Thermal compression bonding of semiconductor chips

• US 8,967,452 B2
• Filed: 04/17/2012
• Issued: 03/03/2015
• Est. Priority Date: 04/17/2012
• Status: Active Grant

• Current Assignee: Asmpt Singapore Pte Limited
• Original Assignee: ASM Technology Singapore Pte Limited (ASMPT Ltd.)
• Inventors: Cheung, Yiu Ming, Li, Ming, Lo, Tsan Yin Peter, Mak, Yick Hong, Lam, Ka San
• Primary Examiner(s): STONER, KILEY SHAWN
• Application Number:
  US13/448,866
• Publication Number:
  US 20130270230A1
• Time in Patent Office: 1,050 Days
• Field of Search: None
• US Class Current: 228/180.21
• CPC Class Codes: H01L 2224/13082 Two-layer arrangements
• CPC Class Codes: H01L 2224/13111 Tin [Sn] as principal constituent
• CPC Class Codes: H01L 2224/13147 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/16238 the bump connector connecting to a bonding area protruding from the surface of the item
• CPC Class Codes: H01L 2224/75251 in the lower part of the bonding apparatus, e.g. in the apparatus chuck
• CPC Class Codes: H01L 2224/75263 in the upper part of the bonding apparatus, e.g. in the bonding head
• CPC Class Codes: H01L 2224/75744 in the lower part of the bonding apparatus, e.g. in the apparatus chuck
• CPC Class Codes: H01L 2224/75753 Means for optical alignment, e.g. sensors
• CPC Class Codes: H01L 2224/78252 in the upper part of the bonding apparatus, e.g. in the capillary or wedge
• CPC Class Codes: H01L 2224/78253 adapted for localised heating
• CPC Class Codes: H01L 2224/81048 Thermal treatments, e.g. annealing, controlled pre-heating or pre-cooling
• CPC Class Codes: H01L 2224/81121 Active alignment, i.e. by apparatus steering, e.g. optical alignment using marks or sensors
• CPC Class Codes: H01L 2224/81191 wherein the bump connectors are disposed only on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/81203 Thermocompression bonding, e.g. diffusion bonding, pressure joining, thermocompression welding or solid-state welding
• CPC Class Codes: H01L 2224/81224 using a laser
• CPC Class Codes: H01L 2224/81907 Intermediate bonding, i.e. intermediate bonding step for temporarily bonding the semiconductor or solid-state body, followed by at least a further bonding step
• CPC Class Codes: H01L 2224/81986 Specific sequence of steps, e.g. repetition of manufacturing steps, time sequence
• CPC Class Codes: H01L 2224/9205 Intermediate bonding steps, i.e. partial connection of the semiconductor or solid-state body during the connecting process
• CPC Class Codes: H01L 24/13 of an individual bump connector
• CPC Class Codes: H01L 24/16 of an individual bump connector
• CPC Class Codes: H01L 24/75 : Apparatus for connecting with bump connectors or layer connectors
• CPC Class Codes: H01L 24/81 : using a bump connector
• 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 2924/00014 : 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 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/07802 : not being an ohmic electrical conductor
• CPC Class Codes: H01L 2924/12042 : LASER
• CPC Class Codes: H01L 2924/15192 : Resurf arrangement of the internal vias
• CPC Class Codes: H01L 2924/15311 : being a ball array, e.g. BGA

Abstract

A die is prepared for thermal compression bonding by first aligning electrical contacts on the die to bond pads on a substrate onto which the die is to be mounted. Those electrical contacts are held against the bond pads on the substrate with a bonding tool. Partially bonding the die onto the substrate by providing heat to a portion of the die to elevate a temperature there to above a melting point of solder in the electrical contacts so as to melt at least some of the solder. Then thermally compress the whole die and heat it to above the melting point of the solder of the electrical contacts so that the solder of the electrical contacts outside the portion of the die are also melted to bond the die to the substrate.

Claims

1. A thermal compression bonding method comprising the steps of:

aligning electrical contacts on a die to bond pads on a substrate onto which the die is to be mounted;

after aligning the die, holding the electrical contacts on the die against the bond pads on the substrate with a bonding tool;

partially bonding the die to the substrate by providing heat to a local portion of the whole die to elevate a temperature at the portion of the die to above a melting point of solder comprised in the electrical contacts so as to melt at least some of the solder of the electrical contacts which are located at the said portion of the die;

and thereafter heating the whole die to above the melting point of the solder of the electrical contacts so that the solder of the electrical contacts outside the said portion of the die are also melted to thermal compression bond the die to the substrate.

