Edge-plated well for circuit board components

• US 20030100197A1
• Filed: 08/13/2002
• Published: 05/29/2003
• Est. Priority Date: 11/26/2001
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Powerwave Technologies Incorporated
• Inventors: Veitschegger, William K., Sauer, Scott B.
• Granted Patent: US 6,818,477 B2
• Time in Patent Office: Days
• US Class Current: 439/55
• CPC Class Codes: H05K 1/0204 using means for thermal conduction connection in the thickness direction of the substrate H05K1/0207 takes precedence
• CPC Class Codes: H05K 1/021 Components thermally connected to metal substrates or heat-sinks by insert mounting
• CPC Class Codes: H05K 1/182 associated with components mounted in the printed circuit board, e.g. insert mounted components [IMC]
• CPC Class Codes: H05K 2201/09845 Stepped hole, via, edge, bump or conductor
• CPC Class Codes: H05K 2201/09981 Metallised walls
• CPC Class Codes: H05K 2201/10416 Metallic blocks or heatsinks completely inserted in a PCB
• CPC Class Codes: H05K 2203/0242 Cutting around hole, e.g. for disconnecting land or Plated Through-Hole [PTH] or for partly removing a PTH
• CPC Class Codes: H05K 2203/0415 Small preforms other than balls, e.g. discs, cylinders or pillars
• CPC Class Codes: H05K 2203/1476 Same or similar kind of process performed in phases, e.g. coarse patterning followed by fine patterning
• CPC Class Codes: H05K 3/0061 onto a metallic substrate, e.g. a heat sink heat sinks for electric apparatus H05K7/20
• CPC Class Codes: H05K 3/341 Surface mounted components
• CPC Class Codes: H05K 3/427 initial plating of through-holes in metal-clad substrates
• CPC Class Codes: H05K 3/429 Plated through-holes specially for multilayer circuits, e.g. having connections to inner circuit layers
• CPC Class Codes: Y10T 29/4913 Assembling to base an electrical component, e.g., capacitor, etc.
• CPC Class Codes: Y10T 29/49156 with selective destruction of conductive paths

Abstract

A printed circuit board (PCB) assembly comprising a PCB having a top circuitry layer and a bottom layer with a hole through the PCB, a component, and a pallet. The printed circuit board manufactured by a method including forming a hole through the top circuitry layer and the bottom layer, attaching the bottom layer to a pallet, placing the component in the hole, and soldering the component to the top circuitry layer and to the pallet.

Claims

1. A method of mounting a component to a multi-layer printed circuit board and a pallet, the multi-layer printed circuit board comprising a top circuitry layer, a bottom layer and a ground plane layer disposed between the top circuitry layer and the bottom layer, the method comprising:

forming a hole through the top circuitry layer, the ground plane layer and the bottom layer, thereby exposing a first edge of the top circuitry layer, a second edge of the ground plane layer and a third edge of the bottom layer;

plating a conductor inside the hole, thereby connecting the first edge, the second edge and the third edge with the conductor;

removing the plating from the first edge;

attaching the bottom layer to the pallet;

placing the component in the hole; and

soldering the component to the top circuitry layer.

2. The method of claim 1, wherein the soldering step comprises:

disposing a pre-formed piece of solder between the component and the pallet; and

heating the pre-formed piece of solder.

3. The method of claim 2, further comprises disposing a heat sink between the pre-formed piece of solder and the component before heating the pre-formed piece of solder.

4. The method of claim 1, wherein the soldering step comprises:

disposing a solder paste between the component and the top circuitry layer; and

heating the solder paste.

5. The method of claim 1, wherein the attaching step comprises attaching the bottom layer to the pallet with an adhesive layer.

6. The method of claim 5, wherein the adhesive layer is of an electrically insulating material.

7. The method of claim 5, wherein the adhesive layer comprises an epoxy.

8. The method of claim 5, wherein the adhesive layer is a resin-preimpregnated glass cloth.

9. The method of claim 1, wherein the removing step comprises a routing of the plating from the first edge.

10. A multi-layer printed circuit board comprising a top circuitry layer, a bottom layer and a ground plane layer disposed between the top circuitry layer and the bottom layer, the multi-layer printed circuit board manufactured by a method comprising:

forming a hole through the top circuitry layer, the ground plane layer and the bottom layer, thereby exposing a first edge of the top circuitry layer, a second edge of the ground plane layer and a third edge of the bottom layer;

plating a conductor inside the hole, thereby connecting the first edge, the second edge and the third edge with the conductor;

removing the plating from the first edge;

attaching the bottom layer to a pallet;

placing the component in the hole; and

soldering the component to the top circuitry layer.

