JPH0778827A - Semiconductor chip, and its manufacture and packaging method - Google Patents

Abstract

PURPOSE:To provide a semiconductor chip wherein suitable bump bonding is simply and easily enabled, and its manufacturing method and packaging method, regarding a semiconductor chip wherein a bump is fused and bonded by using a hot welding method. CONSTITUTION:This semiconductor chip is provided with bumps which connect electrically semiconductor chips together or connect electrically a semiconductor chip with a wiring board. The bump is constituted as a three-layered structure bump 2 composed of an indium film 2a, a flux film 2b, and an indium film 2c, or a two-layered structure bump composed of an indium film and a flux film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor chip in which bumps are melted and joined by using a hot welding method, and more particularly to a method of manufacturing a semiconductor chip and a method of mounting the same.

When a semiconductor chip is joined by melting the bumps by using the hot welding method, if there is an extra flux between the bumps, the molten metal forming the bumps will melt into the flux when the bumps are melted. There is a failure that causes a poor connection after moving from a predetermined position.

Under the circumstances as described above, there is a demand for a semiconductor chip capable of selectively supplying an appropriate amount of flux to the bumps.

[0004]

2. Description of the Related Art A conventional semiconductor chip will be described in detail with reference to FIG. 8 and a method for manufacturing the semiconductor chip will be described in detail with reference to FIG.

FIG. 8 shows a conventional semiconductor chip, and FIG.
FIG. 6A is a side sectional view showing a method of manufacturing a conventional semiconductor chip in the order of steps. A conventional back-illuminated infrared CCD semiconductor chip, in which a conventional HgCdTe chip is bonded face down to a silicon chip by bumps, is a silicon chip in which bumps 31a made of indium are formed on the surface as shown in FIG.
31 and bumps 32a made of indium were formed on the surface.
The HgCdTe chip 32 is faced to the bump 31a and the bump
To prevent the bumps from being broken by the shearing force acting on the bumps due to the difference in the coefficient of thermal expansion between silicon and HgCdTe when the tip surface of 32a is brought into contact and pressure bonded and cooled to the liquid nitrogen temperature (77K) when driving the chip. The bumps 31a and the bumps 32a are melted and integrally joined.

To manufacture such a semiconductor chip,
First, as shown in FIG. 9A, a resist film 33 is formed on the surface of the silicon chip 31, and an opening window 33 is formed at a position where a bump is to be formed.
form a.

Next, as shown in FIG. 9B, the resist film 33
9 and the indium film 34 is formed on the surface of the silicon chip 31 in the opening window 33a, and the resist film 33 is removed as shown in FIG. 9 (c). At the same time, the indium film on the surface of the resist film 33 is lifted off. 34 is removed, and bumps 31a are formed on the surface of the silicon chip 31.

Similarly, bumps are formed on the surface of the HgCdTe chip 32.
32a is formed, and as shown in FIG. 8, the bumps 32a and the tip surfaces of the bumps 31a are brought into contact with each other and pressure-bonded.
The bumps 31a and the bumps 32a are melted and joined together by heating to 90 ° C.

[0009]

In the conventional method of manufacturing a semiconductor chip described above, when the flux 35 for removing the oxide film is applied and adhered to the bump 31a as shown in FIG. 10 (a), The amount of the flux 35 is too large, and the extra flux 35 has two adjacent bumps 31 as shown in the figure.
The bumps 31a and 32a, which are located between a and a, contact the tip surfaces of the bumps 31a and 32a and press-bond them, and when these bumps 31a and 32a are melted, the bumps are added to the extra flux 35 attached as shown in Fig. 10 (b). There is a problem that the bumps are not joined because the indium forming the metal melts and moves from a predetermined position.

Under the circumstances as described above, the present invention has an object to provide a semiconductor chip capable of easily and easily performing proper bump bonding, a manufacturing method thereof, and a mounting method thereof.

