JPH0837207A - Semiconductor mounting method - Google Patents

Abstract

(57) [Summary] [Object] To provide a semiconductor mounting method for CCB bonding and flip-chip bonding a plurality of components at once. [Structure] Temporary fixing is performed by combining bump forming bodies 8 having irregularities formed on both the semiconductor element 1 and the circuit board 9. Further, the bump forming body 8 is formed into an integral bump in which both the bump forming bodies 8 are melted after the reflow for connecting the semiconductor element 1 and the circuit board 9. Here, the area of the bump forming body 8 before reflow, that is, at the time of temporary fixing is
Since it does not have to be the same as the electrode pattern 2, the bump formation 8 smaller than the electrode pattern 2 and the bump formation 8 larger than the electrode pattern 2 can be temporarily fixed. [Effect] The optical element and many other optical components can be collectively reflow-fixed, and the cost can be reduced by reducing the work amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to mounting a semiconductor device and a circuit board.

[0002]

2. Description of the Related Art In computer mounting, in order to achieve a high speed, the wiring length of an LSI is shortened by using a fine solder connection as a medium.
CB mounting method (EMDavis et al.,; Solid Logic Technolo
gy, IBMJ.Res.Develop., 8,2, pp.102-144 (1964)) is often used. In the CCB process, before the LSI wiring process is completed and the wafer is made into a chip, (1) formation of a protective insulating film for mounting (2) formation of a solder base electrode (3) formation of a solder electrode, and at the time of mounting on a circuit board, (4) Flux application (5) Positioning (6) Reflow (7) Flux cleaning is the main process.

On the other hand, in order to reduce the price of optical modules,
For the mounting of the optical element, studies are being made to make the optical axis unadjusted by utilizing the self-alignment effect in which the electrode patterns are positioned with high accuracy by the surface tension of the bumps.

[0004]

When the conventional CCB technology is used as it is for mounting an optical element, the flux that plays a role of removing, preventing oxidation of the oxide film on the surface of the bump, and temporarily fixing the characteristic of the optical element. There is a concern that it may deteriorate and reduce the reliability of the optical module. Therefore, CCB without flux is desirable. CC by fluxless
When performing B, it is necessary to consider (1) prevention of bump oxidation and (2) temporary fixing method of semiconductor element.

An object of the present invention is to CC a plurality of parts at once.
It is to provide a semiconductor mounting method for B-bonding and flip-chip bonding.

[0006]

In order to solve the above problems, according to the present invention, a semiconductor element having a bump forming body made of a convex (or concave) type solder on an electrode, and the bump forming on the electrode as well. The bump forming body of the circuit board having the concave (or convex) type bump forming body to be integrated with the body is superposed and temporarily fixed. As a result, it is possible to prevent the positional deviation between the mounting of the semiconductor element on the circuit board and the reflow.

[0007]

In the mounting of the semiconductor element and the circuit board in which the electrodes of both the semiconductor element and the circuit board are bonded through the metal bumps, the bump forming bodies having irregularities formed on both the semiconductor element and the circuit board are combined. Temporarily fix by.
The shape of the bump forming body becomes an integrated bump in which both bump forming bodies are melted after the reflow for connecting the semiconductor element and the circuit board. Here, since the area of the bump forming body before reflow, that is, at the time of temporary fixing does not need to be the same as the electrode pattern of the lower layer of the bump forming body, a bump forming body smaller than the electrode pattern and a bump forming larger than the electrode pattern are formed. It is possible to facilitate the positioning at the time of temporary fixing by combining the bodies.

[0008]

Embodiments of the present invention will be described with reference to the drawings.

The semiconductor element 1 shown in FIG.
Made of InGaAsP substrate of 00 × 300 × 120tμm, T
An electrode pattern 2 of i / Pt / Au / Mo is formed. An insulating film 3 (SiO2) is formed on the semiconductor element 1 on which the electrode pattern is formed.
Is formed by sputtering (FIG. 1 (b)), the resist 4 is used as a mask pattern (FIG. 1 (c)), and SiO2 and M in the opening 5 for making contact between the electrode pattern 2 and the bump (Au / Sn) are formed.
Etching o by dry etching (Fig. 1
(D)). After the etching, the resist is removed.
(E)). Exposed electrode pattern 2 at this time
The surface of Au becomes Au.

Next, a bump forming process by lift-off will be described with reference to FIG. FIG. 2A shows the insulating film 3
Also, in the semiconductor element 1 in which the opening 5 for making contact between the electrode pattern 2 and the bump (Au / Sn) is formed, the thick film resist 6 is used as a mask pattern (FIG. 2B), and from above.
Au / Sn 7 is vapor-deposited (FIG. 2C), and after vapor deposition, Au / Sn 7 other than the thick film resist 6 and the pattern is removed to complete the bump forming body 8 (FIG. 2D).

