JPH02177547A - Semiconductor device - Google Patents

Abstract

PURPOSE:To contrive the improvement of the humidity resistance and the dust-proof property of a part, on which a semiconductor chip is not mounted, of a transparent conductive film by a method wherein a device is formed into a double protective film constitution, in which a protective film consisting of a metal film and a synthetic resin is formed on the transparent conductive film provided on an insulative substrate. CONSTITUTION:A metal film 15 provided on a transparent conductive film 14a' constitutes an electrode for connection use along with the film 14a'. A double protective film consisting of the film 15 and a synthetic resin 16 is provided on the film 14a'. Protrusion-shaped metallic electrodes 17 for connection use are formed on electrode parts of a semiconductor chip 18 and an anisotropic conductive bonding agent layer obtainable by dispersing conductive powder 20 in a synthetic resin 19 is formed on the surface of the chip 18 including the electrodes 17. Moreover, when a thermocompression bonding is performed from the rear of the chip 18 to a substrate, the protective film 16 is fused, broken through by the electrodes 17 and an electrical connection is obtained. Thereby, moisture, dust and the like can be intercepted and the electrode for connection use can be held in a state that it is completely protected from the air.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention is applied to liquid crystal display devices, etc., in which a driving semiconductor chip is easily and reliably mounted directly on a liquid crystal panel made of a transparent conductive film. The present invention relates to semiconductor devices.

Conventional technology In recent years, thin and lightweight liquid crystal display devices have been developed in which a driving semiconductor chip is directly mounted on a liquid crystal panel in which a liquid crystal material is filled in the gap between two glass plates on which transparent conductive films are formed. There are many attempts to do so. A typical method for this is to place a metal connection electrode in the shape of a protrusion, which is formed by gold plating or the like on the electrode part of a semiconductor chip in advance, and a connection electrode, which has a transparent conductive film formed on a glass plate, facing each other. (the semiconductor chip is in a face-down state),
During this time, there is a method of interposing a conductive adhesive to perform electrical connection, adhesion, and fixation. At this time, the conductive adhesive is
Formed in advance on the protrusion-shaped connecting metal electrode surface of a semiconductor chip by a transfer method or dip method, and placed on a transparent conductive film pattern on a glass plate in alignment with the surface, electrical conductivity is formed by heat curing. It is intended to connect the

FIG. 6 shows a connection structure using a conductive adhesive in this liquid crystal display device. 11L and 1b are two glass plates constituting the liquid crystal panel, each of which is coated with a transparent conductive film 4.
iL, 4b is formed, and the transparent conductive film 4a is extended to the outside of the glass plate 1a to form an eave-like connection electrode 4a as shown in the figure. A semiconductor chip 7 on which a connecting metal electrode 6 is formed.
are electrically connected face-down and glued and fixed. Further, 2 is a liquid crystal, and 3 is a sealant.

Problems to be Solved by the Invention In the above-mentioned connection structure, as shown in FIG. In order to perform electrical connection, adhesion, and fixation via the conductive adhesive 6 when the protrusion-shaped connection metal electrode 6 of the semiconductor chip T is in the 7 ace down state, most of the connection electrode 41L' is The transparent conductive film commonly used for transparent electrodes is exposed (including the part where the semiconductor chip 7 is not mounted) and is stable in dry air because it is an oxide, but decomposes in the presence of moisture. Furthermore, when voltage is applied, the transparent conductive film may be disconnected due to electrolytic corrosion or excessive current caused by adjacent lines, and conductive dirt such as metal scraps and ionic dirt such as sweat and saliva may be generated. When applied to liquid crystal display devices, there were major problems such as a lack of quality and long-term connection reliability, such as adhesion and causing sheeting and corrosion. One of the countermeasures against this problem is to have a structure in which the connection electrode 4&', that is, the transparent conductive film, is plated with nickel by electroless plating, or is plated with nickel and then further plated with gold to form a metal film. can be seen. In this case, if there is slight contamination or the like on the surface of the transparent conductive film, the surface of the transparent conductive film will not be uniformly and completely coated with a plating film, causing a problem that many pinholes will occur. Furthermore, the thickness of the transparent conductive film is usually 300 to 20
00 and is extremely thin, the thickness direction, that is,
On the side surfaces of the transparent conductive film, there are problems such as the plating film being formed with very poor adhesion, and as mentioned above, the presence of moisture can cause pinholes in the plating film and the formation of contact between the transparent conductive film and the plating film. Moisture enters from the interface and electrolytic corrosion occurs when voltage is applied, so there is no permanent solution to this problem.The present invention solves these problems and uses an anisotropically conductive adhesive. This technology completely protects the transparent conductive film in liquid crystal display devices in which semiconductor chips are directly mounted on liquid crystal panels in the 7 ace down state, and provides a semiconductor device that can be applied to high-quality, highly reliable liquid crystal display devices. It is something to do.

