Proportional DC power control system and method
First Claim
1. A control system for low electrical noise semiconductor testing at predetermined temperature using an AC power supply, comprisingAC switching means controllable between and "off" nonconducting state and an "on" conducting state, said switching means being connected to the AC power supply and providing a time proportional AC power output during said "on" conducting state,rectifying means connected to receive said time proportional AC power output and providing DC power output,at least at 300 watt DC heater connected to receive said DC power output,semiconductor test mounting chuck having a semiconductor mounting surface thereon and being thermally connected to said DC heater,temperature sensing means positioned proximate to said semiconductor mounting surface for providing a temperature indicative output signal,control means for receiving said temperature indicative output signal and providing a control signal output, andswitch control means within said AC switching means for receiving said control signal output and controlling said time proportional AC power output to provide the predetermined temperature at said semiconductor mounting surface.
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Accused Products
Abstract
A control circuit is disclosed which uses AC power input and provides DC power output which is not limited by DC semiconductor switch power dissipation capabilities. Switching is performed on the AC signal to provide time proportional AC power which is then transformed and rectified to provide relatively high proportional or adjustable power to a DC load without electrical noise. The DC load is monitored for a controlled characteristic, such as temperature, and a monitor signal is provided to a control for controlling the time proportional AC power output, in accordance with the DC load demand. A dimensionally stable temperature controlled semiconductor test chuck is described presenting a DC heater load for the control circuit.
12 Citations
13 Claims
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1. A control system for low electrical noise semiconductor testing at predetermined temperature using an AC power supply, comprising
AC switching means controllable between and "off" nonconducting state and an "on" conducting state, said switching means being connected to the AC power supply and providing a time proportional AC power output during said "on" conducting state, rectifying means connected to receive said time proportional AC power output and providing DC power output, at least at 300 watt DC heater connected to receive said DC power output, semiconductor test mounting chuck having a semiconductor mounting surface thereon and being thermally connected to said DC heater, temperature sensing means positioned proximate to said semiconductor mounting surface for providing a temperature indicative output signal, control means for receiving said temperature indicative output signal and providing a control signal output, and switch control means within said AC switching means for receiving said control signal output and controlling said time proportional AC power output to provide the predetermined temperature at said semiconductor mounting surface.
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4. A temperature controllable low electrical noise DC power heated semiconductor test chuck, comprising
a top plate having an exterior semiconductor mounting surface and an opposing interior surface, a depending skirt on said top plate surrounding said opposing interior surface, a dielectric wafer having an upper surface abutting said top plate interior surface and a lower wafer surface, a DC heater blanket abutting said lower wafer surface on one side and having a lower heater blanket side, heat reflecting means in contact with said DC heater blanket on said lower heater blanket side, bottom clamping and chuck mounting means adjacent said heat reflecting means on the side thereof remote from said DC heater blanket contact, whereby heat from said DC heater blanket is directed toward said semiconductor mounting surface and away from said bottom clamping and chuck mounting means, and whereby said semiconductor mounting surface is electrically isolated from said DC heater blanket, is maintained substantially flat over operating temperature range, and is substantially free of radiated electrical noise.
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11. A method for controlling temperature level and reducing radiated electrical noise levels during semiconductor component testing, wherein AC power is supplied, comprising the steps of
switching the AC power to provide time proportional AC power output to obtain time proportional DC power output, providing at least 300 watts of the DC power output to a DC heater, thermally connecting said DC heater to a semiconductor component mounting surface, continuously sensing the temperature of the semiconductor component mounting surface, providing a temperature indicative output signal from the continuous sensing, and continuously controlling the time proportional AC power output to provide a predetermined temperature level at the semiconductor mounting surface.
Specification