JPH021929A - Electrode formation and semiconductor using the same - Google Patents

Abstract

PURPOSE:To enhance the productivity of semiconductor device by reducing the dispersion in the shape of bump type electrodes and the manufacturing processes by a method wherein the second manufacturing process to bury the bump type electrodes in a substrate is performed independently from and in parallel with the first manufacturing process to bond the bump type electrodes onto the substrate surface while the level of the bump type electrodes and the plane shape are prescribed by the depth and the shape of the burying holes formed in the substrate. CONSTITUTION:The bump type electrodes 3 are formed through the procedures as follows, i.e. first a filmy substrate 5A is opposed to the surface on the side wherein the outer terminals 1C of a semiconductor chip 1 are arrayed. The burying holes 5B are formed on the positions opposite to the terminals 1C on the chip surface while electrodes 3 are previously buried in these holes 5B. During the second manufacturing process of the substrate 5A prescribing the shape of the electrodes 3, a chip pattern is formed on the semiconductor wafer to form the chip 1 by dicing process while the electrodes 3 are formed on the outer terminals 1C of the chip 1 independently from and in parallel with the first manufacturing process to load this chip 1 on a loading board 4. Through these procedures, the manufacturing time can be cut down to enhance the productivity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrode forming technique, and particularly to a technique effective when applied to a CCB electrode forming technique.

[Conventional technology]

In semiconductor devices, there is a tendency to mount a plurality of semiconductor chips on a single mounting board to increase the packaging density.

CCBm is used to mount the semiconductor chip.

In the CCB method, protruding electrodes (bump electrodes) are interposed between external terminals (ponding pads) arranged on the surface of a semiconductor chip and electrodes on a mounting board, and the two are electrically and mechanically connected. It's technology. The protruding electrodes are designed to prevent the wiring layer formed on the surface of the semiconductor chip from melting.
It is made of solder, a metal with a low melting point.

Semiconductor devices using the CCB method have a feature that packaging density can be improved compared to semiconductor devices using the bonding wire method.

The protruding electrodes used in this CCB method are formed using photolithography technology as follows.

First, a base gold scrap film is deposited on external terminals arranged in each semiconductor chip pattern on the surface of a semiconductor wafer. The base metal film is mainly formed to improve the adhesion of the protruding electrodes.

Next, a photoresist film is applied to the entire surface of the semiconductor wafer using photolithography. Next, this photoresist film is exposed and developed to form a photoresist mask in which external terminal portions arranged in the semiconductor chip pattern are opened.

Next, a protruding electrode layer is selectively deposited on the underlying metal film (external terminal) exposed through the opening of the photoresist mask. This protruding electrode layer is deposited by a vapor deposition method or a plating method.

Next, the photoresist mask is removed.

Then, the protruding electrode layer is subjected to low-temperature heat treatment to form a protruding electrode having a shaped shape.

Thereafter, the semiconductor wafer is subjected to a dicing process along each semiconductor chip pattern to form a plurality of semiconductor chips.

The aforementioned protruding electrodes are used not only in semiconductor devices formed by the CCB method but also in semiconductor devices formed by the TAB method. A semiconductor device formed by the TAB method has a semiconductor chip mounted on a flexible film-like substrate.

The lead wires of the film-like substrate and the external terminals of the semiconductor chip are electrically and mechanically connected via protruding electrodes.

The protruding electrode formation technology used in the CCB method and the TAB method is described, for example, in Nikkei McGraw-Hill, Besshu [Micro Devices Jno, 2. Published June 11, 1984, pp. 130 to 147. has been done.

[Problem to be solved by the invention]

As a result of studying the above-mentioned technology, the inventor found the following problems.

The protruding electrodes used in the CCB method and TAB method are formed by a photolithography technique that includes the steps of coating a photoresist film, exposing, developing, and removing the photoresist film. Therefore, the process for manufacturing these protruding electrodes is incorporated into the process for manufacturing semiconductor wafers, thereby increasing the number of processes for manufacturing semiconductor wafers. This increase in manufacturing processes for semiconductor wafers significantly increases manufacturing time and reduces the productivity of semiconductor devices.

