KR20090098893A - Probe inspecting device, displacement correcting method, information processor, information processing method, and program - Google Patents

Abstract

[PROBLEMS] To always and optimally keep the contact position of a probe needle even if the probe needle is brought into contact with the negative electrode pad by appropriately correcting the displacement of the contact position of the probe needle. [MEANS FOR SOLVING PROBLEMS] In a probe inspecting device (100) a CCD camera (6) captures a pre-contact image (51) and a post-contact image (52) of a probe needle (8a) brought into contact with each pad (40) of a chip (30) by means of a CCD camera (6), and an image processing PC (10) extracts a difference image (53) of the images, calculates the displacement value between the position of the latest needle trace (41b) shown in the difference image (53) and a target position for each pad (30), calculates the overall correction of the probe card (8) from each displacement value, and corrects the displacement by reflecting the correction on the inspection of each pad (40) of the chip (30) to be inspected next.

Description

PROBE INSPECTING DEVICE, DISPLACEMENT CORRECTING METHOD, INFORMATION PROCESSOR, INFORMATION PROCESSING METHOD, AND PROGRAM}

The present invention is a probe inspection device for contacting the probe needle (Probe Needle) to the electrode pad of the inspected object, the probe inspection device for inspecting the electrical characteristics of the inspected object, the position deviation correction method in the probe inspection device, information used in the probe inspection device A processing apparatus, an information processing method and a program in the information processing apparatus.

Background Art Conventionally, probe inspection apparatuses for inspecting electrical characteristics of electronic devices such as semiconductor chips (hereinafter, simply referred to as chips) formed on semiconductor wafers (hereinafter, also simply referred to as wafers) have been known. In this probe inspection apparatus, a probe needle provided in a probe card is brought into contact with an electrode pad on a chip, a predetermined voltage is applied by a tester connected to the probe card, and the output is measured.

In this probe inspection, it is important to accurately contact the probe needle with the target position of the electrode pad. If the probe needle comes in contact with a periphery that is away from the center of the electrode pad or a position other than the electrode pad, it will lead to a false test. In addition, in order to perform a plurality of measurements on one chip, the area on the electrode pad may be divided and used for each of the plurality of measurements. Become.

As a technique for correcting the positional deviation of the probe needle, Patent Document 1 below observes a needle trace of a probe of a probe card with a color camera, and the needle trace is a proper position on the electrode pad (for example, If the position of the needle trace is deviated from an appropriate position, for example, the stage may be minutely removed so as to eliminate the positional deviation between the center of the needle trace and the center of the electrode pad. A method of moving finely is disclosed. In addition, Patent Documents 2 to 5 also describe techniques related to the position adjustment of the probe needles.

Patent Document 1: Japanese Patent Laid-Open No. 2004-63877 (paragraph [0006], etc.)

Patent Document 2: Japanese Patent Application Laid-Open No. 06-005690

Patent Document 3: Japanese Patent Application Laid-Open No. 07-013990

Patent Document 4: Japanese Patent No. 2575072

Patent Document 5: Japanese Patent No. 2984541

Problems to be Solved by the Invention

However, in the probe test, a plurality of measurements may be performed for various electrode conditions on one electrode pad, and in this case, a plurality of needle traces remain on one electrode pad. However, in the technique of each of the above patent documents, it is not possible to determine which needle trace is the latest needle trace even when imaging the electrode pads left by the plurality of needle traces. You will not be able to make corrections.

In view of the above circumstances, an object of the present invention is to maintain the optimum contact position of the probe needle at all times by appropriately correcting the positional deviation of the contact position of the probe needle even when the probe needle contacts a single electrode pad a plurality of times. The present invention provides a probe inspection apparatus, a position deviation correction method in the probe inspection apparatus, an information processing apparatus used in the probe inspection apparatus, an information processing method and a program in the information processing apparatus.

Means to solve the problem

In order to solve the above problems, the probe inspection device according to the main aspect of the present invention is a probe inspection device for inspecting the electrical characteristics of the inspected object by contacting the probe needle to the electrode pad of the inspected object, Imaging means for imaging each of the electrode pad before contact of the probe needle and the electrode pad after contact of the probe needle, and an image of the electrode pad before the captured contact as a first image, and storing the image after contact Among the storage means for storing the image of the electrode pad as a second image, the difference extracting means for extracting the difference between the stored first image and the second image as a difference image, and the extracted difference image. Neck on the electrode pad to which the probe needle should contact the needle trace position of the probe needle that appears Calculating means for calculating a correction amount for correcting the positional deviation from the table position, and correction means for correcting the positional deviation by varying a relative position between the object under test and the probe needle based on the calculated correction amount. .

Here, the object under test is a semiconductor wafer or other electronic device in which a plurality of semiconductor chips are formed, for example. With this configuration, even when the probe needle contacts the object under test a plurality of times, only the latest needle trace can be extracted by extracting the difference image, so that the contact state is always optimally corrected by correcting the position deviation for each contact of the probe needle. Can be maintained. Therefore, it is possible to prevent the measurement failure of the electrical characteristics of the inspected object due to poor contact, and consequently to improve the yield of the inspected object. In addition, the relative position of the correction means is changed by, for example, moving the inspected object in the X direction or the Y direction on a plane perpendicular to the contact direction of the probe needle. In addition, in the case where the inspected object is a semiconductor wafer having a plurality of semiconductor chips provided with a plurality of electrode pads, the correction amount calculated for each electrode pad of one semiconductor chip that is the current inspection target is determined by each of the other semiconductor chips that are the next inspection target. The electrode pads may be reflected.

