The present invention relates to a probe correction device, and more particularly to a parallel plate capacitor as the probe calibration device to correct the accurately of the probe.
In generally, after the wafer manufacturing process is finished, the electricity and the functional testing of the testing wafer must be performed to identify the operation of the IC chips on the wafer. The wafer test is performed to inspect each chip on the testing wafer by the probe and test apparatus to identify the functional and performance of the IC circuit on the chips which is fabricated according to the design rule of the semiconductor manufacturing process. The inspection processes of the testing wafer include a probe that is fixed on the test head by the test apparatus. Then, the probe is contacted with the pad on the testing wafer to measure the electricity signal of the pad. Next, the electricity signal is communicated to the test apparatus. Thus, the yield of each chip on the testing wafer can be identified according to the electricity signal by the test apparatus. In general, an indentation is formed on the pad when the probe contacted with the pad, and the indentation area is an index for the probe stress contacting with the pad. The size of the indentation area can be observed by the optical microscope. The usage of the probe can also be determined according to the indentation area on the pad. However, the different user will have the different observation standard by using the optical microscope, so that the usage of the probe cannot be exactly determined, for example, the tip of the probe has been suffered a lot of wear and tear, but the probe is still performed to test to affect the testing accuracy for the testing wafer. If the probe still contacted with the pad, the pads would be cracked when the damage has been occurred underneath the pads on the testing wafer.
In accordance with an aspect, the present invention provides a calibration method. The electricity is generated corresponding to the contact degree when the probe that is contacted with the calibration device, the electricity can identify the location of the probe and the height difference between the probe and the under testing wafer.
In accordance with an aspect, the present invention provides a calibration device. The probe is calibrated by the calibration device before the under testing wafer inspection is performed. The driving force for the probe can be identified by the electricity. The electricity is generated corresponding to the contact degree when the probe is contacted with the calibration device.
In accordance with an aspect, the present invention provides a correction device. The probe is calibrated by the calibration device before the under testing wafer inspection is performed. The height difference between the probe and the under testing wafer is whether to be adjusted according to the electricity which is generated corresponding to the contact degree when the probe is contacted with the calibration device.
The present invention provides a calibration device which applied for a test apparatus with a first probe and a second probe. The calibration device includes a first testing region and a second testing region, the first testing region and the second testing region includes n×n sensing units respectively, the first testing region for generating n×n average electricity corresponding to the contact degree when the first probe is contacted with the first testing region and a second testing region for generating another n×n average electricity corresponding to the contact degree when the second probe is contacted with the second testing region, wherein the pitch is the distance between the center of the first testing region to the center of the second testing region that is the same as that of the center of the first probe to the center of the second probe.
In an embodiment, the first testing region and the second testing region is a parallel plate capacitor which is made of a top metal layer, a dielectric layer and a bottom metal layer.
In an embodiment, the dielectric layer is an inter-metal dielectric (IMD) layer or inter-layer dielectric (ILD) layer.
In an embodiment, the numerical n is an integer larger than 1.
In an embodiment, the n×n average electricity is average capacitance.
In an embodiment, the first testing region and the second testing region include a first sub testing region and a second sub testing region respectively, and an interconnect structure is electrically connected the first sub testing region with the second sub testing region.
The present invention provides a calibration device which applied for a test apparatus with a first probe and a second probe. The calibration device includes a first testing region and a second testing region. The first testing region and the second testing region include m×m sensing units respectively. The first testing region for generating m×m electricity corresponding to the contact degree when the first probe is contacted with the first testing region, in which the pitch is the distance between the center of first testing region to the center of the second testing region that is the same as that of the center of the first probe to the center of the second probe.
In an embodiment, the first testing region and the second testing region is a parallel plate capacitor which is made of a top metal layer, a dielectric layer and a bottom metal layer.
In an embodiment, the dielectric layer is an inter-metal dielectric (IMD) layer or inter-layer dielectric (ILD) layer.
In an embodiment, the numerical n is an integer larger than 1.
In an embodiment, the n×n average electricity is average capacitance.
In an embodiment, the first testing region and the second testing region include a first sub testing region and a second sub testing region respectively, and an interconnect structure is electrically connected the first sub testing region with the second sub testing region.
