HOLLOW SOLDER STRUCTURE HAVING IMPROVED RELIABILITY AND METHOD OF MANUFACTURING SAME

• US 20030052156A1
• Filed: 09/18/2001
• Published: 03/20/2003
• Est. Priority Date: 09/18/2001
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Moon, Ho-Jeong, Shin, Dong-Kil, Mok, Seung-Kon, Kim, Sang-Young
• Granted Patent: US 6,638,638 B2
• Time in Patent Office: Days
• US Class Current: 228/180.22
• CPC Class Codes: B23K 1/0008 specially adapted for particular articles or work
• CPC Class Codes: B23K 2101/40 Semiconductor devices
• CPC Class Codes: B23K 35/0222 for use in soldering, brazing B23K35/0205 takes precedence
• CPC Class Codes: B23K 35/0244 Powders, particles or spheres; Preforms made therefrom
• CPC Class Codes: H01L 2224/05568 the whole external layer protruding from the surface
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/13 of an individual bump connector
• CPC Class Codes: H01L 2224/13011 comprising apertures or cavities, e.g. hollow bump
• CPC Class Codes: H01L 2224/13099 Material
• CPC Class Codes: H01L 2224/29099 Material
• CPC Class Codes: H01L 2224/81801 Soldering or alloying
• CPC Class Codes: H01L 24/10 Bump connectors bumps on insulating substrates, e.g. chip carriers, H01L23/49816; Manufacturing methods related thereto
• CPC Class Codes: H01L 24/13 of an individual bump connector
• 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 2924/00013 Fully indexed content
• CPC Class Codes: H01L 2924/01004 Beryllium [Be]
• 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 2924/01015 : Phosphorus [P]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01039 : Yttrium [Y]
• 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 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/01084 : Polonium [Po]
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/09701 : Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/351 : Thermal stress
• CPC Class Codes: H05K 1/111 : Pads for surface mounting, e.g. lay-out
• CPC Class Codes: H05K 2201/09381 : Shape of non-curved single flat metallic pad, land or exposed part thereof; Shape of electrode of leadless component notches in edge pads H05K2201/09181
• CPC Class Codes: H05K 2201/0969 : Apertured conductors
• CPC Class Codes: H05K 2201/10257 : Hollow pieces of metal, e.g. used in connection between component and PCB
• CPC Class Codes: H05K 2203/0465 : Shape of solder, e.g. differing from spherical shape, different shapes due to different solder pads
• CPC Class Codes: H05K 3/3436 : having an array of bottom contacts, e.g. pad grid array or ball grid array components
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10T 428/12014 : having metal particles
• CPC Class Codes: Y10T 428/12222 : Shaped configuration for melting [e.g., package, etc.]

Abstract

A solder structure comprising a radially-curved exterior surface enclosing a predetermined-sized cavity used for flexibly joining together at predetermined conductive contact points two planar elements having dissimilar properties. By assembling the two planar elements in a tiered arrangement, one planar element having an annular conductive pad and the other planar element having either a corresponding annular or circular conductive pad, separated by a spherical solder compound comprised of solder and a fluxing agent, a hollow solder structure can be created during a melting and subsequent cooling of the solder compound. The plasticity/resiliency characteristics of the resulting hollow solder structure absorbs lateral movement of the two planar elements relative to each other without degradation of the solder joint.

Claims

1. A solder structure for electrically and mechanically connecting a first metal contact on a first planar surface to a second metal contact on a second planar surface, comprising:

a soldering means having a curved exterior surface enclosing a first volume; and

an interior cavity having a displacement constituting a second volume.

2. A solder structure as claimed in claim 1, wherein the solder means comprises a hollow cylindrical solder structure, the hollow cylindrical solder structure having:

a cylindrical exterior wall;

a top connecting the cylindrical exterior wall to the first metal contact; and

a bottom connecting the cylindrical exterior wall to the second metal contact.

3. A solder structure as claimed in claim 1, wherein the solder means comprises a hollow circular solder structure, the hollow circular solder structure having:

a generally circular exterior surface wall;

a top connecting the circular exterior wall to the first metal contact; and

a bottom connecting the circular exterior wall to the second metal contact.

4. A solder structure as claimed in claim 1, wherein the second volume comprises not less than 1% of the first volume.

5. A solder structure as claimed in claim 1, wherein the second Volume comprises not more than 90% of the first volume.

6. A solder structure as claimed in claim 1, wherein the soldering means comprises a mixture of one or more selected from the group consisting of solder, silver, tin, and a solder fluxing means.

7. The solder structure of claim 6, wherein the solder fluxing means comprises one or more from the group consisting of rosin, resin, activator, thixotropic agent, and a high temperature boiling solvent.

8. A catalytic means for creating a cavity in a solder ball upon heating and subsequent cooling, comprising

an annular metal land pattern on a planar surface;

and

the solder ball, positioned in contact with the annular land pattern, the solder ball further comprising

a solder material; and

a fluxing material.

9. A catalytic means as claimed in claim 8, wherein the annular metal land pattern has an inner diameter defined by an inner hole and an outer diameter, wherein the inner diameter is less than 90% of the outer diameter of the annular metal land pattern.

10. A catalytic means as claimed in claim 8, wherein a diameter of the solder ball is greater than an outer diameter of the annular metal land pattern.

11. A catalytic means as claimed in claim 8, wherein a mass of the solder material is less than a mass of the fluxing material.

12. A catalytic means as claimed in claim 8, wherein a weighted proportion of the solder material is less than a weighted proportion of the fluxing material.

13. A method for creating a hollow solder structure for electrically and mechanically connecting a first metal contact on a first planar surface to a second metal contact on a second planar surface, comprising the steps of:

a) etching the first metal contact having an annular land pattern;

b) etching the second metal contact having a circular land pattern;

c) placing a soldering means in contact with the annular land pattern;

d) positioning the second planar surface parallel to the first planar surface with the second metal contact contacting the soldering means;

e) applying heat to change the state of the soldering means to a molten state;

f) maintaining temperature for a predetermined amount of time in order for the molten solder to reflow across the surface of the first and second metal contacts; and

g) reducing the heat to allow the soldering means to return to a solid state.

14. A method for creating a hollow solder structure for electrically and mechanically connecting a first metal contact on a first planar surface to a second metal contact on a second planar surface as claimed in claim 13, wherein the soldering means comprises a solder ball made from a mixture of one or more selected from the group consisting of solder, silver, tin, and a solder fluxing means.

15. A method for creating a hollow solder structure for electrically and mechanically connecting a first metal contact on a first planar surface to a second metal contact on a second planar surface as claimed in claim 14, wherein the solder fluxing means comprises one or more from the group consisting of rosin, resin, activator, thixotropic agent, and a high temperature boiling solvent.

16. A method for creating a hollow solder structure for electrically and mechanically connecting a first metal contact on a first planar surface to a second metal contact on a second planar surface as claimed in claim 13, wherein step b) further comprises a step of etching a hole in the second metal contact to create an annular ring.