JP2780293B2 - Semiconductor device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to, for example, a liquid crystal display device in which a semiconductor chip for driving is directly and easily and reliably mounted on a liquid crystal panel formed of a transparent conductive film. The present invention relates to a semiconductor device.

2. Description of the Related Art In recent years, a thin and light-weight liquid crystal display device in which a driving semiconductor chip is directly mounted on a liquid crystal panel having a structure in which a liquid crystal material is filled in a gap between two glass plates having a transparent conductive film formed thereon. Attempts have been made actively. As a typical method, a protruding connection metal electrode formed in advance by gold plating or the like on a semiconductor chip electrode portion and a connection electrode having a transparent conductive film formed on a glass plate are opposed to each other. State (semiconductor chip is in face-down state)
In this case, there is a method of performing electrical connection and bonding / fixing with a conductive adhesive interposed therebetween. At this time, the conductive adhesive is previously formed on the protruding connection metal electrode surface of the semiconductor chip by a transfer method or a dipping method, and is aligned with the transparent conductive film pattern on the glass plate. After doing
The electrical connection is made by thermosetting.

FIG. 4 shows a connection structure when a conductive adhesive is used in this liquid crystal display device. Reference numerals 1a and 1b denote two glass plates constituting a liquid crystal panel, on which transparent conductive films 4a and 4b are respectively formed. On the glass plate 1a, the transparent conductive film 4a extends to the outside and is shown as a connection electrode 4a 'in the figure. Semiconductor chip 7, which is formed in an eaves-like manner, and on which a protruding connection metal electrode 6 is formed in advance via conductive adhesive 5, is electrically connected face-down, and is bonded and fixed. ing. Reference numeral 2 denotes a liquid crystal, and reference numeral 3 denotes a sealant.

Problems to be Solved by the Invention In the above connection structure, as shown in FIG. 4, a transparent conductive film generally formed on the surface of an eave-shaped glass plate 1a
The connecting metal electrode 6 having a protruding shape of the semiconductor chip 7 is directly connected to the connecting electrode 4a 'made of the semiconductor chip 7 through the conductive adhesive 5 in a face-down state, and the bonding / fixing is performed. Most of the connection electrode 4a 'is exposed (including a portion where the semiconductor chip 7 is not mounted). A transparent conductive film generally used for a transparent electrode is an oxide and is stable in a dry atmosphere because it is an oxide. However, it is easily decomposed in the presence of moisture. It is applied to liquid crystal display devices, for example, because the transparent conductive film may be broken due to conductive dust such as metal scraps and ionic contaminants such as sweat and saliva adhere to it, causing short circuit and corrosion. In some cases, there was a major problem that lacked quality and long-term connection reliability. As one of the measures, the connection electrode
4a ', that is, a structure in which nickel plating is applied to the transparent conductive film by an electroless plating method or the like and a metal film is applied by further gold plating. In this case, if there is slight contamination on the surface of the transparent conductive film, the surface of the transparent conductive film is not uniformly and completely covered with the plating film, and there is a problem that a large number of pinholes are generated.
Further, since the thickness of the transparent conductive film is usually 300 to 2000 mm, which is extremely thin, there is a problem in that the thickness direction, that is, on the side surface of the transparent conductive film, the adhesion of the plating film is formed in a very poor state. As described above, permanent measures such as the intrusion of moisture from the pinholes of the plating film due to the presence of moisture and the interface between the transparent conductive film and the plating film and the occurrence of electrolytic corrosion by applying a voltage are provided. Not.

The present invention solves such a problem, and completely achieves protection of a transparent conductive film in a liquid crystal display device or the like in which a semiconductor chip provided with protruding connection metal electrodes is directly mounted on a liquid crystal panel, An object of the present invention is to provide a semiconductor device applicable to a high-quality, high-reliability liquid crystal display device.

Means for Solving the Problems In order to solve the above problems, a semiconductor device of the present invention is provided with a connection electrode made of a transparent conductive film having a metal film formed on a surface thereof on an insulating substrate; A protective film made of a synthetic resin is formed thereon, and a semiconductor chip provided with a protruding connection metal electrode is disposed so as to face the connection electrode formed on the insulating substrate; The connection metal electrode of the chip is configured to penetrate the protective film by thermocompression bonding so as to be electrically connected to the connection electrode.

