US4176602A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dry film screen stencil and method of making
Assignee: Hughes Missile Systems Co
•
Filing: 1977-06-10
•
Granted: 1979-12-04
•
Expires: 1997-06-10
Abstract
Abstract A method of making a relatively thick dry film stencil for uses such as depositing solder paste through a screen chase. A stencil consisting of four mil thick dry film photoresist is formed by passing the photoresist layers through a roller and laminating them onto a support screen. The outer protective film coatings are removed and the film photoresist developed. It is then placed in a chase with the developed film face on the bottom. The solder paste is then squeegeed through the screen and deposited on a desired part. An alternate method of making the stencil uses two layers of dry film photoresist laminated together with the protective film coating removed. The stencil is cut to the size needed and exposed. Using a hydraulic press, the stencil is then connected to a screen in a chase by applying a pressure of 250 psi at 300° F. for 10 seconds.
Inventors
- 👤 Phyllis A. Feddersen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 16:33
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/10; H05K3/12; H05K3/1216; H05K3/1225; G; G03; G03F; G03F7/00; G03F7/12
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
78 words
A method of making a dry film stencil comprising the steps of: selecting an open mesh support screen selecting and laminating a facing layer and a backing layer of dry film photoresist together through and from opposite sides of said screen by applying pressure thereto for forming a film laminate, exposing the film laminate through a transparency for forming an exposed film, and p1 developing the film for thereby forming a screen stencil of the developed film laminate.
Claim 2
Independent Claim
78 words
A method of making a dry film stencil comprising the steps of: selecting an open mesh support screen selecting and laminating a facing layer and a backing layer of dry film photoresist together through and from opposite sides of said screen by applying pressure thereto for forming a film laminate, exposing the film laminate through a transparency for forming an exposed film, and p1 developing the film for thereby forming a screen stencil of the developed film laminate.
Claim 3
Dependent Claim
27 words
The method of claim 1 including the step of selecting said backing layer to have a thickness at least equal to the thickness of said support screen.
Claim 4
Dependent Claim
33 words
The method of claim 1 wherein the step of selecting said facing layer includes selecting a layer of film equal to the desired thickness of the material to be deposited through said stencil.
Claim 5
Dependent Claim
29 words
The method of claim 1 wherein the step of laminating said layers of photoresist together includes the step of applying heat simultaneously with the step of applying pressure thereto.
Claim 6
Dependent Claim
32 words
The method of claim 1 including the step of laminating at least a second layer of dry film photoresist to said facing layer for obtaining a desired thickness of said screen stencil.
Claim 7
Dependent Claim
25 words
The method of claim 1 wherein said pressure is applied to said layers of dry film photoresist by means of a pair of opposed rollers.
Claim 8
Dependent Claim
15 words
The method of claim 6 including applying heat to said layers by heating said rollers.
Claim 9
Dependent Claim
20 words
The method of claim 7 wherein the step of selecting said layers includes selecting said layers to have different thicknesses.
Claim 10
Dependent Claim
21 words
The method of claim 8 including the step of laminating at least a second layer of photoresist to said facing layer.
Claim 11
Dependent Claim
19 words
The method of claim 9 wherein: the exposing step comprises exposing only the facing layer of the film laminate.
Claim 12
Dependent Claim
42 words
The method of claim 9 wherein: the facing layer and the backing layer are initially provided with protective backings, removing the protective backing from one side of each of the layers before laminating the layers of dry film photoresist to the screen.
Claim 13
Dependent Claim
18 words
The method of claim 9 including the step of: placing the exposed and developed laminate in a chase.
Claim 14
Independent Claim
88 words
A method of making a dry film stencil comprising the steps of: laminating two layers of dry film photoresist together to form a film laminate, exposing the film laminate through a transparency thereby forming an exposed film laminate, attaching the exposed film laminate to a screen by pressing the laminate onto the screen for a period of between 6 and 10 seconds at a pressure of approximately 250 psi and at a temperature of up to 300° F., developing the exposed film laminate to thereby form a stencil.
Claim 15
Independent Claim
88 words
A method of making a dry film stencil comprising the steps of: laminating two layers of dry film photoresist together to form a film laminate, exposing the film laminate through a transparency thereby forming an exposed film laminate, attaching the exposed film laminate to a screen by pressing the laminate onto the screen for a period of between 6 and 10 seconds at a pressure of approximately 250 psi and at a temperature of up to 300° F., developing the exposed film laminate to thereby form a stencil.
Claim 16
Dependent Claim
29 words
The method of claim 13 wherein: the layers of film are selected to have protective backings, and removing some of the protective backings after exposing the layers of film.
Claim 17
Dependent Claim
38 words
The method of claim 13 wherein the attaching step include first placing said screen in a chase; then assembling the laminate layers of film to the screen; and finally laminating said layers to said screen in said chase.
Claim 18
Dependent Claim
28 words
The method of claim 13 including the step of: depositing a fluid material on a surface by squeegeeing solder paste through the open areas defined by the stencil.
Claim 19
Dependent Claim
19 words
The method of claim 13 including: selecting each layer of film photoresist to have a thickness of two mils.
Claim 20
Dependent Claim
75 words
A film screen laminate for the production of screen stencils comprising: an open mesh support screen, a facing layer of dry film photoresist having a predetermined uniform thickness disposed on one side of said screen, and a backing layer of dry film photoresist disposed on the other side of said screen, portions of at least one of said layers extending through the open mesh of said screen and bonded to the other of said layers.
Claim 21
Dependent Claim
75 words
A film screen laminate for the production of screen stencils comprising: an open mesh support screen, a facing layer of dry film photoresist having a predetermined uniform thickness disposed on one side of said screen, and a backing layer of dry film photoresist disposed on the other side of said screen, portions of at least one of said layers extending through the open mesh of said screen and bonded to the other of said layers.
Claim 22
Dependent Claim
19 words
The film screen laminate of claim 18 wherein said facing layer and said backing layer are of different thicknesses.
Claim 23
Dependent Claim
22 words
The film screen laminate of claim 19 wherein said backing layer is at least as thick as the wire in said screen.
Claim 24
Dependent Claim
22 words
The film screen laminate of claim 18 including at least a second layer of dry film photoresist bonded to said facing layer.
Claim 25
Dependent Claim
13 words
the film screen laminate of claim 18 wherein said layers are fused together.
References Cited (Backward Citations)
US2969732A
Cited
US2949848A
Cited
US3100702A
Cited
US3376138A
Cited
US3676128A
Cited
US3526504A
Cited
US3507654A
Cited
US3532052A
Cited
US3469982A
Cited
DE2050285A1
Cited
US3853561A
Cited
US3836367A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-12-03 | 1983-06-04 | 1983-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-12-03 | 1987-06-04 | 1987-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-12-03 | 1991-06-04 | 1991-12-04 | $7700.00 | Window Closed / Lapsed |