The probe inspection device regulates the imaging of the first image by the imaging means in the next inspection when the electrical characteristic inspection by the contact of the probe needle is performed with respect to the electrode pad a plurality of times. The control means may be further provided, and the storage means may store an image stored as the second image in the one inspection as the first image in the next inspection.

Thereby, since the 2nd image image | photographed at the time of the previous test | inspection can be used as a 1st image at the time of a next test | inspection, the effort which image | photographs a 1st image for every test | inspection can be skipped, and the memory of a storage means The dose can also be reduced.

In the probe inspection device, the storage means may have a means for deleting the first image after the difference extraction. As a result, the storage capacity of the storage means can be further reduced.

In the probe inspection device, the inspected object is a semiconductor wafer having a plurality of semiconductor chips provided with a plurality of the electrode pads, and the probe needle is once in each of the electrode pads of one of the semiconductor chips. And a plurality of the imaging means are capable of successively imaging the first and second images of the respective electrode pads of the one semiconductor chip, respectively, and the storage means being the respective electrode pads. And storing said second image in correspondence with first identification information for identifying said one semiconductor chip and second identification information for identifying said electrode pad of said one semiconductor chip, wherein said calculating means The amount of correction for correcting each position deviation between the needle trace position of each probe needle and each target position on the electrode pad at one time may be calculated. All.

Thereby, each 1st and 2nd image in each electrode pad can be image | photographed continuously, the positional deviation in each electrode pad can be corrected at once, and the processing efficiency which a correction requires can be improved. Further, in order to store the first and second images of each electrode pad in correspondence with the first and second identification information, respectively, the electrode pads of one semiconductor chip are inspected for each electrode pad of the plurality of semiconductor chips. Even when the test is performed a plurality of times, the second image of the previous time can be easily recalled as the first image of the next meeting with reference to the respective identification information. Thereby, positional deviation can be corrected efficiently by omitting the said continuous imaging process of a 1st image, and reducing the processing burden of an imaging means, and the use capacity of a storage means. In addition, the correction amount calculated in this case is calculated in consideration of not only the X and Y directions but also the movement in the rotation (θ) direction on the plane, and the correction means determines the plane to be inspected based on the correction amount. The positional deviation is corrected by moving in at least one direction among the X, Y, and θ directions of the image.

In the probe inspection device, the inspected object is a semiconductor wafer having a plurality of semiconductor chips provided with a plurality of the electrode pads, and the probe needle is each of the respective electrode pads of at least two semiconductor chips of the semiconductor chips. A plurality of each of the at least two semiconductor chips so as to be in contact at a time, and the imaging means, respectively, the first and second images of the respective electrode pad of each of the at least two semiconductor chips Image capturing can be performed continuously, and said storage means respectively identifies the second image of the respective electrode pads with first identification information for identifying the at least two semiconductor chips, respectively, and the respective electrode pads of the at least two semiconductor chips. Correspondingly stored in association with the second identification information to be identified, the calculation means is the probe needle in the at least two semiconductor chips. No matter if the calculated correction amount for correcting the angular position deviation between a respective target position on the needle trace location and each of the electrode pads at a time.

Thereby, the positional deviation of each electrode pad of a some semiconductor chip can be corrected at once, and the processing efficiency of correction improves further. In addition, even when the plurality of semiconductor chips are inspected a plurality of times, the first image is easily retrieved as the next image of the first image by referring to the first and second identification information. The positional deviation can be corrected efficiently by omitting.

According to another aspect of the present invention, there is provided a method for correcting a positional deviation in a probe inspection apparatus for inspecting electrical characteristics of the object by contacting a probe needle with an electrode pad of the object. Imaging each of the electrode pad before contact of the probe needle and the electrode pad after contact of the probe needle, and storing an image of the electrode pad before the photographed contact as a first image, and storing the electrode after the photographed contact Storing an image of the pad as a second image, extracting a difference between the stored first image and the second image as a difference image, and needle trace position of the probe needle appearing in the extracted difference image Position deviation from the target position on the electrode pad to which the probe needle And by the step, based on the calculated correction amount for calculating the correction amount for determining the relative position of the variable and the object to be inspected with the probe needle, and a step of correcting the displacement.

An information processing apparatus according to another aspect of the present invention is an information processing apparatus used in a probe inspection apparatus for contacting a probe needle with an electrode pad of an inspected object to inspect electrical characteristics of the inspected object, wherein the probe to the inspected object is Storage means for storing a first image in which the electrode pads before the contact of the needle is imaged and a second image in which the electrode pads after the contact of the probe needle are imaged, and the stored first image and the second image. A difference extracting means for extracting the difference as a difference image, and a correction amount for correcting a positional deviation between a needle trace position of the probe needle appearing in the extracted difference image and a target position on the electrode pad to which the probe needle should be brought into contact with A calculating means for calculating is provided.

