JP2008147276A - Probe card and device and method for inspecting semiconductor wafer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To set a fixed quantity of an overdrive at each measuring point in a semiconductor wafer at all times, and to realize a stable contact between a probe and a pad for inspection. <P>SOLUTION: A probe card is used when inspecting the semiconductor wafer. The probe card concretely has a card body 101 arranging a first surface while being opposed against the surface to be inspected of the semiconductor wafer and the probes 104 and 104 fitted to the first surface and brought into contact with the pad for inspection fitted to the surface to be inspected of the semiconductor wafer. The probe card concretely has projections 105, 106, 107 and 108 formed at a center and a periphery in the first surface so as to be projected from the first surface so that the expansion and contraction of the card body 101 due to a temperature change can be detected. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a probe card, a semiconductor wafer inspection apparatus, and a semiconductor wafer inspection method, and more particularly to a probe card used when inspecting a semiconductor device, a semiconductor wafer inspection apparatus and a probe card provided with the probe card, and the like. The present invention relates to a method for inspecting a used semiconductor wafer.

  In manufacturing a semiconductor device, a non-defective wafer / defective wafer is determined by inspecting device characteristics after a manufacturing process (hereinafter referred to as a preprocessing process) for forming a device on a wafer is completed. Furthermore, due to recent strict requirements for quality represented by in-vehicle applications, not only inspection at normal temperature but also inspection at high temperature of 100 ° C. or higher and low temperature of −20 ° C. or lower is required. For this reason, a measurement problem caused by heat that has not been seen in a normal temperature inspection in a semiconductor wafer inspection using a wafer prober has been highlighted.

  FIG. 8 shows the probe shape during high-temperature measurement and the shape of the needle trace on the inspection pad formed by contact with the probe. The shape of the probe at room temperature is the same as that at room temperature in FIG. 8A, but the shape at high temperature is such that the probe 104 is extended as shown in FIG. 8B (in FIG. 8B, the broken line indicates room temperature). The shape of the probe 104 at the time, and the solid line is the shape of the probe 504 at the high temperature). Therefore, as shown in FIG. 8C, the needle trace shape 132 fits in the test pad 131 at room temperature, but the needle trace 133 protruding from the test pad 131 as shown in FIG. 8D at high temperature. become that way.

  On the other hand, FIG. 10 shows the probe shape at the time of low temperature measurement and the needle trace shape on the inspection pad formed by contact with the probe. The probe shape is lower than that at room temperature in FIG. 10A, and the shape at low temperature is that the probe 104 is contracted as shown in FIG. 10B (in FIG. 10B, the broken line indicates room temperature). The shape of the probe 104 at the time, and the solid line is the shape of the probe 604 at the low temperature). Therefore, as shown in FIG. 10C, the appropriate needle trace shape 132 fits in the test pad 131 at room temperature, but a small needle trace is formed on the test pad 131 as shown in FIG. 10D at low temperatures. In some cases, the needle mark may not be formed as shown in FIG.

  An inspection pad provided in a recent semiconductor device has a side as small as about 50 μm, and even a slight thermal displacement of about 10 μm may cause a contact abnormality.

  For this reason, in the automatic inspection of semiconductor wafers using a wafer prober, a mechanism for removing the influence of probe expansion and contraction on temperature is installed.

  FIG. 11 shows a conventional semiconductor wafer inspection method using a wafer prober equipped with a mechanism for removing the influence of the probe expansion and contraction.

First, a semiconductor wafer is set on a wafer prober and measurement is started. Here, in the case of measurement at a high temperature or low temperature other than normal temperature, the semiconductor wafer, probe card, and wafer prober to be inspected are preheated to adjust to the temperature in order to expand and contract as the temperature changes. Although preheating is performed over about 30 minutes to 1 hour, the inspection does not proceed during this period.
When the preheating is finished, an alignment operation is performed in order to realize contact between the probe tip and the inspection pad formed on the semiconductor wafer. 3D coordinate acquisition of the probe tip using a camera (hereinafter referred to as “probe alignment”), alignment of the wafer shape and the arrangement of semiconductor devices formed on the semiconductor wafer, and the like are performed with the camera (hereinafter referred to as “wafer alignment”). ) To obtain the average thickness of the semiconductor wafer. Here, the distance from the probe tip to the wafer surface is calculated from the probe tip coordinates and the wafer thickness. After the probe tip comes into contact with the test pad, an overdrive is performed to further load the pad to ensure contact. The prober stage is raised by the amount obtained by adding the distance from the probe tip to the inspection pad and the set overdrive amount to bring the probe and the pad into contact with each other.

  Thereafter, a signal is output from the tester to each pad, and the semiconductor device is inspected and measured.

  When the measurement is completed, it moves to the next chip and repeats the measurement as described above. If a preset time, for example, 5 minutes or more has elapsed since the previous probe alignment or wafer alignment, the probe alignment, Perform wafer alignment. This is to minimize the influence of probe expansion and contraction due to high and low temperatures and to allow overdrive to the pads as originally set.

  When all the chips have been measured, the wafer is replaced with another wafer, and the above operation is repeated until all the wafers have been measured.

  However, even if the inspection considering the influence of the expansion and contraction of the probe as in the above method is performed, the initially set overdrive amount cannot be realized, and the correct characteristic is often not obtained due to abnormal contact between the probe and the inspection pad. .

  During preheating, the probe is in a non-contact state in the wafer prober. High and low temperature control is performed by a heater provided in the stage and a coolant flowing in the stage. Therefore, the wafer in contact with the stage quickly follows the temperature change of the stage, and the temperature of the stage and the wafer is almost the same. On the other hand, since heat is not easily transmitted through the air, the temperature of the stage or wafer is not easily transmitted to the probe. Even if the wafer temperature reaches the set temperature due to preheating, the probe does not reach the set temperature. When measurement starts in this state and the probe comes into contact with the inspection pad, the heat of the wafer is transmitted directly to the probe. Therefore, the probe expands at high temperature, and the probe expands and contracts at low temperature. Such contact abnormality occurs.

