# US 10,370,771 B2 · Method of manufacturing cu core ball

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 10,370,771 B2
- Document ID: US10370771B2
- Status: Granted
- Kind: B2
- Application number: 15/461,866
- Filed: 2017-03-17
- Published: 2017-08-17
- Granted: 2019-08-06
- Earliest claimed: 2014-01-28
- Assignees: Senju Metal Industry Co., Ltd.
- Applicants: Senju Metal Industry Co., Ltd.
- Inventors: Hiroyoshi Kawasaki; Takahiro Roppongi; Daisuke Soma; Isamu Sato
- Web page: https://patentgrep.com/patent/US10370771B2

## CPC

- C25D 3/60: containing more than 50% by weight of tin
- B22F 1/17: Metallic particles coated with metal
- B22F 9/08: by casting, e.g. through sieves or in water, by atomising or spraying (using electric discharge B22F9/14)
- B23K 35/0222: {for use in soldering or brazing (B23K35/0205 takes precedence)}
- B23K 35/0244: {Powders, particles or spheres; Preforms made therefrom}
- B23K 35/025: {Pastes, creams or slurries}
- B23K 35/26: with the principal constituent melting at less than 400°C
- B23K 35/262: {Sn as the principal constituent}
- B23K 35/30: with the principal constituent melting at less than 1550°C
- B23K 35/302: {Cu as the principal constituent}
- C22C 9/00: Alloys based on copper
- C22C 13/00: Alloys based on tin
- C25D 3/30: of tin
- C25D 5/10: Electroplating with more than one layer of the same or of different metals (for bearings C25D7/10)
- C25D 5/12: at least one layer being of nickel or chromium
- C25D 5/20: Electroplating using ultrasonic waves
- C25D 5/611: {Smooth layers}
- F16B 5/08: by means of welds or the like (welding B23K)
- H01B 1/02: mainly consisting of metals or alloys
- B22F 2301/10: Copper
- B22F 2301/30: Low melting point metals, i.e. Zn, Pb, Sn, Cd, In, Ga
- B23K 2101/40: Semiconductor devices
- H05K 3/3436: {having an array of bottom contacts, e.g. pad grid array or ball grid array components}
- H05K 2201/0218: Composite particles, i.e. first metal coated with second metal
- H05K 2201/10734: Ball grid array [BGA]; Bump grid array
- H10W 72/223: {characterised by the structure of the outermost layers, e.g. multilayered coatings}
- H10W 72/232: {Plan-view shape, i.e. in top view}
- H10W 72/252: {comprising solid metals or solid metalloids, e.g. PbSn, Ag or Cu}
- H10W 72/255: {of outermost layers of multilayered bumps, e.g. material of a coating}
- C25D: PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- F16B: DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING (couplings for transmitting rotation F16D)
- H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K})
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A Cu core ball and a method of manufacturing such a Cu core ball. Purity of the Cu internal ball is at least 99.9% and not greater than 99.995%. A total contained amount of Pb and/or Bi in impurity contained in the Cu ball is equal to or larger than 1 ppm. Its sphericity is at least 0.95. A solder plating film coated on the Cu ball is of Sn solder or a lead free solder alloy whose primary component is Sn. In the solder plating film, a contained amount of U is not more than 5 ppb and that of Th is not more than 5 ppb. A total alpha dose of the Cu ball and the solder plating film is not more than 0./0200 cph/cm2. An arithmetic average roughness of the Cu core ball is equal to or less than 0.3 μm.

## Claims

### Claim 1

A method of manufacturing a Cu core ball, comprising:
providing a Cu ball as an inside ball, of least 99.9 mass percent but not more than 99.995 mass percent of said Cu ball being Cu, said Cu ball having a contained amount of U equal to or less than 5 ppb by mass, a contained amount of Th equal to or less than 5 ppb by mass, a total contained amount of at least one of Pb and Bi equal to or larger than 1 ppm by mass, and a sphericity equal to or higher than 0.95;
surrounding the inside ball with a solder plating film of a lead free solder alloy whose primary component is Sn;
thereafter, placing the inside ball, surrounded by the solder plating film, into a quantity of a plating solution and irradiating the inside ball, the solder plating film, and the plating solution with an ultrasonic wave for a period time that is sufficient to provide a Cu core ball having an arithmetic roughness equal to or less than 0.3 μm.

### Claim 2 (depends on 1)

The method of claim 1 wherein the lead free solder alloy contains no more than 5 ppb by mass of U and no more than 5 ppb by mass of Th.

### Claim 3 (depends on 2)

The method of claim 2 including performing the step of irradiating for a time that is great enough to provide an arithmetic roughness equal to or less than 0.22 μm.

### Claim 4 (depends on 2)

The method of claim 2 including the step of covering the inside ball with a plating layer comprising at least one element selected from the group consisting of Ni and Co before performing the step of surrounding the inside ball with a solder plating film.

### Claim 5 (depends on 2)

The method of claim 2, wherein said Cu core ball has an alpha dose equal to or less than 0.0200 cph/cm2.

### Claim 6 (depends on 1)

The method of claim 1 including performing the step of irradiating for a time that is great enough to provide an arithmetic roughness equal to or less than 0.22 μm.

### Claim 7 (depends on 6)

The method of claim 6 including the step of covering the inside ball with a plating layer comprising at least one element selected from the group consisting of Ni and Co before performing the step of surrounding the inside ball with a solder plating film.

### Claim 8 (depends on 6)

The method of claim 6, wherein said Cu core ball has an alpha dose equal to or less than 0.0200 cph/cm2.

### Claim 9 (depends on 1)

The method of claim 1 including the step of covering the inside ball with a plating layer comprising at least one element selected from the group consisting of Ni and Co before performing the step of surrounding the inside ball with a solder plating film.

### Claim 10 (depends on 9)

The method of claim 9 wherein said Cu core ball has an alpha dose equal to or less than 0.0200 cph/cm2.

### Claim 11 (depends on 1)

The method of claim 1, wherein said Cu core ball has an alpha dose equal to or less than 0.0200 cph/cm2.