An information processing method according to another aspect of the present invention is an information processing method in an information processing apparatus used for a probe inspection apparatus for contacting a probe needle with an electrode pad of an inspected object to inspect electrical characteristics of the inspected object. Storing a first image in which the electrode pad before the contact of the probe needle with the test object is imaged and a second image in which the electrode pad after the contact of the probe needle is imaged, respectively, the stored first image and the first image; Extracting the difference from the two images as a difference image, and correcting the positional deviation of the needle trace position of the probe needle appearing in the extracted difference image from the target position on the electrode pad to which the probe needle should contact Calculating a correction amount.

A program according to another aspect of the present invention is an information processing apparatus used for a probe inspection apparatus for contacting a probe needle with an electrode pad of an inspected object to inspect electrical characteristics of the inspected object, wherein the probe needle to the inspected object is Storing the first image photographed by the electrode pad before contacting and the second image photographed by the electrode pad after contacting the probe needle, respectively, and the difference between the stored first image and the second image Extracting as an image, and calculating a correction amount for correcting a position deviation of a needle trace position of the probe needle appearing in the extracted differential image with a target position on the electrode pad to which the probe needle should be in contact. It is to let.

The present invention may also be configured as a recording medium on which this program is recorded. Here, the storage medium is, for example, a compact disc (CD), a digital versatile disk (DVD), a Blu-ray Disc (BD), a hard disk drive (HDD), a flash memory, or the like.

Effects of the Invention

As described above, according to the present invention, even when the probe needle contacts a single electrode pad a plurality of times, the contact position of the probe needle can be optimally maintained at all times by appropriately correcting the positional deviation of the contact position of the probe needle.

1 is a view showing the configuration of a probe inspection apparatus according to an embodiment of the present invention.

Fig. 2 is a block diagram showing the configuration of an image processing PC in one embodiment of the present invention.

3 is a top view of a wafer in one embodiment of the present invention.

4 is an enlarged top view of each chip of the wafer in one embodiment of the present invention.

FIG. 5 is a flowchart illustrating an operation flow when an electrical characteristic test of each chip is performed in one embodiment of the present invention.

FIG. 6 is a diagram illustrating an imaging trajectory of a CCD camera on one chip in one embodiment of the present invention.

7 is a diagram conceptually illustrating a state in which a difference image is extracted in an embodiment of the present invention.

8 is a diagram conceptually showing a calculation process of the position deviation amount in one embodiment of the present invention.

FIG. 9 is a diagram illustrating a state of the latest needle traces remaining on a plurality of pads of a chip in an embodiment of the present invention.

10A to 10C are diagrams illustrating a pre-contact image, a post-contact image, and a differential image when each pad is divided into a plurality of regions and a target position of the contact is set for each region in another embodiment of the present invention.

Explanation of the sign

3: stage

4: motor

5: encoder

6: CCD camera

7: light source

8: probe card

8a: probe needle

9: tester

10: PC for image processing

14: Lens

21: CPU

23: RAM

25: HDD

30: semiconductor chip (chip, die)

40: electrode pad (pad)

41: Needle Trace

51: Before Contact

52: Burn after contact

53: difference image

100: probe inspection device

EMBODIMENT OF THE INVENTION Hereinafter, the Example of this invention is described based on drawing.

1 is a view showing the configuration of a probe inspection apparatus according to an embodiment of the present invention.

As shown in FIG. 1, the probe inspection device 100 includes, for example, a wafer table 2 holding a semiconductor wafer 1 made of silicon (hereinafter, simply referred to as a wafer 1). A stage 3 for moving the wafer table 2 in the X, Y, Z, and θ directions of FIG. 1, a CCD camera 6 for imaging the wafer 1 from above, and the CCD camera 6. Control the operation of each of these parts and the light source 7 for illuminating the wafer 1, the probe card 8 provided with the plurality of probe needles 8a, and the following image processing. It has a PC (Personal Computer) 10 for image processing.

The wafer 1 is conveyed onto the wafer table 2 by a conveyance arm or the like not shown, and is adsorbed onto the wafer table 2 and fixed by, for example, a suction pump such as a vacuum pump (not shown). In addition, instead of directly adsorbing the wafer 1 to the wafer table 2, for example, a tray (not shown) capable of holding the wafer 1 separately is prepared, and the wafer 1 is held in the tray. The tray may be sucked and fixed in a closed state. In the case where a hole is formed in the wafer 1 or the like, it may be difficult to directly vacuum-adsorb the wafer, so the adsorption method using this tray is effective.

3 is a top view of the wafer 1. As shown in FIG. 3, on the wafer 1, for example, 88 semiconductor chips (dies) 30 (hereinafter, simply referred to as chips 30) are formed in a grid shape. Of course, the number of chips 30 is not limited to 88.

4 is an enlarged top view of each chip 30 of the wafer 1. As shown in Fig. 4, each chip 30 (30a to 30e) is provided with a plurality of electrode pads 40 (hereinafter simply referred to as pads) having a bump shape along the periphery, for example. have. In the present embodiment, each pad 40 is provided on each side of the chip 30, a total of 48, but the number of the pad 40 is not limited to this. In addition, the layout of the pad 40 is not limited to the case where it is provided in the periphery of each chip 30, and may be provided over the whole surface of each chip 30. As shown in FIG. Each electrode pad 40 is made of metal such as gold, silver, copper, solder, nickel, aluminum, or the like, and is connected to an integrated circuit formed inside each chip 30.