[0011]

The semiconductor chip of the present invention is a semiconductor chip having bumps for electrically connecting the semiconductor chips to each other or between the semiconductor chips and the wiring board, and the bumps are the molten metal film and the flux film. It is configured as a bump having a three-layer structure composed of a molten metal film and a molten metal film, or as a bump having a two-layer structure composed of a molten metal film and a flux film.

A method of manufacturing a semiconductor chip of the present invention is a method of manufacturing a semiconductor chip having the above bumps, wherein a resist film is formed on the surface of the semiconductor chip, and the position of the semiconductor chip at which the bump is to be formed. A step of forming an opening window of the resist film, a step of forming a molten metal film on the surface of the resist film and the surface of the semiconductor chip in the opening window, and a flux film on the surface of the molten metal film. Forming step, forming a molten metal film on the surface of the flux film, and forming the molten metal film, flux film and molten metal film on the surface of the resist film by a lift-off method for removing the resist film Or a metal mask provided with an opening window having the shape of the bump at the position of the bump of the semiconductor chip. The position of forming the bump of the body chip and the opening window of the metal mask are aligned and placed on the surface of the semiconductor chip, and the surface of the metal mask and the surface of the semiconductor chip in the opening window are aligned. A step of forming a molten metal film, a step of forming a flux film on the surface of the molten metal film, and a step of removing the metal mask and simultaneously removing the molten metal film and the flux film formed on the surface of the metal mask. And a removing step.

A semiconductor chip mounting method of the present invention is a semiconductor chip mounting method for electrically connecting semiconductor chips to each other or between a semiconductor chip and a wiring board, wherein a flux film is formed on a surface of a glass plate having a smooth surface. And a step of bringing the tip end surface of the bump provided on the semiconductor chip into contact with the flux film and adhering the flux film to the tip end surface.

[0014]

That is, in the present invention, the opening window formed in the resist film formed on the surface of the semiconductor chip is used to form a bump having a three-layer structure of molten metal, flux, and molten metal, and the resist film is formed by the lift-off method. Or remove
Alternatively, a double-layered bump composed of molten metal and flux is formed using an opening window formed in a metal mask placed on the surface of a semiconductor chip, and the flux is selectively supplied to the bump by removing the metal mask. Therefore, if the bumps are made to face each other and are in contact with each other, and they are pressure-bonded and then fused and joined, there is no excess flux, so each bump can be fused and joined independently. Therefore, it is possible to perform the bonding with proper bumps.

Further, a flux film is applied to the surface of a glass plate having a smooth surface, the tip surfaces of the bumps provided on the semiconductor chip are brought into contact with the flux film, and the flux film is applied to the tip surface. Because it attaches
Since the extra flux does not adhere to the bumps, it is possible to perform the proper bump bonding.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIGS. 1 is a diagram showing a semiconductor chip of a first embodiment according to the present invention, FIG. 2 is a diagram showing a semiconductor chip of a second embodiment according to the present invention, and FIGS. 3 to 4 are the first embodiment according to the present invention. 5 to 6 are views showing the method of manufacturing a semiconductor chip in the order of steps, FIGS. 5 to 6 are views showing the method of manufacturing the semiconductor chip of the second embodiment of the present invention in the order of steps, and FIG. 7 is a semiconductor chip of the embodiment 1 of the present invention 5A to 5C are diagrams showing the mounting method in step order.

In the semiconductor chip of the first embodiment according to the present invention, as shown in FIG. 1, a bump 2 having a three-layer structure composed of an indium film 2a, a flux film 2b and an indium film 2c is formed on the surface of a silicon chip 1. It is a semiconductor chip.

As shown in FIG. 2, the semiconductor chip of the second embodiment according to the present invention is a semiconductor chip in which a bump 12 having a two-layer structure composed of an indium film 12a and a flux film 12b is formed on the surface of a silicon chip 11. is there.

