JP2728393B2 - Liquid crystal display device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device having a liquid crystal driving semiconductor chip mounted on one of substrates constituting a liquid crystal display cell. [Prior art] Conventionally, a metal film wiring is formed in a pattern on one substrate constituting a liquid crystal display cell, and a semiconductor chip for driving a liquid crystal (hereinafter referred to as an LSI chip) is formed on the metal film wiring by a flip chip method. The liquid crystal display element directly connected by the above has a structure as shown in FIG. Lower electrode substrate 2 made of glass
Transparent electrodes 9 and 10 are formed on the inner surface of the upper electrode substrate 4, and a liquid crystal 11 is sandwiched between the upper and lower electrode substrates 2 and 4. 1
Is formed. On the lower electrode substrate 2, a multilayer metal thin film wiring 12 containing a metal having good wettability with solder is formed, and the LSI chip 6 is fixedly connected to the multilayer metal thin film wiring 12 via the solder 5. The LSI chip 6 and the metal thin film wiring 12
Is protected by a resin 7 having substantially the same coefficient of thermal expansion as that of the solder in order to protect it from the external environment (Japanese Patent Laid-Open No. 60-63951).
issue). Japanese Patent Application Laid-Open No. 60-63951 discloses a technique in which a low-expansion epoxy resin is applied around a semiconductor element and a silicon gel is applied between the semiconductor element and a substrate. However, the idea of applying a silicon gel around the semiconductor element and applying a low expansion epoxy resin between the semiconductor element and the substrate has been disclosed. Furthermore, as a result of an investigation by the applicant, the inventors have found JP-A-53-107242 and JP-A-53-142138. JP-A-53-107242 and JP-A-53-142138 disclose a technique of applying a silicon resin around a semiconductor element and applying a silicon adhesive between the semiconductor element and a substrate. I have. However, the idea of applying a low expansion epoxy resin between the semiconductor element and the substrate is not disclosed. [Problems to be Solved by the Invention] In the above conventional example, cracks may occur in the glass substrate in a test such as a temperature cycle due to a difference in thermal expansion coefficient between the resin and the glass substrate, and this is prevented. Therefore, there has been a problem that the amount and shape of the applied resin must be precisely controlled. SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal display element which prevents the occurrence of the above-mentioned glass crack and has a large manufacturing work latitude. [Means for Solving the Problems] The above problem is caused only by filling the resin having substantially the same coefficient of thermal expansion as the solder for bonding the LSI chip and the glass substrate on which the LSI chip is mounted, The problem is solved by coating the chip and its periphery with a resin having a low elastic modulus. [Operation] Filling only the gap formed between the LSI chip and the glass substrate with a resin that has almost the same coefficient of thermal expansion as the solder connecting them, minimizes the resin application area and prevents the occurrence of glass cracks In addition, since the LSI chip and its surroundings are covered with a resin having a low elastic modulus, the moisture resistance is also improved, and with such a structure, strong stress is not applied to the glass and the occurrence of glass cracks is eliminated. Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of one embodiment of a liquid crystal display device according to the present invention, and the same or corresponding parts as those in FIG. 2 are denoted by the same reference numerals. First, transparent electrodes 9 and 10 are formed on the surfaces of the lower electrode substrate 2 and the upper electrode substrate 4 made of glass using indium oxide or the like in a display pattern shape, respectively. Next, on the lower electrode substrate 2, first, a NiCr film having good adhesion to glass,
A multilayer metal thin film is formed by depositing and depositing a Cu film having good wettability with solder and a Cr film for preventing Cu oxidation and solder wetting. Next, the position on the lower electrode substrate 2 where the LSI chip 6 is mounted and the transparent electrode 9 will be described later.
The multi-layered metal thin film is etched into a wiring pattern for electrically connecting between the metal thin film and the metal thin film wiring 12.
Next, a high heat-resistant polyimide resin having a thermolysis initiation temperature of 400 ° C. or higher, and in this embodiment, a photosensitive polyimide high heat-resistant resin (for example, Hitachi Chemical
