KR-20260065955-A - Bonding wire for semiconductor devices

Abstract

The present invention aims to improve the productivity of the bonding process by improving the build-up resistance of the capillary tip while ensuring the bonding reliability of the primary bond (also called 1st bond, FAB bond, or ball bond) or secondary bond (also called 2nd bond, or wedge bond), and aims to provide such an Ag bonding wire. The bonding wire that achieves the above objective is an Ag bonding wire made of an Ag alloy comprising In: 0.05 to 3.0 mass%, one or more of Pd, Pt, and Au: 0.010 to 5.0 mass%, one or more of Sc, Ti, and Mn: 0.0005 to 0.050 mass%, and one or more of P, Zn, Bi, and Cu: 0 to 0.030 mass%.

Inventors

• 오오카베 다쿠미
• 오다 다이조
• 에토 모토키
• 오이시 료
• 오야마다 데츠야
• 우노 도모히로

Assignees

• 닛데쓰마이크로메탈가부시키가이샤
• 닛테츠 케미컬 앤드 머티리얼 가부시키가이샤

Dates

Publication Date

20260511

Application Date

20241025

Priority Date

20231026

Claims (3)

1. In 0.05 mass% to 3.0 mass%, One or more of Pd, Pt, and Au in a total of 0.010 mass% to 5.0 mass%, 0.0005 mass% to 0.050 mass% of one or more of Sc, Ti, and Mn in total, It comprises 0 mass% to 0.030 mass% of one or more of P, Zn, Bi, and Cu in total, Bonding wire for a semiconductor device characterized by the remainder being composed of Ag and unavoidable impurities.
2. In paragraph 1, A bonding wire for a semiconductor device containing 0.0001 mass% to 0.030 mass% of one or more of P, Zn, Bi, and Cu in total.
3. In paragraph 1 or 2, A bonding wire for a semiconductor device, wherein in a cross-section perpendicular to the wire axis of the bonding wire, the ratio of the total length of twin grain boundaries to the total length of crystal grain boundaries is 40% or more.

Description

Bonding wire for semiconductor devices The present invention relates to a bonding wire for a semiconductor device used to connect the wiring of a circuit wiring board, such as an electrode on a semiconductor device and an external lead. A fine wire with a wire diameter of about 15 to 50 μm is mainly used as a bonding wire for semiconductor devices (hereinafter referred to as a bonding wire or simply a wire) that joins an electrode on a semiconductor device and an external lead. Excellent ball-forming ability, ball-joining ability, wedge-joining ability, and loop-forming ability are required for the bonding wire, and to comprehensively satisfy these requirements, bonding wires made of Au (gold) have been mainly used. However, since Au is expensive, there is a demand for low-cost wire materials to replace Au, and as one such material, a bonding wire made of Ag (silver) (hereinafter referred to as an Ag bonding wire) is being proposed. For example, Patent Document 1 proposes an Ag bonding wire in which the content of Pd and Pt and the content of P, Cr, Zr, and Mo are optimized to ensure bonding reliability in a high-temperature environment even with a mold resin having a high sulfur (S) content and to suppress chip damage during ball bonding. In Patent Documents 2 and 3, an Ag-Pd-Pt ternary Ag bonding wire for ultra-high frequency signals (several GHz range) is proposed. Patent document 4 proposes an Ag bonding wire containing one or more of In, Ga, and Cd to satisfy bonding reliability, spring performance, and chip damage performance. In Patent Document 5, an Ag bonding wire containing one or more of Be, B, P, Ca, Y, La, and Ce and one or more of In, Ga, and Cd is proposed to achieve bonding strength of the ball joint required for high-density packaging while securing bonding reliability and to improve the lining characteristics of the ball upright portion. The following description is based on one embodiment of the present invention (hereinafter simply referred to as the present invention). Unless otherwise specified, "%" regarding components indicates the mass percentage in the wire. Cases where a lower limit is not specifically defined or where the lower limit is 0% include cases where it is not contained (0%). Furthermore, as described above, in this specification, a bonding wire for a semiconductor device may be referred to as a bonding wire or simply a wire. [In: 0.05% to 3.0%] In has the effect of improving the reliability of the primary bonding (ball (FAB) bonding) of Ag bonding wires. For example, in a HAST test (high temperature and high humidity test) in an atmosphere of 130°C and 85% humidity, when wires containing In and wires containing In were evaluated, it was confirmed that the time for the shear strength of the ball bonding section to become half of the initial strength was more than twice that of the wire containing In compared to the wire not containing In. Therefore, the In content is set to 0.05% or more. The lower limit of the In content can be 0.10%, 0.15%, 0.20%, 0.30%, 0.40%, or 0.50%. Meanwhile, if the In content increases, stress concentration occurs during ball bonding in the bonding process, making chip damage more likely to occur. In addition, In is prone to enriching on the FAB surface, which is thought to facilitate the formation of In-based precipitate buildup at the capillary tip. Therefore, the In content is set to 3.0% or less. The upper limit of the In content can be set to 2.7%, 2.5%, 2.3%, 2.1%, or 1.9%. [One or more of Pd, Pt, and Au: 0.010% to 5.0%] Pd, Pt, and Au have suppressed sulfur adsorption compared to Ag (excellent sulfur resistance). Therefore, sulfurization of the surface of the Ag bonding wire can be suppressed, and the floor life (service life of the bonding wire) can be extended. In addition, these elements have a strong bonding affinity with In, so containing them in combination is effective in suppressing deterioration over time due to a synergistic effect. For this reason, the total content of at least one of Pd, Pt, and Au is set to 0.010% or more. The lower limit of the total content of these elements can be 0.030%, 0.050%, 0.070%, 0.100%, 0.200%, 0.300%, 0.400%, or 0.500%. Meanwhile, if the content of Pd, Pt, and Au increases, the resistivity increases, and the conductivity and thermal conductivity decrease, making it unsuitable for practical use. Therefore, the total content of one or more of Pd, Pt, and Au is set to 5.0% or less. The upper limit of the content may be 4.5%, 4.0%, 3.5%, 3.0%, or 2.5%. [One or more of Sc, Ti, and Mn: 0.0005% to 0.050%] It has been confirmed that the formation of buildup at the capillary tip (particularly the buildup of In-based precipitates) is suppressed by containing Sc, Ti, and Mn. Although the mechanism is not clear, it is thought that the concentration of In on the FAB surface is suppressed by the inclusion of Sc, Ti, and Mn. Therefore, it is thought that the attachment of In-based precipitates to the capillary