The probe card 8 is configured by fixing a plurality of probe needles 8a corresponding to the number and layout of electrode pads of each chip 30 on a substrate. For example, in the present embodiment, 48 probe needles 8a are provided along the layout of each chip 30. Each probe card 8 is connected to the tester 9, and each probe needle 8a contacts each pad 40, and through each of the probe needles 8a, the tester 9 is connected to each pad 40. The electrical characteristics of each chip 30 can be inspected by applying a voltage according to various conditions, measuring the output value, comparing the predetermined value with a predetermined expected value, and the like.

Referring back to FIG. 1, the CCD camera 6 is fixed at a predetermined position above the wafer 1 and incorporates a lens or a shutter (not shown). On the basis of the trigger signal output from the image processing PC 10, the CCD camera 6 uses an image (each pad) of each pad 40 on each chip 30 enlarged by a built-in lens. The image of the needle trace remaining on 40) is imaged under flashing light emitted by the light source 7, and the captured image is transferred to the image processing PC 10. FIG. Specifically, the CCD camera 6 includes an image before each probe needle 8a contacts each pad 40 (hereinafter referred to as a pre-contact image) in the electrical characteristic inspection for one chip 30. An image after contact (hereinafter referred to as an after contact image) is captured. Instead of the CCD camera 6, a camera incorporating another imaging device such as a CMOS sensor may be used.

The light source 7 is fixed at a predetermined position above the wafer 1, and includes, for example, a flash lamp made of a high brightness white LED or a Xenon lamp and a flash lighting circuit for controlling the lighting of the flash lamp. Has The light source 7 emits a flash of high brightness for a predetermined time, for example, about several seconds, based on a flash signal output from the PC 10 for image processing, thereby for each pad 40 of each chip 30. Illuminate.

The stage 3 includes a motor 4 for moving the X stage 11 and the Y stage 12 along the movement axis 13 in the X direction, the Y direction, the Z direction and the θ direction, respectively, It has an encoder 5 for determining the moving distance in each direction of the X stage 11 and the Y stage 12. The motor 4 is, for example, an AC servo motor, a DC servo motor, a stepping motor, a linear motor, or the like, and the encoder 5 is, for example, various motor encoders or linear scales. The encoder 5 generates an encoder signal which is its movement information (coordinate information) whenever the X stage 11 and the Y stage 12 move by a unit distance in the X, Y, Z and θ directions, and the encoder signal is converted into the encoder signal. Output to the PC 10 for image processing.

In the case of performing the electrical characteristic inspection on each chip 30, first, the stage 3 is moved in the XY plane so that the inspection target chip 30 is located directly under each probe needle 8a of the probe card 8. Then, each probe needle 8a is contacted to each pad 40 by moving the stage 3 directly above (Z1 direction), and voltage is applied from the tester 9 in this state. When the inspection is completed, the stage 3 is moved immediately below (Z2 direction) to return to the original state. When the inspection target chip 30 is changed to another chip 30, the stage 3 is moved on the XY plane by the distance amount between these chips, and similar operations are repeated.

In addition, when imaging each pad 40 of each chip 30 with the CCD camera 6, the stage 3 is moved on XY plane so that the CCD camera 6 may be located directly over the pad 40 which is imaging object. The image is taken under flashing light from the light source 7. In the inspection by the probe card 8, the CCD camera 6 is evacuated to another position so that the wafer 1 and the CCD camera 6 do not come into contact with each other by the rise of the stage 3. Only is set above the wafer 1 as shown in FIG.

The image processing PC 10 receives the encoder signal from the encoder 5, outputs a flash signal to the light source 7 based on the encoder signal, and triggers the CCD camera 6. Output the signal. Further, the image processing PC 10 controls the driving of the motor 4 at the time of inspection of each chip 30 and the imaging of each pad 40 based on the encoder signal input from the encoder 5. The motor control signal is output to the motor 4.

2 is a block diagram showing the configuration of the image processing PC 10.

As shown in FIG. 2, the image processing PC 10 includes a central processing unit (CPU) 21, a read only memory (ROM) 22, a random access memory (RAM) 23, and an input / output interface 24. ), An HDD 25, a display unit 26, and an operation input unit 27, and each unit is electrically connected to each other by an internal bus 28.

The CPU 21 collectively controls each unit of the image processing PC 10 and performs various operations in image processing and the like described later. The ROM 22 is a nonvolatile memory that stores programs necessary for starting up the image processing PC 10 or other programs or data that do not need updating. The RAM 23 is used as a work area (work area) of the CPU 21 and is a volatile memory that reads and temporarily stores various data or programs from the HDD 25 or the ROM 22.

The input / output interface 24 is connected to the operation input unit 27 or the motor 4, the encoder 5, the light source 7, the CCD camera 6, and the internal bus 28, from the operation input unit 27. It is an interface for inputting an operation input signal or exchanging various signals with the motor 4, the encoder 5, the light source 7, and the CCD camera 6.