As a method for suppressing the influence of probe expansion and contraction in high and low temperature measurement, the probe is in contact with a heat block in advance to thermally saturate the expansion and contraction of the probe, and the probe under measurement is expanded or contracted. A suppression method has been proposed (see, for example, Patent Document 1).
JP 2003-344498 A

  FIG. 7 shows the problem at the time of high temperature measurement in more detail.

  FIG. 7A shows a measurement state at normal temperature, and FIG. 7B shows a measurement state at high temperature measurement. The above method focuses on thermal expansion and contraction of the probe, but in addition to this, deflection of the probe card and thermal expansion of the wafer appear as changes due to heat. Although the probe card itself is thermally expanded by placing it in a high temperature state, the probe card is normally fixed to the wafer prober top plate 122 with screws or a fixing ring 123 at the peripheral portion, so that the expansion in the horizontal direction is suppressed. (B) Deflection (the horizontal plane of the probe card 101 changes from the broken line 101a shown in FIG. 7B to the solid line 101b). Since the wafer 111 is fixed to the stage 121 by vacuum, the expansion in the horizontal direction is suppressed, the expansion is mainly in the thickness direction, and the wafer surface position changes from the broken line position 111a to the solid line position 111b. The stage is made of a material that is not easily displaced by heat. However, since the stage is slightly thermally expanded, the wafer on the stage is also slightly expanded in the horizontal direction, and the wafer diameter is increased.

  FIG. 9 shows the problem in the low temperature measurement in more detail.

  FIG. 9A shows a measurement state at normal temperature, and FIG. 9B shows a measurement state at low temperature measurement. At low temperatures, the probe, probe card, and wafer shrink. Since the probe card is fixed to the wafer prober top plate 122 with screws and fixing rings 123 at the periphery, there is no deflection or displacement due to heat at high temperatures. Since the wafer 111 is fixed to the stage 121 by vacuum, contraction in the horizontal direction is suppressed, contracting mainly in the thickness direction, and the wafer surface position changes from the broken line position 111a to the solid line position 111c. The stage is made of a material that is not easily displaced by heat. However, since the stage slightly shrinks, the wafer on the stage slightly shrinks in the horizontal direction, and the wafer diameter is reduced.

  Furthermore, at present, the wafer thickness uses the average value of the thickness measured at several points within the wafer surface, but in addition to the in-plane variation of the original wafer thickness, thermal expansion and expansion due to temperature uniformity at high and low temperatures There is a wafer warpage due to thickness variation and stress accompanying the above.

  Excessive overdrive during high-temperature measurement not only causes contact abnormalities due to pad stepping, but also destroys semiconductor elements formed in the vicinity of the pad, so that semiconductor products that are normally formed in the pretreatment process can also become defective during inspection. There is sex. On the other hand, insufficient overdrive at the time of low temperature measurement causes the probe and the inspection pad to be in non-contact, and a good product is judged as a defective product.

  As described above, in order to accurately determine whether the product is good or defective, it is necessary to always realize an optimum overdrive amount at each measurement point on the wafer. The thermal displacement associated with high and low temperature measurements requires not only the expansion and contraction of the probe, but also an inspection method that takes into account the effects of other thermal displacements. In addition, it may take several hours for the entire measurement system to become thermally stable, and it is necessary to monitor the thermal displacement during the inspection and measurement and appropriately correct the overdrive amount.

  The present invention has been made in view of the above problems, and by monitoring probe card warpage, probe expansion / contraction, wafer thickness change, and wafer diameter change accompanying temperature change in high / low temperature probe inspection of a semiconductor device, It is an object of the present invention to provide a wafer inspection apparatus that always sets a fixed overdrive amount at each measurement point to realize stable contact between a probe and an inspection pad, and a wafer inspection method using the same.

  The probe card of the present invention is used when inspecting a semiconductor wafer. The probe card includes a card body that has a first surface facing the surface to be inspected of the semiconductor wafer, a probe that is provided on the first surface and contacts an inspection pad provided on the surface to be inspected of the semiconductor wafer, , Provided at the center and peripheral edge of the first surface so as to protrude from the first surface, and provided with a position detection projection for detecting expansion or contraction of the card body due to a temperature change.

  According to the above configuration, it is possible to acquire the position coordinates of the position detection protrusion using the camera for detecting the probe tip position mounted on the semiconductor wafer inspection apparatus. For this reason, it is possible to detect the occurrence of bending associated with the thermal expansion or thermal contraction of the probe card, and to determine whether the thermal expansion or thermal contraction is continuously occurring.

  In the probe card of the present invention, it is preferable that the tip of the position detection projection is sharp.

  In the probe card of the present invention, the probe is formed such that the tip is located at a position away from the surface of the first surface, and the height of the position detection projection is from the first surface to the tip of the probe. It is preferable to be lower than the height. In the preferred embodiment described later, the probe is bent so that the tip exists at a position away from the surface of the first surface. However, the probe does not necessarily have to be bent. The probe may be arranged on the probe card so that the tip is linear and the tip exists at a position away from the surface of the first surface.

  The semiconductor wafer inspection apparatus of the present invention is used when a semiconductor wafer is inspected. Specifically, a card body arranged with the first surface facing the surface to be inspected of the semiconductor wafer, and a probe that is provided on the first surface and contacts an inspection pad provided on the surface to be inspected of the semiconductor wafer; A probe card provided at the center and peripheral edge of the first surface so as to protrude from the first surface, and a position detection protrusion for detecting expansion or contraction of the card body due to temperature change, and the probe tip coordinates at regular intervals A first storage means for detecting and storing the first position, a second storage means for detecting and storing the tip coordinates of the position detection projection at regular intervals, and measuring the wafer thickness of the semiconductor wafer at regular intervals. Third storage means for storing and fourth storage means for measuring and storing the wafer diameter of the semiconductor wafer at regular time intervals are provided.

  With the above-described configuration, it is possible to monitor over time the probe card warpage, probe expansion / contraction, the wafer thickness of the semiconductor wafer, and the thermal variation of the wafer diameter during high / low temperature measurement. Further, since the distance between the probe tip and the inspection pad provided on the semiconductor wafer can be accurately calculated at an arbitrary measurement point, the initially set overdrive amount can be accurately executed.