To manufacture the semiconductor chip of the first embodiment of the present invention, first, as shown in FIG. 3A, a resist film 3 having a film thickness of 10 μm is formed on the surface of the silicon chip 1 to form bumps. An opening window 3a having a diameter of 50 μm, which corresponds to the shape of the bump, is formed at the position.

Next, as shown in FIG. 3 (b), the resist film 3
Of the indium film 2a having a film thickness of 3 μm is formed on the surface of the indium film 2a and the surface of the silicon chip 1 in the opening window 3a by vapor deposition. Then, as shown in FIG.
The flux film 2b of μm was applied using a spinner, and
As shown in (a), an indium film 2c having a film thickness of 3 μm is further formed on the surface of the flux film 2b by vapor deposition.

Finally, as shown in FIG. 4B, the resist film 3 is removed, and at the same time, the indium film 2a, the flux film 2b, and the indium film 2c on the surface of the resist film 3 are removed by the lift-off method, and the silicon chip 1 is removed. The bump 2 is formed on the surface of the.

Similarly, bumps 5 are formed on the surface of the HgCdTe chip 4 as shown in FIG.
The tip surfaces of the bumps 2 are brought into contact with each other and pressure-bonded, and heated to 190 ° C. in a nitrogen atmosphere to melt and bond these bumps 2 and 5 together.

In the first embodiment, since the bump 2 having the structure in which the flux film 2b is sandwiched between the indium films 2a and 2c is used, it is possible to perform good hot welding without excess or deficiency in the amount of flux. .

The pitch of the bumps of the second embodiment of the present invention is
In order to manufacture semiconductor chips of 100 μm or larger, first,
As shown in (a), a metal mask 13 made of nickel and having a thickness of 0.1 mm is provided at the position where the bump 12 of the silicon chip 11 is provided, and an opening window 13a having a diameter of 50 μm corresponding to the shape of the bump 12 is provided on the semiconductor chip. The position where the bump 12 of 11 is formed and the opening window 13a of the metal mask 13 are aligned and placed on the surface of the semiconductor chip 11, and a film is formed on the surface of the metal mask 13 and the surface of the silicon chip 11 in the opening window 13a. The indium film 12a having a thickness of 20 μm is formed by vapor deposition, and then the flux film 12b having a film thickness of 1 μm is applied to the surface of the indium film 12a by using a spinner as shown in FIG.
As shown in (c), the metal mask 13 is removed to simultaneously remove the indium film 12a and the flux film 12b on the surface,
Bumps 12 are formed on the surface of the silicon chip 11.

Similarly, as shown in FIG. 6A, bumps 15 are formed on the surface of the HgCdTe chip 14 and the tip surfaces of the bumps 12 and the bumps 15 are brought into contact with each other and pressure-bonded to the bumps 12 and the bumps 15. Are melted and joined together.

Next, a semiconductor chip mounting method according to an embodiment of the present invention for mounting a semiconductor chip by accurately attaching a flux film to the tip surfaces of bumps will be described. First, a glass plate 24 having a smooth surface as shown in FIG.
7 is formed by applying a flux film 23 on the surface of the
The bumps 22 formed on the silicon chip 21 as shown in (b)
When the tip surface of the is contacted with the flux film 23, and then the silicon chip 21 is lifted upward, the flux film 23 adheres to the tip surface 22a of the bump 22.

In this way, the silicon chip 21 having the flux film 23 attached to the tip surface 22a of the bump 22 can be bonded to the bumps of other semiconductor chips in the same manner as the semiconductor chip 11 of the second embodiment. Becomes

[0028]

As is apparent from the above description, according to the present invention, a bump having an extremely simple structure is provided on a semiconductor chip, or a flux film is accurately attached to the tip end surface of the bump, whereby When bonding the semiconductor substrates, there is an advantage that it is possible to prevent the bumps from moving from a predetermined position due to excess flux and prevent the semiconductor chip from becoming defective, which is extremely economical and It is possible to provide a semiconductor chip that can be expected to improve reliability, a method of manufacturing the same, and a method of mounting the same.

