Methods and systems for material bonding

• US 8,536,047 B2
• Filed: 03/18/2011
• Issued: 09/17/2013
• Est. Priority Date: 09/18/2008
• Status: Active Grant

• Current Assignee: IMEC International
• Original Assignee: IMEC International
• Inventors: Zhang, Wenqi, Beyne, Eric
• Primary Examiner(s): CHU, CHRIS C
• Application Number:
  US13/051,357
• Publication Number:
  US 20110233792A1
• Time in Patent Office: 914 Days
• Field of Search: 257/E23.01, 257/E23.021, 257/738, 257/748, 257/762, 257/772, 257/773, 257/775, 257778-781, 257/786, 438/108, 438/612, 438/614, 438/638, 438/666, 420/558, 420/560, 228/180.22
• US Class Current: 438/614
• CPC Class Codes: H01L 2224/13 of an individual bump connector
• CPC Class Codes: H01L 2224/13099 Material
• CPC Class Codes: H01L 2224/131 with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
• CPC Class Codes: H01L 2224/291 with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
• CPC Class Codes: H01L 2224/29111 Tin [Sn] as principal constituent
• CPC Class Codes: H01L 2224/32507 comprising an intermetallic compound
• CPC Class Codes: H01L 2224/81203 Thermocompression bonding, e.g. diffusion bonding, pressure joining, thermocompression welding or solid-state welding
• CPC Class Codes: H01L 2224/81208 applying unidirectional static pressure
• CPC Class Codes: H01L 2224/81801 Soldering or alloying
• CPC Class Codes: H01L 2224/81894 Direct bonding, i.e. joining surfaces by means of intermolecular attracting interactions at their interfaces, e.g. covalent bonds, van der Waals forces
• CPC Class Codes: H01L 2224/83099 Ambient temperature
• CPC Class Codes: H01L 2224/83801 Soldering or alloying
• CPC Class Codes: H01L 2224/83894 Direct bonding, i.e. joining surfaces by means of intermolecular attracting interactions at their interfaces, e.g. covalent bonds, van der Waals forces
• CPC Class Codes: H01L 2224/9211 Parallel connecting processes
• CPC Class Codes: H01L 2225/06513 Bump or bump-like direct electrical connections between devices, e.g. flip-chip connection, solder bumps
• CPC Class Codes: H01L 24/13 of an individual bump connector
• CPC Class Codes: H01L 24/32 of an individual layer connector
• CPC Class Codes: H01L 24/81 using a bump connector
• CPC Class Codes: H01L 24/83 using a layer connector
• CPC Class Codes: H01L 24/91 Methods for connecting semiconductor or solid state bodies including different methods provided for in two or more of groups H01L24/80 - H01L24/90
• CPC Class Codes: H01L 25/0657 : Stacked arrangements of devices
• CPC Class Codes: H01L 25/50 : Multistep manufacturing processes of assemblies consisting of devices, each device being of a type provided for in group H01L27/00 or H01L29/00 H01L21/50 takes precedence
• 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 2924/01005 : Boron [B]
• CPC Class Codes: H01L 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01019 : Potassium [K]
• CPC Class Codes: H01L 2924/01023 : Vanadium [V]
• CPC Class Codes: H01L 2924/01027 : Cobalt [Co]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01032 : Germanium [Ge]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01046 : Palladium [Pd]
• CPC Class Codes: H01L 2924/01049 : Indium [In]
• CPC Class Codes: H01L 2924/0105 : Tin [Sn]
• CPC Class Codes: H01L 2924/01075 : Rhenium [Re]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/0132 : Binary Alloys
• CPC Class Codes: H01L 2924/01327 : Intermediate phases, i.e. intermetallics compounds
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/07802 : not being an ohmic electrical conductor
• CPC Class Codes: H01L 2924/10253 : Silicon [Si]
• CPC Class Codes: H01L 2924/10329 : Gallium arsenide [GaAs]
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/1461 : MEMS
• CPC Class Codes: H01L 2924/30105 : Capacitance
• CPC Class Codes: H01L 2924/3512 : Cracking

Abstract

A device and a method for realizing reliable electrical contacts at low temperature and low pressure between conducting materials on, for example, different substrates are disclosed. In one aspect, a rough and brittle intermetallic layer is formed on a conducting material on a first substrate. A soft solder material layer on the other substrate is used for contacting the brittle and rough intermetallic layer that will break. As the solder material is relatively soft, contact between the broken intermetallic layer and the solder material can be realized over a large portion of the surface area. At that stage, a second intermetallic layer is formed between the solder material and the first intermetallic layer realizing electrical contact.

Claims

1. A method of realizing electrical contact between a first conducting material on a first substrate and a second conducting material on a second substrate, the method comprising:

(a) receiving a first intermetallic layer on the first conducting material on the first substrate, wherein the first intermetallic layer is brittle and has a roughness such that it breaks upon contacting a solder material with a low pressure, wherein excess metal on the first intermetallic layer is removed;

(b) receiving a solder material on the second conducting material, wherein the solder material has a lower melting point than the first and second conducting materials and the first intermetallic layer, wherein the solder material is softer than the first intermetallic layer;

(c) bringing the solder material in contact with the first intermetallic layer at a temperature below the melting temperature of the solder material such that the first intermetallic layer breaks;

(d) bringing the solder material in closer contact with the first intermetallic layer at a temperature below the melting temperature of the solder material such that the solder material fills at least part of the holes in the surface of the first intermetallic layer after breaking the first intermetallic layer; and

(e) forming a second intermetallic layer at the interface between the solder material and the first intermetallic layer at a temperature below the melting temperature of the solder material.

2. The method according to claim 1, wherein the first intermetallic layer is in a stable phase such that it does not react with the first conducting material on the first substrate.

3. The method according to claim 1, wherein the thickness of the first intermetallic layer is between about 1000 nm and 2000 nm.

4. The method according to claim 1, wherein the intermetallic layer has a root mean square (RMS) surface roughness higher than about 0.2 μ

m and a peak-to-valley height difference higher than about 0.5 μ

m.

5. The method according to claim 1, wherein the first intermetallic layer breaks if between about 30% and 70% of the solder material area is in contact with the first intermetallic layer.

6. The method according to claim 1, wherein the solder material fills at least part of the holes in the surface of the first intermetallic layer when more than about 50% of the solder material area is in contact with the first intermetallic layer.

7. The method according to claim 1, wherein the solder material substantially fills all the holes in the surface of the first intermetallic layer in the contacting area such that it is fully in contact with the first intermetallic layer.

8. The method according to claim 1, wherein the solder material has a volume such that it is fully consumed after forming the second intermetallic layer.

9. The method according to claim 1, the method further comprising depositing an intermediate layer on the first conducting material prior to receiving the first intermetallic layer.

10. The method according to claim 1, wherein the first conducting material comprises a first metal and wherein the first intermetallic layer is received by depositing a layer of a second metal on the first metal and reacting the first metal with the second metal layer to form the first intermetallic layer.

11. The method according to claim 1, wherein the low pressure is a pressure of about 50 MPa or lower.

12. The method according to claim 11, wherein the low pressure is a pressure of about 20 MPa or lower.

13. The method according to claim 1, wherein the low pressure is a pressure of about 20 MPa or lower.