  The method for inspecting a semiconductor wafer according to the present invention includes a card body having a first surface opposed to a surface to be inspected of a semiconductor wafer, and an inspection pad provided on the surface to be inspected provided on the first surface. And a probe card having a probe that contacts the card and a position detection protrusion provided at the center and periphery of the first surface so as to protrude from the first surface and detecting expansion or contraction of the card body due to temperature change. Inspect the wafer. Specifically, a first step of detecting and storing a wafer thickness and a probe tip coordinate at an arbitrary point within the wafer surface of the semiconductor wafer, a probe tip coordinate and a semiconductor stored in the first step, respectively. The second step of calculating and storing the first distance from the tip of the probe to the surface to be inspected of the semiconductor wafer by using the wafer thickness of the wafer, and adding the first distance and the overdrive amount, A third step of calculating a moving distance to be moved and a fourth step of moving the semiconductor wafer by the moving distance and inspecting the semiconductor wafer are provided. In the third step, the moving distance is calculated so that the overdrive amount becomes equal to the overdrive amount at the normal temperature even when the inspection is at a temperature higher or lower than the normal temperature.

  According to the above inspection method, even if thermal displacement of the wafer thickness or thermal expansion / contraction of the probe occurs during measurement, the distance between the probe tip and the inspection pad formed on the semiconductor wafer is accurately calculated at any measurement point. Therefore, the overdrive amount set in the initial stage can be accurately executed.

  In the first method for inspecting a semiconductor wafer of the present invention, in the first step, it is preferable to detect the wafer thickness at several locations of the semiconductor wafer and obtain the wafer thickness distribution on the semiconductor wafer using the detected wafer thickness.

  Thereby, even if it is a case where it test | inspects in many measurement locations, it can test | inspect in a comparatively short time.

  In the first semiconductor wafer inspection method of the present invention, in the first step, the wafer thickness in the portion of the semiconductor wafer provided with the inspection pad is detected, and in the fourth step, the wafer thickness is measured in the first step. It is preferable to inspect the semiconductor wafer by bringing the inspection pad and the tip of the probe close to each other.

  As a result, the initially set overdrive amount can be accurately executed.

  The first method for inspecting a semiconductor wafer according to the present invention further includes a fifth step of determining whether or not a set time has elapsed since the execution of the first step after the fourth step. When it is determined that a set time or more has elapsed since the execution of one process, it is preferable to perform the processes sequentially from the first process when inspecting another pad of the semiconductor wafer.

  According to the second method for inspecting a semiconductor wafer of the present invention, the first surface is provided on the surface to be inspected of the semiconductor wafer provided on the first surface, the card body being arranged to face the surface to be inspected of the semiconductor wafer. A probe card having a probe that comes into contact with an inspection pad and a position detection protrusion that is provided at the center and peripheral edge of the first surface so as to protrude from the first surface and detects expansion or contraction of the card body due to a temperature change is used. The semiconductor wafer is inspected. Specifically, a probe tip coordinate, a tip coordinate of a position detection protrusion, a wafer thickness at an arbitrary point on the wafer surface of the semiconductor wafer, and a wafer diameter of the semiconductor wafer are detected and stored. A first step, and a second step of calculating and storing a first distance from the tip of the probe to the surface to be inspected of the semiconductor wafer using the tip coordinates of the probe and the wafer thickness of the semiconductor wafer stored in the first step; Adding a first distance and an overdrive amount to calculate a moving distance for moving the semiconductor wafer; and moving the semiconductor wafer by the moving distance to move the semiconductor wafer to the first inspection pad. A fourth step of performing the inspection, a fifth step of preparing for the inspection of the second inspection pad of the semiconductor wafer after the fourth step, a tip coordinate of the probe, and a position after the fifth step The sixth step of detecting and storing the tip coordinates of the protrusions, the wafer thickness at an arbitrary point in the wafer surface of the semiconductor wafer, and the wafer diameter of the semiconductor wafer, the detection result in the sixth step, and the When the difference between the detection result in one step is calculated and it is determined that the difference is less than or equal to the set value in the seventh step and whether or not the difference is larger than the set value, The fourth step is performed after the step, or the second step, the third step, and the fourth step are performed after the eighth step that extends the time interval between the first step and the sixth step after the seventh step. If it is determined that the difference is larger than the set value in the seventh step, the second step, the third step, and the fourth step are sequentially performed after the seventh step.

  According to the second wafer inspection method of the present invention, it is possible to determine that the thermal displacement has converged when the time displacement amount is equal to or less than a preset displacement amount, and the probe is performed at regular time intervals. The measurement time interval for the measurement of the tip position coordinates, the protrusion tip position coordinates, the wafer thickness, and the wafer diameter is set longer or the measurement is stopped, so that the measurement time of the semiconductor wafer can be shortened. This makes it possible to accurately calculate the distance between the probe tip where the probe inspection is performed and the inspection pad formed on the semiconductor wafer by using the data measured immediately before the wafer thickness data and probe tip position coordinates. It is possible to improve the measurement throughput while accurately executing the initially set overdrive amount.

  According to the probe card of the present invention, the semiconductor wafer inspection apparatus, and the semiconductor wafer inspection method using the semiconductor wafer inspection apparatus, a constant overdrive amount is always set at each measurement point in the semiconductor wafer, Test pad contact can be realized.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiment.

(First embodiment)
A probe card according to a first embodiment of the present invention will be described with reference to FIG.

  FIG. 1 is an example of a schematic diagram of a probe card provided with position detection projections, and FIG. 1A is a surface (first surface) provided with probes 104, 104,..., That is, a surface to be inspected of a semiconductor wafer. The probe card is seen from the surface opposite to.

  There is an opening 109 in the center of the probe card substrate 101, and a probe 104 is connected to the probe card wiring 102. The semiconductor wafer is inspected when the probe 104 contacts an inspection pad formed on the surface to be inspected of the semiconductor wafer.

  On the other hand, in the probe card wiring 102, a portion 103 indicated by a dotted circle located at the periphery of the probe card substrate 101 has a pogo pin provided on a test head of a semiconductor inspection apparatus (described later) on the back side of the probe card (the first side and the first side). Are connected to the probe card wiring 102 through through holes provided in the probe card substrate.

