Production Testing Of Discrete Power Products

By Vineet Pancholi and Dennis Dinawanao

Metal Oxide Silicon Field Effect Transistors (MOSFETs), Insulated Gate Bipolar Transistors (IGBTs), Bipolar Junction Transistors (BJTs), diodes, and application specific multi-transistor packaged modules are some of the more popular discrete products. Switches control the flow of current within a circuit. MOSFETs are a building block of most electronics equipment. There has been a sharp increase in battery powered devices. Computers, smartphones, wearable devices, hand-held devices, and migration of the automobile’s internal combustion engine to a battery powered motor driven engine have resulted in the increase of discrete power products.

Fig. 1: Si, SiC, and GaN.

Traditional building material used for power devices was Si (silicon). SiC (silicon carbide) and GaN (gallium nitride) have penetrated as building materials for power discrete products due to higher band gap, power, switching frequencies, and smaller sizes and lower switching and conduction losses. Si to SiC/GaN based fabrication technologies have evolved over the past decade and a half. IDMs have thousands of variants of these products. All device datasheet specifications, static and transient attributes must be tested in production before shipping to the end customer. There are more than a dozen test equipment manufacturers. The test equipment includes ATE (Automatic Test Equipment), device prober, handler, and the test hardware. Typical ATEs include source and measure instruments that cater to a range of voltages and currents to test the complete production test list.

Amkor power packages

Tabulated below, are some of Amkor’s popular power discrete packages. Additional data and details about these packages are available on Amkor’s website.

Production test

Test flow

The typical IC production test flow is shown below in figure 2.

Fig. 2: Typical IC production test flow.

For power discrete products, wafer probe, burn-in and system level test insertion test steps have less popularity for mature fabrication technologies. Since some of the SiC and GaN based technologies may be newer, customers tend to include production qualification and burn in tests. System level testing may not be required, because the production test list includes parametric test of all relevant attributes of the drain & transfer characteristics.

(A) 

(B) 

Fig. 3: Example drain (A) and transfer (B) characteristics from NTMFS4C06N (onsemi) MOSFET.

Test list, production test rigor & ATE

Typical DC test parameters included in the customer’s test list include: I_GSS – gate to source leakage current, I_DSS – drain to source leakage current, VGS(th) – gate to source threshold voltage, RDS(on) – drain to source resistance at ON state, GM – trans conductance gain, BVDSS – breakdown drain to source voltage.

Typical AC test parameters included in the customer’s test list include: Cg – gate capacitance, Rg (ESR) – gate resistance, resistive switching (Tdon/off, Trise/fall), unclamped inductive switching (UIS w/VDs & IDs measure), Qg – gate charge inductive switching, diode reverse recovery (Trr) inductive switching.

Power products for automotive applications require stable operation in stringent environments, like wide temperature and voltage ranges of operation. Amkor production test factories have decades of experience testing power parts and are readily equipped to handle the future production test requirements. For higher voltage and current and faster switching speeds found in SiC and GaN based products, Amkor is working closely with automated test equipment (ATE) vendors to develop and deploy new test platforms with newer instruments that cater to the wider range of operation.

Dennis Dinawanao is a manager for test at Amkor Technology Philippines.