Method for making memory cards and similar devices using isotropic thermoset materials with high quality exterior surfaces

• US 20060162156A1
• Filed: 01/27/2005
• Published: 07/27/2006
• Est. Priority Date: 01/27/2005
• Status: Active Grant

• Current Assignee: Cardxx Incorporated
• Original Assignee: Cardxx Incorporated
• Inventors: Reed, Paul
• Granted Patent: US 7,225,537 B2
• Time in Patent Office: Days
• US Class Current: 29/841
• CPC Class Codes: B29C 2045/14532 injecting between two sheets
• CPC Class Codes: B29C 45/14467 Joining articles or parts of a single article B29C45/14377, B29C45/14385, B29C45/14581, B29C45/14614 and B29C45/006 take precedence
• CPC Class Codes: B29C 45/14647 Making flat card-like articles with an incorporated IC or chip module, e.g. IC or chip cards
• CPC Class Codes: B29K 2027/06 PVC, i.e. polyvinylchloride
• CPC Class Codes: B29K 2063/00 Use of EP, i.e. epoxy resins or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2075/00 Use of PU, i.e. polyureas or polyurethanes or derivatives thereof, as moulding material
• CPC Class Codes: H01L 21/565 Moulds
• CPC Class Codes: H01L 2224/05553 being rectangular
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48472 the other connecting portion not on the bonding area also being a wedge bond, i.e. wedge-to-wedge
• CPC Class Codes: H01L 2224/49175 Parallel arrangements
• CPC Class Codes: H01L 23/3135 Double encapsulation or coating and encapsulation
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/49 of a plurality of wire connectors
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/14 Integrated circuits
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/207 : Diameter ranges
• CPC Class Codes: H05K 1/117 : Pads along the edge of rigid circuit boards, e.g. for pluggable connectors
• CPC Class Codes: H05K 2203/063 : of preperforated insulating layer
• CPC Class Codes: H05K 2203/1316 : Moulded encapsulation of mounted components
• CPC Class Codes: H05K 3/0058 : Laminating printed circuit boards onto other substrates, e.g. metallic substrates H05K1/0281 takes precedence
• CPC Class Codes: H05K 3/284 : for encapsulating mounted components H05K1/185 takes precedence
• CPC Class Codes: H05K 3/386 : by the use of an organic polymeric bonding layer, e.g. adhesive
• CPC Class Codes: H05K 3/4007 : Surface contacts, e.g. bumps H05K3/4092 takes precedence; deposition of finish layers on pads H05K3/24; forming solder bumps H05K3/3457
• CPC Class Codes: Y10T 29/49121 : Beam lead frame or beam lead device
• CPC Class Codes: Y10T 29/49146 : with encapsulating, e.g., potting, etc.
• CPC Class Codes: Y10T 29/49172 : by molding of insulating material
• CPC Class Codes: Y10T 29/49176 : with molding of electrically insulating material

Abstract

Memory Cards containing Integrated Circuits and other electronic components (e.g. resistors) in a variety of form factors having high quality external surfaces of polycarbonate, synthetic paper (e.g. Teslin), or other suitable material (e.g. PVC) can be made through use of injection molded thermoplastic material or thermosetting material that becomes the core layer of said Memory Cards and similar devices. The object of the invention is to provide the following properties to Memory Cards: rapid production cycle, high volume manufacturing throughput, security, electronics protection, better tamper resistance, durability, and highly reliable complex electronics encapsulation, achieved through a process utilizing low temperature and low pressure.

Claims

1. A method for making a Memory Card or similar device comprising a top layer of synthetic paper or other suitable material, a bottom layer of synthetic paper or other suitable material, and a core layer in which electronic components reside, said method comprising:

(1) constructing a bottom layer with precisely positioned openings for external electrical contacts;

(2) placing at least one mound of low shrinkage glue on an inside surface of the bottom layer;

(3) mounting an electronic component, having external electrical contacts, on the at least one mound of low shrinkage glue, thereby forming a bottom layer assembly, wherein the external electrical contacts are positioned in alignment with the openings in the bottom layer;

(4) partially curing the at least one mound of low shrinkage glue, wherein the electronic component is secured in a stable position;

(5) positioning the bottom layer assembly in a bottom mold;

(6) positioning the top layer in a top mold;