11. A method of mounting a component to a printed circuit board and a pallet, the printed circuit board comprising a top circuitry layer and a bottom layer, the method comprising:

forming a hole through the top circuitry layer and the bottom layer, thereby exposing a first edge of the top circuitry layer and a second edge of the bottom layer;

plating a conductor inside the hole, thereby connecting the first edge and the second edge with the conductor;

removing the plating from the first edge;

attaching the bottom layer to the pallet;

placing the component in the hole; and

soldering the component to the top circuitry layer.

12. The method of claim 11, wherein the soldering step comprises:

disposing a pre-formed piece of solder between the component and the pallet; and

heating the pre-formed piece of solder.

13. The method of claim 12, further comprises disposing a heat sink between the pre-formed piece of solder and the component before heating the pre-formed piece of solder.

14. The method of claim 12, wherein the soldering step further comprises:

disposing a solder paste between the component and the top circuitry layer; and

heating the solder paste.

15. The method of claim 11, wherein the attaching step comprises attaching the bottom layer to the pallet with an adhesive layer.

16. The method of claim 15, wherein the adhesive layer is an insulating layer.

17. The method of claim 15, wherein the adhesive layer is an epoxy.

18. The method of claim 15, wherein the adhesive layer is a layer of resin-preimpregnated glass cloth.

19. The method of claim 11, wherein the removing step comprises the step of routing the plating from the first edge.

20. A printed circuit board comprising a top circuitry layer and a bottom layer, the printed circuit board manufactured by a method comprising:

forming a hole through the top circuitry layer and the bottom layer of a printed wiring board, thereby exposing a first edge of the top circuitry layer and a second edge of the bottom layer of the printed wiring board;

plating a conductor inside the hole, thereby coupling the first edge and the second edge of the printed wiring board with the conductor;

removing the plating from the first edge;

attaching the bottom layer of the printed wiring board to a pallet;

placing a component in the hole with solder between a flange of the component and the pallet attached to the bottom layer; and

soldering the component to the top circuitry layer and to the pallet.

21. The method of claim 20, in which soldering the component in which soldering is done with a reflow operation.

22. A method of mounting a component to a printed circuit board (PCB) and a pallet forming a PCB assembly, the printed circuit board including a top circuitry layer and a bottom layer, the method comprising:

forming a hole through the top circuitry layer and the bottom layer;

attaching the bottom layer to the pallet; and

soldering the component to the top circuitry layer.

23. The method of claim 22, wherein the soldering step comprises:

disposing a pre-formed piece of solder in the hole;

disposing a component in the hole; and

heating the PCB assembly.

24. The method of claim 23, wherein the heating step in a reflow solder operation.

25. The method of claim 23, wherein the heating step is an IR reflow operation.

26. The method of claim 22, wherein the soldering step comprises:

disposing a first solder paste area between a lead mounting area of the component and the top circuitry layer;

disposing a second solder paste area between a flange of the component and the pallet; and

heating the PCB assembly.

27. The method of claim 26, wherein the heating step is a reflow operation

28. The method of claim 22, wherein the attaching step comprises attaching the bottom layer of the PCB to the pallet with an adhesive layer.

29. The method of claim 28, wherein the adhesive layer is an electrically insulating material.

30. The method of claim 28, wherein the adhesive layer is an epoxy.

31. The method of claim 28, wherein the adhesive layer is a sheet of resin-preimpregnated glass cloth.

32. A printed circuit board comprising a top circuitry layer and a bottom layer, the printed circuit board manufactured by a method comprising:

forming a hole through the top circuitry layer and the bottom layer;

attaching the bottom layer to a pallet;

placing the component in the hole; and

soldering the component to the top circuitry layer.

33. A method of mounting a component to a multi-layer printed circuit board and a pallet to form a printed wiring board assembly (PWB assembly), the multi-layer printed circuit board (PCB) comprising a top circuitry layer, a bottom circuitry layer and a ground plane circuitry layer disposed between the top circuitry layer and the bottom circuitry layer each layer separated by a dielectric material, the method comprising:

forming a hole in the PCB extending through the top circuitry layer, the ground plane layer and the bottom layer of the PCB, thereby exposing a first edge of the top circuitry layer, a second edge of the ground plane layer and a third edge of the bottom layer;

plating a conductor inside the hole, thereby coupling the first edge, the second edge and the third edge with the conductor;

removing the plating from the first edge;

attaching the multi-layer printed circuit board to the pallet by disposing an adhesive layer between the bottom layer of the PCB and the pallet such that the pallet covers the hole in the PCB;

placing a piece of pre-formed solder inside the hole such that the piece of pre-formed solder makes contact with the pallet;

inserting a portion of the component that is to be coupled to the pallet into the hole; and

heating the multi-layer printed circuit board and the attached pallet.