2. The thermal compression bonding method as claimed in claim 1, wherein the step of providing heat to the said portion of the die comprises the step of firing a laser beam onto the said portion of the die.

3. The thermal compression bonding method as claimed in claim 2, wherein the said portion of the die comprises two separate localized heating regions located at diagonally-opposite corners of the die.

4. The thermal compression bonding method as claimed in claim 2, wherein the laser beam produces a laser spot having a diameter of about 1 mm.

5. The thermal compression bonding method as claimed in claim 2, wherein the wavelength of the laser beam is in the range of 700-980 nm.

6. The thermal compression bonding method as claimed in claim 1, wherein during the step of aligning the electrical contacts on the die, the die is heated to a temperature which is substantially higher than room temperature but is less than 100°

C.

7. The thermal compression bonding method as claimed in claim 1, further comprising the step of transferring the partially-bonded die and substrate to a buffer station which is heated to a pre-heat temperature that is higher than a temperature of the die when it is being aligned but less than a melting point of the solder, before subsequently heating the whole die to above the melting point of the solder at a thermal compression bonding station.

8. The thermal compression bonding method as claimed in claim 1, wherein during heating of the whole die to above the melting point of the solder, a temperature of a bonding tool holding the die is elevated to a temperature which is above the melting point of the solder, and the temperature of the bonding tool is then reduced to below a solidification temperature of the solder so as to form conductive joints between the die and the substrate.

9. The thermal compression bonding method as claimed in claim 1, wherein one die is being aligned at a first station while another die is being heated in parallel to above the melting point of the solder at a second station separate from the first station to melt the solder outside the said portion of the die.

10. The thermal compression bonding method as claimed in claim 1, wherein each electrical contact comprises a copper pillar topped with a solder cap.

11. The thermal compression bonding method as claimed in claim 1, wherein multiple dies are heated to above the melting point of the solder simultaneously at a plurality of thermal compression stations.

12. The thermal compression bonding method as claimed in claim 1, wherein multiple dies are held by a bonding tool and the multiple dies are simultaneously heated to above the melting point of the solder at a same thermal compression station.

13. A thermal compression apparatus comprising:

a precision alignment station for aligning a die comprising electrical contacts to bond pads on a substrate onto which the die is to be mounted;

a bonding tool for holding the electrical contacts on the die against the bond pads on the substrate;

a heating device operative to partially bond the die to the substrate by providing heat to a local portion of the whole die to elevate a temperature at the portion of the die to above a melting point of solder comprised in the electrical contacts so as to melt at least some of the solder of the electrical contacts which are located at the said portion of the die;

and a thermal compression station for heating the whole die to above the melting point of the solder of the electrical contacts so that the solder of the electrical contacts outside the said portion of the die are also melted to bond the die to the substrate.

14. The thermal compression apparatus as claimed in claim 13, further comprising a pre-heat buffer station that is operative to heat the partially-bonded die to a pre-heat temperature that is higher than a temperature to which the die is heated at the precision alignment station but less than the melting point of the solder.

15. The thermal compression apparatus as claimed in claim 13, wherein the heating device comprises at least one laser device that is operative to fire a laser beam to provide heat to the said portion of the die.

16. The thermal compression apparatus as claimed in claim 15, wherein the heating device comprises two laser devices that are operative to fire separate laser beams at two separate localized heating regions located at diagonally-opposite corners of the die.

17. The thermal compression apparatus as claimed in claim 14, wherein the laser beam produces a laser spot having a diameter of about 1 mm.

18. The thermal compression apparatus as claimed in claim 14, wherein the wavelength of the laser beam is in the range of 700-980 nm.

19. The thermal compression apparatus as claimed in claim 13, wherein processing at the precision alignment station and thermal compression station are conducted simultaneously in parallel on different dies.

20. The thermal compression apparatus as claimed in claim 19, wherein the thermal compression station further comprises a plurality of separate stations where multiple dies are simultaneously heated to above the melting point of the solder at the stations.