  In addition, position detection projections 105 to 108 are formed on the same plane where the probe 104 is provided, that is, in the vicinity of the center and on the periphery of the surface of the semiconductor wafer facing the surface to be inspected. Position detection protrusions 107 and 108 provided in the vicinity of the center are arranged between the opening 109 of the probe card substrate 101 and the probe card wiring 102, and position detection protrusions 105 and 106 provided at the periphery are probe card wirings. It is arranged outside 102. Actually, since the periphery of the probe card is fixed to the wafer probe top plate by screws or rings, it is necessary to provide the position detection projections 105 and 106 at a position different from the position fixed to the wafer probe top plate. .

  FIG. 1B is a cross-sectional view taken along the line IB-IB shown in FIG. Position detection projections 105 to 108 are provided on the surface of the probe card substrate 101 on which the probe 104 is provided.

  The probe card having the above configuration is attached to a wafer prober (semiconductor wafer inspection apparatus), and the three-dimensional coordinates (vertical, horizontal, vertical) of the position detection projections using a probe tip position detection camera mounted on the wafer prober. ) Measured at regular time intervals and monitored as the amount of change over time, it can be determined whether probe card deflection caused by probe card thermal expansion during high-temperature measurement or probe card thermal expansion continues. It becomes possible to do. Since the thermal displacement data of the probe card can be provided in this way, it becomes possible to perform stage control to always apply a constant overdrive by collating with the wafer thickness data, and a stable probe and inspection pad without pad penetration Can be contacted.

  When detecting the coordinates of the tip of the position detection projection, the probe tip position detection camera is usually used to detect the position of the position detection projection tip. Using the depth of focus, the coordinates of the tip are detected by the method of where the projection for position detection clearly matches. In order to monitor the thermal displacement of the probe card, it is necessary to detect the coordinates of the tip in units of 1 μm. In order to accurately detect the exact position of the position detection projection, the tip of the position detection projection is sharp. It is preferable.

  Further, the position detection protrusions 105 to 108 are provided on the same plane as the probe 104 and face the semiconductor wafer to be inspected. In order to prevent the position detection protrusions 105 to 108 from coming into contact with the surface to be inspected of the semiconductor wafer, the height of the position detection protrusion is preferably lower than the height from the upper surface of the probe card substrate 101 to the probe tip. .

(Second Embodiment)
A wafer prober according to a second embodiment of the present invention will be described with reference to FIGS. The wafer prober according to the present embodiment includes the probe card according to the first embodiment.

  FIG. 2A is a conceptual diagram of a mechanism for detecting the tip coordinates of the probe provided on the probe card and the tip coordinates of the position detection projection. In the figure, for convenience, the numbers 1 to 7 are assigned to seven probes, and the symbols a to d are assigned to the four position detection projections. Both the tip coordinate of the probe and the tip coordinate of the position detection projection are detected using the camera 141. In a conventional wafer prober, a camera that detects the tip coordinates of the probe is installed below the probe card 101. In the wafer prober according to this embodiment, a camera for detecting the tip coordinates of the position detection protrusion may be provided separately from the camera for detecting the tip coordinates of the probe. However, the detection area of the camera provided in the conventional wafer prober If the camera is used to detect the coordinates of the tip of the position detection projection, the manufacturing cost of the wafer prober can be reduced. If the coordinate system (x, y, z) for coordinate acquisition is defined as in the coordinate system shown in FIG. 2A, the position coordinates in the horizontal direction can be obtained by moving the camera 141 in the horizontal direction with respect to the substrate surface of the probe card. (X, y) can be detected. Further, by using the depth of focus of the lens used in the camera 141, it is possible to detect the coordinate (z) by a method in which the position detection projection is clearly focused.

  FIG. 2B is a conceptual diagram of a mechanism for detecting the wafer thickness and the wafer diameter of the semiconductor wafer. Further, FIG. 2C shows 17 locations on the wafer surface as an example of locations where the wafer thickness is measured. The camera 142 provided above the semiconductor wafer performs wafer thickness measurement and wafer diameter measurement. Usually, the camera 142 is fixed and moves to the measurement locations 1 to 17 by moving the stage. By using the focal depth of the lens used in the camera at the designated measurement location, the wafer thickness can be calculated by the method of where the wafer surface is clearly focused. Further, since the wafer shape can be acquired by detecting the edge of the wafer, the diameter of the wafer can be calculated.

  Note that a method of measuring the wafer thickness using a capacitance sensor instead of a camera is also generally implemented. The wafer diameter may be calculated by wafer edge detection using an edge sensor instead of a camera.

  FIG. 3 is a conceptual diagram for storing the probe, the three-dimensional coordinates of the position detection projection, and the wafer thickness as data in the prober system. In the wafer prober, a data storage area for storing a probe tip coordinate, a tip coordinate of a position detection projection, a wafer thickness, and a wafer diameter is configured on a memory or a recording disk. The data measured at time 1, time 2,..., Time n are stored so that the temporal change of the thermal displacement of each data can be obtained. The data stored in each time is a plurality of probe tip coordinates, a plurality of position detection projection tip coordinates, a plurality of wafer thicknesses and wafer diameters. For example, when measuring the data illustrated in FIGS. 2A to 2C, seven probes from the tip coordinates (x1, y1, z1) of the probe 1 to the tip coordinates (x7, y7, z7) of the probe 7 are used. Each three-dimensional coordinate, the three-dimensional coordinates of each of the four projections from the tip coordinates (xa, ya, za) of the position detection projection a to the tip coordinates (xd, yd, zd) of the position detection projection d, the wafer surface The thickness of each of 17 locations from the thickness 1 of the inner location 1 to the thickness 17 of the location 17 and the wafer diameter are stored in each time region.

  In summary, the wafer prober according to the present embodiment includes a means 31 for measuring and storing the position coordinates of the probe tip, a means 32 for measuring and storing the position coordinates of the position detection protrusion, and the wafer of the semiconductor wafer. Means 33 for measuring and storing the wafer thickness at a specific location in the plane and means 34 for measuring and storing the wafer diameter of the semiconductor wafer are provided. The means 31 has the measuring means 11 and the storage means 21, and the means 32-34 have the measuring means 12-14 and the storage means 22-24, respectively.