PL-1000 or UR3100 manufactured by Toray Co., Ltd.) is formed on the lower electrode substrate 2, and the LSI chip 6 and the metal thin film wiring 12 are electrically connected to each other via the solder 5 by using the photosensitivity. By etching, a polyimide-based wiring protection film 13 provided with through holes is formed. Next, a polyimide resin film is applied as a liquid crystal molecule alignment film on the side of the lower electrode substrate 2 and the upper electrode substrate 4 where the transparent electrodes 9 and 10 are formed, and formed by heat treatment (200 ° C. to 350 ° C.) ( The details are Japanese Patent Publication No. 58-5
5488 publication). After an epoxy resin is applied as a sealant 3 along the periphery of the upper electrode substrate 4 and leaving an injection port (not shown) for injecting the liquid crystal 11, the upper electrode substrate 4 and the lower electrode substrate 2 are separated. The transparent electrodes 9 and 10 are arranged so as to face each other with an interval of 5 to 10 μ, and the epoxy resin is cured at 180 ° C.
To form Next, the liquid crystal 11 is injected into the liquid crystal cell 1 through the injection port, and the injection port is sealed with an adhesive. A through hole is formed at a position corresponding to the chip bonding solder 5 in the Cr layer, which is the uppermost layer of the metal thin film wiring 12. A filling layer 18 made of epoxy resin is applied to a position where the LSI chip 6 is to be mounted. Next, the LSI chip 6 is bonded to a predetermined position on the metal thin film wiring 12 via the solder 5 (flip chip method). Next, for the purpose of protecting the LSI chip 6, the entire LSI chip 6 is covered with a chip protection resin 17 made of silicon gel resin. Here, the filling layer 18 has a thermal expansion coefficient of 24.7 × 10
^{It has a} coefficient of thermal expansion (25 × 10 ⁻⁶ / ° C.) substantially equal to ⁻⁶ / ° C., and for example, an epoxy resin having the following composition is used. Epoxy resin (Yukaka Shell KK product name Epicoat 828) ... 100 g dicyan diamide ... 10 g imidazole (curing accelerator, Shikoku Fine Chemical KK product name 2P4MHZ) ... 5 g Silane coupling agent ... 2 g Polybutadiene ... 15 g quartz powder 242 g As the chip protection resin 17, a silicon gel having a low elastic modulus, for example, KE-104 (trade name of Shin-Etsu Chemical KK) can be used. As a reliability test of the liquid crystal display device according to the present embodiment, 10
The thermal shock test for 0 samples, in which −40 ° C. and 85 ° C. were alternately repeated, was performed for 1000 cycles, but no disconnection or glass crack occurred at the connection portion of the LSI chip. A high-temperature and high-humidity test at -70 ° C and 95% RH was performed for 1000 hours, but no abnormality occurred. [Effects of the Invention] According to the present invention, it is possible to reduce the cost without reducing the connection life, eliminating the occurrence of glass cracks, increasing the reliability, and increasing the manufacturing work margin.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view showing one embodiment of a liquid crystal display device according to the present invention, and FIG. 2 is a schematic sectional view of a conventional liquid crystal display device. 1 ... liquid crystal cell, 2 ... lower electrode substrate, 5 ... solder, 6 ...
... Semiconductor chip for driving liquid crystal, 9 ... Transparent electrode, 12 ... Metal thin-film wiring, 13 ... Polyimide wiring protection film, 17 ... Chip protection resin, 18 ... Gap filling layer.

   ────────────────────────────────────────────────── ─── Continuation of front page    (56) References JP-A-60-63951 (JP, A)                 JP-A-53-107242 (JP, A)                 JP-A-53-142138 (JP, A)

Claims (1)

(57) [Claims] A first substrate and a second substrate having an electrode pattern formed on the opposing surface, a liquid crystal display element in which liquid crystal is sealed inside by sealing the periphery of the first substrate and the second substrate with a sealing material, A semiconductor element for driving the liquid crystal display element, which is provided on at least the first substrate, and which is provided on the first substrate and electrically connects the semiconductor element and the electrode pattern; A wiring disposed under the semiconductor element so as to overlap at least a part thereof; a surface of the semiconductor element on the first substrate side; a conductive member for electrically connecting the wiring; and the semiconductor element A first resin that covers a peripheral portion of the semiconductor element, between the semiconductor element and the first substrate, a second resin filled in a gap generated by the thickness of the wiring and the conductive member, The first resin is a silicone resin, The liquid crystal display element characterized by second resin is an epoxy resin.