ELECTRONIC DEVICE AND MANUFACTURING METHOD

• US 20090014873A1
• Filed: 04/21/2008
• Published: 01/15/2009
• Est. Priority Date: 07/13/2007
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Yokota, Yasuo, Yoshida, Hisahiko
• Granted Patent: US 7,993,984 B2
• Time in Patent Office: Days
• US Class Current: 257/737
• CPC Class Codes: B23K 1/018 Unsoldering; Removal of melted solder or other residues
• CPC Class Codes: H01L 21/56 Encapsulations, e.g. encapsulation layers, coatings
• CPC Class Codes: H01L 21/67126 Apparatus for sealing, encapsulating, glassing, decapsulating or the like processes H01L23/02, H01L23/28
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/16227 the bump connector connecting to a bond pad of the item
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/73203 Bump and layer connectors
• CPC Class Codes: H01L 2224/81052 Detaching bump connectors, e.g. after testing
• CPC Class Codes: H01L 2224/81203 Thermocompression bonding, e.g. diffusion bonding, pressure joining, thermocompression welding or solid-state welding
• CPC Class Codes: H01L 2224/81801 Soldering or alloying
• CPC Class Codes: H01L 2224/831 the layer connector being supplied to the parts to be connected in the bonding apparatus
• CPC Class Codes: H01L 23/3185 the coating covering also the sidewalls of the semiconductor body
• CPC Class Codes: H01L 24/81 using a bump connector
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01029 Copper [Cu]
• CPC Class Codes: H01L 2924/0103 Zinc [Zn]
• CPC Class Codes: H01L 2924/01033 Arsenic [As]
• CPC Class Codes: H01L 2924/01046 : Palladium [Pd]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/0105 : Tin [Sn]
• CPC Class Codes: H01L 2924/01075 : Rhenium [Re]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/19041 : being a capacitor
• CPC Class Codes: H01L 2924/3511 : Warping
• CPC Class Codes: H05K 2201/0212 : Resin particles
• CPC Class Codes: H05K 2201/10689 : Leaded Integrated Circuit [IC] package, e.g. dual-in-line [DIL]
• CPC Class Codes: H05K 2201/10734 : Ball grid array [BGA]; Bump grid array
• CPC Class Codes: H05K 2201/10977 : Encapsulated connections
• CPC Class Codes: H05K 2203/176 : Removing, replacing or disconnecting component; Easily removable component
• CPC Class Codes: H05K 2203/304 : Protecting a component during manufacturing
• CPC Class Codes: H05K 3/284 : for encapsulating mounted components H05K1/185 takes precedence
• CPC Class Codes: H05K 3/305 : Affixing by adhesive
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product

Abstract

An electronic device including a semiconductor device with a plurality of bump electrodes, a mounting board connected to the semiconductor device, thermally expandable particles, and adhesive. The thermally expandable particles are provided on the sides of the semiconductor device and the surface of the mounting board around a projected area of the semiconductor device. The adhesive is provided on the sides of the semiconductor device and the surface of the mounting board such that it covers the area of thermally expandable particles. This improves the impact resistance of the semiconductor device soldered onto the mounting board, and also facilitates removal of the semiconductor device from the mounting board when the semiconductor device needs repair.

Claims

1. An electronic device comprising:

a semiconductor device having a plurality of connecting terminals; and

a mounting board facing the semiconductor device, and being connected to the connecting terminals;

wherein thermally expandable particles are provided on at least one of a side of the semiconductor device and a surface of the mounting board around a projected area of the semiconductor device, the thermally expandable particles being covered with adhesive.

2. The electronic device of claim 1,

wherein

the plurality of connecting terminals are a plurality of bump electrodes, and

the mounting board has a placement area for placing the semiconductor device on one face, and lands for electrically connecting to the plurality of bump electrodes of the semiconductor device provided at the placement area.

3. The electronic device of claim 1, wherein the adhesive is mainly made of thermosetting resin, and an expansion temperature of the thermally expandable particles is higher than a thermal curing temperature of the thermosetting resin.

4. The electronic device of claim 2, wherein the thermally expandable particles are provided at discontinuous points on the surface of the mounting board around the projected area of the semiconductor device.

5. The electronic device of claim 2, wherein

the plurality of connecting terminals are a plurality of outer leads extending from a side of a package in which a semiconductor element of the semiconductor device is installed,

the mounting board has connecting electrodes for connecting to the outer leads, the connecting electrodes being provided on the mounting board around the projected area of the semiconductor device, and

the thermally expandable particles are provided on a top part of portions where the outer leads and the connecting electrodes are connected.

