture for use with an improved multi-chip-module wherein the multi-chip-module has a plurality of chips on the top surface, the module having at least one net associated with the chips completely embedded within the substrate and wherein at least one pad is attached to the bottom surface of the substrate and a conductive path provided between the pad and the net. The test fixture includes a zero-insertion-force socket having at least one socket pin having a surface for conductively contacting the pad on the multi-chip-module and extending through the socket and a circuit board having a plurality of inlets for conductively receiving the socket pins including the socket pin contacting the pad.

Claims

1. A fixture for use with a multi-chip module, the multi-chip module having a substrate having top and bottom surfaces, a plurality of chips on the substrate top surface, a plurality of pins attached to the substrate bottom surface, the pins being arranged in an array having a central portion devoid of pins, each chip having at least one lead extending through the substrate and conductively coupled to a corresponding pin, the module having at least one net associated with the chips that is completely embedded within the substrate, at least one pad attached to the bottom surface of the substrate, and a conductive path conductively coupled between the pad and the net, the fixture comprising:

a zero-insertion-force socket having a top surface for receiving the multi-chip-module, the socket top surface having an array of pin inlets for receiving the pins of the array attached to the substrate bottom surface, the socket top surface further comprising at least one pin having a surface for conductively contacting the pad on the substrate bottom surface, the socket bottom surface having a plurality of socket pins attached thereto, at least one socket pin being conductively coupled to the pad contacting surface pin and the remaining socket pins being conductively coupled to the pin inlets; and

a circuit board having a plurality of inlets for conductively receiving the socket pins.

2. The fixture as set forth in claim 1 wherein the socket pin conductively coupled to the pad contacting surface pin comprises a pogo-pin.