  As described above, with the wafer prober according to the present embodiment, it is possible to monitor over time the probe card warpage, the probe expansion / contraction, the wafer thickness, and the thermal displacement of the wafer diameter that occur during measurement at higher and lower temperatures than room temperature. Further, since the wafer prober stores the wafer thickness at a plurality of points in the wafer surface, the distance between the probe tip and the inspection pad formed on the semiconductor wafer can be accurately calculated at any measurement point. A prober system that accurately executes the initially set overdrive amount can be constructed.

  2A and 2B show the case where the semiconductor wafer is inspected at a temperature higher than room temperature. However, the present embodiment is applicable even when the semiconductor wafer is inspected at a temperature lower than normal temperature. Inspection can be performed using the wafer prober according to the embodiment.

(Third embodiment)
A semiconductor wafer inspection method according to the third embodiment of the present invention will be described with reference to FIGS.

  FIG. 4 is an example of a flowchart of the inspection method according to the present invention.

  In the semiconductor wafer inspection method according to the present embodiment, the semiconductor wafer is set on a wafer prober and inspection is started.

  Here, in the case of measurement at a high or low temperature other than normal temperature, the semiconductor wafer, probe card, or wafer prober to be inspected undergoes preheating to adjust to the temperature in order to cause expansion or contraction as the temperature changes (step) S301). Although preheating is performed over about 30 minutes to 1 hour, the inspection does not proceed during this period. However, since the temperature control at high and low temperatures is performed by a heater mounted on the wafer stage of the prober or a coolant flowing in the stage, the semiconductor wafer that is in direct contact with the stage can be brought close to the set temperature by preheating. However, since the probe is not in contact with the stage, the set temperature is not reached.

  When the preheating is finished, an alignment operation is performed in order to realize contact between the probe tip and the inspection pad formed on the semiconductor wafer. First, the three-dimensional coordinates of the probe tip are acquired using a camera (step S302; first step). Here, a plurality of probe tip coordinates are acquired. Each probe may vary in tip position due to processing and several measurements. In order to correct this variation in the tip position, when actually contacting the inspection pad, the value of the center of gravity calculated from the probe tip coordinates is obtained, and the contact operation is performed by applying an offset.

  Next, after performing wafer alignment (step S303) for reading the wafer shape and the arrangement of semiconductor devices formed on the semiconductor wafer with a camera (step S303), wafer thicknesses at a plurality of points in the semiconductor wafer surface are acquired (step S304). The data is stored in the system as data, and a wafer surface thickness distribution is created (step S305; first step).

  Here, in the inspection of a semiconductor wafer having a relatively small number of measurement points, it is preferable to measure the wafer thickness at a location corresponding to the measurement location. This is because the distance between the probe and the inspection pad can be accurately calculated by using the directly measured numerical value.

  On the other hand, when the number of measurement points is large, if all the wafer thicknesses corresponding to the measurement place are measured, the total measurement time from the start to the end of the inspection becomes long. Therefore, it is efficient to measure the wafer thickness at arbitrary multiple points, store it as data, and predict and calculate the thickness distribution in the wafer surface based on this data, and it is effective for shortening the inspection time. . The thickness of the wafer at the place where measurement is not performed is obtained by calculation.

  In addition, if the measurement points at which the thickness of the semiconductor wafer is measured at regular intervals are the locations where the probe is in contact with the pads of the semiconductor device and the probe inspection is performed, the probe tip and the semiconductor at the location where the probe inspection is performed Since the distance from the inspection pad formed on the wafer can be accurately calculated, the initially set overdrive amount can be accurately executed.

  Next, the distance (first distance) from the probe tip to the wafer surface is calculated from the probe tip coordinates and the wafer thickness at the measurement location (step S306; second step). If the wafer thickness at the measurement location is stored as data, it is read as the wafer thickness at the current measurement location. When the number of wafer thickness measurement locations is smaller than the number of inspection / measurement points of the semiconductor device, the wafer thickness at the current measurement location is obtained from the thickness distribution in the wafer plane calculated by calculation / prediction. Thus, measurement time loss can be reduced and measurement stability by more accurate overdrive can be efficiently realized.

  Next, after the probe tip comes into contact with the inspection pad, an overdrive is further performed to apply a load to the pad to ensure contact. The prober stage is raised by the amount obtained by adding the distance from the probe tip to the test pad and the set overdrive amount to bring the probe into contact with the pad (step S307; third step).

FIG. 5 shows a method for calculating the amount of stage rise in consideration of overdrive during high temperature measurement. FIG. 5 (a) shows a calculation method at room temperature, and FIG. 5 (b) shows the calculation method. A calculation method at a high temperature is shown. Assuming that the distance between the initial probe tip and the pad is Zo and the set overdrive amount is Zd, as shown in FIG.
Initial stage lift = Zo + Zd
It is expressed.

On the other hand, if a probe elongation Zp and a wafer thickness increase Zw are generated as thermal displacement after a certain time, and the distance between the probe tip and the pad becomes Zn, as shown in FIG.
Stage rise after a certain time = Zn + Zd = Zo + Zd− (Zp + Zw)
It can be expressed as.

  That is, in order to realize the same overdrive amount, it is necessary to reduce the stage lift amount by (Zp + Zw) from the immediately preceding state. Note that Zp includes the amount of displacement of the probe tip accompanying the probe card deflection due to heat.

  Next, a signal is output from the tester to each pad, and the semiconductor wafer is inspected (step S308; fourth step).

  When the measurement is completed, it moves to the next chip (step S310), and the above measurement is repeated, but when a preset time, for example, 5 minutes or more has elapsed since the previous probe alignment or wafer alignment ( Step S311) is executed again from the probe alignment (step S302) for acquiring the probe tip coordinates again. This is because the thermal displacement Zp, Zw such as probe expansion / contraction due to high or low temperature, thermal expansion or contraction of the semiconductor wafer is re-measured, and the appropriate stage rise amount is set so that the same overdrive can be applied at each measurement location. This is to decide.

  On the other hand, if the time set in advance from the previous probe alignment or wafer alignment, for example, less than 5 minutes, is less than 5 minutes, the wafer thickness at the next measurement location is extracted from the stored data and the distance between the probe tip and the pad is calculated. Proceeding to (S306), the probe / pad contact / measurement is subsequently executed.

