Noble metal-coated copper wire for ball bonding

A precious metal and coating technology, applied in the direction of conductive materials, conductors, electrical components, etc., can solve the problems of extremely difficult to be practical, uneven molten spheres, etc.

Active Publication Date: 2017-08-11
TANAKA DENSHI KOGYO KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, if the palladium (Pd) extension layer is thickened, the molten sphere tends to become uneven.
Therefore, it is extremely difficult to put the invention disclosed in the aforementioned Japanese Patent Application Laid-Open No. 2013-42105 (Patent Document 2 mentioned later) into practical use.

Method used

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  • Noble metal-coated copper wire for ball bonding
  • Noble metal-coated copper wire for ball bonding
  • Noble metal-coated copper wire for ball bonding

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1-3

[0136] A palladium (Pd)-sulfur (S) amorphous alloy coating layer was formed as follows. To a commercially available palladium (Pd) plating bath (ADP700 manufactured by EEJA Co., Ltd.), 0.1 g / L, 0.005 g / L, and 0.15 g / L of ADP700 additives manufactured by the same company were added, respectively. The concentration of sulfur (S) in the electroplating bath is made to be medium concentration, low concentration and high concentration by the addition amount of the additive. In this bath, make the current flow at a current density of 0.75A / dm 2 A copper wire with a diameter of 1.0 mm was flowed in to form a coating layer of palladium (Pd)-sulfur (S) eutectoid plating. The three types of coated copper wires were coated with gold (Au) having a predetermined thickness by magnetron sputtering.

[0137] Afterwards, no baking treatment is performed, that is, the wire is drawn twice continuously through a diamond mold, and then subjected to a tempering heat treatment at 480° C. for 1 seco...

Embodiment 4

[0140] The palladium (Pd)-phosphorus (P) amorphous alloy coating layer was formed in the following manner. First, nickel (Ni) plating is performed as base plating. In Watts bath, for a copper wire with a diameter of 1.0mm, the current density is 2A / dm 2 A current was applied to form a nickel (Ni) coating layer of 0.2 μm. Next, phosphorous acid (H 3 PO 3 )0.2g / L. In this bath, for a copper wire with a diameter of 1.0mm, at a current density of 0.75A / dm 2 An electric current is applied to form a palladium (Pd)-phosphorous (P) amorphous alloy coating layer. Thereafter, in the same manner as in Example 1, the noble metal-coated copper wire for ball bonding of Example 4 was produced.

[0141] The hydrogen concentration in the noble metal-coated copper wire of Example 4 and the phosphorus (P) concentration in the palladium (Pd) shell layer were 6 mass ppm and 420 mass ppm, respectively.

Embodiment 5

[0143] A coating layer containing a palladium (Pd)-carbon (C)-boron (B) alloy was formed in the following manner. In a commercially available palladium (Pd) plating bath (ADP700 manufactured by EEJA Co., Ltd.), a surfactant (JSwetter manufactured by EEJA Co., Ltd.) was added at 2 mL / L, a boron inorganic compound was added in a predetermined amount, and a chain high Molecular gloss. In this bath, for a copper wire with a diameter of 1.0mm, at a current density of 0.75A / dm 2 A current is supplied to form a coating layer of palladium (Pd)-carbon (C)-boron (B) eutectoid plating. Thereafter, in the same manner as in Example 1, the noble metal-coated copper wire for ball bonding of Example 5 was produced.

[0144] The hydrogen concentration in the noble metal-coated copper wire of Example 5 and the element concentration in the palladium (Pd) shell layer were 0.3 ppm by mass, 630 ppm by mass for carbon (C), and 300 ppm by mass for boron (B).

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Abstract

The invention discloses a noble metal-coated copper wire for ball bonding, with a wire diameter between 10 [mu]m or more, and 25 [mu]m or less, the noble metal-coated copper wire including a core material having a copper alloy having a copper purity of 98 mass % or higher, and a noble metal-coating layer formed on the core material. The noble metal-coating layer includes a palladium cavitating layer containing palladium; at least one element selected from the group consisting of Group 13 to 16 elements or an oxygen element, finely dispersed in the palladium; and a diffusion layer formed of copper diffused into the palladium. According to the invention, the noble metal-coated copper wire for ball bonding can enable a palladium enriching layer to be evenly dispersed on the entire surface of the fusion copper ball of the core material and the palladium does not flow into a solidified copper ball, such that cavities do not form. The noble metal-coated copper wire here is suitable for mass production.

Description

technical field [0001] The present invention relates to a noble metal-coated copper wire for ball bonding, which is suitable for connecting "IC chip electrodes used in semiconductor devices" and "substrates such as external leads" and has a wire diameter in the range of 10 μm to 25 μm; especially The present invention relates to a noble metal-coated copper wire for ball bonding in which a high-concentration palladium (Pd) concentrated layer is stably formed on the surface of a solidified sphere. Background technique [0002] Generally, in the first bonding of the copper-covered bonding wire and the electrode, a method called ball bonding is used, and in the second bonding of the copper-covered bonding wire and the wiring on the circuit wiring board for semiconductors, is using what is known as a wedge joint. In this first bonding, arc heating is applied to the tip of the coated copper bonding wire by a discharge current of discharge ball (EFO) type. In the EFO formula, gen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L21/60
CPCH01L24/42H01L2224/45099H01L2224/45147H01L2924/01029H01L2924/01028H01L2924/01046H01L2924/013H01B1/026H01L2924/10253H01L2224/45664H01L2224/45644H01L2224/45655H01L2224/45572H01L2224/45573H01L2224/43125H01L2224/45015H01L2924/14H01L2224/43848H01L2224/05624H01L2924/15311H01L2224/4321H01L2224/78301H01L24/05H01L2224/48463H01L24/45H01L24/43H01L2924/00012H01L2924/01201H01L2924/01016H01L2924/01006H01L2924/01015H01L2924/01005H01L2924/01014H01L2924/01032H01L2924/01033H01L2924/01034H01L2924/01049H01L2924/0105H01L2924/01051H01L2924/01052H01L2924/01083H01L2924/01008H01L2924/01078H01L2924/01001H01L2924/20751H01L2924/20752H01L24/11H01L24/16H01L2224/1134H01L2224/16503
Inventor 天野裕之枪田聪明崎田雄祐安德优希陈炜
Owner TANAKA DENSHI KOGYO KK
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