JPH04314337A - Semiconductor device and its manufacture - Google Patents

Abstract

PURPOSE:To relieve a stress in a soldering part with which the electrode terminal of a semiconductor chip is connected to a wiring terminal on a circuit board, avoid the solder erosion of the soldering part and avoid a cost increase by a method wherein multilayer metal electrodes are provided on both the terminals. CONSTITUTION:Same type double-layer structures composed of Ni layers on the surfaces and the Al layers under the Ni layers are provided on both the wiring terminals 8 of a circuit board 6 and the electrode terminals of a semiconductor chip 1 in order to have same stress distributions on both the sides of solder bumps 5. The degration of a connection strength is reinforced by a bonding stress produced by sealing resin 9 filling a space between the chip 1 and the board 6. With this constitution, the sufficient connection strength can be obtained with a low cost terminal structure. Such a connection method can be effectivly applied to an electroluminescense display device having the circuit board as a display panel.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device in which a plurality of semiconductor elements are mounted on a circuit board by brazing their electrode terminals to wiring terminals on the circuit board, and a method for manufacturing the same.

0002

[Prior Art] In recent years, there has been an active development of devices and equipment that mount a large number of semiconductor elements on a substrate at a fine pitch. Examples include memory cards, liquid crystal, electroluminescent (EL), or plasma display panels. These all have a large number of inputs and outputs (power, signals,
Control) Using a driving IC with terminal electrodes, this IC
must be mounted in a thin and high-density manner on a panel substrate having a certain area.

Conventional mounting methods for semiconductor elements in such semiconductor devices include (a) a method in which metal protruding electrodes (Au bumps) made of Au are brought into pressure contact with each other, or (b) There is a method of connecting by heating and melting metal protruding electrodes (solder bumps) made of solder, but method (b) is called electroluminescence (EL), referring to Figures 2(a) and (b). An example of a display panel will be explained.

In this display substrate, a metal electrode 41 is provided on one surface of the IC chip 1 on an Al electrode pad (not shown) exposed through a contact hole in an insulating protective film 2, and a solder bump 5 is formed on the metal electrode 41. ing. On the other hand, the EL display substrate has terminals 8 made of ends of ITO electrode wiring and Al electrode wiring formed by soldering a light emitting layer on the glass substrate 6. IT at the terminal section
An Al layer is laminated on the O wiring, and the Al wiring is used as it is as a terminal. And IC chip 1
The solder bumps 5 and the terminals 8 on the display substrate 6 are aligned, and electrically connected by heating and reflowing the solder bumps 5. Thereafter, the gap between the IC chip 1 and the substrate 6 is filled with a sealing resin 9 to protect the connection portion and to increase the connection strength between the IC chip 1 and the substrate 6.

[0005]

However, in the EL display device shown in FIG. 2, since the IC chip 1 and the glass substrate 6 have different thermal expansion coefficients, the solder bumps 5
During cooling from the heating temperature for reflow, stress is generated in the connection, which may cause peeling. Furthermore, there is a possibility that the metal electrode 41 may be eaten away by the solder during solder reflow. Therefore, in order to relieve stress and prevent solder from being eaten away, the metal electrode 41 is made of, for example, Cr/Cu/
A multilayer structure such as Au, Ti/Pd/Au, Ti/W/Au or Ti/Pt/Au is adopted. As a result, the connection strength of the connection portion is several hundred grams per mm2. However, the large number of layers of electrode pads on an IC chip has the disadvantage of increasing costs.

An object of the present invention is to eliminate the above-mentioned drawbacks and provide a low-cost semiconductor device in which an IC chip having electrode pads with a reduced number of laminated layers is connected to wiring terminals of a circuit board, and a method for manufacturing the same. There is a particular thing.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a method in which electrode terminals of a semiconductor element and wiring terminals of a circuit board are soldered, and a resin is filled in a gap between the semiconductor element and the circuit board. In the semiconductor device to be filled, the electrode terminals of the semiconductor element and the wiring terminals of the circuit board both have a nickel layer on the side in contact with the solder, and have an aluminum layer below the nickel layer. Further, it is effective that the semiconductor device is an EL display device, that the circuit board is made of glass, and that a Cr layer is interposed between the Al layer and the circuit board. Further, in the manufacturing method of the present invention, an electrode terminal is formed on one surface of a semiconductor substrate of a semiconductor element, the surface of which is a Ni layer and the bottom of which is an Al layer, a bump made of solder is fixed thereon, and a circuit board is A wiring terminal is formed with a Ni layer on top and an Al layer on the bottom, and the wiring terminal and the solder bump are heated in contact with each other to melt and solidify the solder, and then the semiconductor substrate and the circuit are bonded. The gap between the substrates is filled with resin and cured.