6. The electronic device of claim 1, wherein

the mounting board has a plurality of lands at positions facing the semiconductor device and corresponding to positions of the connecting terminals in the placement area of the semiconductor device, and a dent created in the surface of the mounting board around the projected area of the semiconductor device;

the thermally expandable particles are embedded in the dent in the mounting board; and

the adhesive covers the thermally expandable particles embedded in the dent.

7. The electronic device of claim 6, wherein the mounting board is a multilayer board, and the dent passes through an outermost layer of a face, where the semiconductor device is mounted, of the multilayer board.

8. The electronic device of claim 6, wherein an insulating film is provided on a face, where the semiconductor is mounted, of the mounting board, and

the dent is created in the insulating film.

9. The electronic device of claim 6, wherein the dent is discontinuously created in a face, where the semiconductor is mounted, of the mounting board.

10. The electronic device of claim 1, wherein

the plurality of connecting terminals are formed by aligning electrodes on one main face of the semiconductor device;

the mounting board has board electrodes electrically connected to the electrodes of the semiconductor device by solder bumps;

the thermally expandable particles are mixed with the curable resin, and provided on at least one of

at least a part of a boundary area between the curable resin and the mounting board, and

at least a part of a boundary area between the curable resin and the side of the semiconductor device; and

the adhesive is made of thermosetting resin, the adhesive bonding and fixing at least one of a part of the side of the semiconductor device and the mounting board.

11. The electronic device of claim 10, wherein an expansion temperature of the thermally expandable particles is higher than a curing temperature of the thermosetting resin, and not higher than 260°

C.

12. A method of manufacturing an electronic device, comprising:

electrically connecting a semiconductor device and a mounting board, the semiconductor device having a plurality of connecting terminals; and

applying thermally expandable particles to at least one of a side of the semiconductor device and a surface of the mounting board around a projected area of the semiconductor device, and covering the thermally expandable particles with adhesive.

13. The method of manufacturing the electronic device of claim 12, wherein the connecting step adopts reflow soldering, and the thermally expandable particles are applied by injecting the thermally expandable particles together with disperse media from an injector in the application step.

14. The method of manufacturing the electronic device of claim 13, wherein

the injector in the application step has a first nozzle and a second nozzle for separately injecting the thermally expandable particles and the adhesive, the first nozzle and the second nozzle being disposed with a predetermined distance in between, and at least one of an injection pressure and injection time of the first nozzle and the second nozzle being independently controllable;

and

the thermally expandable particles are injected from the first nozzle to at least one of the side of the semiconductor device and the surface of the mounting board around the projected area of the semiconductor device, and then the adhesive is injected from the second nozzle so as to cover the thermally expanded particles.

15. The method of manufacturing the electronic device of claim 13, wherein the thermally expandable particles are dispersed in disperse media in the application step.

16. The method of manufacturing the electronic device of claim 14, wherein a width of a rectangular tube of the second nozzle seen from a direction of movement is at least one of the same and wider than a width of a rectangular tube of the first nozzle seen from a direction of movement, and the disperse media contains an adhesive resin component.

17. The method of manufacturing the electronic device of claim 15, wherein the disperse media contains an adhesive resin component.

18. The method of manufacturing the electronic device of claim 12, wherein

electrodes aligned on one main face of the semiconductor device and board electrodes of the mounting board are electrically connected by soldering with solder bumps in the connecting step;

the thermally expandable particles are provided on at least one of at least a part of the surface of the mounting board around the projected area of the semiconductor device, and at least a part of the side of the semiconductor device, and then thermosetting adhesive is applied to the mounting board and the side of the semiconductor device, the adhesive covering the thermally expandable particles in the application step; and

the adhesive applied in the application step is cured for bonding and fixing in a fixing step.

19. The method of manufacturing the electronic device of claim 18, wherein an expansion temperature of the thermally expandable particles is higher than a curing temperature of the adhesive and not higher than 260°

C.

20. A method of removing a semiconductor device in an electronic device, the electronic device including:

the semiconductor device having an electrode aligned on its one main face; and

a mounting board having a board electrode, the board electrode being electrically connected to the electrode of the semiconductor device by a solder bump;

wherein curable resin bonds and fixes at least one of a part of a side of the semiconductor device and the mounting board, and thermally expandable particles are mixed in at least a part of a boundary area between the curable resin and the mounting board; and

the removal method comprising;

heating the curable resin at a temperature higher than its curing temperature but not higher than a melting point of the solder bump so as to thermally expand the thermally expandable particles; and

removing the semiconductor device bonded and fixed by the curable resin from the mounting board.