Method of seating connector terminals on circuit board contact pads

• US 4,303,291 A
• Filed: 11/24/1980
• Issued: 12/01/1981
• Est. Priority Date: 11/24/1980
• Status: Expired due to Term

• Current Assignee: AT&T, Inc.
• Original Assignee: Western Electric Co., Inc. (Nokia Corporation)
• Inventors: Dines, David R.
• Primary Examiner(s): Welsh, John D.
• Application Number:
  US06/210,073
• Time in Patent Office: 372 Days
• Field of Search: 430/311, 430/312, 430/317, 430/319, 339/17 R, 339/17 A, 339/17 C, 339/17 CF, 339/17 E, 339/17 LM, 174/68.5, 427/96
• US Class Current: 29/843
• CPC Class Codes: H05K 1/117 Pads along the edge of rigid circuit boards, e.g. for pluggable connectors
• CPC Class Codes: H05K 2203/167 Using mechanical means for positioning, alignment or registration, e.g. using rod-in-hole alignment
• CPC Class Codes: H05K 3/28 Applying non-metallic protective coatings H05K3/0091 takes precedence; methods for intermediate insulating layers for build-up multilayer circuits H05K3/4673
• CPC Class Codes: H05K 3/325 by abutting or pinching, i.e. without alloying process; mechanical auxiliary parts therefor adaptations of leads inserted in holes for press-fit connections H05K3/308
• CPC Class Codes: H05K 3/3405 Edge mounted components, e.g. terminals
• CPC Class Codes: H05K 3/3452 Solder masks
• CPC Class Codes: Y10S 439/951 PCB having detailed leading edge
• CPC Class Codes: Y10T 29/4913 Assembling to base an electrical component, e.g., capacitor, etc.
• CPC Class Codes: Y10T 29/49133 with component orienting
• CPC Class Codes: Y10T 29/49149 by metal fusion bonding

Abstract

A protective coating (13) on a printed circuit board (10) is formed to extend into spaces (22) between spaced contact pads (16) adhered along an edge portion of the board. The protective coating is selected to be thicker than the thickness of the contact pads to provide fillets between the contact pads that function to form pockets (33) with the contact pads (16) being at the bottom of the pockets. When a multi-terminal connector (21) is assembled on the edge of the circuit board, the terminals (18) tend to fall into and seat within the pockets.

Claims

1. A method of forming seats on a printed wiring board to receive terminals extending from a connector, which comprises:

forming a series of parallel contact pads along one edge section of one surface of printed wiring board, and

applying an insulating layer over said one surface with sections of said layer extending as fillets between said contact pads, said fillets being thicker than the thickness of said contact pads to form recessed seats to receive the terminals.

2. A method of fabricating a printed circuit board, which comprises:

forming a circuit board with circuits running to contact paths extending in spaced relation along one marginal edge of the board;

placing a photosensitive layer of insulating material over the contacts and the spaces therebetween, and said layer being at least as thick as the height of the contact pads; and

p1 developing the photosensitive layer to form insulating fillets in the spaces between the contact pads, the heights of which are at least equal to the heights of the contact pads.

3. A method as defined in claim 2, wherein the step of forming the circuit board includes forming spaced contact pads on both the top and bottom marginal edges of the board;

and

photosensitive layers are placed over both top and bottom contact pads to provide fillets between both top and bottom contact pads.

4. A method as defined in claim 2, wherein the photosensitive layers completely overlie and extend beyond the contact pads, and the photosensitive layer is developed to form insulating fillets about all sides of the contact pads to provide pockets having the exposed contact pads seated at the bottom of the pockets.

7. A method as defined in claim 2, wherein the photosensitive layer is extended to project beyond the contact pads, and the fillets are formed to completely surround the contact pads to form pockets around the contact pads.

5. A method of fabricating a printed circuit board, which comprises:

forming a printed circuit board with circuit paths running to contact pads spaced along a marginal surface of the board;

placing a photosensitive layer of insulating material over the board to overlie the contact pads;

placing a mask over the photosensitive layer with dark spots overlaying the contact pads;

subjecting the photosensitive layer to light to develop and set the portions of layer overlaying the spaces between the contact pads; and

removing the undeveloped portions of the photosensitive layers to form fillets of insulating material in the spaces between the contact layers.

6. A method as defined in claim 5, wherein the photosensitive layer is thicker than the height of the contact pads, and the fillets form seats about the contact pads.

8. A method of aligning terminals projecting from a connector with like spaced contact pads arrayed in parallel along the edge of a circuit board, which comprises:

depositing a photoresist layer over the contact pads and the spaces between the pads, said layer being thicker than the thickness of the pads;

placing a mask over the contact pads leaving exposed the portions of the layer of photoresist overlaying the spaces between the contact pads;

subjecting the exposed portions of the photoresist to light to set the photoresist; and

removing the mask and the unexposed photoresist to leave fillets having heights greater than the heights of the contact pads so that upon assembly of the connector with the circuit board, the terminals tend to fall into the grooves between the fillets and onto the contact pads.

9. A method as set forth in claim 8, wherein the contact pads are coated with a layer of solder and the solder is heated and reflowed within the seat to secure the terminals to the contact pads.