[0008]

[Operation] The present invention improves the connection strength between the semiconductor element and the circuit board, not only by increasing the soldering strength between the electrode terminal of the element and the wiring terminal of the circuit board, but also by increasing the strength of the soldering between the semiconductor element and the circuit board. This is based on the idea that since the adhesive strength of the resin is also added, it does not matter if the soldering strength is somewhat lower. Therefore, there is no need for a conventional multilayer metal electrode structure,
It is sufficient to have two layers: an Al layer and a Ni layer with good solderability thereon. Same N on both sides of the solder at the same time.
The presence of the i/Al layer structure provides a balanced stress distribution and ensures connection reliability.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1(a) and 1(b) show an embodiment of the present invention, and parts common to those in FIG. 2 are given the same reference numerals. The IC chip 1 is, for example, a high voltage Bi-CMOS for driving a display element on an EL display substrate. FIG. 3 shows a part of this IC chip in an enlarged manner, and shows chip 1.
An Al thin film with a thickness of about 4000 Å is deposited on one surface by electron beam (EB) evaporation and patterned by a photo process, and part of it is made into an Al electrode pad 3 as an electrode terminal. Next, a 300 mm thick insulating protective film is applied to the surface.
A SiO2 film 2 having a thickness of approximately 0 Å is formed, and a contact hole is formed by photoprocessing, leaving the SiO2 film overlapping the peripheral edge of the electrode pad 3. Thereafter, a Ni thin film with a thickness of about 4000 Å is deposited on the entire surface, and a Ni electrode pad 4 is formed on the Al electrode pad 3 by a photo process. Another method is to stack an Al thin film and a Ni thin film on the IC chip 1, and then use a photo process to etch the Ni thin film and then the Al thin film to form electrode pads, and then form an insulating protective film. Contact holes may also be made. The electrode pad 3 of the IC chip 1 made as above,
4, a solder pump 5 having a thickness of 20 to 100 μm is formed by vapor deposition or plating.

On the other hand, in an EL display panel, as shown in FIG.
This is formed to a certain thickness and is etched using a photo process to form the electrode wiring 7 on the data side. Next, although not shown, a first insulating layer with a thickness of 3000 to 4000 Å and a Z layer with a thickness of 5000 to 12000 Å are formed by vapor deposition or sputtering.
nS: a light emitting layer made of Mn, further 3000 to 4000
A second insulating layer with a thickness of Å is deposited. Next, by EB evaporation, thin Al films 81 and N thin films of approximately 4000 Å thick were formed.
The i thin film 82 is laminated, and then Ni is first deposited by a photo process.
The thin film 82 and then the Al thin film 81 are partially covered with the ITO wiring 7.
An etching process is performed so as to overlap with the glass substrate 6, and the portion in contact with the glass substrate 6 is used as the data side Al/Ni wiring terminal 8. The back electrode on the scanning side provided on the second insulating layer has an Al single layer or Al/Ni double layer structure, and even in the case of an Al single layer, a Ni thin film is laminated on the part extending to the glass substrate. Each thickness is 3000 Å as shown in Figure 5.
It has a two-layer structure of an Al thin film 81 and a Ni thin film 82 of about 100 mL. Alternatively, a Cr layer with a thickness of about 2000 Å is placed under the Al thin film.
A thin film may be interposed to improve the adhesion strength to the glass substrate 6. In either case, the end portion becomes the wiring terminal 8.

By using the electrode pads 3, 4 and solder bumps 5 of the IC chip 1 on the four sides of the chip as shown in FIG. 1(b), high-density terminals can be formed. However, as shown in FIGS. 6(a) and 6(b), the electrode pads 3 and 4 and the solder bumps 5 are placed on the entire surface of the IC chip 1, or as shown in FIGS. 7(a) and 7(b), the electrode pads 3, There is also an example in which the solder bumps 4 and 5 are arranged on two sides of the IC chip 1 in the long side direction.