(7) closing the top mold to the bottom mold in a manner that creates a void space between the top layer and bottom layer;

(8) injecting a thermosetting polymeric material into the void space at temperature and pressure conditions which are such that;

(a) the electronic component is secured in position by the partially cured glue while the electronic component and partially cured glue are immersed in the thermosetting material, (b) gases and excess polymeric material are driven out of the void space, (c) the electronic component is encapsulated in the thermosetting polymeric material before the partially cured glue becomes completely cured, (d) the shrinking of the partially cured glue as it is fully cured brings the lower surface of the external electrical contacts flush with the bottom surface of the bottom layer, and (e) the thermosetting polymeric material bonds with both the top layer and the bottom layer to produce a unified precursor Memory Card body;

(9) removing the unified precursor Memory Card body from the mold device; and

(10) trimming the precursor Memory Card or similar device to a desired dimension to produce a Memory Card.

2. The method of claim 1 wherein the electronic component does not come in physical contact with the bottom layer.

3. The method of claim 1 wherein the electronic component is positioned at least 0.01 mm above the bottom layer.

4. The method of claim 1 wherein the electronic component is an Integrated Circuit that is pedestaled on at least two mounds of glue that hold the Integrated Circuit at least 0.01 mm above the bottom layer.

5. The method of claim 1 wherein the low shrinkage glue is a cyanoacrylate adhesive type glue that is capable of at least partially curing in about 5 seconds or less.

6. The method of claim 1 wherein the low shrinkage glue is a UV-curable glue that is capable of at least partially curing in about 5 seconds or less.

7. The method of claim 1 wherein the low shrinkage glue is 10 percent cured in 3 seconds or less.

8. The method of claim 1 wherein the low shrinkage glue is 10 to 90 percent cured while it is immersed in the thermosetting material.

9. The method of claim 1 wherein the inside surface of the top layer and the inside surface of the bottom layer are treated to facilitate the creation of a strong bond between the top layer and the thermosetting material and the bottom layer and the thermosetting material.

10. The method of claim 1 wherein the inside surface of the top layer and the inside surface of the bottom layer are treated by coating each with a bonding agent.

11. The method of claim 1 wherein the inside surface of the top layer and the inside surface of the bottom layer are treated by a corona discharge process.

12. The method of claim 1 wherein the thermosetting material is injected into the void space at a pressure between ambient pressure and 500 psi.

13. The method of claim 1 wherein the thermosetting material is injected into the void space at a pressure between 80 and 120 psi.

14. The method of claim 1 wherein the thermosetting material is injected into the void space at a temperature between 56°

F. and 120°

F.

15. The method of claim 1 wherein the thermosetting material is injected into the void space between the top layer and the bottom layer at a temperature between 65°

F. and 70°

F.

16. The method of claim 1 wherein a film bearing alphanumeric/graphic information is applied to the inside surface of the top layer.

17. The method of claim 1 wherein a layer of opacity preventing material is applied to the inside surface of the top layer and the inside surface of the bottom layer.

18. The method of claim 1 wherein the electronic component is

(a) a MultiMedia Card die assembly,

(b) a Secure Digital card die assembly, or

(c) another memory card die assembly,

that is electrically connected to the external contacts.

19. The method of claim 1 wherein the top layer and the bottom layer are each formed from a flat sheet of polymeric material.

20. The method of claim 1 wherein the top layer is preformed with at least one Memory Card-forming cavity.

21. The method of claim 1 wherein the top layer is molded into a Memory Card-forming cavity of a top mold and the bottom layer is molded against a substantially flat surface of a bottom mold.

22. The method of claim 1 wherein the thermosetting material is a polyurethane.

23. The method of claim 1 wherein the thermosetting material is an epoxy.

24. The method of claim 1 wherein the thermosetting material is an unsaturated polyester.

25. The method of claim 1 wherein the void space is filled by a gate whose width is at least 25 percent of the width of an edge of a precursor Memory Card or similar device being serviced by said gate.

