Browse Prior Art Database

SLOTTED WELL EPOXY BUILD BLOCK

IP.com Disclosure Number: IPCOM000007963D
Original Publication Date: 1997-Mar-01
Included in the Prior Art Database: 2002-May-08
Document File: 4 page(s) / 203K

Publishing Venue

Motorola

Related People

Long Lam: AUTHOR [+2]

Abstract

In semiconductor device final probe operation, either blade or epoxy ring probe cards are used to make electrical connection between the tester instruments and the die. In high pins count and high frequency application, epoxy ring probe card is usu- ally used. Because of the existing problems with the conventional epoxy build block, the Slotted Well Epoxy Build Block is designed to improve probe card quality and reduce production cycle time.

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MO-LA Technical Developments

SLOnED WELL EPOXY BUILD BLOCK

by Long Lam and Caroline Dupuis

I. ABSTRACT

  In semiconductor device final probe operation, either blade or epoxy ring probe cards are used to make electrical connection between the tester instruments and the die. In high pins count and high frequency application, epoxy ring probe card is usu- ally used. Because of the existing problems with the conventional epoxy build block, the Slotted Well Epoxy Build Block is designed to improve probe card quality and reduce production cycle time.

II. STATEMENT OF THE PROBLEMS

  The epoxy ring probe card contains the printed circuit board which has all electrical components and the epoxy ring are mounted underneath the board. The epoxy ring holds all probes in place and probes are soldered to the probe runs on the probe card.

  Figure 1 shows all parts of the conventional epoxy ring building block. The block contains one trace ring collar, one ring drop collar, one ring drop insert, one ring drop base and six screws. Before the ring is built, the block needs to be setup. First, the ring drop insert is inserted into the ring drop base and secured by two screws. Then, the x-y coordi- nates of the probe pads of the die are punched on a

mylar. The mylar is glued on top of the ring drop insert. Next, the ring drop collar is placed on top of the ring drop base with the ring drop insert sits inside the ring drop collar. Finally, the trace ring collar is placed on top the block. Now, the block is setup and the ring is ready to be built.

  A 0.004 inch diameter wire is placed just behind the row of holes in the mylar. Probes are placed in the row of holes in the mylar and pushed down until they touch the wire. This process is repeated until all rows of holes are tilled with probes. Probes are then aligned to the traces on the trace ring collar

and secured with a small amount of cement and all the wires are removed. Epoxy is then applied to the probes around the ring drop collar. The anodized aluminum ring is then dropped on the epoxy to hold all probes together with the epoxy in between.

There are three major problems with the con- ventional epoxy ring building block:

1. EPOXY SQUEEZE OUT ON BOTH SIDES OF THE RING

  One of the requirements of the epoxy ring is epoxy must completely cover the ring surface in order to provide sufficient integrity of the probes attachment. It is hard to control the exact dispensed amount of epoxy every time and therefore normally too much epoxy is applied and squeezed out on both sides of the ring. Uneven epoxy creates uneven applied force (gram/mil square) among the probes since the amount of epoxy on each probe is signifi- cantly different. The second effect of uneven epoxy is difficulty of mounting the ring to probe cards.

2. UNEVEN EPOXY THICKNESS THROUGHOUT THE RING SURFACE

  The surface of the epoxy ring must be even and lower than the length of the probe tips. Uneven thickness of epoxy can scratch wafers during prob-...