Furthermore, the protruding electrodes tend to vary in height and planar shape within the semiconductor wafer due to variations in the film thickness of the photoresist mask, unevenness in heat treatment during shaping, and the like. For this reason, the yield of the manufacturing process of the protruding electrodes is reduced due to defects in the shape of the protruding electrodes.

In addition, the manufacturing process for this protruding electrode is incorporated into the semiconductor wafer manufacturing process.

A decrease in yield in the protrusion electrode manufacturing process directly leads to a decrease in yield in the semiconductor wafer manufacturing process.

An object of the present invention is to provide a technology that can reduce the manufacturing process of the protruding electrodes incorporated into the semiconductor device manufacturing process and improve the productivity of the semiconductor device in a semiconductor device using protruding electrodes. There is a particular thing.

Another object of the present invention is to provide a technique that can reduce variations in the shape of the protruding electrodes and improve the yield of the protruding electrode manufacturing process itself.

Another object of the present invention is to provide a technique that can improve the yield of the semiconductor device manufacturing process.

Another object of the present invention is to provide a technique capable of achieving the above object and simplifying the structure of a semiconductor device using the protruding electrode.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means to solve the problem]

A brief overview of typical inventions disclosed in this application is as follows.

(1) An electrode forming method in which protruding electrodes are formed on electrodes arranged on the surface of a substrate, in which holes for embedding are formed in a film-like substrate at positions corresponding to the electrodes arranged on the surface of the substrate; embedding the protruding electrodes in the embedding holes; placing the film-like substrate facing the surface of the substrate; and adhering the protruding electrodes embedded in the film-like substrate onto the electrodes arranged on the surface of the substrate; and a step of doing so.

(2) A semiconductor device having protruding electrodes, in which an insulating film-like substrate is provided opposite to the surface of the semiconductor chip on which external terminals are arranged, and the external terminals arranged on the surface of the semiconductor chip are Protruding electrodes embedded in the film-like substrate and having one end bonded to the external terminals are provided at corresponding positions, and the protruding electrodes are provided on the surface of the film-like substrate opposite to the surface facing the semiconductor chip. A wiring electrically connected to the other end is provided.

[For production]

According to the above-mentioned means (1), in the first manufacturing process of bonding the protruding electrodes to the electrodes arranged on the surface of the substrate,
The second manufacturing process (manufacturing process that defines the shape of the projecting electrodes) for embedding the protruding electrodes in the film-like substrate is performed independently and in parallel with the first manufacturing process. The manufacturing time of the first manufacturing process can be shortened by an amount corresponding to the manufacturing process, and productivity can be improved.

In addition, since the height and planar shape of the protruding electrode were defined by the depth and shape of the embedding hole formed in the film-like substrate,
It is possible to reduce variations in the shape of the protruding electrodes and improve the yield of the second manufacturing process itself.

Further, since the first manufacturing process and the second manufacturing process are made independent, the yield of the first manufacturing process can be improved by an amount corresponding to the yield of the second manufacturing process.

Moreover, according to the above-mentioned means (2), in addition to the effect of the above-mentioned means (1), since a film-like substrate that defines the height and planar shape of the protruding electrode is used as a wiring board,
The structure of the semiconductor device itself can be simplified.

Hereinafter, the structure of the present invention will be described together with one embodiment in which the present invention is applied to a semiconductor device.

Note that throughout the description of the embodiments, parts having the same functions are given the same reference numerals, and repeated explanations thereof will be omitted.

[Embodiments of the invention]

(Example I) Example 1 is a first example of the present invention in which the present invention is applied to a semiconductor device formed by the CCB method.

FIG. 1 (partial cross-sectional configuration diagram) shows an outline of a semiconductor device which is Embodiment 2 of the present invention.

As shown in FIG. 1, the semiconductor device has one or more semiconductor chips 1 mounted on a mounting substrate 4. As shown in FIG.

The semiconductor chip 1 includes a plurality of semiconductor elements (not shown) on the surface of a semiconductor substrate IA made of, for example, single crystal silicon. A plurality of external terminals (ponding pads) IC are arranged on the surface of the semiconductor substrate IA on which the semiconductor elements are formed, with an interlayer insulating film IB interposed therebetween. The external terminal IC is made of a low resistance wiring material such as an aluminum film or an aluminum alloy film. A final passivation film ID having an opening IE in the external terminal IC portion is provided on the external terminal IC.