The HDD 25 is an OS (Operating System) or various programs for performing image processing and image processing described later, other various applications, and images of the pads 40 captured by the CCD camera 6, or For each pad 40, data indicating a target position for contacting each probe needle 8a, other various data, and the like are stored in an internal hard disk. In addition, you may install the various programs for performing the said imaging process or image process from the recording medium which recorded these, for example, CD, DVD, BD, a flash memory.

The display unit 26 is made of, for example, a liquid crystal display (LCD), a cathode ray tube (CRT), or the like, and displays an image captured by the CCD camera 6 or various operation screens for image processing. The operation input unit 27 is made of, for example, a keyboard or a mouse, and receives an operation from a user in image processing or the like described later.

Next, the operation of the probe inspection device 100 in the present embodiment will be described. When the probe inspection apparatus 100 examines the electrical characteristics of each chip 30, the contact position of each probe needle 8a with respect to each pad 40 is separated from a predetermined target position. Deviation can be corrected. Hereinafter, the operation based on this position deviation correction will be described.

FIG. 5 is a flowchart showing the flow of operation when the electrical characteristics of each chip 30 are inspected. In addition, in this embodiment, inspection is performed sequentially for each of the 88 chips 30 shown in FIG. For example, inspection is performed for each row, for example, starting from the chip 30 at the left end of the top row (Y coordinate is maximum) of the chips 30 shown in FIG. 3. In addition, even when all the inspections are completed for each chip 30, a plurality of inspections may be performed for the same chip 30 by changing electrical conditions. Therefore, when examining each chip 30, the needle trace by the probe needle 8a may already remain in each pad 40 of each chip 30. FIG. In FIG. 5, one chip 30 (for example, the chip 30a of FIG. 4) of each chip 30 is inspected as an inspection target, and another chip 30 (for example, before the inspection) is examined. For example, the same inspection is performed on the chip 30e of FIG. 4.

As shown in FIG. 5, the probe inspection apparatus 100 first determines the contact position of the probe needle 8a on the basis of the correction amount calculated in the inspection of the other chip 30 that is the inspection target before one inspection this time. Position deviation is corrected (step 101). Detailed description of this operation will be described later.

Subsequently, the CPU 21 of the image processing PC 10 of the probe inspection device 100 has the same chip 30 as the current inspection target chip 30, so that the image after contact at the time of the previous inspection is the HDD ( It is judged whether or not it is stored in 25) (step 102). If the image after the previous contact is stored (Yes in step 102), the image after the contact is read out from the HDD 25 for use as the image before contact in the current inspection (step 103).

When the image after the previous contact is not stored (that is, when a contact is made for each pad 40 of the one chip 30 for the first time), the CPU 21 moves down the CCD camera 6. The inspection target chip 30 of the wafer 1 is moved to the CCD camera 6 so as to capture an image before contacting each pad 40 (step 104).

FIG. 6 is a diagram showing an imaging trajectory of the CCD camera 6 on one chip 30. As illustrated in FIG. 6, the CPU 21 uses the CCD camera 6 as a starting point, for example, using the pad 40 at the uppermost side of the left side of the pads 40 of the chip 30 as a starting point. The image pickup position on the i) is moved while drawing the image pickup trajectory in the counterclockwise rotation direction, and a motor drive signal is output to the motor 4 to continuously image all the contacts before the pads 40. In addition, since the position itself of the CCD camera 6 is fixed at the time of imaging, in this case, the stage 3 will move in the reverse direction (clockwise rotation direction) with the locus shown in FIG. The CCD camera 6 continuously flash-images each pad 40 under the flash from the light source 7 based on the trigger signal output from the CPU 21 in accordance with this movement. Each captured before-contact image is stored in the buffer area of the RAM 23, for example.

Subsequently, after evacuating the CCD camera 6 from above the inspection target chip 30, the CPU 21 outputs a motor drive signal for moving the stage 3 in the Z1 direction to the motor 4, and then inspects it. Each probe needle 8a of the probe card 8 is contacted to each pad 40 of the target chip 30 (step 105). In this state, a voltage is applied to each pad 40 from the tester 9 via the probe needle 8a, and the output value from each pad 40 is measured.

When the contact and measurement are finished, the CPU 21 moves the inspection target chip 30 back to the lower side of the CCD camera 6, and then photographs the image after the contact of each pad 40 (step 106). That is, as in the imaging of the pre-contact image, the CPU 21 continuously moves each pad 40 after the contact of each probe needle 8a while the CCD camera 6 moves as shown in FIG. The motor drive signal is output to the motor 4 so as to capture an image, and the trigger signal is output to the CCD camera 6. An image after each contact of each pad 40 captured is stored in the buffer area of the RAM 23 and the like.

Next, the CPU 21 extracts the difference between the pre-contact image and the post-contact image of each pad 40 as the difference image (step 107). FIG. 7 is a diagram conceptually showing how the difference image is extracted by one of the pads 40.

