Bundled probe apparatus for multiple terminal contacting
View Patent ↗A probe apparatus having probe groups comprising two or three probes that independently contact single terminals of tested chips. As a result, the probe apparatus is capable of recognizing voltage drops of a test signal applied prior to the chip testing onto a test path along two or three probes contacting, the terminal and the interfaces between them. The test path does not pass through the chip. An electronic circuit measures the voltage drops and compensated accordingly operational signals passing through the terminals, the probes and the interfaces during the chip testing. A first embodiment comprises two probes per group. A second embodiment comprises three probes per group. In the second embodiment, the variable resistance component of three resistance measurements of first/second, first/third and second/third resistance paths are compared by the electronic circuit, in order to determine absolute resistance values for each of the three signal paths. Consequently, in the second embodiment, the voltage drops may be individually adjusted for each of the three operational signal paths.
1. A method of compensating for a voltage drop of an operational signal passing through an operational signal path, said method comprising the steps of:
contacting a single terminal of an integrated circuit device with a probe group comprising two or more probes;
determining a plurality of path resistances along respective pairs of said two or more probes of said probe group, said single terminal and respective interfaces between said probes and said single terminal;
deriving an operational signal path resistance based on said plurality of path resistances, the deriving step including (a) identifying a constant portion of each of the path resistances and a variable portion of each of the path resistances, and (b) comparing the variable portion of each of the path resistances with one another to derive the operational signal path resistance; and
compensating for said voltage drop in correspondence to said derived operational signal path resistance.
2. The method of claim 1 , wherein said contacting step is provided by said probe group including a first, a second and a third of said probes, wherein said determining step includes determining a first, a second and a third path resistance corresponding to conductive paths including said first, said second and said third of said probes, and wherein said deriving includes deriving an absolute value of a first, a second and a third variable portion or each of said first path resistance, said second path resistance and said third path resistance.
3. The method of claim 1 wherein the contacting step includes contacting the single terminal with the two or more probes such that the probes are electrically isolated from one another.
4. The method of claim 1 wherein the contacting step includes contacting the single terminal with the two or more probes such that a substantially spherically shaped tip of each of the probes contacts the single terminal.
5. The method of claim 4 further comprising the step of self centering the probe group on the single terminal at least partially via the substantially spherically shaped tips.
6. The method of claim 4 wherein the contacting step includes substantially concurrently contacting the single terminal with each of the two or more probes.
7. The method of claim 1 further comprising the step of establishing a force induced contact between (1) an end of each of the two or more probes opposite the single terminal, and (2) a terminal of a system configured to provide a voltage signal to the two or more probes.
8. The method of claim 1 further comprising the step of establishing a friction based contact between (1) an end of each of the two or more probes opposite the single terminal, and (2) a terminal of a system configured to provide a voltage signal to the two or more probes.
9. The method of claim 1 wherein the deriving step includes identifying the constant portion to include a resistance of (1) each of the two or more probes, and (2) the single terminal.
10. The method of claim 1 wherein the deriving step includes identifying the variable portion to include a resistance of an interface between (1) each of the two or more probes, and (2) the single terminal.
11. The method of claim 10 wherein the deriving step includes identifying the variable portion to also include a resistance of another interface between (1) each of the two or more probes, and (2) a terminal of a system configured to provide a voltage signal to the two or more probes.
12. The method of claim 1 wherein the compensating step includes increasing an applied voltage to at least a portion of the two or more probes.
13. The method of claim 1 wherein the contacting step includes contacting the single terminal with the probe group consisting of two probes.
14. The method of claim 1 wherein the contacting step includes contacting the single terminal with the probe group consisting of three probes.
15. The method of claim 1 wherein the contacting step includes contacting the single terminal with the probe group consisting of three probes, and wherein the determining step includes (1) determining a first path resistance along a first and a second of the three probes, (2) determining a second path resistance along the first and a third of the three probes, and (3) determining a third path resistance along of the second and a third of the three probes.
16. The method of claim 1 wherein the contacting step includes contacting the single terminal with the probe group consisting of four probes.
17. The method of claim 1 wherein the contacting step includes contacting the single terminal with the probe group consisting of four probes, and wherein the determining step includes utilizing a 4-Wire Ohm's Measurement to determine at least a portion of each of the plurality of path resistances.