Method for encasing array packages

• US 6,117,382 A
• Filed: 02/05/1998
• Issued: 09/12/2000
• Est. Priority Date: 02/05/1998
• Status: Expired due to Term

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Thummel, Steven G.
• Primary Examiner(s): ORTIZ, ANGELA Y
• Application Number:
  US09/019,226
• Time in Patent Office: 950 Days
• Field of Search: 264/272.11, 264/272.13, 264/272.14, 264/272.15, 264/272.17, 425/116, 425/123, 425/544, 438/107, 438/109, 438/112
• US Class Current: 264/272.14
• CPC Class Codes: B29C 45/14655 connected to or mounted on a carrier, e.g. lead frame
• CPC Class Codes: B29C 70/72 Encapsulating inserts having non-encapsulated projections, e.g. extremities or terminal portions of electrical components B29C70/742 takes precedence
• CPC Class Codes: H01L 21/565 Moulds
• CPC Class Codes: H01L 2224/48091 Arched
• 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 2924/15311 being a ball array, e.g. BGA
• CPC Class Codes: H01L 2924/19041 being a capacitor
• CPC Class Codes: H05K 3/0097 Processing two or more printed circuits simultaneously, e.g. made from a common substrate, or temporarily stacked circuit boards H05K3/0052 takes precedence
• CPC Class Codes: H05K 3/284 for encapsulating mounted components H05K1/185 takes precedence
• CPC Class Codes: Y10S 425/812 Venting

Abstract

The upper and lower mold plates of a transfer molding machine are configured for one-side encapsulation of a pair of substrate mounted electronic devices having an opposite conductor-grid-array and/or bare heat sink/dissipator. The pair of devices is positioned back-to-back within a single mold cavity for simultaneous encapsulation. A buffer member, optionally with cut-outs or apertures, may be placed between the two back-to-back substrates for protecting the grid-arrays and enabling encapsulation of devices with varying thicknesses without adjustment of the molding machine. Alternately, the upper and lower plates are configured for one-side encasement using covers of a pair of substrate mounted electronic devices having an opposite conductor-grid-array and/or bare heat sink/dissipator.

Claims

1. A method for encapsulation of a plurality of electronic devices within a mold cavity, each electronic device having at least one electronic component mounted on a first side of a substrate, said method comprising:

providing at least one electronic component on a first side of a first substrate, said first substrate having a first side and having a second side;

providing at least one electronic component on a first side of a second substrate, said second substrate having said first side and having a second side;

providing upper and lower mating mold plates, each mold plate of said upper and lower mold plates having a mold cavity portion, each said mold cavity portion of said upper and lower mold plates having a feed runner leading from a material supply to said mold cavity portion, said mold cavity portions together comprising said mold cavity;

placing said first substrate having said at least one electronic component on said first side thereof and said second substrate having said at least one electronic component on said first side thereof into said mold cavity, said first substrate and said second substrate each having said second side thereof being located between said upper and lower mold plates;

moving said upper and lower mold plates toward each other to form said mold cavity, portions of said upper mold plate engaging portions of the first surface of said first substrate and portions of said lower mold plate engaging portions of the first surface of said second substrate;

injecting a first material into said upper mold cavity portion and a second material into said lower mold cavity portion to separately encapsulate said at least one electronic component on said first side of said first substrate and said at least one electronic component on said first side of said second substrate and said at least one electronic component on said first side of said second substrate; and

removing said first substrate and said second substrate from said upper and lower mating mold plates, said first substrate and said second substrate each having at least one encapsulated electronic component on said first side thereof.

2. The method of claim 1, wherein each mold cavity portion of said upper and lower mold plates includes a vent runner connected thereto for venting said mold cavity portion.

3. The method of claim 1, wherein the step of injecting said second material into said lower mold cavity portion comprises injection of a material substantially identical to said first material.

4. The method of claim 1, wherein the step of injecting said second material into said lower mold cavity portion comprises injection of a material substantially different from said first material.

5. The method of claim 1, wherein said first material and said second material are injected substantially simultaneously.

6. The method of claim 1, wherein said first material and said second material are injected at different times.

7. The method of claim 1, further comprising the step of cleaning said second side of each of said first substrate and said second substrate.

8. The method of claim 1, further comprising the step of curing said plurality of electronic devices at an elevated curing temperature.

9. A method for encapsulation of a plurality of electronic devices within a mold cavity, each electronic device of said plurality of electronic devices having at least one electronic component mounted on a first side of a substrate, said method comprising:

providing at least one electronic component on a first side of a first substrate, said first substrate having said first side and having a second side;

providing at least one electronic component on a first side of a second substrate, said second substrate having said first side and having a second side;

providing upper and lower mating mold plates, each mold plate of said upper and lower mating mold plates having a mold cavity portion, each said mold cavity portion of said upper and lower mold plates having a feed runner leading from a material supply to said mold cavity portion, said mold cavity portions together comprising said mold cavity;

placing said first substrate having at least one electronic component on said first side thereof and said second substrate having said at least one electronic component on said first side thereof into said mold cavity, said second side of said first substrate and said second side of said second substrate placed in a back-to-back orientation between said upper and lower mold plates;

moving said upper and lower mold plates to form said mold cavity, portions of said upper mold plate engaging portions of the first surface of said first substrate and portions of said lower mold plate engaging portions of the first surface of said second substrate;

injecting a first material into said mold cavity portion of said upper mold plate and a second material into said mold cavity portion of said lower mold plate to separately encapsulate said at least one electronic component mounted on said first side of each of said first and second substrates of said plurality of electronic devices; and

removing said plurality of electronic devices from said mold cavity.

10. The method of claim 9, wherein each mold cavity portion of said upper and lower mold plates is connected to a vent runner for venting said mold cavity portion.

11. The method of claim 9, wherein the step of injecting said second material into said lower mold cavity portion comprises injection of a material substantially identical to said first material.

12. The method of claim 9, wherein the step of injecting said second material into said lower mold cavity portion comprises injection of a material substantially different from said first material.

13. The method of claim 9, wherein said first material and said second material are injected substantially simultaneously.

14. The method of claim 9, wherein said first material and said second material are injected at different times.

15. The method of claim 9, further comprising the step of cleaning said second side of each of said first substrate and said second substrate.

16. The method of claim 9, further comprising the step of subjecting said plurality of electronic devices to a curing temperature.

17. The method of claim 9, wherein said second side of each of said first substrate and said second substrate of said electronic device includes solder bumps thereon.