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Apparatus and Method of Thermal Stress Recognition in a System Environment

IP.com Disclosure Number: IPCOM000167120D
Original Publication Date: 2008-Jan-30
Included in the Prior Art Database: 2008-Jan-31
Document File: 4 page(s) / 250K

Publishing Venue

IBM

Abstract

Apply a temperature sensing device to specific electronic components which permanently records an over stress condition, even though the device has not been functionally destroyed. Over stress is an indication of potential reliability degradation and would represent an inferior assembly without component replacement. The indication of the over stress aids in failure analysis and repair action prior to returning the electronic assembly to service.

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Apparatus and Method of Thermal Stress Recognition in a System Environment

One of the most devastating incidents that can happen for electronic components, is to have a burn condition in a Customer's facility. There is a considerable amount of design emphasis to prevent the classic "Smoke" or "Burn" incidents.

Nature of Burn incidents:

Defects: Burn incidents can occur as a result of electronic assembly defects, initial component defects or latent reliability defects. Usually assembly and component defects can be screened during the initial manufacturing test process. The latter, latent reliability defects, often times escape the manufacturing test process and do not manifest themselves until later in time.

Product Environment: Temperature or electrical over stress can also initiate Burn conditions. Although the operating conditions of an electronic assembly are specified and usually adhered to by the Customer, on rare occasions the temperature or electrical environment may exceed the product specification and damage the electronic assembly either to a point of failure or product life degradation.

Examples would be:
- Electrical over Stress (EOS) due to lightening strikes or system power supply regulation failure.

- Heating and cooling outages resulting in temporary over temperature conditions.

Current Methods:

- In today's manufacturing environment, recognition of electronic over stress is limited to functional test or by visual inspection (i.e.: recognizing discoloration due to thermal over heating). - Most micro electronic components electrically fail as a result of a significant over stress condition.

One exception is "Power Components":

DC to DC voltage regulators, motor drivers, and power components in general are designed to operate within high voltages and high power levels.
- It is this group of components that could result in either a Smoke or Burn condition.

- The electronics industry does use a high temperature stress process, "Burn in", to screen for early life failures. In this process, the stress conditions are not severe enough to damage all of the product (only the weak components) and the pass fail criteria is the post functional test. This process is very expensive and does not cover the case where the over stress occurs in the Customers environment. Further, the Burn In process may only be a temporary process as a product is initially screened to verify the design margins and assembly processes. Once the process and design are refined, the Burn In step is no longer employed.

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Solution

Apply a temperature sensing device to selected components which could be subjected to over stress but would not necessarily fail instantly but could be degraded.

Component examples (but not limited to) would be:
- DC to DC voltage regulators
- Motor Drivers
- Field Effect Transistors (FETs) used in power regulation applications
A temperature sensing device would be applied to selecti...