As shown in FIG. 7, the needle trace 41a remains on the pad 40 in the pre-contact image 51. This needle trace 41a is a needle trace left by a contact in the last inspection for this inspection target chip 30. In addition, in the post-contact image 52, another needle trace 41b remains on the pad 40 in addition to the needle trace 41a. This needle trace 41b is the needle trace left by the contact (step 105 above) at the present inspection.

CPU21 extracts the difference image 53 by performing the image process which takes the difference of the before-contact image 51 from this after-contact image 52. FIG. In this difference image 53, only the needle trace 41b in the post-contact image 52 is shown. That is, even when a plurality of contacts are made to the chip 30 by the extraction process of this difference image 53, only the latest needle trace can be extracted, and the needle trace which becomes a correction object of a position deviation in this test | inspection is performed. It can be specified. The extraction process of this difference image 53 is performed with respect to all the pads 40 on the inspection target chip 30 at this time.

Subsequently, the CPU 21 recognizes the needle traces 41b shown in the extracted difference image 53 with respect to all of the pads 40 of the inspection target chip 30 at this time, and the needle traces 41b in advance. The position deviation amount between the set needle trace and the target position is calculated (step 108). This positional deviation is due to, for example, deterioration due to an increase in the number of contacts of each probe needle 8a. In addition, in the probe inspection apparatus 100, for example, the test is performed by applying heat to the pad 40 via the probe needle 8a from the tester 9 (so-called thermal stress test). In some cases, positional deviation may occur due to variations in the probe needle 8a due to this heat.

FIG. 8 is a diagram conceptually showing a process of calculating this position deviation amount in one pad 40 of each pad 40. In the probe inspection apparatus 100 of this embodiment, for example, the center of the pad 40 is set as a target position of a contact, and the target position data (coordinate data) is stored in the HDD 25 or the like. On the other hand, as shown in Fig. 8, the needle trace 41b in the current inspection in the differential image 53 has the origin of the pad 40 as the origin, and the + direction in the X coordinate and the-direction in the Y coordinate. Appears in the off position. Therefore, the position deviation amount of the vector a in FIG. 8 exists between the needle trace 41b and the target position. The CPU 21 recognizes the needle trace 41b from the difference image 53 by image processing such as binarization processing, for example, and centers the target position data and the needle trace 41b. By comparing the coordinates, this position deviation amount is calculated. The CPU 21 performs this process on all the pads 40 of the inspection target chip 30 at this time.

Subsequently, the CPU 21 calculates the correction amount as the entire probe card 8 based on the calculated amount of position deviation in each of the pads 40 (step 109). FIG. 9 is a diagram illustrating a state where the latest needle traces 41b remain on the plurality of pads 40 of the chip 30. In addition, in FIG. 9, the needle trace 41a in the last test is not shown for convenience of description. As shown in FIG. 9, the positional deviation amount of each needle trace 41b in each pad 40 may be different for each pad 40. This may be caused from an error in the design of the probe card 8, or may be due to a difference in the progress state such as age deterioration for each probe needle 8a. The CPU 21 is configured so that the entire position of the probe card 8 is such that the position deviation amounts of each of the pads 40 are as close to zero as possible, that is, the coordinates of each needle trace 41b and the coordinates of each target position are as close as possible. The correction amount as the movement amount is calculated. This calculation is performed by using well-known methods, such as the least square method, for example. This correction amount is calculated taking into account not only the movement in the XY direction of the probe card 8 but also the movement in the θ direction. The calculated correction amount data is stored in the HDD 25.

Subsequently, the CPU 21 erases the data of the before-contact image 51 from the buffer area of the RAM 23 (step 110). Since the before-contact image 51 is necessary only for the extraction of the difference image 53, after the extraction of the difference image 53, the use capacity of the RAM 23 can be reduced by erasing the before-contact image 51. have. Of course, this erasing process may be performed before the processing of calculating the respective positional deviation amounts and the correction amounts.

Subsequently, the CPU 21 writes the data of the images 52 after each contact from the buffer area of the RAM 23 to the HDD 25 (step 111). At this time, the CPU 21 associates the post-contact image 52 with the chip ID for identifying the chip 30 which is the object of inspection at this time and the pad ID for identifying each pad 40 of the chip 30. The HDD 25 is stored. Thereby, when the chip | tip 30 used as a test | inspection of this time becomes a test | inspection again later, the after-contact image 52 memorize | stored in the HDD 25 is read with reference to the said chip ID and the pad ID, and the It becomes possible to use it as the image before contact 51 in a retest. Therefore, the imaging process of the pre-contact image in step 106 becomes unnecessary, and the processing load according to the imaging process is greatly reduced, leading to the reduction of the storage capacity of the RAM 23 or the HDD 25 and the like.

In addition, the image after each contact is stored in the data format of BMP (BitMaP) of monochrome, for example. By using a monochrome image instead of color, the write time to the HDD 25 is shortened by setting it as an uncompressed format while suppressing the use capacity of the HDD 25 as much as possible. Of course, the image may be a color image, or may be an image in a compressed format such as JPEG (Joint Photographic Experts Group) or GIF (Graphic lnterchange Format).