The mounting substrate 4 is mainly composed of a substrate 4A made of, for example, single crystal silicon, silicon carbide, ceramic, or resin. A groove t4B extends on the surface side of the mounting board 4 facing the surface of the semiconductor chip 1. The wiring 4B is made of Cu, for example.
It is formed of a composite film in which a film and a Ni film are sequentially laminated.

The external terminal IC of the semiconductor chip 1 is electrically and mechanically connected to the arrangement 1A4B of the mounting board 4 with a protruding electrode (bump electrode) 3 interposed therebetween. The external terminal IC
A base metal film 2 is interposed between the protruding electrode 3 and the protruding electrode 3.

The protruding electrode 3 is made of solder, which is a low melting point metal. The protruding electrode 3 is formed by the following procedure, as shown in FIGS. 2 and 3 (enlarged sectional views showing each protruding electrode manufacturing process).

First, as shown in FIG. 2, the film-like substrate 5A is made to face the surface of the semiconductor chip 1 on the side where the external terminals IC are arranged. The film-like substrate 5A has embedding holes 5B at positions corresponding to the external terminal ICs arranged on the surface of the semiconductor chip 1.
is provided.

The protruding electrode 3 is embedded in the embedding hole 5B in advance. The film-like substrate 5A is made of an insulating and flexible resin such as polyimide resin. The thickness of the film-like substrate 5A varies depending on the height of the protruding electrodes 3 to be formed, but is, for example, 100 to 200 μm.
] Formed to the extent of. The embedding hole 5B is formed as a through hole. The embedding hole 5B is formed in a shape corresponding to the planar shape of the protruding electrode 3 to be formed, and may be formed in any shape such as a circular shape, an elliptical shape, or a rectangular shape.

For example, as shown in FIG. 4 (a perspective view showing the original structure of the film-like substrate), this film-like substrate 5A is a thick rectangular substrate ( It can be formed by thinly slicing 5 (not limited to a rectangular shape). The manufacturing process (second manufacturing process) of this film-like substrate 5A includes forming a semiconductor chip pattern on a semiconductor wafer, forming semiconductor chips 1 from the semiconductor wafer in a dicing process,
A projecting electrode 3 is formed on the external terminal IC of this semiconductor chip 1, and the process is performed independently and in parallel with a series of manufacturing processes (first manufacturing process) in which this semiconductor chip 1 is mounted on a mounting substrate 4. It is being said.

Next, heat treatment is performed with the semiconductor chip 1 and the film-like substrate 5A facing each other. When forming the protruding electrodes 3 with solder, the heat treatment is performed at approximately 200 to 300['C].
] at a low temperature. By this heat treatment, the base metal film 2 previously formed on the external terminal 1C of the semiconductor chip 1 and one end side of the protruding electrode 3 are bonded together. Then, by pulling up the film substrate 5A from the surface of the semiconductor chip 1 using the adhesion between one end side of the protruding electrode 3 and the base metal film 2, the film substrate 5A is buried as shown in FIG. The protruding electrode 3 can be removed from the insertion hole 5B. That is, the protruding electrode 3 can be formed on the external terminal IC of the semiconductor chip 1 with the base metal film 2 interposed therebetween.

The formation of this protruding electrode 3 on the external terminal IC is as follows.

This process can be performed both in the semiconductor wafer state and in the semiconductor chip 1 state. Further, the protruding electrode 3 may be formed on the wiring 4A of the mounting substrate 4 together with the external terminal IC of the semiconductor chip 1, or may be formed independently.

The base metal film 2 is formed of a metal material that has good adhesion to each of the external terminals IC1 and protruding electrodes 3. The base metal film 2 is formed of, for example, a composite film in which a Ti film, a Cu film, and a Ti film are sequentially laminated, or a composite film in which an Au film, a Cu film, and a Cr film are sequentially laminated.