Means for Solving the Problems In order to solve the above-mentioned problems, the semiconductor device of the present invention includes a semiconductor device on an insulating substrate, on a connecting electrode in which the upper layer is a metal film and the lower layer is a transparent conductive film. A semiconductor chip provided with a protective film made of synthetic resin and provided with a protrusion-shaped connection metal electrode is arranged so as to face the connection electrode provided on the insulating substrate, and the connection metal of the semiconductor chip is disposed so as to face the connection electrode provided on the insulating substrate. The electrode is attached by thermocompression bonding via an anisotropic conductive adhesive so as to break through the protective film and be electrically connected to the connection electrode.

According to this structure, a protective film made of a synthetic resin is further formed on an insulating substrate, on a connection electrode whose upper layer is a metal film and whose lower layer is a transparent conductive film. In the electrical connection between the semiconductor chip provided with the protrusion-shaped connection metal electrode and the connection electrode provided on the insulating substrate, the protective film melts during thermocompression bonding of the semiconductor chip and is damaged by the pressure force. A stain-free connection is obtained by being pierced by a protrusion-shaped connection metal electrode provided on the chip and removing most of it to the peripheral area other than the connection metal electrode. Moreover, by providing the metal film on the upper layer on the insulating substrate as described above, the transparent conductive film on the lower layer is roughly protected in advance, and the metal electrodes for connection on the semiconductor chip are electrically connected. Since the protective film remains on the connection electrodes on the parts that are not exposed, and on the parts other than the semiconductor chip (exposed parts where the semiconductor chip is not mounted), there is double protection, and moisture and dirt are removed. As a result, the connecting electrodes can be kept completely protected from the outside air, and a high quality and highly reliable semiconductor device can be obtained.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings. Second
In Figure a, 11&, 11b are glass plates serving as two insulating substrates constituting the liquid crystal panel, and have transparent conductive films 141L and 141L', respectively.

14b is formed, and the transparent conductive film 14&' extends outward from the glass plate 111L and is exposed in the shape of an eave.

Note that 12 is a liquid crystal, and 13 is a sealant. Reference numeral 16 denotes a metal film provided on the transparent conductive film 141', and the transparent conductive film 141L' and the metal film 15 constitute a connection electrode. 16 is a protective film made of synthetic resin provided on the metal film 15, and the transparent conductive film 1
A double protective film of a metal film 16 and a synthetic resin 16 is provided on 4a'. In addition, as the metal film 15,
In this example, after forming a nickel plating film with a thickness of 0.8 μm by electroless plating, a gold plating film of OLOS μm was further formed by electroless plating. silver, copper, chrome, platinum,
Single-layer films of palladium, aluminum, solder, etc., as well as multi-layer films of these two alloy films, etc., formed using electroless plating, electrolytic plating, sputtering, vapor deposition, etc., are also effective. . Further, in this embodiment, as the protective film 16 made of synthetic resin, a thermoplastic polyester resin that is easily melted and has high adhesive strength is used in the connection of semiconductor chips by thermocompression bonding, and is used as the protective film 16 on the transparent conductive film 141L'. In order to completely cover the formed metal film 15, the entire surface was coated to form a protective film. In addition, as the protective film, thermoplastic resins such as acrylic, polyvinyl butyral, and polystyrene, thermoplastic rubbers such as styrene-butadiene/copolymer rubber, uncured liquid 7-enol resin, epoxy resin, and epoxy-modified phenol resin. , curable resins such as silicone resins, uncured liquid epoxy acrylate oligomers, photocurable resins such as acrylate monomers, etc. alone or in mixtures are also effective. FIG. 2 is a cross-sectional view of the 5' portion of FIG. a connection electrode consisting of;
A protective film 16 is applied to the entire surface including the blank area other than the connection electrode.
This figure shows the state in which .