Then, the CPU 21 ends the inspection of the inspection target chip 30 (for example, the chip 30a of FIG. 4) at this time, and the other chip 30 on which the probe card 8 is the next inspection target. (3, for example, the chip 30b of FIG. 4), when the stage 3 is moved, based on the correction amount calculated in the step 109 as in the step 101, as the pre-process of the inspection. The stage 3 is moved to perform position deviation correction (step 112). In this case, when viewed in units of pads 40, for example, at a predetermined position (for example, the third position from the left side column) on the current inspection target chip 30a shown in FIG. The amount of position deviation in the existing pad 40a is corrected in the pad 40b existing at the same position as the pad 40a on the next inspection target chip 30b. In addition, although the other chip | tip 30 used as a test | inspection object is a chip | tip adjacent to the chip | tip 30 used as a test | inspection object of this time, it does not matter even if it is an adjacent chip | tip.

The CPU 21 repeats the above process for all the chips 30 to be inspected. Thereby, the correction amount calculated by the inspection of the chip 30 which has become the inspection target of the previous one can be reflected in feedback control in the inspection of the next chip 30. In addition, when the inspection of all the chips 30 of one wafer 1 is finished, the CPU 21 performs the same processing on each chip 30 of the other wafer 1 which is the next inspection target. .

As described above, in this embodiment, even when a plurality of probe traces are performed on each pad 40 of each chip 30 and a plurality of needle traces remain, the pre-contact image 51 and the post-contact image 52 ), The difference image 53 is extracted, and the position deviation amount between the position of the latest needle trace 41b and the target position in the difference image 53 is calculated for each of the pads 40, and from the respective position deviation amounts By calculating the correction amount as the entire probe card 8 and reflecting the correction amount in the inspection of the chip 30 to be inspected next, the contact position of the probe needle 8a can always be maintained at the target position.

This invention is not limited only to the above-mentioned embodiment, Of course, various changes can be added within the range which does not deviate from the summary of this invention.

In the above-mentioned embodiment, although the center position of the pad 40 is made into the target position of the probe needle 8a, it is not limited to this position. For example, one pad 40 may be divided into a plurality of areas, and may be used separately for a plurality of times of contact in the inspection under different electrical conditions. 10A to 10C show the before-contact image 51 and the after-contact image 52 and the difference image 53 in the inspection in this case.

 As shown in FIG. 10A, in the pre-contact image 51, the needle trace 41a remains in the region 80a of the four divided regions 80a to 80d of the pad 40. This is the needle trace left during the inspection of the last inspection for this chip 30. In this last inspection, the center position of the region 80a is the target position.

As shown in Fig. 10B, in the post-contact image 52, the needle trace 41b remains around the boundary between the region 80b and the region 80c. However, in this inspection, since the center position of the area 80b becomes the target position, positional deviation occurs between the target position and the needle trace 41b.

Here, as shown in FIG. 10C, the CPU 21 has the needle trace 41b at the center of the region 80b at each pad 40 of another chip 30 to be the next inspection target of the chip 30. The positional deviation amount used as a position is calculated, and a correction amount is calculated based on the positional deviation amount of each pad 40.

In the above-described embodiment, although the probe card 8 has probe needles 8a so as to correspond to the contacts to each pad 40 of one chip, the probe cards 8 have contacts to each pad 40 of the plurality of chips 30. The present invention can also be applied when the inspection is performed by the probe card 8 having the probe needle 8a corresponding at one time. In this case, the CCD camera 6 continuously photographs each pad 40 for each chip 30, and the CPU 21 calculates the amount of deviation from each pad 40 for each chip 30. The amount of correction as the entire probe card 8 is calculated so that each position deviation amount is as close to zero as possible with respect to each pad 40 of the plurality of chips 30.

In the above-described embodiment, the post-contact image 52 is stored in the HDD 25. However, when the capacity of the RAM 23 is sufficient, the post-contact image 52 is not stored in the HDD 25, but the RAM ( 23) may be remembered. Thereby, the writing time and reading time of the post-contact image 52 can be shortened and processing efficiency can be improved.

In the above-described embodiment, the chip ID and the pad ID are stored in the HDD 25 of the image processing PC 10, but the chip ID and the pad ID are managed together with the wafer ID for identifying each wafer 1. You may separately prepare a server for ID management.

In the above-described embodiment, before and after contact images are prepared for all the pads 40 of the inspection target chip 30, and the correction amount is calculated based on the amount of position deviation in all the pads 40, but all the pads 40 Image of the contact before and after only for any number of pads 40 (for example, four), and the amount of correction is calculated based on the amount of positional deviation in the arbitrary number of pads 40. Does not matter. Thereby, the processing time according to the imaging process, the differential image extraction process, the correction amount calculation process, or the like can be reduced to shorten the processing time. In addition, you may make it possible for a user to set the number of pads 40 made into the calculation process of the correction amount via the said operation input part 27 etc. arbitrarily. However, it is preferable to make all the pads 40 the object of processing in terms of improving the accuracy of the correction of the positional deviation amount. Moreover, even if it processes in this way, processing time can be shortened by carrying out high speed scan imaging of each pad 40 by the said CCD camera 6 continuously.

