Substrate testing apparatus and substrate testing method

Electricity: measuring and testing – Fault detecting in electric circuits and of electric components – Of individual circuit component or element

Reexamination Certificate

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Details

C324S761010

Reexamination Certificate

active

06747466

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a substrate testing apparatus and a substrate testing method for testing the surface of a semiconductor wafer or the like.
2. Description of the Background Art
Hitherto, in order to carry out the testing of the surface of a semiconductor wafer such as a silicon wafer at plural locations collectively and efficiently, there has been a method of allowing a probe card
26
to abut against a semiconductor wafer
18
from above, as shown in
FIG. 11. A
substrate testing apparatus based on the prior art is provided with such a probe card
26
, where a probing needle
27
is fixed onto the lower surface of probe card
26
with its tip end pointing downwards. On the semiconductor wafer
18
side, the locations against which probing needle
27
is allowed to abut hereafter referred to as “abutment points”) are inherently defined by formation of pads or wirings on the surface. Plural probing needles
27
are arranged in such a manner as to correspond to the plural abutment points on the semiconductor wafer
18
surface, respectively. In order to carry out simultaneous testing of the entire surface of semiconductor wafer
18
, one makes use of a probe card
26
having a size approximately equal to that of semiconductor wafer
18
.
The semiconductor wafers are exposed to various temperature environments due to circumstances of the process for producing semiconductor devices. The semiconductor wafers themselves expand or contract depending on the temperature at each time. When the temperature of semiconductor wafer
18
changes to expand or contract semiconductor wafer
18
, the positional relationship among the abutment points on the semiconductor wafer side is also enlarged or diminished.
In the case of a substrate testing apparatus where probing needle
27
is fixed to probe card
26
, if a semiconductor wafer expands or contracts to change the arrangement of abutment points, the interval between probing needles
27
will not accord with the interval between the abutment points, thereby raising a possibility that the testing cannot be carried out normally. From now on, according as the semiconductor wafers increase in size and individual elements on the semiconductor wafer surface decrease in size, the thermal expansion/contraction will have a larger influence and the aforesaid problem will be more serious.
Thus, an object of the present invention is to provide a substrate testing apparatus and a substrate testing method capable of performing a collective testing over a wide area of the substrate surface even under different temperature environments by adjusting the interval between the probing needles in accordance with the expansion/contraction of the substrate such as a semiconductor wafer.
SUMMARY OF THE INVENTION
In order to achieve the aforementioned object, a substrate testing apparatus according to one aspect of the present invention includes a first rail, a second rail that crosses the first rail, and a probe unit disposed to cover an intersection of the first and second rails and being respectively movable along the first and second rails, wherein the probe unit includes a probing needle that is brought into contact with a surface of a substrate subjected to measurement. By adopting this construction, one can suitably change the relative positional relationship of the probing needle by moving the probe unit along the rails. Therefore, a substrate testing apparatus can be provided that can accord with the change of abutment points due to expansion/contraction of the substrate.
Further, in order to achieve the aforementioned object, a substrate testing apparatus according to another aspect of the present invention includes a first rail group made of a plurality of rails disposed in parallel with each other, a second rail group made of a plurality of rails disposed in parallel with each other in a direction that crosses the first rail group, a plurality of probe units disposed to cover respective intersections of the rails included in the first rail group and the rails included in the second rail group and being movable along the rails included in the first rail group and the second rail group, and corresponding interval maintaining means for keeping each rail included in the first rail group at an interval corresponding to an arrangement of locations to be measured on a substrate subjected to measurement, wherein the plurality of probe units each include a probing needle to be brought into contact with a surface of the substrate. By adopting this construction, one can suitably change the relative positional relationship of the probing needles by moving the plurality of probe units all at a time along the rails even if the measurement is to be conducted at plural sites. Therefore, a substrate testing apparatus can be provided that can accord with the change of abutment points due to expansion/contraction of the substrate.
In the above-described invention, the corresponding interval maintaining means preferably maintains the interval after changing the interval every time the arrangement of the locations to be measured changes. By adopting this construction, one can test the substrate without bringing the probing needles into contact with the parts of the substrate subjected to measurement where the probing needles should not be brought into contact. This eliminates the fear of undesirably damaging the substrate with the probing needles.
In the above-described invention, the corresponding interval maintaining means preferably includes equal interval maintaining means for keeping each rail included in the first rail group at an equal interval. By adopting this construction, one can move the plurality of rails while keeping the rails at an equal interval, so that the plurality of probe units mounted on these rails are also moved all at a time while the interval thereof is kept equal, making it possible to appropriately change the relative positional relationship of the probing needles. Therefore, a substrate testing apparatus can be provided that can accord with the change of abutment points due to expansion/contraction of the substrate.
In the above-described invention, the substrate testing apparatus further includes displacement measuring means for measuring a displacement of one or more observation points on the substrate subjected to measurement, and displacement measurement value feedback means for setting the interval of each rail included in the first rail group, as defined by the equal interval maintaining means, in accordance with a displacement measurement value given by the displacement measuring means. By adopting this construction, one can quantitatively sense the amount of expansion/contraction of the substrate subjected to measurement with the use of displacement measuring means, and can change the interval of rails to accord with the arrangement of the abutment points after the expansion/contraction with the use of displacement measurement value feedback means.
In the above-described invention, the substrate testing apparatus further includes temperature measuring means for measuring a temperature, and temperature measurement value feedback means for setting the interval of each rail included in the first rail group, as defined by the equal interval maintaining means, in accordance with a temperature measurement value given by the temperature measuring means. By adopting this construction, one can quantitatively sense the amount of thermal expansion/contraction of the substrate subjected to measurement on the basis of the data retained in advance. When the amount of expansion/contraction is obtained, one can change the interval of rails to accord with the arrangement of the abutment points after the expansion/contraction with the use of temperature measurement value feedback means.
In order to achieve the aforementioned object, a substrate testing method according to the present invention uses a plurality of probe units disposed to cover respective intersections of rails included

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