In this way, the external terminal ICs arranged on the semiconductor chip 1
In this electrode forming method, a protruding electrode 3 is formed in a film-like substrate 5A at a position corresponding to an external terminal IC arranged on the surface of the semiconductor chip 1, and a hole 5B for embedding is formed in a film-like substrate 5A. A step of embedding the protruding electrode 3 in the hole 5B, and placing the film-like substrate 5A facing the surface of the semiconductor chip 1, and embedding the protruding electrode 3 embedded in the film-like substrate 5A on the semiconductor chip 1. By including the step of adhering the protruding electrodes 3 onto the external terminal ICs arranged on the surface of the semiconductor chip 1, the film-like Second manufacturing process of embedding the protruding electrode 3 in the substrate 5A (manufacturing process that defines the shape of the protruding electrode 3)
Since the steps are performed independently and in parallel with the first manufacturing process, the amount corresponding to the second manufacturing process.

The manufacturing time of the first manufacturing process can be shortened and the productivity of semiconductor devices can be improved.

In addition, since the height and planar shape of the protruding electrode 3 are defined by the depth and shape of the embedding hole 5B formed in the film-like substrate 5A, variations in the shape of the protruding electrode 3 can be reduced, and shape defects etc. , the yield of the second manufacturing process itself can be improved.

Further, since the first manufacturing process and the second manufacturing process are made independent, the yield of the first manufacturing process can be improved by an amount corresponding to the yield of the second manufacturing process.

In addition, in the manufacturing process of the protruding electrode 3, the photolithography technology, which includes the steps of applying a photoresist film, exposing, developing, and removing the photoresist film, has been abolished, thereby further improving the productivity of semiconductor devices. I can do it.

Furthermore, since the protruding electrodes 3 can be formed in either the semiconductor wafer state or the semiconductor chip 1 state, the degree of freedom in the first manufacturing process is improved.

In this embodiment (2), the projecting electrode 3 is formed of solder, but the present invention is also applicable to other materials such as Au.
The protruding electrode 3 is made of highly malleable metal material such as film, Cu film, Mo film, etc.
may be formed. The protruding electrode 3 made of a highly malleable metal material is bonded onto the external terminal IC of the semiconductor chip 1 by means such as thermocompression bonding.

Further, when the protruding electrode 3 is formed of substantially the same metal material as the external terminal IC of the semiconductor chip 1.

Since the adhesiveness of the same metal material is good, the base metal film 2 which increases the adhesiveness can be omitted.

(Example 2) This example 2 is a second example of the present invention in which the present invention is applied to a semiconductor device formed by the TAB method.

FIG. 5 (partially sectional perspective view) shows an outline of a semiconductor device which is Embodiment 2 of the present invention.

As shown in FIG. 5, the semiconductor device uses a film-like substrate 5A on which protruding electrodes 3 are formed on the external terminal IC of the semiconductor chip 1 as it is as a wiring board. In other words,
The film-like substrate 5A is an external terminal IC of the semiconductor chip 1.
A protruding electrode 3 is embedded in a position corresponding to the wiring (lead wiring) 5C on the surface opposite to the surface facing the semiconductor chip 1.
has been established. The external terminal IC of the semiconductor chip 1 and the protruding electrode 3 are bonded together in the same manner as in the embodiment (2), and the protruding electrode 3 and the wiring SC are also bonded together.

The semiconductor chip 1 is attached at the center of the film-like substrate 5A. A peripheral portion of the film-like substrate 5A of this semiconductor device is attached to a wiring board 6 of an external device. The wiring 5C of the film-like substrate 5A is electrically and mechanically connected to the wiring 6A of the wiring board 6 through the embedded protruding electrode 3. Although not shown in the figure, the layout rule for connecting the wiring 5C of the film-like substrate 5A and the wiring 6A of the wiring board 6 is based on the semiconductor chip 1.
Since the layout rules for connecting the external terminal IC and the wiring 5C are looser than the layout rules for connecting the wiring 5C and the wiring 6A, the wiring 5C and the wiring 6A may be connected by a bonding wire method or a conventional protruding electrode.

