Browse Prior Art Database

Probe for Circuit Module

IP.com Disclosure Number: IPCOM000089133D
Original Publication Date: 1977-Sep-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Loeffel, EG: AUTHOR [+2]

Abstract

The probe of Fig. 1 makes contact with pads 2 and 3 on a substrate 4 of a circuit module. This probe is adapted to compensate for variations that occur in the height of the surface of the pads that are to be probed.

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Probe for Circuit Module

The probe of Fig. 1 makes contact with pads 2 and 3 on a substrate 4 of a circuit module. This probe is adapted to compensate for variations that occur in the height of the surface of the pads that are to be probed.

Coaxial cables 5 are mounted in a printed-circuit board 6, with their center conductors 7 extending below the lower surface of board 6. Thus the ground conductors for the probe are located very close to the points to be probed, and each conductor 7 is shielded from other conductors of the probe and from other sources of electrical noise.

An elastic film 8 carries conductive interposers 9 and 10. Each of the interposers makes contact between a center conductor 7 of a coaxial cable and a pad that is to be probed. Because the interposers are mounted in the elastic layer at a slight angle to the board, they easily flex to accommodate irregularities in the height of the pads that are to be probed.

Fig. 2 shows a manufacturing method for this probe. A copper foil 11 is etched to a depth of about .0005 inch using the mask for the circuit that is to be probed. The etched area is then gold plated to form a layer 12. This gold plating will later form an etch resist for removing the copper foil from the completed probe, and it will form an oxide free contact surface for the interposer. Next, a photoresist is applied, and a thin layer 13 of copper is plated over the gold-plated etched region. The photoresist is removed, and a new layer of...