Project Number: C95-18

Use of Electronic Hardware at Elevated Temperature

Point of Contact: Dr. Yogi Joshi email: yogi@calce.umd.edu Phone: (301) 405-5428 Fax: (301) 314-9269

Objectives

Background

Work Accomplised

Objective

Describe effects that limit the use of electronic hardware at elevated temperatures up to 200° C.

Background

Limiting operation to temperatures below the traditional barrier of 85° C can be extremely costly for electronics used for sensing and control in such environments as automotive underhood, aerospace, chemical processing and well logging. The costs are associated with the price, size, weight, and reliability limitations of cooling systems and/or the hardware associated with remote placement of the electronics. This is particularly true for avionic systems where the allowable weight and volume are severely constrained. Developments in the design and manufacture of electronic components indicate that the presently accepted temperature limits may be unduly restrictive, particularly when compared to the actual benefit realized. Many systems should be able to perform adequately up to 200° C with no changes, and others may require only minor materials or design alterations. Knowledge of the effects of elevated temperatures and strategies to accommodate these temperatures can be useful to engineers, allowing them to make informed design tradeoffs based on the actual costs and benefits involved in operation at elevated temperatures.

Work Accomplished

This project consisted of a feasibility study of six candidate electronic modules to determine the technical challenges to their operation under the desired high temperature conditions. It involved the collection and analysis of material data for temperatures up to 200° C, including mechanical, electrical, and thermal properties of materials, and their relationship to temperature within that range and the application of this information to the design analysis. Design information on each module was provided by the member companies, including block diagrams and parts lists, as well as information on the use environments. The following are the key deliverables:

A document describing generic materials-related limitations to the use of electronics at elevated temperatures up to 200° C. These reports include tables of maximum use temperatures for electronic materials along with relevant mechanical, electrical, and thermal properties of these materials and their relationship to temperature. Materials were characterized from many elements of packaging, including but not limited to the

semiconductor die
die attach
leadframe/substrate
case
first-level interconnect
boards
solders
connectors
boxes

Reports were generated for each of the six representative electronic modules listed below:

A proposed subsonic flight control product.
A proposed supersonic engine control.
An existing cockpit lamp dimmer.
An existing ARINC 629 SIM.
A point-of-use power supply for aircraft.
An existing automotive engine controller.

These reports identify the technical challenges to be met in the temperature ranges of interest, the risks involved, and potential solutions to those challenges.
A book on high temperature electronics has been published based on contributions from experts in the field.