US-12628408-B2 - Metal film and manufacturing method of the metal film, and semiconductor device and method of manufacturing the semiconductor device

Abstract

A metal film, a manufacturing method of the metal film, semiconductor device, and a manufacturing method of semiconductor device are provided with high crack resistance (higher hardness) during wire bonding. The Metal film has first metal crystal grains, and the second metal crystal grains. Each of the first metal crystal grains has dislocations. Each of the second metal crystal grains has no dislocations. The number of the first metal crystal grains having the dislocations is larger than the number of the second metal crystal grains having no dislocations.

Inventors

• Tadashi Yamaguchi

Assignees

• RENESAS ELECTRONICS CORPORATION

Dates

Publication Date

20260512

Application Date

20230420

Priority Date

20220610

Claims (8)

1. 1 . A metal film comprising: a plurality of first metal crystal grains having dislocations and a plurality of second metal crystal grains not having the dislocations, wherein a number of the plurality of first metal crystal grains is greater than a number of the plurality of second metal crystal grains.
2. 2 . The metal film according to claim 1 , wherein the metal film made of a material containing at least one selected from a group consisting of aluminum, tungsten, copper, cobalt and nickel.
3. 3 . The metal film according to claim 1 , wherein a density of the dislocations of the plurality of first metal crystal grains is 60 particles/square micrometer or more.
4. 4 . The metal film according to claim 1 , wherein a mean crystal grain size of a plurality of metal crystal grains including the plurality of first metal crystal grains and the plurality of second metal crystal grains is 1 micrometer or more and 5 micrometers or less.
5. 5 . The metal film according to claim 4 , wherein the mean crystal grain size of the plurality of metal crystal grains is 1.7 micrometers or less.
6. 6 . The metal film according to claim 1 , further comprising: a plurality of third metal crystal grains located on grain boundaries between first metal crystal grains, between second metal crystal grains, or between first metal crystal grain and second metal crystal grain, wherein the plurality of third metal crystal grains made of a different material of the plurality of first metal crystal grains and the plurality of second metal crystal grains.
7. 7 . The metal film according to claim 6 , wherein the plurality of first metal crystal grains and the plurality of second metal crystal grains made of a material containing aluminum and the plurality of third metal crystal grains made of a material containing silicon or copper.
8. 8 . A semiconductor device comprising: a metal film including a plurality of first metal crystal grains each having dislocations and a plurality of second metal crystal grains each not having the dislocations, wherein a number of the plurality of first metal crystal grains is greater than a number of the plurality of second metal crystal grains, and the metal film is comprised as a bonding pad or a wiring.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The disclosure of Japanese Patent Application No. 2022-094618 filed on Jun. 10, 2022, including the specification, drawings and abstract is incorporated herein by reference in its entirety. BACKGROUND The present invention relates to a metal film, a method for manufacturing the metal film, a semiconductor device, and a method for manufacturing the semiconductor device. In Japanese Unexamined Patent Application Publication No. 2007-165663 (Patent Document 1), a stress relaxing film is formed on a conductive film in order to reduce a warpage of a semiconductor wafer. The conductive film becomes as a gate pad or a source pad, and is made of aluminum (Al) or the like. The conductive film is formed by sputtering. SUMMARY The aluminum pads are required to have high crack resistance (high hardness) during wire bonding. Other objects and novel features will become apparent from the description of this specification and the accompanying drawings. According to an embodiment of a metal film, a number of first metal grains having dislocations is larger than a number of second metal grains having no dislocations. The semiconductor device according to an embodiment includes the metal film as a bonding pad or a wiring. According to the metal film according to a manufacturing method of the embodiment, the dislocations is formed in the metal film by performing annealing in which metal grains recrystallize after point defects are introduced into the metal film. According to manufacturing method of the semiconductor device according to an embodiment, the metal film is formed as the bonding pad or the wiring. According to the above-described embodiment, the metal film having high crack resistance (high hardness) during wire bonding, a method for manufacturing the metal film, the semiconductor device including the metal film, and a method for manufacturing the semiconductor device are realized. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing a configuration of a metal film according to an embodiment. FIG. 2 is a cross-sectional view showing a configuration of a IGBT (Isolated Gate Bipolar Transistor) having the metal film shown in FIG. 1. FIG. 3 is a cross-sectional view showing a configuration of a semiconductor package having the IGBT shown in FIG. 2. FIG. 4 is a cross-sectional view illustrating a first step of a manufacturing method of the metal film according to the embodiment. FIG. 5 is a cross-sectional view illustrating a second step of the manufacturing method of the metal film according to the embodiment. FIG. 6 is a cross-sectional view illustrating a third step of the manufacturing method of the metal film according to the embodiment. FIG. 7 is a plan view showing a configuration of a photoresist mask for a selectively ion-implantation the region to be wire bonded. FIG. 8 is a cross-sectional view of the metal film according to a comparative embodiment not performed to the ion-implantation. FIG. 9 is a cross-sectional view of the metal film performed to the ion-implantation with aluminum. FIG. 10 is a cross-sectional view of a silicon implanted metal film. FIG. 11 is a cross-sectional view of a metal film according to a comparative embodiment annealed without ion-implantation. FIG. 12 is a cross-sectional view of the metal film annealed after ion-implantation with aluminum. FIG. 13 is a cross-sectional view of the metal film annealed after ion-implantation with silicon. FIG. 14 shows a degree of relaxation of an inner stress of the metal film by ion-implantation. DETAILED DESCRIPTION Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the specification and drawings, the same or corresponding components are denoted by the same reference numerals, and a repetitive description thereof is not repeated. In the drawings, for convenience of explanation, the configuration or manufacturing method may be omitted or simplified. Note that a plan view in this specification means a viewpoint viewed from a direction perpendicular to a first surface FS of a semiconductor substrate. A planar shape also means a shape in plan view. Also, an opening area means an area of the opening in plan view. (Structure of a Metal Film) First, a configuration of a metal film according to an embodiment will be described with reference to FIG. 1. As shown in FIG. 1, the metal film MF is made of a material containing at least one selected from the group consisting of aluminum, tungsten (W), copper (Cu), cobalt (Co), and nickel (Ni). The metal film MF is made of a material containing, for example, aluminum, pure aluminum, an alloy of aluminum and silicon (Si), an alloy of aluminum and copper, or an alloy of aluminum, silicon and copper. The metal film MF has a thickness of, for example, 1 micrometer or more and 4 micrometers or less. The metal film MF has a plurality of metal crystal grains GR. The plurality of metal crystal