  When all the chips have been measured, the wafer is replaced with another wafer, and the above operation is repeated until all the wafers have been measured.

  In this example, probe alignment is performed at intervals of 5 minutes or more. However, when setting the time, check the needle trace from the actual measurement or calculate the time when the measurement value abnormality does not occur due to contact abnormality. You only have to set it.

  With the above configuration, even if thermal displacement of the wafer thickness or thermal expansion / contraction of the probe occurs during measurement, the distance between the probe tip and the inspection pad formed on the semiconductor wafer is accurately calculated at any measurement point, and the stage is raised Since the amount is controlled, it is possible to accurately execute the overdrive amount initially set for the inspection pad.

  In the present embodiment, the case where thermal expansion occurs during high temperature measurement has been described. However, the same procedure may be performed when thermal contraction occurs during low temperature measurement.

(Fourth embodiment)
A semiconductor wafer inspection method according to the fourth embodiment of the present invention will be described with reference to FIG. In the semiconductor wafer inspection method according to the present embodiment, the probe tip position, protrusion tip position, wafer thickness and wafer diameter thermal displacement are calculated, and if the thermal displacement is greater than a predetermined value, the probe tip position is detected. The semiconductor wafer is inspected without detecting the probe tip position if the amount of thermal displacement is less than or equal to a predetermined value.

  FIG. 6 is an example of a flowchart of the inspection method according to the present invention.

  First, a semiconductor wafer is set on a wafer prober and inspection is started.

  Here, in the case of measurement at a high or low temperature other than room temperature, the semiconductor wafer, probe card, and wafer prober to be inspected are preheated to adjust to the temperature in order to cause expansion or contraction as the temperature changes (step) S501). Although preheating is performed over about 30 minutes to 1 hour, the inspection does not proceed during this period. However, since the temperature control at high and low temperatures is performed by a heater mounted on the wafer stage of the prober or a coolant flowing in the stage, the semiconductor wafer that is in direct contact with the stage can be brought close to the set temperature by preheating. However, since the probe is not in contact with the stage, the set temperature is not reached.

  When the preheating is finished, an alignment operation is performed in order to realize contact between the probe tip and the inspection pad formed on the semiconductor wafer. First, the three-dimensional coordinates of the probe tip are acquired using a camera (step S502). Here, a plurality of probe tip coordinates are acquired, and data is stored in the prober system. In each probe, the position of the tip may vary due to processing and several measurements. In order to absorb this variation in the tip position, when actually contacting the inspection pad, the value of the center of gravity calculated from the probe tip coordinates is obtained, and the contact operation is performed by applying an offset.

  Subsequently, using the camera that acquires the probe tip coordinates, the tip coordinates of a plurality of position detection protrusions provided on the probe card substrate are acquired in the same manner as when the probe tip coordinates are acquired, and the prober system receives the data. Store (step S503).

  Next, wafer alignment is performed by reading the wafer shape and the arrangement of semiconductor devices formed on the semiconductor wafer with a camera (step S504), the wafer diameter is measured, and data is stored in the prober system (step S505). The wafer thicknesses at a plurality of points in the semiconductor wafer surface are acquired and stored as data in the prober system (step S506).

  Each data measured in the present embodiment is preferably stored in the prober system in the form as shown in FIG. 3 described in the second embodiment.

  When the above data acquisition is completed, the data stored in the prober system is called and the thermal displacement amount calculation step is started. Now, for the measurement of the first chip immediately after loading the semiconductor wafer (step S507), The step is skipped, and a wafer in-plane thickness distribution is created from the acquired wafer thickness data (step S511).

  In the inspection of a semiconductor wafer having a relatively small number of measurement points, it is preferable to measure the wafer thickness at a location corresponding to the measurement location. This is because the distance between the probe and the inspection pad can be accurately calculated by using the directly measured numerical value.

  On the other hand, when the number of measurement points is large, if all the wafer thicknesses corresponding to the measurement place are measured, the total measurement time from the start to the end of the inspection becomes long. Therefore, it is efficient to measure the wafer thickness at arbitrary multiple points, store it as data, and predict and calculate the thickness distribution in the wafer surface based on this data, and it is effective for shortening the inspection time. . The thickness of the wafer at the place where measurement is not performed is obtained by calculation.

  Next, the distance from the probe tip to the wafer surface is calculated from the probe tip coordinates and the wafer thickness at the measurement location (step S512). If the wafer thickness at the measurement location is stored as data, the wafer thickness at the current measurement location is read as data. When the number of wafer thickness measurement locations is smaller than the number of inspection / measurement points of the semiconductor device, the wafer thickness at the current measurement location is obtained from the thickness distribution in the wafer plane calculated by calculation / prediction. Thus, measurement time loss can be reduced and measurement stability by more accurate overdrive can be efficiently realized.

  Next, after the probe tip comes into contact with the inspection pad, an overdrive is further performed to apply a load to the pad to ensure contact. The prober stage is raised by the amount obtained by adding the distance from the probe tip to the inspection pad and the set overdrive amount to bring the probe into contact with the pad (step S513).

FIG. 5A and FIG. 5B show a method for calculating the amount of stage rise in consideration of overdrive at the time of high temperature measurement. Assuming that the distance between the initial probe tip and the pad is Zo and the set overdrive amount is Zd, as shown in FIG.
Initial stage lift = Zo + Zd
It is expressed. On the other hand, if the probe extension Zp and the thickness increase Zw due to wafer expansion occur as thermal displacement after a certain time, and the distance between the probe tip and the pad becomes Zn, as shown in FIG.
Stage rise after a certain time = Zn + Zd = Zo + Zd− (Zp + Zw)
It can be expressed as. In other words, in order to achieve a constant overdrive amount, it is necessary to reduce the stage lift by (Zp + Zw) from the previous state. Note that Zp includes the amount of displacement of the probe tip accompanying the probe card deflection due to heat.

  Subsequently, a signal is output from the tester to each pad, and an inspection measurement of the semiconductor wafer is executed (step S514).