According to this configuration, a protective film made of a synthetic resin is further formed on the connection electrode made of a transparent conductive film having a metal film formed on the surface of the insulating substrate, and the connection metal having a projection shape is formed. In the electrical connection between the semiconductor chip provided with the electrodes and the connection electrode formed on the insulating substrate, the protective film is formed by melting the semiconductor chip at the time of thermocompression and applying a pressing force to the semiconductor chip. Electrical connection can be obtained by being pierced by the connection metal electrode and being excluded at the peripheral portion other than the connection metal electrode. In addition, by forming a metal film on the surface of the insulating substrate as described above, the connection electrode made of a transparent conductive film is roughly protected in advance, and the portion of the semiconductor chip where the connection metal electrode is not connected is not connected. Since the protective film remains on portions other than the connection electrode and the semiconductor chip, the protection film is doubly protected, and moisture and dust can be cut off. As a result, the connection electrode is completely exposed to the outside air. A high-quality and high-reliability semiconductor device can be obtained while maintaining the state protected from the semiconductor device.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In FIG. 2a, reference numerals 11a and 11b denote glass plates as two insulating substrates constituting a liquid crystal panel, on which transparent conductive films 14a and 14b are respectively formed. On the glass plate 11a, the transparent conductive film 14a is provided. It extends outside and is exposed like an eave. In addition, 12 is a liquid crystal and 13 is a sealant. Reference numeral 15 denotes a metal film formed on the transparent conductive film 14a, and is constituted by the transparent conductive film 14a and the metal film 15 as a connection electrode. Numeral 16 denotes a protective film made of a synthetic resin formed on the metal film 15, and a double protective film of the metal film 15 and the synthetic resin 16 is formed on the connection electrode 14a. In the present embodiment, the thickness of the metal film 15 is set to 0 by electroless plating.
An 8 μm nickel plating film was formed, and then a 0.05 μm gold plating film was formed by an electroless plating method. In addition, gold, silver, copper, chromium, platinum, palladium, aluminum, solder, etc. And a metal film formed by electroless plating, electrolytic plating, sputtering, vapor deposition or the like of these multilayer films, alloy films and the like are also effective. Further, in the present embodiment, as the protective film 16 made of a synthetic resin, in the connection by thermocompression bonding of the semiconductor chip, it is easily melted, and is formed on the connection electrode using a thermoplastic polyester resin having a high adhesive strength. In order to completely cover the metal film 15, the entire surface was coated to form a protective film. Others
Examples of the protective film include a thermoplastic resin such as acrylic, polyvinyl butyral, and polystyrene; a thermoplastic rubber such as styrene-butadiene copolymer rubber; an uncured liquid phenol resin; an epoxy resin; an epoxy-modified phenol resin; A single substance or a mixture of a photocurable resin such as a curable resin, an uncured liquid epoxy acrylate oligomer, and an acrylate monomer is also effective. FIG. 2B is a cross-sectional view taken along the line AA ′ in FIG. 2A, and shows a transparent conductive film 14a formed on a glass plate 11a and a metal film 15 formed thereon. This shows a state in which a protective film 16 is formed on the entire surface including the connection electrode and a blank portion other than the connection electrode.

Next, as shown in FIG. 1, the electrode portions of the semiconductor chip 18 are previously provided with the protruding connection metal electrodes 17 formed by gold plating and the connection electrodes formed on the glass plate 11a (semiconductor chip 18). Is in a face-down state), and is electrically connected from the back of the semiconductor chip 18 with a 140 ° C heating tool at a pressure of 3 kg / cm ² for 30 seconds.
The liquid crystal display was fixed. According to such a connection structure, as shown in FIG.
Melting at the time of thermocompression bonding of the semiconductor chip 18 and being pierced by the protruding connection metal electrode 17 formed on the semiconductor chip 18 due to the applied pressure, flowing and being eliminated by the peripheral portion other than the connection metal electrode 17, The connection is obtained. In addition, the entire surface of the semiconductor chip 18 other than the connection metal electrodes 17 is also bonded by the protective film 16, so that the bonding strength can be significantly improved. Further, the protective film 16 remains in a portion of the connection electrode 14 where the semiconductor chip 18 is not mounted, and is shielded from the outside air, so that a moisture-proof effect can be obtained. In the present embodiment, gold was used as the protruding connection metal electrode 17 on the semiconductor chip 18.
A single substance or a composite substance of silver, copper, platinum, palladium, nickel, or the like may be used. Also, connection metal electrode 17
The cross-sectional shape may be flat or bowl-shaped, but in this embodiment, as shown in FIG. 3, both ends (actually, when viewed from the top, correspond to the periphery of the connection metal electrode). ,
One shape is particularly effective in breaking through the protective film 16. Specifically, in the present embodiment, gold is used in which the total thickness of the connecting metal electrode 17 including one portion is approximately 20 μm and the total thickness of the other portions is approximately 17 μm.