An electrode pattern 2 under the bump forming body 8
Has a diameter of 60 μm for both the semiconductor element 1 and the circuit board 9.
Is. On the other hand, as shown in FIG. 3, the bump forming body 8 of the semiconductor element 1 after the lift-off has a diameter of 20 μm × t20.
It is located at the center of the electrode pattern 2 in μm. Further, as shown in FIG. 4, the bump forming body 8 of the circuit board 9 has an outer circumference φ12.
It has a deformed shape of a donut with 0 μm and an inner circumference φ40 μm × t20 μm. Here, it should be noted that the bump forming body 8 of the circuit board 9 avoids a perfect donut shape in order to prevent the thick film resist 6 and Au / Sn 7 in the central portion of the donut from remaining at the time of lift-off.

Next, the semiconductor element 1 and the circuit board 9 are joined. This process is performed in two steps, that is, element mounting and reflow. First, as shown in FIG. 5A, the bump forming body 8 of the semiconductor element 1 is fitted into the bump forming body 8 on the circuit board 9 by using a bonding apparatus having an alignment function with an alignment accuracy of ± 10 μm or more. To be installed on. After that, reflow heating is performed under an inert atmosphere condition or a reducing atmosphere condition using hydrogen gas. At this time, the semiconductor element 1
The bump forming body 8 of the circuit board 9 becomes an integrated sphere when melted (FIG. 5B), and the surface tension of the bumps at that time causes the electrode patterns 2 of the semiconductor element 1 and the circuit board 9 to self-align. To Au / Sn solidification (Fig. 5
In (c), the positioning is performed with high accuracy.

In this embodiment, Au / Sn is used as the bump material.
However, the same can be realized by using Pb / Sn or Ag / Sn.

This embodiment is basically the same as the first embodiment except that the bump forming body has a different shape. FIG. 6 shows the shape of the semiconductor element, and FIG. 7 shows the shape of the circuit board. It is also possible to make the bump forming body asymmetrical as in the present embodiment.

[0015]

According to the present invention described above, in CCB bonding and flip chip bonding by fluxless, temporary fixing from alignment to reflow can be performed without mechanical holding. Therefore, the optical element and many other optical components can be reflow-fixed at one time, and the cost can be expected to be reduced by reducing the work amount.

[Brief description of drawings]

1A to 1E are sectional views of an insulating film forming process in a first embodiment.

2A to 2D are sectional views of the bump forming body forming process in the first embodiment.

3A is a plan view of a semiconductor element before reflow in Example 1, and FIG. 3B is a sectional view taken along line AA ′.

4A is a plan view of a circuit board before reflow in Embodiment 1, and FIG. 4B is a sectional view taken along line AA ′.

5A is a sectional view of a bump-formed body before reflow in Example 1, FIG. 5B is a sectional view of a bump-formed body during melting of Au / Sn, and FIG. 5C is a sectional view of a bump-formed body during solidification of Au / Sn.

6A is a plan view of a semiconductor element before reflow in Example 2, and FIG. 6B is a sectional view taken along line AA ′.

7A is a plan view of the circuit board before reflow in the second embodiment, and FIG. 7B is a cross-sectional view taken along line AA ′.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Semiconductor element, 2 ... Electrode pattern, 3 ... Insulating film, 4 ... Resist pattern, 5 ... Aperture for making contact between electrode pattern and bump forming body, 6 ... Thick film resist pattern, 7 ... Au / Sn
Deposition film, 8 ... Bump forming body, 9 ... Circuit board.

Claims (5)

[Claims] 1. A semiconductor mounting method, wherein, in connection between a semiconductor element and a circuit board by means of metal bumps, temporary bumping is carried out by combining bump-shaped bump-formed bodies formed on both the semiconductor element and circuit board. 2. The bump forming body on the semiconductor element and the bump forming body on the circuit board which is in contact with the bump forming body are melted to form an integral bump at the time of reflow for connecting the semiconductor element and the circuit board. 1. The semiconductor mounting method described in 1. 3. The area of the bump forming body before the bonding of the semiconductor substrate and the circuit board is made larger than the area where the electrodes of the semiconductor substrate and the electrodes of the circuit board and the bump forming body are in electrical contact with each other. 1. The semiconductor mounting method according to 1 or 2. 4. A semiconductor device comprising a bump forming body, a metallization layer having a role of adhering the semiconductor element and the bump forming body, and a passivation layer which does not adhere the semiconductor element and the bump forming body. 5. A circuit board comprising a bump forming body, a metallization layer having a role of adhering the circuit board and the bump forming body, and a passivation layer that does not adhere the circuit board and the bump forming body.