  When the measurement is completed, if it is not the final chip (step S515), the next chip is moved (step S516; fifth step), and the above-described measurement is repeatedly performed. The measurement is performed in advance from the previous probe alignment and wafer alignment. If, for example, 5 minutes or more have elapsed (step S517), probe tip coordinates, position detection projection tip coordinates, wafer thickness, and wafer diameter are acquired again (sixth step). The reason is that the thermal displacement Zp and Zw, such as probe expansion and contraction due to high and low temperatures, and thermal expansion and contraction of the semiconductor wafer, are remeasured, and an appropriate amount of stage rise is set so that a constant overdrive can be applied at each measurement location. This is to decide. When measurement and storage of each data is completed, the probe tip coordinates, position detection projection tip coordinates, wafer thickness, and wafer diameter are displaced by heat 5 minutes after the previous measurement and compared with the data previously measured and stored. Is calculated (step S508). If the allowable value (setting value) of the thermal displacement amount of each item is set in advance as 5 μm, for example, if there is a thermal displacement of 5 μm in one or more data (step S509), the next probe tip coordinates, The position detection protrusion tip coordinates, wafer thickness, and wafer diameter are set to be measured after 5 minutes (step S510), and the wafer thickness at the next measurement location is extracted from the stored data, and the distance between the probe tip and the pad is determined. The process proceeds to the calculation process (step S511), and the probe / pad contact / measurement is subsequently executed.

  On the other hand, if the time set in advance from the previous probe alignment or wafer alignment, for example, less than 5 minutes, is less than 5 minutes, the wafer thickness at the next measurement location is extracted from the stored data and the distance between the probe tip and the pad is calculated. The process proceeds to (Step S512), and contact / measurement between the probe and the pad is subsequently executed.

  When the above measurement is repeated, the probe card, the probe, and the semiconductor wafer are eventually in a thermally stable state, and the thermal displacement is reduced. Therefore, the same overdrive amount can be stably applied without performing displacement amount correction by probe alignment or wafer alignment. For example, in the step of calculating the thermal displacement amount after probe alignment and wafer alignment, it is assumed that all thermal displacement amounts are an allowable value of 5 μm or less and the maximum value is 2.5 μm. Since it can be calculated that it takes 10 minutes to reach a displacement of 5 μm, the next probe tip coordinates, position detection projection tip coordinates, wafer thickness, and wafer diameter measurement are automatically set to be performed after 10 minutes. If the amount of displacement is all 0, the measurement time interval is infinite, that is, the probe tip coordinates, position detection projection tip coordinates, wafer thickness, and wafer diameter are automatically set not to be measured and measurement is continued. To go.

  When all the chips have been measured, the wafer is replaced with another wafer, and the above operation is repeated until all the wafers have been measured.

  In this example, probe alignment is performed at intervals of 5 minutes or more. However, when setting the time, check the needle trace from the actual measurement or calculate the time when the measurement value abnormality does not occur due to contact abnormality. You only have to set it.

  With the above configuration, even if thermal displacement of the wafer thickness or thermal expansion / contraction of the probe occurs during measurement, the distance between the probe tip and the inspection pad formed on the semiconductor wafer can be accurately calculated at any measurement point, and the stage Since the amount of increase is controlled, the overdrive amount initially set for the inspection pad can be accurately executed.

  In addition to the probe tip position coordinates, wafer thickness, and wafer diameter measurement at fixed time intervals implemented in the third embodiment, the position detection protrusion tip coordinates are also measured. Accordingly, it is possible to calculate and monitor the thermal displacement of the measuring apparatus, determine whether the thermal variation of the measuring apparatus has converged, and change the setting of the measurement time interval. That is, if the thermal displacement has converged, it is not necessary to repeat the measurement in a short time, and the measurement can be stopped if the time interval of the measurement is set longer or if the thermal displacement becomes zero. The probe alignment and wafer alignment operations for performing the above measurement vary depending on the number of points to be measured, but it takes 2 to 5 minutes. Become. The wafer thickness and probe tip coordinates may be obtained using the data measured immediately before, and the distance between the probe tip where the probe inspection is always performed and the inspection pad formed on the semiconductor wafer can be accurately calculated. Measurement throughput can be improved while accurately executing the initially set overdrive amount.

  In the present embodiment, the case where thermal expansion occurs during high temperature measurement has been described. However, the same procedure may be performed when thermal contraction occurs during low temperature measurement.

  As described above, the probe card, the wafer inspection apparatus and the wafer inspection method using the probe card according to the present invention are a probe card warp, a probe expansion / contraction, a wafer thickness change, By monitoring the change in wafer diameter, a constant overdrive amount can always be set at each measurement point to achieve stable contact between the probe and the inspection pad. In particular, probe cards and semiconductors for inspecting semiconductor devices The present invention is useful for a wafer inspection apparatus including a wafer prober, a wafer inspection method using the wafer inspection apparatus, and the like.

It is the schematic of the probe card for semiconductor device inspection concerning the 1st embodiment of the present invention, and the projection for position detection is provided. It is explanatory drawing which shows the semiconductor inspection system which concerns on the 2nd Embodiment of this invention. It is a figure which shows the structure of the semiconductor inspection system which concerns on the 2nd Embodiment of this invention. It is an example of the flowchart of the high-low temperature wafer inspection method which concerns on the 3rd Embodiment of this invention. It is a conceptual diagram which calculates the stage raise amount for making a probe and a test pad contact in the high-low temperature wafer inspection method which concerns on the 3rd Embodiment of this invention. It is an example of the flowchart of the high-low temperature wafer inspection method which concerns on the 4th Embodiment of this invention. It is a conceptual diagram which shows the thermal displacement of the probe card at the time of high temperature measurement, and a semiconductor wafer. It is a conceptual diagram which shows the thermal displacement of the probe at the time of high temperature measurement, and the needle trace shape after the probe contact seen in the inspection pad. It is a conceptual diagram which shows the thermal displacement of the probe card at the time of high temperature measurement, and a semiconductor wafer. It is a conceptual diagram which shows the thermal displacement of the probe at the time of low-temperature measurement, and the needle trace shape after the probe contact seen in the test pad. It is an example of the flowchart of the conventional high-low temperature wafer inspection method.