Next, in order to confirm the moisture-proof effect of the liquid crystal display device obtained in this example, 90-95% R at 60 ° C. was applied to each of the ten liquid crystal display devices while applying an applied voltage of 15 V DC.
H was placed in a constant temperature and constant humidity atmosphere, and an electrolytic corrosion resistance test was performed. The results obtained are shown in the following table.

Further, as Comparative Examples 1 and 2, liquid crystal display devices were manufactured by a conventional technique.

COMPARATIVE EXAMPLE 1 As shown in FIG. 4, transparent conductive films 4a and 4b were formed on two glass plates 1a and 1b, respectively. As 4a, a liquid crystal panel exposed in an eaves shape was produced. Silver powder is dispersed in epoxy resin on the transparent conductive film 4a formed on the eaves-like portion of the liquid crystal panel and on the protruding connection metal electrode 6 formed on the electrolytic portion of the semiconductor chip 7 in advance by gold plating. The conductive adhesive obtained by dipping is opposed to each other, aligned, and placed at 150 ° C.
And then electrically connected and fixed to obtain a liquid crystal display device.

Comparative Example 2 As Comparative Example 2, on the connection electrode 4a made of the transparent conductive film 4a exposed in an eaves shape of the liquid crystal panel in Comparative Example 1,
After forming a nickel plating film having a thickness of 0.8 μm, a gold plating film having a thickness of 0.05 μm was further formed in the same manner as in the present embodiment. It was fixed to obtain a liquid crystal display device.

In these Comparative Examples 1 and 2, similarly to the present Example, an electrolytic corrosion resistance test was performed on ten liquid crystal display devices. The results obtained are shown in Table 1 below.

As shown in the above table, in the liquid crystal display device of the present example, in the electric corrosion resistance test, no electric corrosion breakage failure occurred at all.

Effect of the Invention In a semiconductor device configured as in the present invention, a semiconductor chip is mounted by a double protective film configuration in which a protective film made of a metal film and a synthetic resin is formed on a transparent conductive film formed on an insulating substrate. The moisture resistance and dust resistance of the transparent conductive film in the part where it is not placed can be significantly improved, and the semiconductor chip is electrically connected and fixed in a face-down manner. An ohmic connection is obtained because the connection is made to penetrate the protective film made of resin and penetrate into the metal film formed on the transparent conductive film (usually, the surface of the metal film has a larger surface roughness than the surface of the transparent conductive film) In this state, the entire surface of the semiconductor chip other than the connection metal electrodes is adhered and fixed with a protective film made of a synthetic resin, thereby significantly improving connection reliability. it can. Also, attempts to form a metal film on a transparent conductive film for the purpose of reducing the resistance value in order to prevent crosstalk in a liquid crystal display device have hitherto failed to completely prevent electrolytic corrosion disconnection. With such a configuration, a semiconductor chip mounting type liquid crystal display device having a high reliability and a high quality can be obtained.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a semiconductor device according to one embodiment of the present invention,
2a and 2b are partial cross-sectional views for explaining the configuration of one embodiment of the present invention, and FIG. 3 is a semiconductor chip provided with a protruding connection metal electrode used in one embodiment of the present invention. FIG. 4 is a partial sectional view showing a connection state of a conventional semiconductor device. 11a, 11b: insulating substrate, 12: liquid crystal, 13: sealant, 14a, 14b: transparent conductive film, 15: metal film, 16 ...
Protective film, 17 ... Metal electrode for connection, 18 ... Semiconductor chip.

Claims (1)

(57) [Claims] A connection electrode comprising a transparent conductive film having a metal film formed on a surface thereof is provided on an insulating substrate, and a protective film made of a synthetic resin is formed on the connection electrode to form a projection-shaped connection. A semiconductor chip provided with metal electrodes for connection is disposed so as to face the connection electrodes formed on the insulating substrate, and the metal electrodes for connection of the semiconductor chip break through the protective film by thermocompression bonding. A semiconductor device mounted so as to be electrically connected to the connection electrode.