High Temperature Wafer Probe Testing
Electronics are increasingly being exposed to harsh environments and pushing further the requirement for reliability and continuous operation. One of the key areas is high temperature electronics. Traditionally the majority of semiconductors available in the market are usually sold in plastic packages which aren't particularly rugged or reliable at high temperature. Using plastic typically leads to reduced lifetime of the end product and in worse cases critical failures in the field. There are 2 principle alternatives to improve the situation which both require going back to bare die level…
- Re-house the bare die into a single ceramic package designed specifically for high temperature
- Use bare die to build an MCM (Multiple-Chip-Module) or Hybrid and apply high temperature design rules
Both techniques will give higher durability and better reliability under high temperature exposure. However there are some Pros and cons to each solution, the main ones are below.
Single Ceramic Package - Pros - Quicker design & assembly time, some suppliers offer these packages as standard, where they don't we can make them specially.
Single Ceramic Package - Cons - Not always the most efficient use of space, ceramic packages tend to be bulky and unsuitable when access or area is limited
MCM / Hybrid - Pros - Small form factor and customisation for heat dissipation allows better all round performance then using single ceramic packages
MCM / Hybrid - Cons - Design and qualificaton can take longer, requires majority of components to be supported in bare die form
Generally standard packaging of active components lets down the actual bare die material inside it. Although it is also true to say that bare die themselves can vary in their performance and junction temperature capabilities under high temperature. For example some silicon bare die are more than capable of operating at 200°C+ whereas some may only be capable of 125°C at best…
At Micross Components we specialise in the selection and identification of bare die that will perform best under high temperature.
We achieve this by performing a real environmental high temperature probe test of a wafer. The wafer chuck is typically heated to 200°C, temperature is then stablised. For each bare die we probe at high temperature we design and manufacture a bespoke probe card which compensates for thermal expansion as the temperature rises. When the wafer is tested every single bare die is datalogged and characterised, we create a wafer map based on the performance of all the die and can categorise them based on desired criteria provided by either our customer or by ourselves. This means we can both characterise a wafer for it's temperature performance and then for all subsequent wafers make sure we select from these wafers only the die that meet the required test criteria. Each die is individually traceable and is picked via the wafer map generated using automatic equipment. This means that the customer receives only 100% tested good die for a given specification and temperature. This extra level of reliability is important as often the finished module / circuit / hybrid cannot be easily re-worked and certainly when they are in position in the field are not easily recoverable.
At Micross Components we characterise, test, select support bare die for high temperature from our semiconductor supply partners and we also process our customers own wafers such as ASICs and other prototype wafers.
Typical Applications:
Downhole exploration
Environmental Research
High Temperature Probe Testing - Capabilities
- Testing of both Bare Die & Hybrid substrates
- Precision hot probing up to 200°C (higher on special request with setup)
- Temperature accuracy ±0.5°C (Post calibration)
- Temperature stability ±0.1°C
- Fully automated multiple wafer handling
- Lot characterisation
- Customisable output data and logging
- Complete wafer mapping, selection and traceability to single die for KGD