Explanation of symbols

101 Probe card substrate 101a Probe card horizontal surface at normal temperature 101b Probe card horizontal surface at high temperature 102 Probe card wiring 103 Test head poco pin contact portion 104 Probe (at normal temperature)
105, 106, 107, 108 Position detection projection 109 Opening 111 Semiconductor wafer 111a Surface position 111b of semiconductor wafer at normal temperature Surface position 111c of semiconductor wafer at high temperature Surface position of semiconductor wafer at low temperature 121 Stage 122 Wafer prober Plate 123 Probe card fixing ring 131 Inspection pads 132, 133, 134 Needle trace 141, 142 Camera 504 Probe (at high temperature)
604 Probe (at low temperature)

Claims (9)

A probe card used when inspecting a semiconductor wafer,
A card body arranged such that the first surface faces the surface to be inspected of the semiconductor wafer;
A probe provided on the first surface and in contact with an inspection pad provided on the surface to be inspected of the semiconductor wafer;
A probe card, comprising: a position detection protrusion provided at a center and a periphery of the first surface so as to protrude from the first surface and detecting expansion or contraction of the card body due to a temperature change.   The probe card according to claim 1, wherein a tip of the position detection projection is pointed. The probe is formed such that a tip thereof exists at a position away from the surface of the first surface,
2. The probe card according to claim 1, wherein a height of the position detection projection is lower than a height of the tip of the probe with respect to the first surface. A semiconductor wafer inspection apparatus used when inspecting a semiconductor wafer,
A card body disposed with the first surface facing the surface to be inspected of the semiconductor wafer; a probe that is provided on the first surface and contacts an inspection pad provided on the surface to be inspected of the semiconductor wafer; A probe card having a position detection protrusion provided at the center and the periphery of the first surface so as to protrude from the first surface and detecting expansion or contraction of the card body due to a temperature change;
First storage means for detecting and storing the tip coordinates of the probe at regular intervals;
Second storage means for detecting and storing the tip coordinates of the position detection projection at regular intervals;
Third storage means for measuring and storing the wafer thickness of the semiconductor wafer at regular intervals;
A semiconductor wafer inspection apparatus, comprising: a fourth storage unit that measures and stores the wafer diameter of the semiconductor wafer at regular intervals. A card body disposed with the first surface facing the surface to be inspected of the semiconductor wafer, a probe provided on the first surface and in contact with an inspection pad provided on the surface to be inspected of the semiconductor wafer, A probe card provided at a center and a periphery of the first surface so as to protrude from the first surface and having a position detection protrusion for detecting expansion or contraction of the card body due to a temperature change; A method for inspecting a semiconductor wafer for inspecting,
A first step of detecting and storing a wafer thickness and a tip coordinate of the probe at an arbitrary point within the wafer surface of the semiconductor wafer;
A first distance from the tip of the probe to the surface to be inspected of the semiconductor wafer is calculated and stored using the tip coordinates of the probe and the wafer thickness of the semiconductor wafer stored in the first step. Process,
A third step of calculating a moving distance for moving the semiconductor wafer by adding the first distance and the overdrive amount;
A fourth step of moving the semiconductor wafer by the moving distance and inspecting the semiconductor wafer;
The method for inspecting a semiconductor wafer, wherein, in the third step, the moving distance is calculated so that the overdrive amount is equal to the overdrive amount at the normal temperature even when the inspection is at a temperature higher or lower than the normal temperature.   6. The method for inspecting a semiconductor wafer according to claim 5, wherein, in the first step, the wafer thickness at several locations of the semiconductor wafer is detected, and a wafer thickness distribution in the semiconductor wafer is obtained using the detected wafer thickness. In the first step, a wafer thickness in a portion of the semiconductor wafer provided with the inspection pad is detected,
6. The semiconductor wafer according to claim 5, wherein in the fourth step, the semiconductor wafer is inspected by bringing the inspection pad whose thickness was measured in the first step close to the tip of the probe. Inspection method. After the fourth step, further comprising a fifth step of determining whether or not a set time has elapsed since the execution of the first step,
If it is determined in the fifth step that the set time has elapsed since the execution of the first step, the first step, the second step, the third step, and the fifth step, The semiconductor wafer inspection method according to claim 5, wherein inspection is performed on another inspection pad of the semiconductor wafer by sequentially performing the fourth step. A card body disposed with the first surface facing the surface to be inspected of the semiconductor wafer, a probe provided on the first surface and in contact with an inspection pad provided on the surface to be inspected of the semiconductor wafer, A probe card provided at a center and a periphery of the first surface so as to protrude from the first surface and having a position detection protrusion for detecting expansion or contraction of the card body due to a temperature change; A method for inspecting a semiconductor wafer for inspecting,
First coordinates for detecting and storing the coordinates of the probe tip, the coordinates of the tip of the position detection projection, the wafer thickness at an arbitrary point on the wafer surface of the semiconductor wafer, and the wafer diameter of the semiconductor wafer, respectively Process,
A second step of calculating and storing a first distance from the tip of the probe to the surface to be inspected of the semiconductor wafer using the probe tip coordinates and the wafer thickness of the semiconductor wafer stored in the first step. When,
A third step of calculating a moving distance for moving the semiconductor wafer by adding the first distance and the overdrive amount;
A fourth step of inspecting the first inspection pad of the semiconductor wafer by moving the semiconductor wafer by the moving distance;
After the fourth step, a fifth step of preparing for inspection of the second inspection pad of the semiconductor wafer;
After the fifth step, the tip coordinates of the probe, the tip coordinates of the position detection protrusion, the wafer thickness at an arbitrary point in the wafer surface of the semiconductor wafer, and the wafer diameter of the semiconductor wafer, respectively A sixth step of detecting and storing;
Calculating a difference between the detection result in the sixth step and the detection result in the first step, and determining whether the difference is larger than a set value;
If it is determined in the seventh step that the difference is less than or equal to the set value, the fourth step is performed after the seventh step, or the first step and the first step are performed after the seventh step. After passing through the eighth step that widens the time interval between the six steps, the second step, the third step, and the fourth step are performed in order,
A method of inspecting a semiconductor wafer, in which, when it is determined that the difference is larger than the set value in the seventh step, the second step, the third step, and the fourth step are sequentially performed after the seventh step .

Images