88000 ATS-620 Array Test System

Provides full thin film transistor (TFT) array testing of a-Si LCDs used in the manufacturing of large/wide size flat panel displays

On this page: Introduction · Industry Challenges · Summary · Features and Benefits · Components · Key Specifications

Introduction

Flat-panel displays (FPDs) continue to grow in popularity. They are widely used in mobile phones and computer displays, and most recently their use in large-screen televisions has expanded. Correspondingly, competition is increasing among FPD manufacturers as they strive to reduce costs and improve quality. In addition, the FPD manufacturing process has evolved to the point where seventh- and eighth-generation fabrication lines can now accommodate more than four square meters of total glass area.

Industry Challenges

Providing full thin film transistor (TFT) testing of a-Si LCDs used in manufacturing FPDs is a challenging process. Adding to this test challenge is the dramatic increase in glass size as large- and wide-screen televisions become more and more popular. Because picture quality is a major competitive differentiator in the marketplace, FPD manufacturers must affordably test all panels with sure defect detection, while decreasing test time and increasing quality and yield. The majority of the cost of manufacturing an LCD panel is incurred during the back-end process, i.e. the cell and module processes. To avoid unnecessary cost, therefore, ideal FPD testing is necessary to enable accurate selection of good panels and repair of defective panels, wherever possible, in order to prevent defective panels from advancing through the back-end process. Panel manufacturers must continuously improve process yield by monitoring process quality and acting to address

Most currently available FPD test solutions fall short in addressing the challenges presented by rapidly evolving technologies and markets:

• Insufficient defect detection High-volume testing of FPDs in the production line must be done quickly and with high sensitivity (measuring absolute value of capacitance, voltage and current).
• Inadequate testing speed Because TFT array testers are built into the fabrication line, testing time (as measured by total average cycle time, TACT) immediately impacts production throughput and economics. With many FPD manufacturers targeting a 60-second TACT per glass, today's test solutions require more testers to accommodate larger glass size.
• Lack of quality standards No definitive standard test technologies or associated metrics exist for assessing panel picture quality. There are wide variations in uniformity and moving picture performance throughout the industry.
• Immature test processes Test results cannot be linked with repair directives to achieve predefined quality goals. Continued inefficient operation impairs the realization of highly productive fabrication lines.

Summary

Reduce manufacturing cost and improve process quality and yield through precise upstream defect detection of large/wide-size FPDs under allotted testing time.

The Agilent 88000 ATS-620 Array Test System, together with the complete line of Agilent 88000 Series FPD Test Systems, provides FPD manufacturers with a high-quality, low-cost production test solution for all key technologies in the rapidly growing FPD market. Agilent Technologies has expanded its test coverage into FPD test by providing FPD manufactures with the Agilent 88000 ATS-620, providing both high sensitivity and short cycle time (TACT).

An array tester can provide significant cost savings by detecting defects early in the process of manufacturing flat-panel displays. This produces downstream savings in parts and cell assembly cost. The Agilent 88000 ATS-620 is a fast and proven solution for amorphous silicon (a-Si) TFT array testing of 7th and 8th generation FPD production lines.

Agilent Solutions Meet FPD Test Challenges

The Agilent 88000 ATS-620 Series tests TFT arrays of a-Si LCD panels based on TN, MVA and IPS, with wide coverage up to Q-HDTV. The ATS-620 reduces manufacturing costs and improves process quality and yield by providing precise upstream defect detection in large and wide-size FPDs, while reducing TACT. The ATS-620 is a fast and proven solution for testing FPDs on seventh- and eighth- generation production lines, with greater sensitivity than competitive solutions. This means the ATS-620 can detect more performance inconsistencies, which helps to reduce scrap cost, improve quality, and boost yield.

• Sure defect detection capability with short TACT
  Through the use of up to four test heads, multiple gate activation, and up to 15,360 data channels by two test heads, the ATS-620 can achieve the fastest throughput of the current generation of testers. This makes full testing an efficient and much less costly option for manufacturers.
• High test sensitivity improves process and product quality
  The ATS-620 enables electrical testing of all pixels, bus lines, and sub-pixels covering transistor, capacitance, electrode, and peripheral circuits, which prevents any defective pixels in the array process from flowing into the next phase. The tester automatically checks the TFT characteristics and the open/short status of the lines and pixels, then effectively analyzes the defect mode based upon the result of the check.
• Efficient process feedback and productivity improvement
  The ATS-620's full array test capability eliminates process defects, which leads to a large increase in process yield, improved manufacturing productivity and a significant reduction in cost.
  

Total test solution
The ATS-620 Series is a complete test solution comprising hardware, software, services, and application consulting. It lowers test cost and, through close collaboration with prober and probe unit suppliers, shortens the ramp-up period for achieving effective test results. The complete line of Agilent 88000 Series FPD Test Systems, pro-vides manufacturers with high-quality, low-cost production test solutions for all key technologies in the rapidly growing FPD market.

Features and Benefits

Features	Benefits
Precise and wide range measurement for various panel and pixel designs	Highest defect detection in the industry. Applicable to both production test and engineering analysis.
Improved TACT using multiple test heads	Reduced test time produces higher test productivity with smaller investment.
Automatic defect classification	Helps to achieve superior process quality and to determine suitable repair action.
Multi site test	Improved throughput
Highly integrated test environment with prober and probe unit	Safe buy and easy-to-operate, backed by total support from Agilent and prober and probe unit suppliers..
Test application support and optimization consulting	Quick start-up of effective test and analysis according to panel design and test objective.

Tester Components

• Tester Rack (Main Frame)
  - Control Unit
  - AC Unit
  - Power Unit
  - Controller
• Test Head
• Master Controller
• System Software

Key Specifications

Primary test target	TFT arrays of a-Si LCD panels
Maximum number of test heads	Four
Typical evaluation item	Line and Pixel area: Open, Short, Ion, Ioff, Vth, Cs
Number of channels	15,360 data and 3072 gate
Multi site test	Up to 8