Next, as shown in FIG. 3, protrusion-shaped connection metal electrodes 17 are formed in advance on the electrode portions of the semiconductor chip 18 by gold plating, and the surface of the semiconductor chip 18 including the connection metal electrodes 17 is synthesized. An anisotropic conductive adhesive layer 21 was formed by dispersing conductive powder 2o in resin 19. To explain this structure in detail, in this embodiment, gold was used as the protrusion-shaped connection metal electrode 17 on the semiconductor chip 18, but solder, silver, and copper may also be used.

Single or composite materials such as platinum, palladium, nickel, and chromium may be used.

Furthermore, as the synthetic resin 19 constituting the anisotropically conductive adhesive 21, the same resin as that for the protective film 16 is suitable, and in this example, a thermoplastic polyester resin was used. Furthermore, as the conductive powder 20, in this example, a polystyrene resin ball with a particle size of 1 to 40 μm was coated with an electroless nickel plating film, and then an electroless gold plating film was further formed. Depending on the balance, metal powders such as nickel, solder, gold, silver, and copper, and conductive powders such as carbon powder and graphite powder may also be used.

In order to obtain the anisotropic conductive adhesive 21, in this example, 24 parts by weight of the above-described conductive powder in the form of styrene resin balls with a plating film were added to 100 parts by weight of the thermoplastic polyester resin, and the mixture was milled in a ball mill. They were mixed to form an anisotropically conductive adhesive. This anisotropic conductive adhesive 21 is made into a sheet,
At a low temperature of about 0.degree. C., it was temporarily fixed to the surface of the semiconductor chip 18 including the connection metal electrodes as shown in FIG. 3 by thermocompression bonding. Further, in this embodiment, the anisotropic conductive adhesive 21 is formed on the surface of the semiconductor chip 18 as described above, but the present invention is not limited to this, and as shown in FIG. 141L', the metal film 16, and the protective film 16)), there is no problem in the present invention even if the anisotropically conductive adhesive (sheet) 21 is formed in advance on the film 141L', the metal film 16, and the protective film 16.

Next, as shown in FIG. 1, the connection metal electrodes 17 in the semiconductor chip 18 on which the protrusion-shaped connection metal electrodes 17 made of gold and the anisotropically conductive adhesive 21 have been formed in advance are placed on the glass plate 11a. The connecting electrodes formed in the above are aligned so that they face each other (the semiconductor chip 18 is in a face-down state), and the semiconductor chip 18 is pressed from the back side with a 140'C heating tool and a pressure of 3 kq for 30 seconds. It was electrically connected and fixed to form a liquid crystal display device.

According to such a connection structure, as shown in FIG. 1, the protective film 16 melts during thermocompression bonding of the semiconductor chip 18, and due to the pressure, the protrusion-shaped connection metal electrode 17 formed on the semiconductor chip 1B. As it is pierced, most of the conductive powder 20 in the anisotropic conductive adhesive 21 flows and is removed to the peripheral area other than the connection metal electrode 17, and at the same time, the conductive powder 20 in the anisotropic conductive adhesive 21 connects to the connection metal electrode 17 of the semiconductor chip 18 and the glass. It is sandwiched between the plate 11 and the connection electrode on the plate 11 to establish an electrical connection. In addition, parts of the semiconductor chip 18 other than the connecting metal electrodes 17 are also covered with the protective film 16 and the anisotropically conductive adhesive 21.
Since the synthetic resin 19 constituting the composite resin 19 is bonded to the entire surface in a mixed manner by thermocompression bonding, the adhesive strength can be significantly improved. Furthermore, the protective film 16 remains in the portion of the connection electrode where the semiconductor chip 18 is not placed, and is shielded from the outside air to provide a moisture-proofing effect. Incidentally, in order to confirm the moisture-proofing effect of the liquid crystal display device obtained in this example, each of the 10 liquid crystal display devices was placed in a constant temperature and humidity atmosphere of 90 to 954 RH at 60'C while applying an applied voltage of 1 sV DC. and conducted an electrolytic corrosion resistance test. The results obtained are shown in the following table.