[Brief description of drawings]

FIG. 1 is a diagram showing a semiconductor chip of a first embodiment according to the present invention.

FIG. 2 is a diagram showing a semiconductor chip of a second embodiment according to the present invention.

FIG. 3 is a diagram showing the method of manufacturing the semiconductor chip of the first embodiment according to the present invention in the order of steps (1)

FIG. 4 is a view showing the method of manufacturing the semiconductor chip of the first embodiment according to the present invention in the order of steps (2)

FIG. 5 is a diagram showing the method of manufacturing a semiconductor chip of the second embodiment according to the present invention in the order of steps (1)

FIG. 6 is a view showing the method of manufacturing a semiconductor chip of the second embodiment according to the present invention in the order of steps (2)

FIG. 7 is a diagram showing a method of mounting a semiconductor chip according to an embodiment of the present invention in process order.

FIG. 8 is a diagram showing a conventional semiconductor chip.

FIG. 9 is a diagram showing a conventional method of manufacturing a semiconductor chip in process order.

FIG. 10 is a diagram showing a problem of a conventional semiconductor chip mounting method.

[Explanation of symbols]

 1,11,21 Silicon chip 2,12,22 Bump 2a, 12a Indium film 2b, 12b Flux film 2c Indium film 3 Resist film 3a Opening window 4 HgCdTe chip 5 Bump 13 Metal mask 13a Opening window 22a Tip surface 23 Flux film 24 Glass plate

Claims (5)

[Claims] 1. A semiconductor chip having bumps for electrically connecting semiconductor chips to each other or to a wiring substrate, wherein the bumps are a molten metal film (2a), a flux film (2b), and a molten metal film. A semiconductor chip comprising a bump (2) having a three-layer structure including (2c). 2. A semiconductor chip having bumps for electrically connecting semiconductor chips to each other or to a wiring board, wherein the bumps are composed of a molten metal film (12a) and a flux film (12b). A semiconductor chip, which is a bump (12) having a layered structure. 3. A method of manufacturing a semiconductor chip having bumps (2) according to claim 1, wherein a resist film (3) is formed on the surface of the semiconductor chip (1), and the semiconductor chip (1) is formed. A step of forming an opening window (3a) of the resist film (3) at a position where the bump (2) is to be formed, and the semiconductor chip in the surface of the resist film (3) and the opening window (3a) A step of forming a molten metal film (2a) on the surface of (1), a step of forming a flux film (2b) on the surface of the molten metal film (2a), and a molten metal film on the surface of the flux film (2b) A step of forming a film (2c), the molten metal film (2a) formed on the surface of the resist film (3), the flux film (2b) and the molten metal film (2
A method of manufacturing a semiconductor chip, comprising the step of removing c). 4. A method of manufacturing a semiconductor chip comprising a bump (12) according to claim 2, wherein the bump (12) has a shape corresponding to the position of the bump (12) of the semiconductor chip (11). Metal mask with open window (13a)
(13) on the surface of the semiconductor chip (11) by aligning the position where the bump (12) of the semiconductor chip (11) is formed with the opening window (13a) of the metal mask (13). Placing, forming a molten metal film (12a) on the surface of the metal mask (13) and the surface of the semiconductor chip (11) in the opening window (13a), and forming the molten metal film (12a). Forming a flux film (12b) on the surface, and removing the metal mask (13) at the same time, the molten metal film (12a) and the flux film (12b) formed on the surface of the metal mask (13) ) Is removed, and the manufacturing method of the semiconductor chip characterized by the above-mentioned. 5. A semiconductor chip mounting method for electrically connecting semiconductor chips to each other or a semiconductor substrate and a wiring board, wherein a flux film is formed on a surface of a glass plate (24) having a smooth surface.
Step of forming (23) and tip surface of bump (22) provided on semiconductor chip (21)
(22a) is contacted with the flux film (23),
A method of mounting a semiconductor chip, comprising the step of attaching the flux film (23) to (22a).