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BR-112025020304-B1 - Solder alloy, solder ball, solder preform, solder joint and circuit.

BR112025020304B1BR 112025020304 B1BR112025020304 B1BR 112025020304B1BR-112025020304-B1

Abstract

SOLDER ALLOY, SOLDER BALL, SOLDER PREFORM, SOLDER JOINT AND CIRCUIT. The present invention relates to a solder alloy, a solder ball, a solder preform, a solder joint and a circuit that have excellent wettability and shear strength, as well as an appropriate fracture mode, suppressed growth of an intermetallic compound at a joint interface even after reflow is performed a plurality of times, excellent drop impact resistance and an appropriate protrusion shape. The solder alloy has an alloy composition consisting of, in % by mass, Ag: 0.10 to 3.00%, Cu: 0.80 to 6.00%, Ni: 0.08 to 0.60%, Ge: 0.0010 to 0.0150%, with the remainder being Sn. Preferably, the alloy composition also contains at least one of Bi, Sb, In, Zn, Ga, Mn, Cr, Co, Si, Ti and rare earth elements: 0.1% or less in total.

Inventors

  • Kota SUGISAWA
  • Yuki IIJIMA
  • Shunsaku Yoshikawa

Assignees

  • SENJU METAL INDUSTRY CO., LTD

Dates

Publication Date
20260310
Application Date
20240419
Priority Date
20230428

Claims (7)

  1. 1. Solder alloy, CHARACTERIZED by comprising an alloy composition consisting of, in % by mass, Ag: 0.10 to 3.00%, Cu: 0.80 to 6.00%, Ni: 0.08 to 0.60%, Ge: 0.0010 to 0.0150%, with the remainder being Sn.
  2. 2. Solder alloy according to claim 1, CHARACTERIZED in that the alloy composition further comprises at least one of Bi, Sb, In, Zn, Ga, Mn, Cr, Si, Ti, and rare earth elements: 0.1% or less in total.
  3. 3. Solder alloy according to claims 1 or 2, CHARACTERIZED by the alloy composition satisfying the following relationships (1) and (2): 0.00043 ≤ Cu × Ni × Ge ≤ 0.00149 (1) 0.09 ≤ Ag × Cu × Ni ≤ 0.11 (2) where Ag, Cu, Ni and Ge in relationships (1) and (2) above represent the contents (% by mass) of the same in the alloy composition.
  4. 4. Welding sphere, CHARACTERIZED by consisting of the welding alloy according to claims 1 or 2.
  5. 5. Welding preform, CHARACTERIZED by consisting of welding alloy according to claims 1 or 2.
  6. 6. Welding joint, CHARACTERIZED by comprising welding alloy according to claims 1 or 2.
  7. 7. Circuit, CHARACTERIZED by comprising the desoldered joint according to claim 6.

Description

Technical Field [0001] The present invention relates to a solder alloy, a solder ball, a solder preform, a solder joint and a circuit. Previous Artwork [0002] In recent years, electronic devices have been required to be highly integrated, lightweight, thin, short, and small. The electronic components mounted in electronic devices are also required to be reduced in size and thickness. As a semiconductor package that satisfies these requirements, the BGA (a bead-grid array), which is an area-matrix surface mount package, is primarily used. The BGA has external electrode terminals in which solder balls are arranged in a grid pattern at equal intervals on a mounting substrate of a package. The solder balls are placed on the electrodes, and then heated together with the mounting substrate and melted in a reflow oven to form solder bumps. [0003] To meet additional demands for highly integrated, lighter, thinner, shorter, and smaller electronic devices, electronic components can be connected to both surfaces of a substrate. To connect the electronic components to both surfaces of the substrate, first reflow soldering is performed on one surface, and then a second reflow soldering is performed on the other surface. Furthermore, in the power semiconductor substrate, a third reflow soldering is performed to additionally connect a heat sink. As described above, when reflow soldering is performed multiple times, the solder alloy used for the first or second soldering is repeatedly melted and solidified. [0004] Incidentally, in conventional BGA, a Sn-Ag-Cu based solder alloy represented by Sn-3.0Ag-0.5Cu has been used. However, when such reflow soldering is performed multiple times, voids are generated at the joint interface between the solder alloy that constitutes the solder joint and the electrode. As the voids grow, the shear strength and drop impact resistance properties deteriorate. Furthermore, as the melting and solidification of the solder alloy are repeated, oxidation of the solder alloy progresses, and wettability may deteriorate. [0005] Therefore, Patent Document 1 discloses a Sn alloy containing 1 to 9% Cu and containing various optional elements from the point of view of suppressing the deterioration of the reliability of a weld joint due to reflow welding performed multiple times. Specifically, Sn-Cu-Ni based solder alloys and Sn-Cu-Ni-Ge based solder alloys are disclosed. These solder alloys also contain P and similar elements. It is also disclosed that Ag may be contained as an optional element. Shear strength after reflow welding performed multiple times, die slope and void growth are evaluated in the same document. [0006] Patent Document 2 discloses an Sn-Ag-Cu-Ni solder alloy to improve drop impact resistance by reducing the hardness of the solder alloy. In the invention described in the same document, it is described that P and Ge are contained as elements that suppress discoloration of the solder alloy. [0007] Patent Document 3 discloses a Sn-Ag-Cu-Ni-Ge solder alloy as an inexpensive quinary solder alloy having good bonding capacity. In the invention described in the same document, the void occurrence rate and elongation at break are evaluated. Additionally, the same document also describes that the elongation at break is improved by reducing void generation and reducing the thickness of the Cu3Sn film. The same document also discloses that oxidation is suppressed as a reason for adding Ge. [0008] Patent Document 4 discloses a solder alloy in which an Sn-Ag-Cu solder alloy contains a predetermined amount of at least one of La, Ce, Pr, Nd, Sm, Yb, Y, Gd, and Dy to improve joint strength while reducing the Ag content. The same document also discloses that Ni or Fe may be further contained to refine the crystal structure of the solidified solder alloy and improve mechanical strength. Furthermore, the same document discloses that P, Ga, and Ge may be contained as elements that are very easily oxidized to suppress the occurrence of slag due to the oxidation of La, Ce, Pr, Nd, Sm, Yb, Y, Gd, Dy, Ni, and Fe. List of Citations Patent Document [0009] Patent Document 1: International Publication No. WO 2020/135932 Patent Document 2: International Publication No. WO 2007/102588 Patent Document 3: Publication of Unexamined Japanese Patent Application No. 2008-93701 A Patent Document 4: Publication of Unexamined Japanese Patent Application No. 2013-049073 A Summary of the Invention Technical Problem [0010] In Patent Document 1, several evaluations are made on the alloy composition containing Sn and Cu. However, the evaluation is performed with an alloy composition having different constituent elements according to each evaluation item. For example, in the evaluation of die inclination, a solder alloy having constituent elements exhibiting a melting point such that it does not melt in the second reflow or maintains a high viscosity even when melted is used. Void growth and shear strength after reflow soldering