# US 5,702,868 A · High resolution mask programmable via selected by low resolution photomasking

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 5,702,868 A
- Document ID: US5702868A
- Status: Granted
- Kind: A
- Application number: 08/437,222
- Filed: 1995-05-08
- Granted: 1997-12-30
- Earliest claimed: 1993-04-13
- Assignees: Astarix Inc.
- Inventors: Mark D. Kellam; Gershon Kedem
- Web page: https://patentgrep.com/patent/US5702868A

## CPC

- G03F 7/70283: {Mask effects on the imaging process}
- G03F 7/2022: {Multi-step exposure, e.g. hybrid; backside exposure; blanket exposure, e.g. for image reversal; edge exposure, e.g. for edge bead removal; corrective exposure}
- G03F 7/70466: {Multiple exposures, e.g. combination of fine and coarse exposures, double patterning or multiple exposures for printing a single feature (stitching G03F7/70475)}
- H10P 50/73: {using masks for insulating materials}
- H10P 76/204: {of organic photoresist masks}
- H10P 95/08: {Planarisation of organic insulating materials}
- H10W 20/089: {using processes for implementing desired shapes or dispositions of the openings, e.g. double patterning}
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A photoresist (18) is exposed through a design-independent high resolution reticle (20), producing a high resolution image of exposed resist (18A). Photoresist (18) is exposed for the second time through a design-specific low-resolution reticle (24), exposing selected portions (18D) of previously unexposed resist. The remaining portions (18B) of previously unexposed resist form a design-dependent high resolution image. After development of photoresist (18), its unexposed portions (18B) are removed, producing openings (26) in photoresist (18), that can be transferred to underlying material (36), for example by etching openings in that underlying material (36), thereby transferring the design-dependent high-resolution image to it. Since the design-independent high resolution reticle (20) can be prefabricated ahead of time and used to produce many designs with different functions, the above double-exposure method is suitable for fabricating design-specific high resolution features, e.g., contacts (vias) between conducting layers, within time and at the approximate cost required to fabricate and process a low resolution image. Several variants of the basic method are possible.

## Claims

### Claim 1

A double exposure method for fabricating a selected set of structures on a substrate, said method comprising the steps of:
providing said substrate with a radiation sensitive material disposed on said substrate;
transmitting a first radiation pattern representing a plurality of first substantially identical patterns towards said substrate for exposing first areas of said radiation sensitive material to said first radiation pattern to form a plurality of first substantially identical patterns in said radiation sensitive material;
transmitting a second radiation pattern representing a second plurality of patterns towards said substrate for exposing at least one but not all of said first areas of said radiation sensitive material to said second plurality of patterns to select at least one but not all of said formed plurality of first substantially identical patterns in said radiation sensitive material;
removing portions of said radiation sensitive material in accordance with said first and second radiation patterns; and
forming said selected set of structures in said substrate through said removed portions of said radiation sensitive material.

### Claim 2 (depends on 1)

A method in accordance with claim 1, wherein said radiation sensitive material comprises a negative acting photoresist material.

### Claim 3 (depends on 1)

A method in accordance with claim 1, wherein said first and second radiation is optical radiation.

### Claim 4 (depends on 1)

A method in accordance with claim 1, wherein each of said selected set of structures comprises a via.