34. A multi-layer printed circuit board (PCB) comprising a top circuitry layer, a bottom layer and a ground plane layer disposed between the top circuitry layer and the bottom layer, the multi-layer printed circuit board manufactured by a method comprising:

forming a hole in the PCB extending through the top circuitry layer, the ground plane layer and the bottom layer, thereby exposing a first edge of the top circuitry layer, a second edge of the ground plane layer and a third edge of the bottom layer;

plating a conductor inside the hole in the PCB, thereby coupling the first edge, the second edge and the third edge with the conductor;

removing the plating from the first edge;

disposing an adhesive layer on the pallet;

attaching the multi-layer printed circuit board to the pallet;

placing a piece of pre-formed solder inside the hole such that the piece of pre-formed solder makes contact with the pallet covering the hole;

inserting a portion of the component that is to be coupled to the pallet into the hole; and

heating the multi-layer printed circuit board and the attached pallet to melt those pre-formed solder, coupling the portion of the component to be coupled to the pallet, to the pallet.

35. The method of claim 34 in which the adhesive layer is disposed on the bottom layer.

36. A method of mounting a component to a multi-layer printed circuit board (PCB) and a pallet that forms a PCB assembly, the multi-layer printed circuit board comprising a top circuitry layer, a bottom layer and a ground plane layer disposed between the top circuitry layer and the bottom layer, the method comprising:

forming a well extending through the bottom layer and the ground plane layer, thereby exposing a first edge of the bottom layer and a second edge of the ground plane layer;

plating a conductor inside the well, thereby coupling the first edge and the second edge with the conductor;

forming a hole through a portion of the conductor that forms a bottom of the well and through the top circuitry layer, thereby exposing a third edge of the top circuitry layer and thereby forming a hole through the PCB in which the ground layer and bottom layer are coupled with the conductor, and the top layer is not coupled to the conductor;

attaching the bottom layer to a pallet in which the pallet covers the hole;

inserting a piece of pre-formed solder through the hole into the well such that the piece of pre-formed solder makes contact with the pallet;

placing a component inside the hole; and

heating the multi-layer printed circuit board and the pallet.

40. The method of claim 36, wherein the component is a RF power transistor.

43. The method of claim 36, wherein the component is an attenuator.

45. The method of claim 36, wherein the conductive material is deposited in the well by a plating process.

46. The method of claim 36, wherein the printed circuit board is a multi-layer laminated printed circuit board.

47. The method of claim 36, wherein the heat sink is coupled to the first side of the printed circuit board by bonding with a non-conductive adhesive.

37. A method of fabricating a printed circuit board assembly comprising:

forming a well, having a well side surface and a well bottom, in a printed circuit board (PCB), the PCB having a first surface and an opposing second surface, the well being formed on a side of the first surface;

depositing a conductive material in the well resulting in a conductive well side surface coupled to a conductive well bottom and electrically coupled to the first surface of the printed circuit board;

forming a hole through the printed circuit board such that a portion of the well bottom is removed;

coupling a heat sink to the first surface of the printed circuit board;

disposing a solder material in the well;

disposing a component in the well such that the solder material is between the component and the heat sink; and

heating the assembly to melt the solder material.

38. The method of claim 37, wherein the solder material is solder paste.

39. The method of claim 37, wherein the solder material is conductive epoxy.

41. The method of claim 39, wherein the RF power transistor includes a flange.

42. The method of claim 39, wherein the RF power transistor is flangless.

44. The method of claim 42, wherein the attenuator includes a flange.

48. A multi-layer printed circuit board manufactured by a method comprising:

forming a first hole through pre-assembled layers of a first printed wiring board (PCB) subassembly;

transforming the first hole into a well by bonding a second printed circuitry board (PCB) subassembly to cover the hole in the first PCB assembly;

plating a conductor inside the well;

forming a second hole through the second subassembly and into the well;

attaching a surface of the second subassembly adjacent to the well to a pallet;

inserting a piece of pre-formed solder through the second hole into the well such that the piece of pre-formed solder makes contact with the pallet;

placing a component inside the hole; and

heating the multi-layer printed circuit board and the pallet.