The solder bumps 5 on the IC chip 1 and the wiring terminals 8 on the circuit board 6 are provided at opposing positions,
As shown in FIG. 1(a), an IC chip 1 is placed on a circuit board 6, and alignment is performed visually. Next, the solder is heated by scanning the solder bumps 5 with an infrared spot through the glass substrate 6, or by irradiating all the solder bumps 5 on one side or all the solder bumps 5 on four sides with a line spot. , Reflow. For such irradiation, a reflector or a shielding plate is set in advance on the infrared lamp. By solidifying after reflow, the solder 5 connects the electrode pads 3 and 4 of the IC chip 1 to the wiring terminals 8 on the substrate.

[0013] After this, in order to ensure the reliability of the IC chip 1, an epoxy thermosetting resin 9 is injected into the gap between the IC chip 1 and the circuit board 6, and is heat cured at 150 to 200°C to maintain the usage environment. Strengthen the moisture resistance of the bottom. As the sealing resin 9, a photocurable polymer resin such as a UV cured resin such as polyester acrylate or epoxy acrylate may be filled and photocured. IC after soldering
The connection strength between chip 1 and display board 6 is 100
~200 g/mm2, but by filling the void with the sealing resin 9, the connection strength is further increased.

Although the above embodiments have been described with respect to an EL display device, in the case of a liquid crystal panel, conventionally used ITO electrode wiring, ITO/Cr electrode wiring or ITO electrode wiring may be used.
The present invention can be carried out by overlaying an Al thin film on the TO/Mo electrode wiring or its end, and further overlapping a Ni thin film at the terminal portion.

[0015]

According to the present invention, the surface layers of both the electrode terminals of the semiconductor element connected by solder and the wiring terminals on the circuit board are formed of an Al layer and a Ni layer thereon,
Combined with the adhesive strength of the resin filled between the element and the board, we were able to obtain sufficient connection strength between the element and the board. Furthermore, since the terminal structures on both sides of the solder are the same, there is no occurrence of wire breakage due to changes over time. Furthermore, as the Al layer, it is possible to use Al electrodes conventionally used in semiconductor devices or Al wiring used in circuit boards, so the cost is lower than when using conventional multilayer laminated structure electrode terminals. It was possible to manufacture a semiconductor device with reduced cost.

[Brief explanation of drawings]

FIG. 1 shows an EL display device according to an embodiment of the present invention, in which (a) is a sectional view of the main part, and (b) is a plan view of an IC chip.

[Fig. 2] Shows a conventional EL display device, of which (a) is a cross-sectional view and (b) is a plan view of an IC chip.

FIG. 3 is a cross-sectional view of a main part of an IC chip used in an EL display device according to an embodiment of the present invention.

FIG. 4 is a sectional view of a data side electrode wiring terminal portion of a display substrate used in an EL display device according to an embodiment of the present invention.

FIG. 5 is a cross-sectional view of a scanning side electrode wiring terminal portion of a display substrate used in an EL display device according to an embodiment of the present invention.

FIG. 6 shows an IC chip used in another embodiment of the present invention, of which (a) is a plan view and (b) is a side view.

[
FIG. 7 shows an IC chip used in yet another embodiment of the present invention, of which (a) is a plan view and (b) is a side view.

[Explanation of symbols]

1 IC chip 2 Insulating protective film 3 Al electrode pad 4 Ni electrode pad 5 Solder bump 6 EL display board 7 Electrode wiring 8 Wiring terminal 81 Al thin film 82 Ni thin film 9 Sealing resin

Claims (3)

[Claims] Claim 1: In a device in which the electrode terminals of the semiconductor element and the wiring terminals of the circuit board are soldered and the gap between the semiconductor element and the circuit board is filled with resin, both the wiring terminals of the semiconductor element and the circuit board are soldered. A semiconductor device comprising a nickel layer on a side in contact with solder and an aluminum layer below the nickel layer. 2. The semiconductor device according to claim 1, which is an electroluminescent display device, wherein the circuit board is made of glass, and a chromium layer is interposed between the aluminum layer and the circuit board. 3. An electrode terminal having a nickel layer on the surface and an aluminum layer below is formed on one side of the semiconductor substrate of the semiconductor element, and a bump made of solder is fixed on the electrode terminal, while the surface is on the circuit board. A wiring terminal consisting of a nickel layer and an aluminum layer underneath is formed, and the wiring terminal and the solder bump are heated in contact with each other to melt and solidify the solder. A method for manufacturing a semiconductor device, characterized by filling a void with resin and curing the resin.