JPH0566973U - Bump formation structure - Google Patents

Abstract

(57) [Abstract] [Purpose] A solder layer portion is formed at the tip end portion in order to make the height of the stud bump formed on the pad of the bare chip such as a semiconductor element uniform. [Structure] A wire is ball-bonded on a pad of a bare chip 1 such as a semiconductor element by a wire bonder, then the wire is cut to form a stud bump 2, and then the stud bump 2 is formed by a solder dip process.
A uniform solder layer portion 3 is formed on the tip of the stud bump, the surface on which the stud bump having the solder layer portion is formed is turned upside down, and the stud bump having the solder layer is subjected to a predetermined solder land printing on the ceramic substrate. Then, the stand bump of the bare chip and the conductor land portion of the ceramic substrate are connected by reflow treatment.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to flip chip mounting of a semiconductor, and relates to a bump forming structure.

[0002]

[Prior Art]

 In high-density surface mounting such as hybrid ICs, stud bumps are formed on bare pads such as semiconductor elements, the surface on which the stud bumps are formed is turned over, and the stud bumps and the conductor land of the ceramic substrate are soldered. Alternatively, a flip chip method of connecting with an adhesive is used. Methods for forming stud bumps on bare chip pads include gold plating, wire bonding using gold or solder, solder dipping, etc., but conventional equipment can be used, and no ground treatment is required. The wire bonding method is generally used. In the stud bump forming method by wire bonding, the wire is ball bonded onto the pad of the bare chip, and then the wire is cut to form the stud bump. Here, the wire is cut by pulling the wire that is easily cut at the neck of the ball, but the variation in the remaining part of the ball neck is large, and the height becomes uneven, and the height is 30 to 50 microns. There are some variations. Therefore, in connection with the ceramic substrate, a small portion of the remaining portion of the stud bump is open, and if the beard portion is long, short-circuiting with the adjacent stud bump is likely to occur.

[0003]

[Problems to be solved by the device]

 The present invention has been made in view of such a point, and a bump forming structure that prevents a defect due to connection with a ceramic substrate by reducing the unevenness of the remaining portion of the ball neck after cutting the wire is provided. Is provided.

[0004]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention ball-bonds a wire on a pad of a bare chip such as a semiconductor device, cuts the wire, and then forms a stud bump by a solder dipping process. The bump forming structure is characterized in that a uniform solder layer portion is formed on the tip portion of the bump.

[0005]

[Action]

 With the above structure, in the bump forming structure according to the present invention, the uniform solder layer portion is formed on the tip portion of the stud bump to absorb the variation in height and the beard portion, and the ceramic substrate When connecting with, it is possible to prevent problems such as open and short circuit.

[0006]

【Example】

 Hereinafter, an embodiment of a bump forming structure according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view of an essential part of an embodiment of a bump forming structure according to the present invention. FIG. 1 (A) is a cross-sectional view of an essential part at the time of forming a stud bump, and FIG. 1 (B) is a cross-sectional view of an essential part at the time of forming a solder layer part at the tip of the stud bump. In the figure, after the wire is ball-bonded to the pad of the bare chip 1 such as a semiconductor element by the wire bonder, the wire is cut to form the stud bump 2, and then the tip of the stud bump 2 is formed by the solder dipping process. A uniform solder layer portion 3 is formed on the portion, the surface on which the stud bump having the solder layer portion is formed is turned upside down, and the stud bump having the solder layer is subjected to solder printing processing on the ceramic substrate in a predetermined area. Place it on the place and connect the stand bump of the bare chip and the conductor land of the ceramic substrate by reflow treatment.

[0007]

[Effect of the device]

 As described above, in the bump forming structure according to the present invention, the uniform solder layer portion is formed on the tip portion of the stud bump to absorb the height variation and the beard portion, and to form a ceramic substrate. It is possible to prevent open or short circuit in connection. Moreover, it is possible to use conventional equipment as it is.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of an embodiment of a bump forming structure according to the present invention.

[Explanation of symbols]

 1 Bare chip 2 Stud bump 3 Solder layer part

Claims (1)

[Scope of utility model registration request] 1. A stud bump formed by ball-bonding a wire on a pad of a bare chip such as a semiconductor element, and then cutting the wire, and then performing a solder dipping process to form a uniform wire on the tip portion of the stud bump. A bump forming structure characterized in that a solder layer portion is formed.