Method for fabricating an electronic device and a stacked electronic device

Patent metadata

Field	Value
Publication number	US-2017133520-A1
Application number	US-201715410230-A
Country	US
Kind code	A1
Filing date	Jan 19, 2017
Priority date	Nov 26, 2014
Publication date	May 11, 2017
Grant date	—

Abstract

A method for fabricating an electronic device includes fixing a rear face of an integrated-circuit chip to a front face of a support wafer. An infused adhesive is applied in the form of drops or segments that are separated from each other. A protective wafer is applied to the infused adhesive, and the infused adhesive is cured. The infused adhesive includes a curable adhesive and solid spacer elements infused in the curable adhesive. A closed intermediate peripheral ring is deposited on the integrated-circuit chip outside the cured infused adhesive, and an encapsulation block is formed such that it surrounds the chip, the protective wafer and the closed intermediate peripheral ring.

First claim

1 . A method, comprising:
fixing a rear face of an integrated-circuit chip to a front face of a support wafer; depositing on a front face of the integrated-circuit chip an infused adhesive in a form of drops or segments at a distance from one another outside a central region of the front face of the integrated-circuit chip, the infused adhesive comprising a curable adhesive and solid spacer elements infused in the curable adhesive; placing a protective wafer on the infused adhesive so that a free space remains between the front face of the integrated-circuit chip and a rear face of the protective wafer; curing the curable adhesive to fix the protective wafer to the integrated-circuit chip; producing an intermediate peripheral ring between the integrated-circuit chip and the protective wafer after curing the curable adhesive; and producing an encapsulation ring around the integrated-circuit chip, the protective wafer, and the intermediate peripheral ring on a peripheral zone of the front face of the support wafer.

2 . The method according to claim 1 , wherein producing the intermediate peripheral ring comprises curing a resin using ultraviolet radiation without releasing gas.

3 . The method according to claim 1 , wherein producing the encapsulating ring comprises supplying a coating material and curing the coating material.

4 . The method according to claim 1 , wherein curing the curable adhesive comprises heating to polymerize the curable adhesive and releasing gas.

5 . The method of claim 1 wherein producing the encapsulation ring comprises applying a liquid material in an area separating adjacent stacks formed of the integrated-circuit chips and the protective wafers.

6 . The method of claim 5 further comprising curing the liquid material and dicing the support wafer and the cured liquid material to form a plurality of the electronic devices.

7 . A method for fabricating an electronic device, comprising:
fixing a rear face of an integrated-circuit chip on a front face of a support wafer; depositing on a front face of the integrated-circuit chip an infused adhesive in a plurality of drops or segments separated from each other outside a central region of the front face of the integrated-circuit chip, the infused adhesive comprising a curable adhesive and solid spacer elements infused in the curable adhesive; placing a protective wafer on the infused adhesive so that a free space remains between the front face of the integrated-circuit chip and the protective wafer; curing the infused adhesive to fix the protective wafer to the integrated-circuit chip; and depositing a closed intermediate peripheral ring on the integrated-circuit chip outside of the cured infused adhesive; and producing on a peripheral zone of the front face of the support wafer an encapsulation block around the integrated-circuit chip, the protective wafer, and the closed intermediate peripheral ring.

8 . The method of claim 7 wherein curing the infused adhesive comprises exposing the infused adhesive to heat to polymerize the curable adhesive and thereby release gas.

9 . The method of claim 8 wherein the curable adhesive comprises an epoxy resin.

10 . The method of claim 7 further comprising curing the closed intermediate peripheral ring.

11 . The method of claim 10 wherein curing the closed intermediate peripheral ring comprises exposing the closed intermediate peripheral ring to ultraviolet radiation, the curing of the closed intermediate peripheral ring occurring without releasing gas.

12 . The method of claim 7 wherein the closed intermediate peripheral ring is deposited at least partially outside the protective wafer.

13 . The method of claim 7 further comprising wire bonding front pads of the integrated-circuit chip to an electrical connection network associated with the support wafer.

14 . The method of claim 7 wherein producing the encapsulation block comprises spreading an epoxy resin.

15 . The method of claim 7 wherein producing the encapsulation block comprises injection molding a liquid material.

16 . The method of claim 7 wherein the infused adhesive is deposited using a dispensing needle.

17 . The method of claim 7 wherein the closed intermediate peripheral ring is deposited using a dispensing needle.

18 . The method of claim 7 wherein the integrated-circuit chip is applied to the support wafer with a thin layer of adhesive.

19 . A method of collectively fabricating a plurality of electronic devices, comprising:
forming a plurality of stacks on a support wafer, each stack formed by:
fixing a rear face of an integrated-circuit chip on a front face of the support wafer;
depositing on a front face of the integrated-circuit chip an infused adhesive in a plurality of drops or segments separated from each other, the infused adhesive comprising a curable adhesive and solid spacer elements infused in the curable adhesive;
placing a protective wafer on the infused adhesive and thereby creating a free space between the front face of the integrated-circuit chip and the protective wafer;
curing the infused adhesive to fix the protective wafer to the integrated-circuit chip; and
depositing a closed intermediate peripheral ring on the integrated-circuit chip outside of the cured infused adhesive; and
applying an encapsulation block on the support wafer in areas between adjacent stacks; and dicing the protective wafer and the encapsulation block to form a plurality of the electronic devices.

20 . The method of claim 19 wherein curing the infused adhesive comprises exposing the infused adhesive to heat to polymerize the infused adhesive and thereby release gas.

21 . The method of claim 19 further comprising curing the closed intermediate peripheral ring.

22 . The method of claim 21 wherein curing the closed intermediate peripheral ring comprises exposing the closed intermediate peripheral ring to ultraviolet radiation, the curing of the closed intermediate peripheral ring occurring without releasing gas.

Assignees

• Stmicroelectronics (Grenoble 2) Sas

Inventors

• Saxod Karine
• Sorrieul Marika

Classifications

• H10W90/754

  between a chip and a stacked insulating package substrate, interposer or RDL · CPC title

• H10W90/752

  between stacked chips · CPC title

• H10W90/734

  between a chip and a stacked insulating package substrate, interposer or RDL · CPC title

• H10W76/63

  characterised by their shape or disposition, e.g. between cap and walls of a container · CPC title

• H10W74/00

  Encapsulations, e.g. protective coatings · CPC title