EP0212219A2
Expired / Lapsed
EP
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Visibility enhancement of first order alignment marks
Assignee: International Business Machines Corp
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Filing: 1986-07-11
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Granted: —
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Expires: 2006-07-11
Abstract
Abstract A method of enhancing first order alignment marks (AM1) formed in the respective layers (12) of a processed semiconductor wafer in which critical masking steps are carried out. After a given mark is formed, it is tested for visual contrast. If the contrast is insufficient to provide adequate alignment, a block mask (BM) is formed on the critical mask. The block mask exposes all of the alignment target areas and protects the product regions of the wafer, and the critical mask only exposes the mark to be enhanced. The mark is then etched for a time period which is a function of the measured visual contrast.
Inventors
- 👤 Donald George Chesebro
- 👤 Robert Wayne Sweetser
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 23:51
CPC Classifications
H; H10; H10W; H10W46/00; H10W46/501; Y; Y10; Y10S; Y10S438/00; Y10S438/975
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
55 words
A method of enhancing the first order alignment between the layers of a semiconductor product, comprising the steps of: forming first-order alignment marks (AM1, AM2) in each layer (12, 14) with a critical masking step, testing the first-order alignment marks for visual contrast, selectively enhancing the visibility of selected ones of the first-order alignment marks.
Claim 2
Independent Claim
55 words
A method of enhancing the first order alignment between the layers of a semiconductor product, comprising the steps of: forming first-order alignment marks (AM1, AM2) in each layer (12, 14) with a critical masking step, testing the first-order alignment marks for visual contrast, selectively enhancing the visibility of selected ones of the first-order alignment marks.
Claim 3
Dependent Claim
21 words
The method of claim 1, wherein the step of selectively enhancing is carried out by etching through a block mask (BM).
Claim 4
Dependent Claim
22 words
The method of claim 2, wherein the block mask contains openings for each of the first-order alignment marks of a corresponding layer.
Claim 5
Independent Claim
30 words
The method of one of the claims 1 - 3, wherein the first-order alignment marks are formed through a critical mask (PR1) in a defined region of the semi-conductor product.
Claim 6
Dependent Claim
29 words
The method of claim 4, wherein the block mask overlaps the critical mask, and wherein the block mask and the critical mask are both removed in a single step.
Claim 7
Dependent Claim
22 words
The method of claim 5, wherein the openings of the block mask are wider than the corresponding openings of the critical mask.
Claim 8
Independent Claim
31 words
The method of one of the claims 1 - 6, wherein the step of selectively enhancing is carried out by etching as a function of the test step for visual contrast.
Claim 9
Dependent Claim
21 words
The method of claim 7, wherein the step of selectively enhancing is a reactive ion etch in a carbon tetrafluoride atmosphere.
References Cited (Backward Citations)
No citation records indexed.
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