Browse Prior Art Database

Split Probing Pads

IP.com Disclosure Number: IPCOM000077656D
Original Publication Date: 1972-Sep-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 63K

Publishing Venue

IBM

Related People

Baker, T: AUTHOR [+5]

Abstract

The kerf area on semiconductor chips normally contains several test patterns, for example, dumbbell resistances, base sheet resistance, epitaxial resistance, and isolation and epitaxial contacts. These test patterns are designed so that they can be probed and electrically measured during manufacturing for process control purposes. In the past all previous test patterns are probable only after a contact etch step, i.e., after all diffusions had been completed. The present structure allows additional in-line process measurements of the base sheet resistance, before emitter diffusion, and epitaxial resistivity measurement before base and emitter diffusions.

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Split Probing Pads

The kerf area on semiconductor chips normally contains several test patterns, for example, dumbbell resistances, base sheet resistance, epitaxial resistance, and isolation and epitaxial contacts. These test patterns are designed so that they can be probed and electrically measured during manufacturing for process control purposes. In the past all previous test patterns are probable only after a contact etch step, i.e., after all diffusions had been completed. The present structure allows additional in-line process measurements of the base sheet resistance, before emitter diffusion, and epitaxial resistivity measurement before base and emitter diffusions.

In Fig. 1, the structure comprises a P- monolithic substrate 10 over which an N type epitaxial layer 12 has been deposited. Region 14 represents a diffused P+ isolation region. A silicon dioxide passivation layer 16 is formed over the upper epitaxial layer 12 and a large contact opening 18 is formed therethrough in a conventional manner.

After a P type diffusion, a P diffused region 20 is formed in the region 14, Fig.
2. Then a N type diffusion forms N diffused region 22, Fig. 3. During processing the region 20 is covered by a thinly grown portion 24, and similarly during later processing the N type region 22 is covered by a thinly grown silicon dioxide region 26. In this manner, measurements can be made after introducing spurious diffusions by splitting the pads into two halves, P type region...