Printed circuit board reinforcement structure and integrated circuit package using the same

• US 8,059,384 B2
• Filed: 07/31/2008
• Issued: 11/15/2011
• Est. Priority Date: 07/31/2007
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Park, Se Ho, Kim, Ki-Hyun, Lee, Young-Min, Kang, Seok-Myong
• Primary Examiner(s): Thompson; Gregory
• Application Number:
  US12/183,463
• Publication Number:
  US 20090032292A1
• Time in Patent Office: 1,202 Days
• Field of Search: 174/255, 174/260, 174/261, 361/760
• US Class Current: 361/255
• CPC Class Codes: H05K 1/0271 Arrangements for reducing stress or warp in rigid printed circuit boards, e.g. caused by loads, vibrations or differences in thermal expansion
• CPC Class Codes: H05K 1/181 associated with surface mounted components
• CPC Class Codes: H05K 2201/0133 Elastomeric or compliant polymer
• CPC Class Codes: H05K 2203/063 of preperforated insulating layer
• 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 3/0064 onto a polymeric substrate

Abstract

A printed circuit board reinforcement structure for a printed circuit board receiving a plurality of surface mounting devices, and an integrated circuit package using the same. The structure includes a hard layer having one or more openings formed at areas corresponding to one or more surface mounting devices with a thickness exceeding a predetermined thickness; and a soft layer bonded to a side of the hard layer so that the soft layer can accommodate the protrusion of the surface mounting devices. The structure prevents defects of a printed circuit board, such as deformation, fracture or the like, while substantially reducing the size of a package by applying a reinforcement structure to a thin printed circuit board, thereby reinforcing the rigidity (mechanical strength) of the thin printed circuit board.

Claims

1. A printed circuit board reinforcement structure for reinforcing rigidity of a printed circuit board receiving a plurality of surface mounting devices, comprising:

a hard layer and a soft layer, each having at least one opening formed at an area corresponding to at least one thick surface mounting device among the surface mounting devices, the at least one thick surface mounting device having a thickness exceeding a predetermined thickness,

wherein the soft layer is bonded to a side of the hard layer so that the soft layer can accommodate protrusion of thin surface mounting devices among the surface mounting devices, the thin surface mounting devices being thinner than the predetermined thickness.

2. The printed circuit board reinforcement structure as claimed in claim 1, wherein the hard layer comprises at least one of:

an EMC (Epoxy Mold Compound);

an engineering plastic including PES (Poly Ethylene Sulpone) and PC (Poly Carbonate);

a composite material including FRP (Glass Fiber Reinforced Plastic), GRP (Graphite Reinforced Plastic), Basult or ceramic; and

a metallic material including steel, stainless steel, aluminum, magnesium and alloys thereof.

3. The printed circuit board reinforcement structure as claimed in claim 1, wherein the flexural strength of the hard layer is not less than 100 MPa at a temperature in the range of −

40 to 85°

C.

4. The printed circuit board reinforcement structure as claimed in claim 1, wherein the hard layer further comprises a plurality of holes formed through the hard layer.

5. The printed circuit board reinforcement structure as claimed in claim 1, wherein the soft layer comprises at least one of:

rubber with a visco-elastic characteristic;

a PSA (Pressure Sensitive Adhesive) or EVA (Ethylene Vinyl Alcohol);

hot-melt having a characteristic being softened at a temperature in the range of 60 to 160°

C.; and

resin or gel having viscosity of not less than 1000 cps.

6. The printed circuit board reinforcement structure as claimed in claim 1, wherein the thickness of the soft layer is greater than or equal to that of the thinnest surface mounting device among the thin surface mounting devices.

7. The printed circuit board reinforcement structure as claimed in claim 1, wherein top adhesive force of the top side of the soft layer is greater than bottom adhesive force of the bottom side thereof.

8. The printed circuit board reinforcement structure as claimed in claim 7, wherein the bottom adhesive force is in the range of 1 to 10 N/cm at a temperature in a temperature range of −

40 to 85°

C.

9. The printed circuit board reinforcement structure as claimed in claim 1, further comprising an adhesive layer formed between the hard layer and the soft layer.

10. The printed circuit board reinforcement structure as claimed in claim 9, wherein the adhesive layer comprises at least one of:

epoxy (BPA);

a thermoplastic material including EVA (Ethylene Vinyl Alcohol); and

a PAS (Pressure Sensitive Adhesive).

11. The printed circuit board reinforcement structure as claimed in claim 1, further comprising a hydrophobic sealing layer formed along the circumferential edge of the soft layer.

12. An integrated circuit package comprising:

a printed circuit board receiving a plurality of surface mounting devices; and

a hard layer and a soft layer each having at least one opening formed at an area corresponding to at least one thick surface mounting device among the surface mounting devices, the at least one thick surface mounting device having a thickness exceeding a predetermined thickness,

wherein the soft layer is bonded between the hard layer and the printed circuit board so that the soft layer can accommodate protrusion of thin surface mounting devices among the surface mounting devices, the thin surface mounting devices being thinner than the predetermined thickness.

13. The integrated circuit package as claimed in claim 12, further comprising a plurality of holes formed through the hard layer.

14. The integrated circuit package as claimed in claim 12, wherein the thickness of the soft layer is greater than or equal to that of the thinnest surface mounting device among the thin surface mounting devices.

15. The integrated circuit package as claimed in claim 12, wherein top adhesive force between the soft layer and the hard layer is greater than bottom adhesive force between the soft layer and the printed circuit board.

16. The integrated circuit package as claimed in claim 12, further comprising an adhesive layer formed between the hard layer and the soft layer.

17. The integrated circuit package as claimed in claim 12, further comprising a hydrophobic sealing layer formed along the circumferential edge of the soft layer.