Further, as Comparative Example 1.2, a liquid crystal display device was manufactured using a conventional technique.

Comparative Example 1 As shown in FIG. 5, transparent conductive films 4m and 4b were formed on two glass plates 1m and 1b, respectively, and on glass plate 1&, the transparent conductive film 4a was extended to the outside and a connection electrode 41L was formed. As a result, we fabricated a liquid crystal panel exposed in the shape of an eave. The transparent conductive film 41 formed on the eave-like portion of this liquid crystal panel
A conductive adhesive obtained by dispersing silver powder in an epoxy resin was applied to the connection metal electrode 6 in the shape of a protrusion, which was previously formed by gold plating on the electrode portion of the semiconductor chip 7, using the disode method. After the components were placed facing each other, aligned, and placed, they were thermally cured at 150'C, electrically connected and fixed, and a liquid crystal display device was obtained.

Comparative Example 2 As Comparative Example 2, the transparent conductive film 4 exposed in the eaves of the liquid crystal panel in Comparative Example 1! After forming a nickel plating film with a thickness of 0.8 μm on the connection electrode 4& consisting of Using this method, semiconductor chips were electrically connected and fixed to obtain a liquid crystal display device.

In Comparative Examples 1 and 2, electrolytic corrosion resistance tests were conducted on 10 liquid crystal display devices each in the same manner as in the present example. The results obtained are shown in the table below.

Table As shown in the table above, the liquid crystal display device of this example did not have any electrical corrosion disconnection defects in the electrical corrosion resistance test.

Effects of the Invention The semiconductor device constructed as in the present invention has a double protective film structure in which a protective film made of a metal film and a synthetic resin is formed on a transparent conductive film provided on an insulating substrate, so that the semiconductor chip is The moisture resistance and dust resistance of the transparent conductive film on the parts that are not placed can be significantly improved, and when semiconductor chips are electrically connected and fixed in a face-down manner, the electrical connections are made using protrusion-shaped connecting metal electrodes. The protective film made of synthetic resin is penetrated through the anisotropically conductive adhesive, and an ohmic connection is obtained by the multi-conductive powder in the anisotropically conductive adhesive to the metal film provided on the transparent conductive film. Furthermore, in this state, the entire surface of the semiconductor chip other than the connecting metal electrodes is adhered and fixed by the protective film made of synthetic resin, so that connection reliability can be significantly improved. Furthermore, attempts to provide a metal film on a transparent conductive film for the purpose of reducing resistance in order to prevent crosstalk in liquid crystal display devices have not been able to completely prevent electrical corrosion, but the present invention With this configuration, it is possible to obtain a semiconductor chip mounting type liquid crystal display device with high reliability and high quality, which is of great industrial value.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of a semiconductor device according to an embodiment of the present invention, FIGS. 2a and 2b are partial sectional views illustrating the structure of an embodiment of the present invention, and FIG. A partial cross-sectional view showing a state in which an anisotropic conductive adhesive is provided on the surface of a semiconductor chip provided with a protrusion-shaped connecting metal electrode used in an embodiment of the invention,
FIG. 4 is a sectional view of a main part showing another embodiment of the present invention, and FIG. 5 is a partial sectional view showing a connection state of a conventional semiconductor device. Board, 12...
...Liquid crystal, 13...Sealant, 14 &, 14
&', 14b...Transparent conductive film, 16...
・Metal film, 16...Protective film, 17...
・Metal electrode for connection, 18... Semiconductor chip, 1
9...Synthetic resin, 2o... Conductive powder,
21...Anisotropic conductive adhesive. Name of agent: Patent attorney Shigetaka Awano and 1 other person//
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Claims (1)

[Claims] On an insulating substrate, a protective film made of synthetic resin is provided on a connection electrode whose upper layer is a metal film and a lower layer is a transparent conductive film, and a semiconductor chip is provided with a protrusion-shaped connection electrode. The connection electrodes provided on the insulating substrate are arranged to face each other, and the connection metal electrodes of the semiconductor chip are bonded by thermocompression through an anisotropic conductive adhesive to break through the protective film. A semiconductor device installed to be electrically connected to a connecting electrode.