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Method for Producing Gradually Tapered Openings in Multilayer Dielectrics

IP.com Disclosure Number: IPCOM000039132D
Original Publication Date: 1987-Apr-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Powell, DO: AUTHOR

Abstract

The construction of multilayer dielectrics with various openings sometimes results in steepwall profiles which can cause subsequent problems in production. This occurs with the use of photolithography to pattern circuitry on the dielectric layers because photoresist does not cover steep walls very well and often breaks down during etching, resulting in voids in the circuitry. These steep wall-related problems can be eliminated by constructing multilayer dielectrics with tapered openings by using successively smaller openings in the following manner. Fig. 1 shows a cross section of a conventionally constructed structure with all the layers having holes of the same size and shape. Fig. 2 is the representation of a tapered construction with the bottom layer 1 having the largest opening and layer 2 the next largest opening, etc.

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Method for Producing Gradually Tapered Openings in Multilayer Dielectrics

The construction of multilayer dielectrics with various openings sometimes results in steepwall profiles which can cause subsequent problems in production. This occurs with the use of photolithography to pattern circuitry on the dielectric layers because photoresist does not cover steep walls very well and often breaks down during etching, resulting in voids in the circuitry. These steep wall-related problems can be eliminated by constructing multilayer dielectrics with tapered openings by using successively smaller openings in the following manner. Fig. 1 shows a cross section of a conventionally constructed structure with all the layers having holes of the same size and shape. Fig. 2 is the representation of a tapered construction with the bottom layer 1 having the largest opening and layer 2 the next largest opening, etc. The advantage of this configuration is seen in Fig. 3 when a misregistration occurs and the layers are not in the normal alignment. Fig. 3 shows a steep wall situation in which the photolithography may not work well. In Fig. 4, a tapered hole which is constructed in an alternate fashion also experiences misregistration, but again the tapered effect prevents the photolithographic-related limitation of steep walls.

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