Thermally enhanced packaged semiconductor assemblies

• US 6,354,485 B1
• Filed: 08/30/1999
• Issued: 03/12/2002
• Est. Priority Date: 10/24/1996
• Status: Expired due to Term

• Current Assignee: Tessera, Inc. (Adeia, Inc.)
• Original Assignee: Tessera, Inc. (Adeia, Inc.)
• Inventors: Distefano, Thomas H.
• Primary Examiner(s): Dunn, Tom
• Assistant Examiner(s): STONER, KILEY SHAWN
• Application Number:
  US09/385,324
• Time in Patent Office: 925 Days
• Field of Search: 228/179.1, 228/155, 228/123.1, 228/124.6, 228/160
• US Class Current: 228/179.1
• CPC Class Codes: H01L 2224/05571 the external layer being disposed in a recess of the surface
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/05644 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/05664 Palladium [Pd] as principal constituent
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 23/3121 a substrate forming part of the encapsulation
• 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 2924/01046 Palladium [Pd]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/01322 Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/3025 Electromagnetic shielding

Abstract

A thermally enhanced semiconductor package includes a sheet metal cap having flexible flanges provided with solder contacts for reliable attachment to a circuit board. The package assembly further includes a semiconductor chip with a contact-bearing front surface facing forwardly, and chip bonding contacts overlying the front face of the chip. The flange bonding contacts are coplanar with the chip bonding contacts, or can be brought into coplanar alignment by flexure of the cap. The package can be surface-mounted to a circuit board by placing the package onto pads of solder paste, and then heating the assembly to melt the solder paste in order to join the bonding contacts on the chip and on the flange to corresponding contacts on the circuit board.

Claims

1. A method of making a plurality of chip assemblies comprising:

(a) providing a metallic element having one or more rear regions and one or more flange regions offset from said rear regions in a forward direction;

(b) placing a plurality of semiconductor chips into said one or more rear regions in front-face-forward disposition and attaching a rear face of each chip to a rear region of the metallic element;

(c) providing bondable flange contacts on the flange regions of the metallic element and providing bondable chip contacts overlying the front face of each chip; and

(d) after said placing and attaching step, severing said metallic element to thereby form a plurality of assemblies, each including a metallic cap having a rear wall, one or more flanges with one or more flange contacts thereon, at least one said chip attached to the rear wall and chip contacts overlying the front face of each said chip.

2. A method as claimed in claim 1, wherein said step of providing said chip contacts is performed so that said chip contacts are disposed on said front surfaces of said chips.

3. A method as claimed in claim 1, wherein said step of providing said chip contacts and said flange contacts includes the step of providing solder masses.

4. A method as claimed in claim 3, wherein said step of providing solder masses is performed before said severing step.

5. A method as claimed in claim 1 or claim 2 or claim 3 or claim 4, further comprising the step of providing a flexible potting compound surrounding said chips before said severing step, in such a way that said potting compound does not cover said contacts.