Browse Prior Art Database

FINAL TEST DEVICE TEMPERATURE CONTROL SYSTEM

IP.com Disclosure Number: IPCOM000007764D
Original Publication Date: 1996-Aug-01
Included in the Prior Art Database: 2002-Apr-22
Document File: 5 page(s) / 263K

Publishing Venue

Motorola

Related People

James E. Wilson: AUTHOR

Abstract

Heat is generated during the operation of devices undergoing final test. Any increase in device junc- tion temperature during test increases the difference in temperature between the device and the test envi- ronmental chamber. In addition, temperature varia- tion exists between sites due to equipment and testing conditions. Maintaining a small temperature differ- ential between the device and the environmental chamber and also a uniform temperature differen- tial between sites during test is critical to testing Motorola devices at specified temperatures.

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M-LA Technical Developments

FINAL TEST DEVICE TEMPERATURE CONTROL SYSTEM

by James E. Wilson

ture control during test. The temperature control system includes a control feature to insure that air blows over the test site only during test.

ABSTRACT

  Heat is generated during the operation of devices undergoing final test. Any increase in device junc- tion temperature during test increases the difference in temperature between the device and the test envi- ronmental chamber. In addition, temperature varia- tion exists between sites due to equipment and testing conditions. Maintaining a small temperature differ- ential between the device and the environmental chamber and also a uniform temperature differen- tial between sites during test is critical to testing Motorola devices at specified temperatures.

  This paper addresses these issues by illustrating a system which maximizes heat transfer from the device under test (DUT) while minimizing temper- ature variation between sites. This device tempera- ture control system forces temperature-conditioned air over a set of four devices during final test. This hardware design is integrated within an automatic, quad-site pick-and-place test handler, the Delta-Flex Model 1210. By consistently forcing conditioned air flow over the device during test, generated heat is transferred from the device to the environmental chamber of the handler. With this design, at-tempera- ture testing (THI and TLO) can be conducted relia- bly within an automated test environment.

ENVIRONMENT

  Following wafer fabrication, probe, and assem- bly, final test is responsible for conducting tests to determine if a device meets Motorola specifications. Testing is conducted at three temperatures high tem- perature (THI), low temperature (TLO), and ambi- ent. At-temperature (THI, TLO) testing is neces- sary because the characteristics of the device, including access time, execution time, voltage lev- els, and current levels, change over temperature. For FSRAM devices, high temperature testing is approx- imately 80 C. Low temperature testing is generally done around -5" to 0" C. Ambient temperature is specified as 25°C.

  Automated test equipment is responsible for han- dling and testing the devices at final test. In many applications FSRAM uses San Diego-based Delta Design's Model 1210 handler for automated device handling. This handler operates as a pick-and-place system, using motor-driven assemblies to pick up, shuttle, test, and bin out devices under test.

  During the operation of the Delta Design Model 1210 handler, devices are transported from the input staging area to the environmental chamber. The tem- perature of the chamber, which is programmable and capable of being maintained to within 2" C of handler setpoint, is set at a specified temperature: THI, TLO, or ambient. The devices undergo a soak process in which they are held in the environmen- tal chamber until the specified temperature is met. The purpose of the soak p...