Test signal distribution system for IC tester
AssigneeFormFactor, Inc.
InventorCharles A. Miller
Life of this patent
Estimating the term…
Abstract
A probe board provides signal paths between an integrated circuit (IC) tester and probes accessing terminals on the surfaces of ICs formed on a semiconductor wafer for receiving test signals form the IC tester. A branching signal path within the probe board distributes a test signal produced by one channel of the IC tester to several probes. Resistors within the branching signal path resistively isolate the probes from one another so that a fault occurring at any one IC terminal will not affect the logic state of the test signal arriving at any other IC terminal. The isolation resistors are sized relative to signal path characteristic impedances so as to substantially minimize test signal reflections at the branch points.
Claims32
An apparatus for providing signal paths between an integrated circuit (IC) tester and a plurality of IC terminals so that a driver within the IC tester can concurrently transmit a test signal to the IC terminals, said test signal exhibiting high and low voltage levels representing logic states, wherein a fault at any one of the IC terminals conductively linking that IC terminal to a source of potential can drive that IC terminal near either of said high and low voltage levels, the apparatus comprising:
- a first signal path having a first characteristic impedance for conveying the test signal away from the driver;
- a plurality of probes, each for conveying the test signal to a separate one of the plurality of IC terminals;
- and
- a network comprising resistors for conveying the test signal from the first signal path to each of the probes,
- wherein the resistors isolate the IC terminals from one another by an amount of resistance that is substantially larger than the first characteristic impedance of the first signal path and sufficiently large to prevent the fault at any one of the IC terminals from affecting a logic state represented by the test signal at any other of the IC terminals.
An apparatus for providing signal paths between an integrated circuit (IC) tester and a plurality of IC terminals so that a driver within the IC tester can concurrently transmit a test signal to the IC terminals, said test signal exhibiting high and low voltage levels representing logic states, wherein a fault at any one of the IC terminals conductively linking that IC terminal to a source of potential can drive that IC terminal near either of said high and low voltage levels, the apparatus comprising:
- a first signal path having a first characteristic impedance for conveying the test signal away from the driver;
- a plurality of probes, each for conveying the test signal to a separate one of the plurality of IC terminals;
- and
- a probe board assembly comprising:
- at least one substrate;
- and
- a network comprising resistors supported by the at least one substrate, for conveying the test signal from the first signal path to each of the probes,
- wherein the resistors isolate the IC terminals from one another by an amount of resistance that is substantially larger than the first characteristic impedance of the first signal path and sufficiently large to prevent the fault at any one of the IC terminals from affecting a logic state represented by the test signal at any other of the IC terminals.
Dependencies are inferred from the claim text.