In the above-described embodiment, the latest needle trace is detected by capturing an image before and after the contact when the probe needle 8a contacts each pad 40 of each chip 30 and extracting a differential image from the two images. For example, you may image with the camera which installed separately the state of each pad 40 at the time of contact of the probe needle 8a. As a result, even if the needle trace remains on the pad 40, the latest contact position can be grasped and the position deviation can be calculated if the captured image is provided. And the burden will be reduced.

Claims (9)

A probe inspection device for inspecting electrical characteristics of an object by contacting a probe needle with an electrode pad of the object, Imaging means for imaging each of the electrode pad before contact of the probe needle with the test subject and the electrode pad after contact of the probe needle; Storage means for storing an image of the electrode pad before the imaged contact as a first image, and storing an image of the electrode pad after the imaged contact as a second image; Difference extracting means for extracting a difference between the stored first image and the second image as a difference image; Calculating means for calculating a correction amount for correcting a positional deviation between a needle trace position of the probe needle appearing in the extracted differential image and a target position on the electrode pad to which the probe needle should be in contact; Correction means for correcting the positional deviation by varying a relative position between the object under test and the probe needle based on the calculated correction amount Probe inspection apparatus comprising a. The method of claim 1, In the case where the electrical characteristic inspection by the contact of the probe needle is performed with respect to the electrode pad a plurality of times, further restricting means for regulating the imaging of the first image by the imaging means in the next inspection. Equipped, And the storage means stores the image stored as the second image in the one inspection as the first image in the next inspection. The method of claim 2, And said storage means has means for deleting said first image after said difference extraction. The method of claim 2, The test object is a semiconductor wafer having a plurality of semiconductor chips provided with a plurality of the electrode pads, The probe needle may be provided in plurality so as to be in contact with each of the electrode pads of one of the semiconductor chips at a time, The imaging means may continuously image the first and second images of the respective electrode pads of the one semiconductor chip, respectively, The storage means stores the second image of each electrode pad in correspondence with first identification information for identifying the one semiconductor chip and second identification information for identifying each electrode pad of the one semiconductor chip. and, And the calculating means calculates a correction amount for correcting each positional deviation between the needle trace position of each probe needle and each target position on each electrode pad at a time. The method of claim 1, The test object is a semiconductor wafer having a plurality of semiconductor chips provided with a plurality of the electrode pads, A plurality of probe needles are present for each of the at least two semiconductor chips so as to be in contact with each of the electrode pads of each of the at least two semiconductor chips of the semiconductor chips at one time; The imaging means may sequentially image the first and second images of the respective electrode pads of the at least two semiconductor chips, respectively, The storage means includes first identification information for identifying each of the at least two semiconductor chips, and second identification for identifying each of the electrode pads of the at least two semiconductor chips. I correspond to information and remember it, And the calculating means calculates a correction amount for correcting each positional deviation between the needle trace position of each probe needle and each target position on each electrode pad in the at least two semiconductor chips at one time. Inspection device. A method for correcting position deviation in a probe inspection apparatus for contacting a probe needle with an electrode pad of an object to inspect electrical characteristics of the object, Imaging the electrode pad before the contact of the probe needle with the test subject and the electrode pad after the contact of the probe needle, respectively; Storing an image of the electrode pad before the imaged contact as a first image, and storing an image of the electrode pad after the imaged contact as a second image; Extracting the difference between the stored first image and the second image as a difference image; Calculating a correction amount for correcting a positional deviation between a needle trace position of the probe needle appearing in the extracted differential image and a target position on the electrode pad to which the probe needle should contact; Correcting the positional deviation by varying a relative position between the object under test and the probe needle based on the calculated correction amount. Position deviation correction method characterized in that it comprises a. An information processing apparatus used for a probe inspection apparatus for contacting a probe needle with an electrode pad of an inspected object to inspect electrical characteristics of the inspected object. Storage means for respectively storing a first image of the electrode pad before contact of the probe needle with the test object and a second image of the electrode pad after contact of the probe needle; Difference extraction means for extracting the difference between the stored first image and the second image as a difference image; Calculating means for calculating a correction amount for correcting a positional deviation between a needle trace position of the probe needle appearing in the extracted difference image and a target position on the electrode pad to which the probe needle should be in contact An information processing apparatus, comprising: a. An information processing method in an information processing apparatus for use in a probe inspection device for contacting a probe needle with an electrode pad of an inspected object to inspect electrical characteristics of the inspected object. Storing a first image in which the electrode pad before the contact of the probe needle with the test object is imaged and a second image in which the electrode pad after the contact of the probe needle is imaged, respectively; Extracting the difference between the stored first image and the second image as a difference image; Calculating a correction amount for correcting a positional deviation between a needle trace position of the probe needle appearing in the extracted difference image and a target position on the electrode pad to which the probe needle should be in contact An information processing method comprising: In the information processing apparatus used in the probe inspection device for contacting the probe needle to the electrode pad of the object to be inspected the electrical characteristics of the object, Storing a first image in which the electrode pad before the contact of the probe needle with the test object is imaged and a second image in which the electrode pad after the contact of the probe needle is imaged, respectively; Extracting the difference between the stored first image and the second image as a difference image; Calculating a correction amount for correcting a positional deviation between a needle trace position of the probe needle appearing in the extracted difference image and a target position on the electrode pad to which the probe needle should be in contact Program to run.

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