When using solder, which is a metal with a low melting point, as the protruding electrode 3, the film-like substrate 5A is designed to prevent the adhesion between the embedding hole 5B and the protruding electrode 3 embedded therein from deteriorating. The external terminal IC and the protruding electrode 3 are bonded together using a low-temperature ultrasonic bonding method. The temperature used in this low-temperature ultrasonic bonding method is about 200 ['C] or less.

In this semiconductor device formed by the TAB method, an insulating film-like substrate 5A is provided opposite to the surface of the semiconductor chip 1 on which external terminals IC are arranged. A protruding electrode 3 is embedded in the film-like substrate 5A at a position corresponding to the arranged external terminal IC, and has one end bonded to the external terminal IC.
established.

By providing a wiring msc electrically connected to the other end of the protruding electrode 3 on the surface opposite to the surface facing the semiconductor chip 1 of the film-like substrate 5A, the height of the protruding electrode 3 can be adjusted. Since the film-like substrate 5A that defines the planar shape is used as a wiring board, the structure of the semiconductor device itself can be simplified.

Further, by forming the film-like substrate 5A with resin, the film-like substrate 5A itself has elasticity, so that the surface of the semiconductor chip 1 can be protected.

Furthermore, since substantially the entire area of the wiring 5C on the film-like substrate SA is bonded to the film-like substrate 5A, it is possible to particularly improve the mechanical strength of the thin wiring 5C in the center of the film-like substrate 5A. I can do it. This improvement in the mechanical strength of the wiring 5C of the film-like substrate 5A reduces the deformation of the wiring 5C, and since the position where the external terminals 1 of the semiconductor chip 1 are arranged and the position of the wiring 5C do not change, many terminals are Simultaneous bonding can be easily performed.

The invention made by the present inventor has been specifically explained above based on the above embodiments, but the present invention is as follows.

It goes without saying that the invention is not limited to the embodiments described above, and that various changes can be made without departing from the spirit thereof.

For example, the present invention is not limited to connection between a semiconductor chip and a wiring board, but can be applied to connection between wiring boards.

〔Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows.

In a semiconductor device using a protruding electrode, the number of protruding electrode manufacturing processes incorporated in the semiconductor device manufacturing process can be reduced, and the productivity of the semiconductor device can be improved.

The structure of a semiconductor device using protruding electrodes can be simplified.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional configuration diagram showing an outline of a semiconductor device that is Embodiment I of the present invention, and FIGS. 2 and 3 are enlarged views showing protruding electrodes used in the semiconductor device for each manufacturing process. 4 is a perspective view showing the original structure of the film-like substrate on which the projecting electrodes are formed; FIG. 5 is a partially sectional perspective view showing an outline of a semiconductor device which is Embodiment 2 of the present invention. be. In the figure, 1... semiconductor chip, IC... external terminal, 3
... Protruding electrode, 4... Mounting substrate, 5A... Film-like substrate, 5B... Hole for embedding, 5C... Wiring. Figure 1

Claims (1)

[Claims] 1. An electrode forming method for forming protruding electrodes on electrodes arranged on the surface of a substrate, the method comprising: forming holes for embedding in a film-like substrate at positions corresponding to the electrodes arranged on the surface of the substrate; and embedding protruding electrodes in the embedding holes, placing the film-like substrate facing the surface of the substrate, and arranging the protruding electrodes embedded in the film-like substrate on the surface of the substrate. A method for forming an electrode, comprising the step of adhering the electrode onto the electrode. 2. The protruding electrode is made of low melting point metal such as solder, Au, Cu.
2. The method of forming an electrode according to claim 1, wherein the electrode is made of a highly malleable metal such as Mo, and the film-like substrate is made of a resin. 3. The electrode forming method according to claim 1 or 2, wherein the protruding electrodes are formed of substantially the same metal material as the electrodes arranged on the surface of the substrate. 4. An insulating film-like substrate is provided opposite the surface of the semiconductor chip on which external terminals are arranged, and the film-like substrate is embedded in the film-like substrate at a position corresponding to the external terminals arranged on the surface of the semiconductor chip. Moreover, a protruding electrode is provided with one end adhered to the external terminal, and a wiring electrically connected to the other end of the protruding electrode is provided on the surface of the film-like substrate opposite to the surface facing the semiconductor chip. A semiconductor device characterized in that: