Method of forming a chip assembly with a die attach liquid

Patent metadata

Field	Value
Publication number	US-9837381-B2
Application number	US-201514870064-A
Country	US
Kind code	B2
Filing date	Sep 30, 2015
Priority date	Oct 15, 2014
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

A method of forming a chip assembly may include forming a plurality of cavities in a carrier; The method may further include arranging a die attach liquid in each of the cavities; arranging a plurality of chips on the die attach liquid, each chip comprising a rear side metallization and a rear side interconnect material disposed over the rear side metallization, wherein the rear side interconnect material faces the carrier; evaporating the die attach liquid; and after the evaporating the die attach liquid, fixing the plurality of chips to the carrier.

First claim

What is claimed is:

1. A method of forming a chip assembly, the method comprising:
forming a plurality of cavities in a carrier;
arranging a die attach liquid in each of the cavities;
arranging a plurality of chips on the die attach liquid, each chip comprising a rear side metallization and a rear side interconnect material disposed over the rear side metallization, wherein the rear side interconnect material faces the carrier;
evaporating the die attach liquid; and
after the evaporating the die attach liquid, fixing the plurality of chips to the carrier.

2. The method of claim 1 , further comprising:
holding the plurality of chips, by a holding force, in respective positions in which they are arranged.

3. The method of claim 2 ,
wherein the holding force is provided by the die attach liquid.

4. The method of claim 1 ,
wherein the evaporating of the die attach liquid comprises heating the chip assembly.

5. The method of claim 1 ,
wherein the die attach liquid evaporates essentially completely.

6. The method of claim 1 ,
wherein the die attach liquid comprises an organofluorine compound.

7. The method of claim 1 ,
wherein the die attach liquid comprises a hydrofluoroether.

8. The method of claim 1 ,
wherein the die attach liquid comprises an alcohol or secondary alcohol.

9. The method of claim 1 ,
wherein the fixing the plurality of chips to the carrier comprises heating the chip assembly.

10. The method of claim 1 ,
wherein the fixing the plurality of chips to the carrier comprises diffusion soldering.

11. The method of claim 1 ,
wherein the fixing the plurality of chips to the carrier comprises pressing the plurality of chips onto the carrier until the plurality of chips is flush with a top side of the carrier outside the cavities.

12. The method of claim 1 ,
wherein the forming the plurality of cavities in the carrier comprises forming the plurality of cavities with side walls inclined away from the cavity in a direction from a bottom of the cavity to a top of the cavity.

13. The method of claim 1 , further comprising:
forming a rear side interconnect material repellent coating on at least one of: side walls of the plurality of cavities and side walls of the plurality of chips.

14. The method of claim 1 , further comprising:
forming a barrier coating for the rear side interconnect material on at least one of: side walls of the plurality of cavities and/or the side walls of the plurality of chips.

15. The method of claim 1 , further comprising:
forming a metallic coating for improved wetting or intermetallic formation on the bottom or on at least one of the side walls of the cavities.

16. A method of forming a chip assembly, the method comprising:
forming a plurality of cavities in a carrier;
disposing a carrier interconnect material over a bottom of each of the cavities;
arranging a die attach liquid in each of the cavities;
arranging a plurality of chips on the die attach liquid, each chip comprising a rear side metallization;
evaporating the die attach liquid; and
after the evaporating the die attach liquid, fixing the plurality of chips to the carrier.

Assignees

• Infineon Technologies Ag

Inventors

• Heinrich Alexander

Classifications

• H10W70/682

  comprising holes having chips therein · CPC title

• H10W72/0198

  batch processes · CPC title

• H10W72/07141

  Means for applying energy, e.g. ovens or lasers · CPC title

• H10W72/07125

  Means for controlling the bonding environment, e.g. valves or vacuum pumps · CPC title

• H10W72/944

  Dispositions of multiple bond pads · CPC title