26. A method for making a Memory Card or similar device comprising a top layer, a core layer in which an electronic component is embedded and a bottom layer, said method comprising:

(1) constructing a bottom layer with precisely positioned openings for external electrical contacts;

(2) placing at least one mound of low shrinkage glue having a volume of less than 0.1 cc on an inside surface of the bottom layer;

(3) mounting an electronic component, having external electrical contacts, on the at least one mound of low shrinkage glue, thereby forming a bottom layer assembly, wherein the external electrical contacts are positioned in alignment with the openings in the bottom layer;

(4) curing the mound of low shrinkage glue from 10 percent to 90 percent of the total curing the glue will experience in a period of time less than 5 seconds, wherein the electronic component is secured in a stable position;

(5) positioning the bottom layer assembly in a bottom mold;

(6) positioning a top layer in a top mold;

(7) closing the top mold to the bottom mold in a manner that creates a void space between the top layer and bottom layer;

(8) injecting a thermosetting material into the void space at a temperature between 65°

F. and 70°

F. and at a pressure between 80 psi and 120 psi which are such that;

(a) the electronic component is held in place by the mound of partially cured glue while the electronic component and mound of partially cured glue are immersed in the thermosetting material, (b) gases and excess polymeric material are driven out of the void space, (c) the electronic component is encapsulated in the thermosetting polymeric material before the partially cured glue becomes completely cured, (d) the shrinking of the partially cured glue as it is fully cured brings the lower surface of the external electrical contacts flush with the bottom surface of the bottom layer, and (d) the thermosetting polymeric material bonds with both the top layer and the bottom layer to produce a unified precursor Memory Card body;

(9) removing the unified precursor Memory Card or similar device body from the mold device; and

(10) trimming the precursor Memory Card to a desired dimension to produce a Memory Card.

27. A method for making a Memory Card or similar device comprising a top layer of synthetic paper or other suitable material, and a bottom layer in which an electronic component resides, said method comprising:

(1) constructing an electronic component, having external electrical contacts;

(5) positioning the electronic component in a bottom mold;

(6) positioning the top layer in a top mold;

(7) closing the top mold to the bottom mold in a manner that creates a void space between the top layer and electronic component;

(8) injecting a thermosetting polymeric material into the void space at temperature and pressure conditions which are such that;

(a) the exposed electronic component is completely covered by the thermosetting material, thereby forming the bottom layer, (b) gases and excess polymeric material are driven out of the void space, (c) the electronic component is encapsulated in the thermosetting polymeric material, and (d) the thermosetting polymeric material bonds with both the top layer produce a unified precursor Memory Card body;

(9) removing the unified precursor Memory Card body from the mold device; and

(10) trimming the precursor Memory Card or similar device to a desired dimension to produce a Memory Card.

28. The method of claim 27 wherein the inside surface of the top layer is treated to facilitate the creation of a strong bond between the top layer and the thermosetting material.

29. The method of claim 27 wherein the inside surface of the top layer is treated by coating it with a bonding agent.

30. The method of claim 27 wherein the inside surface of the top layer is treated by a corona discharge process.

31. The method of claim 27 wherein the thermosetting material is injected into the void space at a pressure between ambient pressure and 500 psi.

32. The method of claim 27 wherein the thermosetting material is injected into the void space at a pressure between 80 and 120 psi.

33. The method of claim 27 wherein the thermosetting material is injected into the void space at a temperature between 56°

F. and 120°

F.

34. The method of claim 27 wherein the thermosetting material is injected into the void space between the top layer and the electronic component at a temperature between 65°

F. and 70°

F.

35. The method of claim 27 wherein a film bearing alphanumeric/graphic information is applied to the inside surface of the top layer.

36. The method of claim 27 wherein a layer of opacity preventing material is applied to the inside surface of the top layer.

37. The method of claim 27 wherein the electronic component is

(a) a MultiMedia Card die assembly,

(b) a Secure Digital card die assembly, or

(c) another memory card die assembly,

that is electrically connected to the external contacts.

38. The method of claim 27 wherein the top layer is formed from a flat sheet of polymeric material.

39. The method of claim 27 wherein the top layer is preformed with at least one Memory Card-forming cavity.

40. The method of claim 27 wherein the thermosetting material is a polyurethane.

41. The method of claim 27 wherein the thermosetting material is an epoxy.

42. The method of claim 27 wherein the thermosetting material is an unsaturated polyester.

43. The method of claim 27 wherein the void space is filled by a gate whose width is at least 25 percent of the width of an edge of a precursor Memory Card or similar device being serviced by said gate.