NEW a-Si AMLCD FACTORY

The description of the new Sharp a-Si AMLCD factory in Tenri offers insight into the vigor and magnitude of the displays industry in Japan. A similar scenario was relayed to the committee during the visit to the DTI plant built jointly by Toshiba and IBM Japan in Himeji.

Sharp has a complete product line of a-Si AMLCDs of the following sizes:

Diagonal in Inches Rows Columns
3" 234 382
4" 234 479
5.7" 240 720
8.4" 480 640 x 3
8.6" 456 960
10.4" 480 640 x 3

All of these displays have RGB color with fluorescent backlight modules. They are available with several controller chip designs to accommodate interfaces with NTSC, PAL, VGA, and so forth.

The new factory at Tenri is in a new building designed specifically for a-Si TFT AMLCDs. It is located on a site next to the existing a-Si factory. This existing line was the test bed for the new factory and is set up in a building previously used for LSI chip production.

The new line is going into the first floor of the new multistory building. It was scheduled to start operation in January 1992. The JTEC displays committee members were the very first outsiders to see the factory. The committee saw the factory while the equipment was being installed. The area is separated into Class 10, 100, and 5,000 clean zones for corresponding requirements in the product process. The line is used to make the a-Si TFT substrate, to combine it with the color filter substrate shipped from an outside vendor, and to fill it with LC material. The attachment of the row and column drivers and the backlighting is done by a subcontractor at another location.

Design capacity is 40,000 yielded displays per month, and yield is expected to be over 90%. It is expected that it will take several years of operation and learning to achieve design yield. The plan is to manufacture displays for notebook and lap- top PCs and large workstation-size displays.

It is estimated that over $100 million worth of custom-made machines were being installed at the time of the visit:

Similar machines were grouped together, and cassette-to-cassette substrate carriers were used, requiring manual transport from machine to machine. The substrate size is about 12" x 15", which would accommodate two 10" displays or one 14" display per substrate. The arrangement allows for maximum flexibility in process flow. A major machine can be out of service for repair or cleaning without interrupting the flow.

All of the major support facilities, such as vacuum pumps, air conditioning and filtering, gas supplies, deionized (DI) water, and so forth, and a complete quality- control laboratory with test chambers, scanning electron microscopes (SEMs), and analytical equipment, are in the large basement.

The useful life of this new line was stated to be three to five years. This new line will also be used in designing the next line, planned for the second floor, and the following line, planned for the third floor. Sharp is already planning to build its next factory in Mie Prefecture.

It has been reported in the Japanese technical newspapers that by 1995 the Japanese displays industry may have a production capacity of one million AMLCDs per month.


Published: June 1992; WTEC Hyper- Librarian