In accordance with another aspect, the present invention provides a calibration method which applied for a test apparatus with at least a first probe and a second probe. The steps of the calibration method as follows. Firstly, a first testing region and a second testing region are provided. The pitch is the distance between the center of the first testing region to the center of the second testing region that is the same as that of the center of the first probe to the center of the second probe. The first probe and the second probe are aligned with the first testing region and the second testing region respectively. The first electricity is obtained corresponding to the contact degree of the first probe is contacted with the first testing region and the second electricity is obtained corresponding to the contact degree of the second probe is contacted with the second testing region. The first probe and the second can be calibrated according to the first electricity and/or the second electricity.
In an embodiment, the first testing region and the second testing region is a parallel plate capacitor which is made of a top metal layer, a dielectric layer and a bottom metal layer.
In an embodiment, the dielectric layer is an inter-metal dielectric (IMD) layer or an inter-layer dielectric (ILD) layer.
In an embodiment, the first testing region and the second region are divided into at least n×n sensing units respectively.
In an embodiment, the numerical n is an integer larger than 1.
In an embodiment, the first electricity and the second electricity is capacitance.
In an embodiment, the first electricity and the second electricity is calculated to obtain average electricity. The average height of the first probe and the second probe can be calculated according to the average electricity.
In an embodiment, when the average height is larger than the tolerance, the first probe and/or the second probe with corresponding average height should be changed.
In an embodiment, when the average height of the first probe and the second probe is in the middle of the tolerance, the first probe and the second probe of the test apparatus are adjusted to an inclined angle, so that the first probe and the second probe with same average height to perform the under test wafer inspection process.
In an embodiment, the driving force of the first probe or the second probe can be obtained by calculating the first electricity or the second electricity.
The above objects and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which:
The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for purpose of illustration and description only. It is not intended to be exhaustive or to be limited to the precise form disclosed.
When the probe is contacted with the pads (not shown) on the testing wafer (not shown), the contact degree between the probe and the pads and the displacement of the probe can be identified by the indentation area on pads. In order to avoid the user creating the wrong judgment, the electricity change is generated corresponding to the contact degree when the probe that is contacted with the plurality of testing regions on the calibration device before the inspection of the testing wafer. Thus the probe can be judged to adjust or replace according to the electricity variation to increase the accuracy of the probe and the yield of the testing wafer.
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In order to avoid the probe is not contacting or over contacting with the pads of the under testing wafer. The present invention provides a calibration method for the probe to calibrate the height difference between the each probe and the calibration device.
In this embodiment, the plurality of testing regions for the calibration device 10 is arranged under the test apparatus 20. Each plurality of probes of the testing apparatus 20 is aligned with the each testing region of the calibration device 10 respectively. The pitch is the distance between the centers of the two testing regions that is same as that of the centers of the two probes.
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In this embodiment, each testing region 101˜104 can be divided into n×n sensing units S1, and the numerical n is an integer larger than 1. For example, n is 10, as shown in
Each capacitance is obtained from each testing regions 101˜104 and is substituted into the formula C=εA/d to obtain the thickness variation d of the dielectric layer 100b when the first probe 20a is contacted with the first testing region 101, the second probe 20b is contacted with the second testing region 102, the third probe 20c is contacted with the third testing region 103 and the forth probe 20d is contacted with the forth testing region 104. The optimal testing results can be obtained by the probe contacting the testing region with an appropriate driving force. Thus the capacitance is obtained by the probe contacting the testing region with the appropriate driving force which can be used as a reference value. Thus, a capacitance difference can be estimated by the capacitances which are obtained from the testing regions 101˜104 subtract the reference value. When the capacitance difference is large, the thickness variation d of the dielectric layer of the testing region becomes smaller. It can be obtained that the height difference between the probe and the calibration device 10 is large, for example, the second probe 20b and the forth probe 20d as shown in
According to above steps of the calibration method, the diagram between the capacitance and the height difference between the probe and the calibration device can be drawn according to the capacitance variation which is obtained by the each probe contacted with the calibration device. In
Therefore, the height difference between each probe and the calibration device can be obtained from the capacitance which is generated by the each probe contacted with the calibration device, such that the replacement for the probe or the compensation for the height difference between the probe and the calibration device can be developed.
