Autoclave or Pressure Cooker Test (PCT)  

Autoclave Test, or Pressure Cooker Test (PCT), or Pressure Pot Test (PPOT), is a reliability test performed to assess the ability of a product to withstand severe temperature and humidity conditions. 

It is used primarily to accelerate corrosion in the metal parts of the product, including the metallization areas on the surface of the die.  It also subjects the samples to the high vapor pressure generated inside the autoclave chamber.  Figure 1 shows examples of autoclave chambers.

Autoclave testing consists of soaking the samples for 168 hours at 121 deg C, ** RH, and 2 atm.  Intermediate readpoints at 48H and 96H may also be employed.  

Surface-mount samples are preconditioned prior to autoclave testing.  Preconditioning simulates the board mounting process of the customer.  It normally consists of a bake to drive away the moisture inside the packages of the samples, a soak to drive a controlled amount of moisture into the package, and three cycles of IR or vapor reflow.  

The samples are tested after preconditioning, failures from which are considered as preconditioning failures and not autoclave failures.  Preconditioning failures should be taken seriously, since these imply that the samples are not robust enough to even withstand the board mounting process.

Because of the extreme moisture condition during autoclave testing, moisture-related electrical leakage failures may be encountered after the test.  Unless predefined to be so, such failures must not be considered as valid PCT failures.  Only permanent failures, such as those arising from corrosion, are considered valid PCT failures.                  

Reliability Tests:   Autoclave Test or PCT;  Temperature Cycling;  Thermal Shock;

THB;  HAST;  HTOL;  LTOL;  HTS;  Solder Heat Resistance Test (SHRT); 

Other Reliability Tests

See Also:  Reliability Engineering;  Reliability Modeling;

Qualification Process; Failure Analysis;  Package Failures;  Die Failures