Methods of encapsulating a semiconductor chip using a settable encapsulant

• US 6,458,628 B1
• Filed: 11/14/2000
• Issued: 10/01/2002
• Est. Priority Date: 10/15/1997
• Status: Expired due to Term

• Current Assignee: Tessera, Inc. (Adeia Inc.)
• Original Assignee: Tessera, Inc. (Adeia Inc.)
• Inventors: Mitchell, Craig S., Distefano, Thomas H.
• Primary Examiner(s): Nguyen, Tuan H.
• Assistant Examiner(s): BEREZNY, NEMA O
• Application Number:
  US09/712,635
• Time in Patent Office: 686 Days
• Field of Search: 438/126, 438/127, 264/478, 264/496, 264/614, 264/494
• US Class Current: 438/126
• CPC Class Codes: H01L 21/565 Moulds
• 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A method of making a semiconductor chip package by attaching a chip to a dielectric layer; placing the dielectric layer and chip into a mold; disposing a thixotropic composition that has been sheared to reduce its viscosity into the mold and curing the thixotropic composition after the chip and dielectric layer have been removed from the mold. A method of making a semiconductor chip package without using a mold by disposing a sheared thixotropic composition between a semiconductor chip and a dielectric layer and then curing the thixotropic composition to form a cured encapsulant. A method of making a semiconductor chip package without using a mold during the curing step and without the need to use a thixotropic composition by placing a semiconductor chip attached to a dielectric layer into a mold and disposing a liquid composition between the chip and the dielectric layer, forming a cured skin on the liquid composition, removing the work-piece from the mold and then complete the cure of the liquid composition.

Claims

1. A method of making a semiconductor chip package comprising the steps of

i. attaching at least one microelectronic element to a dielectric layer;

ii. placing the dielectric layer into a mold

iii. sealingly engaging the mold with the dielectric layer;

iv. disposing a liquid composition into the mold to fill the area between the at least one microelectronic element and the dielectric layer;

v. curing a portion of the liquid composition to form a cured skin and an uncured portion of the liquid composition;

vi. then removing the dielectric layer from the mold; and

vii. then curing the uncured portion of the liquid composition to form a cured encapsulant.

2. The method of claim 1, wherein the cured skin is formed by a method selected from the group consisting of:

a. exposing the liquid composition to ultraviolet radiation;

b. exposing the liquid composition to an electronic beam;

c. exposing the liquid composition to x-rays;

d. exposing the liquid composition to moisture;

e. exposing the liquid composition to air; and

f. exposing the liquid composition to heat.

3. The method of claim 1, wherein the dielectric layer is flexible.

4. The method of claim 3, wherein the dielectric layer is comprised of a polyimide.

5. The method of claim 4, wherein the liquid composition is curable to form a compliant encapsulant selected from the groups consisting of silicone elastomers, silicone gels and flexiblized epoxies.

6. The method of claim 5, wherein the at least one microelectronic element is a semiconductor chip.

7. The method of claim 4, wherein the at least one microelectronic element is a wafer.

8. The method of claim 5, wherein said liquid composition comprises a thixotropic composition.