In another embodiment, the calibration device 30 includes a plurality of testing regions 301˜303, as shown in
Next, the first electricity of the first probe 20a is obtained corresponding to the contact degree of the first probe 20a contacted with the first sub testing region 3011 of the first testing region 301, the first electricity of the second probe 20b is obtained corresponding to the contact degree of the second probe 20b contacted with the first sub testing region 3021 of the second testing region 302, and the first electricity of the third probe 20c is obtained corresponding to the contact degree of the third probe 20c contacted with the first sub testing region 3031 of the third testing region 303, where the first electricity of the first probe 20a, the first electricity of the second probe 20b, and the first electricity of the third probe 20c can be used as the reference value for the calibration method. As shown in
Next, the first, second, and third average capacitance is substituted into the formula C=εA/d to obtain the thickness variation d of the dielectric layer 100b for the first testing region 301, the second testing region 302 and the third testing region 303. Thus, the capacitance of each testing region 301˜303 can be determined that the average height difference between the each probes 20a˜20c of the test apparatus 20 and the calibration device 30. If the average height difference is in the middle of the tolerance, the test apparatus 20 can be adjusted to an inclined angle, such that each probe of the test apparatus 20 with the same average height difference to contact the under testing wafer (not shown) under the same driving force when the inspection process is performed. In addition, the probe whose capacitance is larger than the tolerance is to be replaced, so that the average height between all probes of the test apparatus 20 and the calibration device is in the middle of the tolerance.
In addition, the present invention also provides another calibration method for calibrating the probe and the calibration device.
Then the plurality of probes 20a˜20d of the test apparatus 20 is arranged over the calibration device 40, each probe 20a˜20d is aligned with each testing region 401˜404, in which the pitch is the distance between the centers of the two testing region that is the same as that of the centers of the two probes.
Then referring to
It is additionally to explain that each testing region 410˜404 can be divided into m×m sensing units S2, in which the numerical m is an integer larger than 1. In
Then, the 81 capacitances are subtracted the reference value to obtain a capacitance difference. The capacitance difference is substituted into the formula C=εA/d to obtain the thickness variation d of the dielectric layer 100b when the third probe 20c is contacted with the third testing region 403, such that the footprints of the third probe 20c can be drawn as shown in
In this embodiment, the driving force of the third probe 20c contacted with the third testing region 403 that can be changed to obtain the different capacitance, so that the diagram of the different driving force and the capacitance can be obtained as shown in FIG. 4E. In
In a further embodiment, as shown in
In this embodiment, the first electricity is calculated with the second electricity to obtain a capacitance difference. In other words, the capacitance difference can also be the 81 capacitances which is obtained by 81 capacitances of 81 sensing units of the first sub testing region 5031 is calculated with 81 capacitances of 81 sensing units of the second sub testing region 5032. Similarly, the footprints of the third probe 20c can also be drawn as
In the present invention, the testing wafer can be WAT pads (wafer acceptance test pads), BOAC pads (bond pad active circuit pads), or CP test pads (circuit probing test pads).
Thus the usage of each probe can be obtained according to above calibration method so as to characterize the probe impact. In addition, the probe height model can be developed for inspection of testing wafer under higher temperature or lower temperature. Moreover, the usage of the probe can be maintained, and the period of use can also be extended. The calibration device 10 also can be applied for dynamic operation of the back-end-of-line of the semiconductor manufacture.
It is to be illustrated that the calibration device and the calibration method can be built in the wafer testing system. The testing system executes the calibration function for calibration the probe before the testing wafer is performed to inspect. The testing system can be controlled by the multiplex (MUX) or transmission FET. In addition, the calibration device can also be formed on the scribe line on the testing wafer. The calibration device can be easily to remove after the inspecting process is finished. The calibration device can also form on a dummy wafer to be calibrated. After the calibration process is finished, this dummy wafer with the calibration device can be removed. Thus, the electricity and the functional of the testing wafer would not be affected.
While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.