Method of making circuit boards
First Claim
1. A method for making a laminated circuit board having at least one access hole through which electrical contact to conductive traces may be made, comprising the steps of:
- (a) punching at least one access hole in a first coverfilm;
(b) applying an adhesive system to a side of the first coverfilm;
(c) laminating a copper sheet having a tin coating on one side to the adhesive-coated side of the first coverfilm, wherein the tin coated side of the copper sheet and the adhesive-coated side of the first coverfilm adhere to one another, thereby forming a laminate having a copper side and a first coverfilm side;
(d) applying a protective coating over the copper side of the laminate in a pattern corresponding to a circuit, thereby leaving copper to be removed from the laminate exposed;
(e) removing the exposed copper, thereby exposing the tin coating under the removed copper, and wherein the protected copper remains adhered to the first coverfilm; and
(f) stripping the exposed tin coating.
2 Assignments
0 Petitions
Accused Products
Abstract
A method of making circuit boards is disclosed that is suitable for use in a high-volume automated processing plant. The method can be used to produce either single-sided or double-sided circuit boards with access windows allowing electrical access and connection between traces from both sides. In the process, access holes are punched in a coverfilm. A copper sheet having a tin plating on one side is laminated to the coverfilm, with the tin side facing the coverfilm. A pattern representing a circuit is screened on the resulting laminate with a UV-curable resist, developed in a UV dryer, and then the unprotected copper is etched away. The remaining tin is then removed with solder stripping agent, and the resulting circuit is protected with a coverfilm. The process can be applied to large rolls of materials in an automated process, with large numbers of circuits applied to the laminated board. The circuits can then be punched out of the web with a hydraulic press in large numbers. The use of two copper sheets and double-sided covering (i.e., having adhesive on both sides) in a slightly modified process permits the efficient manufacture of double-sided circuit boards.
66 Citations
30 Claims
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1. A method for making a laminated circuit board having at least one access hole through which electrical contact to conductive traces may be made, comprising the steps of:
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(a) punching at least one access hole in a first coverfilm; (b) applying an adhesive system to a side of the first coverfilm; (c) laminating a copper sheet having a tin coating on one side to the adhesive-coated side of the first coverfilm, wherein the tin coated side of the copper sheet and the adhesive-coated side of the first coverfilm adhere to one another, thereby forming a laminate having a copper side and a first coverfilm side; (d) applying a protective coating over the copper side of the laminate in a pattern corresponding to a circuit, thereby leaving copper to be removed from the laminate exposed; (e) removing the exposed copper, thereby exposing the tin coating under the removed copper, and wherein the protected copper remains adhered to the first coverfilm; and (f) stripping the exposed tin coating. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for making a double-sided circuit board having top side access comprising the steps of:
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(a) punching at least one access hole in a first coverfilm; (b) applying an adhesive system to a first and a second side of the coverfilm; (c) laminating a first copper sheet having a tin coating on one side to the first side of the coverfilm, the tin coating facing the first side of the coverfilm; (d) laminating a second copper sheet to the second side of the coverfilm; (e) applying a first protective coating over the first copper side of the resulting laminate in a first pattern corresponding to a first portion of a circuit, thereby dividing the surface into at least a first region of protected copper and at least a first region of exposed copper, wherein the at least a first region of exposed copper is to be removed; (f) applying a second protective coating over the second copper side of the laminate in a second pattern corresponding to a second portion of a circuit, thereby dividing the surface into at least a second region of protected copper and at least a second region of exposed copper, wherein the at least a second region of exposed copper is to be removed; (g) removing the at least a first region and the at least a second region of exposed copper, thereby exposing the tin coating under the first copper sheet where the at least a first region was removed, and leaving the at least a first region and the at least a second region of protected copper adhered to the laminate; and (h) stripping the exposed tin coating. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification