JP6674103B2 - Prober - Google Patents

Description

  The present invention relates to a prober for performing an electrical inspection of a plurality of chips formed on a semiconductor wafer.

  In a semiconductor manufacturing process, various processes are performed on a thin disk-shaped semiconductor wafer to form a plurality of chips (dies) each having a semiconductor device (device). Each chip is inspected for its electrical characteristics, then cut off with a dicer, and fixed to a lead frame or the like to be assembled. The inspection of the electrical characteristics is performed by a wafer test system including a prober and a tester. The prober fixes the wafer to the wafer chuck, and brings the probe into contact with the electrode of each chip. The tester is electrically connected to the probe, and applies current or voltage to each chip for electrical inspection and measures characteristics.

  2. Description of the Related Art Semiconductor devices such as power transistors, power MOSFETs (field effect transistors), IGBTs (Insulated Gate Bipolar Transistors), LEDs, and semiconductor lasers generally have electrodes (chip surface electrodes) formed on the surface of a wafer. An electrode (chip back electrode) is also formed on the back surface of the wafer. For example, in an IGBT, a gate electrode and an emitter electrode are formed on the front surface of a wafer, and a collector electrode is formed on the back surface of the wafer.

  Since a wafer level inspection is performed on a wafer having a plurality of chips having electrodes on both surfaces of the wafer as described above, the wafer chuck is held in a state in which the back surface of the wafer is in contact with the wafer, and a conductive electrode serving as a measurement electrode of the tester A support surface (wafer mounting surface) is provided. This support surface is electrically connected to a tester via a cable pulled out of the wafer chuck. When the inspection is performed, various measurements are performed while the wafer is held on a wafer chuck and a probe is brought into contact with an electrode of each chip (chip surface electrode) formed on the surface of the wafer. I have.

  However, the cable connecting between the wafer chuck and the tester is disposed in a state where the cable is routed inside and outside the housing via a connector provided on the side surface or the back surface of the housing constituting the prober. The length is usually required to be about 1 to 3 m. As a result, the electrical path formed between the electrode on the backside of the chip and the tester is lengthened, and its resistance and inductance are increased. As a result, measurement errors in high-frequency measurement and dynamic measurement occur, and wafer-level inspection can be performed with the required accuracy. There is a problem that can not be performed properly.

  In order to solve such a problem, for example, Patent Literature 1 discloses a chuck lead plate provided so as to face a conductive support surface of a wafer chuck, and a pogo pin fixed to a peripheral portion of the wafer chuck. Are described. According to this inspection device, since the electric path formed between the chip back surface electrode and the tester is configured via the pogo pin and the chuck lead plate, the electric path is generated in the electric path as compared with the conventional configuration described above. Resistance and inductance can be reduced.

  However, in the inspection device described in Patent Document 1, since the pogo pins are fixed to the wafer chuck, the length of the electrical path between the chip back electrode and the tester changes depending on the position of the chip to be inspected on the wafer. . For example, the length of the electric path differs between when inspecting a chip near the center of the wafer and when inspecting a chip near the edge of the wafer. For this reason, the resistance or impedance generated in the electric path changes according to the position of the chip to be inspected on the wafer, which has an adverse effect on high-frequency measurement and dynamic measurement, making it impossible to perform wafer-level inspection with high accuracy. There is a problem.

  In order to solve such a problem, the present applicant has a configuration in which a contact fixed at a position facing the stage member electrically contacts a conductive stage member moving integrally with the wafer chuck. (See Patent Document 2). According to this prober, the resistance and impedance in the electric path formed between the chip rear surface electrode and the tester are small and have little variation without being affected by the position of the chip to be inspected on the wafer, so that high-frequency measurement and Dynamic measurement can be performed stably, and wafer-level inspection can be performed with high accuracy.

JP 2011-138865 A JP 2014-110381 A

  By the way, in the prober proposed by the present applicant, since the stage member moves integrally with the wafer chuck, the height of the contact is adjusted according to the height (contact height) of the wafer chuck at the time of probe contact. There is a need to. In particular, there are many types of probe holders represented by, for example, a probe card and the like, and since the length of the probe is various, when the probe holder is exchanged due to setup change or the like, the contact height is increased each time. In addition, the height of the contact must be adjusted, which causes a reduction in work efficiency and an increase in cost. Also, if the height of the contact is not properly adjusted, the contact pressure of the contact with the stage member will vary, and the resistance and impedance in the electric path formed between the chip back electrode and the tester will change. As a result, the accuracy of the wafer level inspection is reduced.

  SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has a prober capable of improving work efficiency and reducing costs, and performing high-frequency measurement and wafer-level inspection of dynamic characteristics with high accuracy. The purpose is to provide.

  To achieve the above object, a prober according to a first aspect of the present invention is a wafer chuck for holding a wafer on which a plurality of chips having electrodes on both sides are formed, and a chip back electrode formed on the back surface of the wafer. A wafer chuck having a conductive support surface that contacts the wafer, a moving and rotating mechanism that moves and rotates the wafer chuck, and connects the chip surface electrode to the terminal of the tester by contacting the chip surface electrode formed on the surface of the wafer A probe holding unit having a probe, a probe position detection camera for detecting the height of the tip of the probe in the probe holding unit, a wafer alignment camera for detecting the position of a chip surface electrode of a wafer held on a wafer chuck, and a wafer alignment Based on a first elevating mechanism for moving the camera up and down and a detection result of the probe position detection camera, A control unit for controlling the first elevating mechanism so that the height of the tip of the lobe and the focal position of the wafer alignment camera are the same; and a control unit formed parallel to the support surface and electrically connected to the support surface. A stage member having an electrically conductive stage surface and moving integrally with the wafer chuck, and being configured to be movable integrally with the wafer alignment camera. And a conductive contact to be connected.

  According to this aspect, since the conductive contact is configured to be movable integrally with the wafer alignment camera, the height of the probe tip (probing height) and the focal position of the wafer alignment camera (alignment height) The height of the tip of the conductive contact (contact height) is always in a constant positional relationship with the probing height by moving the wafer alignment camera up and down so that the height is the same. Therefore, even if the length of the probe changes when the probe holder is replaced, the height adjustment of the conductive contact is not required, so that it is possible to improve the working efficiency and reduce the cost. Also, even if the probing height changes, the contact pressure of the stage member with respect to the conductive contact is always constant, so it is possible to suppress changes in resistance and inductance due to variations in the contact pressure. As a result, the wafer level inspection can be performed with high accuracy.

  A prober according to a second aspect of the present invention is the prober according to the first aspect, further comprising a second elevating mechanism for changing a relative height of the conductive contact with respect to the wafer alignment camera.

  According to this aspect, even when the wafer chuck moves to the alignment area where the wafer alignment camera is arranged, the relative height of the conductive contact with respect to the wafer alignment camera can be changed by the second elevating mechanism. In addition, it is possible to prevent the conductive contacts from interfering with the wafer chuck or the wafer held thereon.

  A prober according to a third aspect of the present invention is a wafer chuck for holding a wafer on which a plurality of chips having electrodes on both surfaces are formed, and a conductive support surface that contacts a chip back surface electrode formed on the back surface of the wafer. A wafer chuck having a moving and rotating mechanism for moving and rotating the wafer chuck, a probe holding unit having a probe that contacts the chip surface electrode formed on the surface of the wafer and connects the chip surface electrode to the terminal of the tester, A probe position detection camera for detecting the height of the tip of the probe of the probe holding unit, a wafer alignment camera for detecting the position of the chip surface electrode of the wafer held on the wafer chuck, and a second step for vertically moving the wafer alignment camera. 1 The height of the tip of the probe and the A control unit for controlling the first elevating mechanism so that the focal position of the alignment camera is at the same height; and a conductive stage surface formed parallel to the support surface and electrically connected to the support surface. A stage member that moves integrally with the wafer chuck, a head stage on which the probe holding unit is mounted, and a head stage that is provided movably in the up-down direction, and that contacts the stage surface to apply the chip back surface electrode to the tester. A conductive contact that is electrically connected; and a second elevating mechanism that moves the conductive contact up and down.

  According to this aspect, since the conductive contact is configured to be movable independently (separately) from the wafer alignment camera, the height of the probe tip (probing height) and the focal position of the wafer alignment camera By moving the wafer alignment camera up and down so that (alignment height) is the same height, and further by moving the conductive contact up and down in the same movement direction and amount as the wafer alignment camera, The height of the tip of the sex contact (contact height) always has a fixed positional relationship with the probing height. Therefore, even if the length of the probe changes when the probe holder is replaced, the positional relationship between the wafer alignment camera and the conductive contact is kept constant, thereby improving work efficiency and reducing cost. Reduction can be achieved. Also, even if the probing height changes, the contact pressure of the stage member with respect to the conductive contact is always constant, so it is possible to suppress changes in resistance and inductance due to variations in the contact pressure. As a result, the wafer level inspection can be performed with high accuracy. Furthermore, since the conductive contact is provided on the head stage so as to be movable in the vertical direction, the wiring length of the wiring connecting between the tester body fixed (mounted) to the head stage and the conductive contact is provided. Can be shortened.

  A prober according to a fourth aspect of the present invention is the prober according to any one of the first aspect to the third aspect, wherein the stage member is configured to be separated from the wafer chuck, and the stage surface and the support surface are connected via a wiring member. And are electrically connected.

  This embodiment is a preferred embodiment of the present invention. According to this aspect, since the stage member is thermally separated from the wafer chuck, even when the wafer chuck is heated or cooled during a wafer level inspection, a change in the temperature of the wafer chuck is less likely to be transferred to the stage member and the heat insulating effect is obtained. Is obtained, energy efficiency is good, and thermal deformation of the stage member is prevented. Thus, the conductive contact always comes into contact with the stage surface of the stage member with a constant contact pressure without changing the contact position (height in the Z direction) of the conductive contact with the stage surface of the stage member. it can. Therefore, the measurement accuracy and reliability of the wafer level inspection can be improved without being affected by the temperature change of the wafer chuck.

  A prober according to a fifth aspect of the present invention is the prober according to any one of the first to third aspects, wherein the stage member is integrally formed with the wafer chuck.

  This embodiment shows one of the specific embodiments of the present invention. That is, the stage member may be integrally formed with the wafer chuck, and the effect in the first aspect described above can be obtained.

  The prober according to a sixth aspect of the present invention is the prober according to any one of the first to fifth aspects, wherein the stage member is a conductive contact when the probe contacts the chip surface electrode in a movable range of the wafer chuck. Are configured to be able to always contact the stage surface.

  According to this aspect, irrespective of the position of the wafer chuck, when the probe comes into contact with the chip surface electrode, the contact is always configured to be able to contact the stage surface of the stage member, so that the wafer level inspection is performed stably and reliably. It becomes possible.

  ADVANTAGE OF THE INVENTION According to this invention, improvement of work efficiency and cost reduction can be aimed at, and high-frequency measurement and wafer level inspection of dynamic characteristics can be performed with high precision.

Schematic configuration diagram showing a wafer test system according to the first embodiment Plan view showing relationship between wafer chuck and stage member Flow chart showing the flow of the wafer level inspection of the first embodiment FIG. 3 is a view for explaining each step shown in FIG. 3. FIG. 3 is a view for explaining each step shown in FIG. 3. FIG. 3 is a view for explaining each step shown in FIG. 3. FIG. 3 is a view for explaining each step shown in FIG. 3. FIG. 3 is a view for explaining each step shown in FIG. 3. Diagram showing the relationship between the alignment height and the probing height when the probe height of the probe card is different Schematic configuration diagram showing a wafer test system according to a second embodiment Flow chart showing the flow of the wafer level inspection of the second embodiment Diagram for explaining each step shown in FIG. Diagram for explaining each step shown in FIG. Diagram for explaining each step shown in FIG. Diagram for explaining each step shown in FIG. Diagram for explaining each step shown in FIG. Explanatory diagram of a first modified example Explanatory diagram of a second modified example

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

(First embodiment)
First, a first embodiment will be described.

  FIG. 1 is a schematic configuration diagram illustrating a wafer test system 100 according to the first embodiment.

  As shown in FIG. 1, a wafer test system 100 includes a prober 10 for bringing a probe 25 into contact with an electrode of each chip on a wafer W, and a probe 25 electrically connected to the probe 25. And a tester 30 for measuring characteristics by applying a voltage.

  The prober 10 includes a base 11, a moving base 12 provided thereon, a Y-axis moving table 13, an X-axis moving table 14, a Z-axis moving / rotating unit 15, a wafer chuck 16, a probe position, A detection camera 18, a wafer alignment camera 19, a head stage 22, a card holder 23 provided on the head stage 22, a probe card 24 attached to the card holder 23, and a control unit 60 for controlling each part of the prober 10. And The probe card 24 is provided with a probe 25.

  The movement base 12, the Y-axis movement table 13, the X-axis movement table 14, and the Z-axis movement / rotation unit 15 constitute a movement rotation mechanism that rotates the wafer chuck 16 in three directions and around the Z axis. Since the moving and rotating mechanism is widely known, the description is omitted here.

  The wafer chuck 16 holds a wafer W on which a plurality of chips are formed by vacuum suction, and has a conductive support surface (wafer mounting surface) 16a acting as a measurement electrode of the tester 30 provided on an upper surface thereof. Can be Further, inside the wafer chuck 16, a heating / cooling source is used as a heating / cooling source so that chips can be inspected in a high temperature state, for example, at a maximum of 150 ° C., or in a low temperature state, for example, a minimum of −40 ° C. / Cooling mechanism (heating / cooling mechanism). As the heating / cooling mechanism, a known appropriate heater / cooler can be adopted. For example, a heating / cooling mechanism having a double layer structure of a heating layer of a surface heater and a cooling layer provided with a passage of a cooling fluid, Various devices are conceivable, such as a single-layer heating / cooling device in which a cooling pipe in which a heater is wound around a heat conductor is embedded. Instead of electric heating, a heat fluid may be circulated, or a Peltier element may be used.

  The wafer chuck 16 is mounted on the Z-axis moving / rotating unit 15, is movable in the three-axis directions (X, Y, Z directions) by the above-described moving / rotating mechanism, and rotates in the direction around the Z-axis. (Θ direction).

  A probe card 24 is arranged above the wafer chuck 16 holding the wafer W. The probe card 24 has a card holder 23 attached to an opening of a head stage 22 constituting a top plate of a housing of the prober 10.

  The probe card 24 has a probe 25 arranged according to the electrode arrangement of the chip to be inspected, and is exchanged according to the chip to be inspected. The probe card 24 is an example of a probe holding unit.

  The tester 30 includes a tester main body 31 and a contact ring 32 provided on the tester main body 31. The probe card 24 is provided with a terminal connected to each probe 25, and the contact ring 32 has a spring probe arranged so as to contact the terminal. The tester main body 31 is held on the prober 10 by a support mechanism (not shown).

  The probe position detecting camera 18 is mounted on the X-axis moving table 14, and can move in the XY directions integrally with the wafer chuck 16 by the X-axis moving table 14 and the Y-axis moving table 13. The probe position detection camera 18 images the probe 25 of the probe card 24 from below, and detects the tip position of the probe 25. The position (X and Y coordinates) of the tip of the probe 25 in the horizontal plane is detected by the coordinates of the camera, and the position in the vertical direction (Z direction), that is, the height of the tip of the probe 25 (probing height) is the focal position of the camera. Is detected by The detection result by the probe position detection camera 18 is input to the control unit 60.

  The wafer alignment camera 19 is arranged in an alignment area adjacent to the probe area where the probe card 24 is arranged. The wafer alignment camera 19 is supported by a column (not shown), and can be moved in the Z direction (up and down direction) by a camera elevating mechanism (first elevating mechanism) 40. The camera elevating mechanism 40 may be any known linear moving mechanism, for example, a linear guide mechanism, a ball screw mechanism, or the like, and is driven by an output from the control unit 60. The wafer alignment camera 19 captures an image of the wafer W held on the wafer chuck 16 from above, and detects the position of a chip electrode (chip surface electrode) formed on the surface of the wafer W. The detection result by the wafer alignment camera 19 is input to the control unit 60. The control unit 60 uses the well-known image processing technology based on the information obtained by the wafer alignment camera 19 and the position information of the tip of the probe 25 obtained by the probe position detection camera 18 to form the probe 25 and the wafer. Two-dimensional positional alignment of the W chip electrode (chip surface electrode) in the XY plane is automatically performed.

  The prober 10 of the first embodiment further includes a stage member 50 formed of a disc-shaped separation structure formed separately from the wafer chuck 16 in addition to the above-described configuration.

  The stage member 50 is disposed at a position adjacent to the wafer chuck 16, is fixedly connected to the Z-axis moving / rotating unit 15 via an L-shaped connecting member 52, and is integrated with the wafer chuck 16 to form a three-axis unit. It is possible to move in the directions (X, Y, Z directions).

  Further, as a material forming the stage member 50, a material having a small coefficient of thermal expansion such as ceramics is preferable. By forming the stage member 50 from a material having a small coefficient of thermal expansion, even when the wafer chuck 16 is heated and cooled during a wafer level inspection, thermal deformation of the stage member 50 can be prevented. Thereby, the measurement accuracy and reliability of the wafer level inspection can be improved without being affected by the temperature change of the wafer chuck 16.

  On the upper surface of the stage member 50, a conductive stage surface 50a to which a conductive contact 70 described later can contact is provided. As shown in FIG. 2, the stage surface 50a has the same planar shape (circular shape) as the support surface 16a of the wafer chuck 16, and their areas (plane areas) are equal to each other. The stage surface 50a may have a larger area (planar area) than the support surface 16a of the wafer chuck 16, and may be formed in a shape other than a circle.

  A plurality of wirings 64 (wiring members) are provided between the stage member 50 and the wafer chuck 16. In this example, three wirings 64 are provided. One end of each wiring 64 is electrically connected to the stage surface 50 a of the stage member 50, and the other end is electrically connected to the support surface 16 a of the wafer chuck 16. That is, electrical conduction is secured between the stage surface 50 a of the stage member 50 and the support surface 16 a of the wafer chuck 16 by the plurality of wirings 64.

  Returning to FIG. 1, a conductive contact 70 is provided at a position facing the stage member 50. The conductive contact 70 is made of, for example, a conductive thin needle (spring pin) having a spring property, and is electrically connected to the tester main body 31 via a cable 76.

  The conductive contact 70 is held and fixed at a predetermined height position by a holder 74 described later, and when the wafer chuck 16 moves up and the probe 25 contacts the chip surface electrode of the wafer W (that is, the wafer chuck 16). Moves to the contact height), and electrically contacts the stage surface 50a of the stage member 50 with a predetermined contact pressure. Accordingly, when performing various measurements in a state where the probe 25 is in contact with the chip surface electrode formed on the surface of the wafer W, the chip back surface electrode formed on the back surface of the wafer W is attached to the wafer chuck 16 (support surface 16a). ), The wiring 64, the stage member 50 (stage surface 50 a), the conductive contact 70, and the cable 76 are electrically connected to the tester main body 31.

  In the first embodiment, the conductive contact 70 is attached to the wafer alignment camera 19 and is configured to be movable integrally with the wafer alignment camera 19. Specifically, the wafer alignment camera 19 is provided with a Z table 72 that can be moved in the Z direction (vertical direction) by a contact lifting mechanism (second lifting mechanism) 78. A holder 74 for holding and fixing the sex contact 70 is attached. Therefore, the conductive contact 70 can be moved in the Z direction integrally with the wafer alignment camera 19 by the camera lifting mechanism 40, and the conductive contact 70 can be moved relative to the wafer alignment camera 19 by the contact lifting mechanism 78. It is possible to change the target height. The contact lifting mechanism 78 is configured by a known linear moving mechanism such as a linear guide mechanism and a ball screw mechanism, similarly to the camera lifting mechanism 40 described above.

  Next, a wafer level inspection by the wafer test system 100 according to the first embodiment will be described with reference to FIGS. FIG. 3 is a flowchart showing the flow of the wafer level inspection. 4 to 8 are views for explaining each step shown in FIG. 4 to 8 show only the main parts of the wafer test system 100 in an extracted manner. The position of the conductive contact 70 relative to the wafer alignment camera 19 can be moved between the retracted position (upper end position) and the contact position (lower end position) by the contact elevating mechanism 78. Is adjusted in advance so that the tip of the conductive contact 70 (the tip on the side of the stage member 50) coincides with the height of the focal position (alignment height) of the wafer alignment camera 19 when is moved to the contact position. I do.

(Step S10: Probing height detection step)
First, as shown in FIG. 4, the probe position detection camera 18 is moved together with the wafer chuck 16 so that the probe position detection camera 18 is located below the probe card 24, and the probe position detection camera 18 is used to move the height of the tip of the probe 25. (Probing height) h0 is detected. The detection result by the probe position detection camera 18 is input to the control unit 60.

(Step S12: wafer transfer step)
Next, the wafer W to be inspected is loaded on the wafer chuck 16 by a wafer loading mechanism (not shown), and the wafer chuck 16 holds the wafer W.

(Step S14: alignment height adjustment step)
Next, as shown in FIG. 5, while holding the wafer W on the wafer chuck 16, the wafer chuck 16 is moved so that the wafer W is positioned below the wafer alignment camera 19, and then the control unit 60 When the height (alignment height) of the focal position of the wafer alignment camera 19 is h1, the camera elevating mechanism 40 of the wafer alignment camera 19 is controlled to set the wafer alignment camera 19 by Δh (= h1−h0). Is moved in the Z direction. Thereby, as shown in FIG. 6, the probing height h0 and the alignment height h1 become the same.

  Subsequently, as shown in FIG. 7, the control unit 60 controls the wafer chuck so that the wafer W held by the wafer chuck 16 is positioned at the alignment height (ie, the height of the focal position of the wafer alignment camera 19). 16 is moved in the Z direction. At this time, in order to prevent interference with the wafer W held on the wafer chuck 16 or its upper surface (support surface 16a), the control unit 60 moves the Z table 72 in the Z direction by the contact lift mechanism 78, and controls the conductive member. The sex contact 70 is moved to a retreat position where it does not contact the wafer chuck 16 or the wafer W.

(Step S16: Wafer alignment step)
Next, the position of the chip electrode (chip surface electrode) on the wafer W is detected by the wafer alignment camera 19. It is not necessary to detect the positions of all the electrodes of one chip, and it is sufficient to detect the positions of some of the electrodes. Further, it is not necessary to detect the electrodes of all the chips on the wafer W, and the positions of the electrodes of some chips are detected. The detection result by the wafer alignment camera 19 is input to the control unit 60.

  Subsequently, based on the information obtained by the wafer alignment camera 19 and the position information of the tip of the probe 25 obtained by the probe position detection camera 18, the control unit 60 Two-dimensional alignment of the chip electrodes (chip surface electrodes) on the XY plane with the chip 25 on the wafer W is automatically performed. That is, after detecting the position of the probe 25 and the position of the electrode of the chip on the wafer W, the control unit 60 adjusts the Z-axis movement / rotation unit 15 so that the arrangement direction of the chip electrode matches the arrangement direction of the probe 25. Rotates the wafer chuck 16.

(Step S18: Probing process)
Next, the control unit 60 temporarily lowers the wafer chuck 16 slightly in the Z direction, and then moves the wafer W held by the wafer chuck 16 below the probe card 24 as shown in FIG. Then, the wafer chuck 16 is moved. Thereafter, the wafer chuck 16 is raised in the Z direction to the height immediately before lowering the wafer chuck 16 in the Z direction, that is, the height of the tip of the probe 25 (probing height) which is the same height as the alignment height, and the chip to be inspected on the wafer W Is brought into contact with the probe 25.

  At this time, the stage member 50 arranged adjacent to the wafer chuck 16 moves to a position facing the conductive contact 70 integrally with the wafer chuck 16. Further, the control section 60 controls the contact lift mechanism 78 in conjunction with (synchronous with) the movement of the wafer chuck 16, so that the conductive contact 70 relative to the wafer alignment camera 19 becomes a contact position. The sex contact 70 is moved. As a result, the conductive contact 70 comes into contact with the stage surface 50a of the stage member 50 at a predetermined contact pressure, and the chip back surface electrode formed on the back surface of the wafer W includes the wafer chuck 16 (support surface 16a), the wiring 64, The stage member 50 (stage surface 50 a), the conductive contacts 70, and the cable 76 are electrically connected to the tester main body 31. Then, a current or voltage is applied to the chip from the tester main body 31 to measure the characteristics.

  When the inspection of the chip is completed, the wafer W and the probe 25 are once separated, and the other chips are moved so as to be located under the probe 25, and the same operation is performed. Hereinafter, each chip is sequentially selected and inspected. When the inspection of all the specified chips on the wafer W is completed, the inspection of one wafer W is completed.

  When the inspection of all the chips on the wafer W is completed in this manner, the inspection of the wafer W is completed, the inspected wafer W is unloaded, the next wafer W to be inspected is loaded, and the above operation is performed. I do.

  Next, effects of the first embodiment will be described.

  FIG. 9 is a diagram showing the relationship between the alignment height and the probing height when the length of the probe 25 of the probe card 24 is different. (A) shows a case where the length of the probe 25 is short, and (b) shows a case where the length of the probe 25 is long.

  In the first embodiment, as shown in FIGS. 9A and 9B, even when the length of the probe 25 changes when the probe card 24 is replaced, the probing height and the alignment height are the same. Since the wafer alignment camera 19 moves so that the position of the tip of the probe 25 after the alignment of the wafer W and the electrode pad of the chip of the wafer W need only be performed within the XY plane, the wafer alignment camera 19 moves in the Z direction. Errors can be reduced. On the other hand, when the probing height is different from the alignment height, the position alignment in the Z direction must be performed after the alignment of the wafer W, and a tilt error or a twist error of the Z moving / rotating unit 15 may occur. This causes the positioning accuracy to deteriorate.

  According to the first embodiment, the conductive contact 70 is attached to the wafer alignment camera 19, and the conductive contact 70 moves integrally with the wafer alignment camera 19. For this reason, by adjusting the positional relationship with the wafer alignment camera 19 in advance when the conductive contact 70 is attached, even if the length of the probe 25 changes when the probe card 24 is replaced, the probing height and the probing height can be reduced. By moving the wafer alignment camera 19 in the Z direction so that the alignment height is the same, the height of the tip of the conductive contact 70 always has a fixed positional relationship with the height of the tip of the probe 25. Therefore, even when the probe card 24 is replaced, the adjustment of the conductive contact 70 is not required, so that the working efficiency can be improved and the cost can be reduced.

  Further, according to the first embodiment, since the conductive contact 70 is configured to be relatively movable with respect to the wafer alignment camera 19 between the retracted position and the contact position, the conductive contact 70 is provided at the time of wafer alignment. By moving the child 70 to the retreat position, interference with the wafer W or the wafer chuck 16 can be prevented.

  Further, according to the first embodiment, even if the position of the chip to be inspected on the wafer W changes, the distance from the position to the position on the stage member 50 with which the conductive contact 70 contacts is always constant. Become. Therefore, irrespective of the position of the chip to be inspected on the wafer W, the wafer chuck 16 (support surface 16 a), the wiring 64, the stage member 50 (stage surface 50 a), the conductive contact 70, and the cable 76 are transferred from the chip back surface electrode. Since the length of the electric path connected to the tester main body 31 through the electric path is always constant, high-frequency measurement and dynamic measurement can be performed stably without being affected by resistance or impedance in the electric path. Wafer level inspection can be performed with high accuracy.

  Further, according to the first embodiment, the stage member 50 is configured to be separated from the wafer chuck 16 separately, and the stage member 50 is thermally separated from the wafer chuck 16. For this reason, even when the wafer chuck 16 is heated and cooled during the wafer level inspection, the temperature change of the wafer chuck 16 is hardly transmitted to the stage member 50 and an adiabatic effect is obtained, so that the energy efficiency is high and the stage member 50 Is prevented from being thermally deformed. As a result, the contact position (position in the Z direction) of the conductive member 70 with respect to the stage surface 50a of the stage member 50 does not change, and the conductive contact 70 is always kept at a constant contact pressure by the stage surface 50a of the stage member 50. Can abut. Therefore, the measurement accuracy and reliability of the wafer level inspection can be improved without being affected by the temperature change of the wafer chuck 16.

  Further, according to the first embodiment, since the wafer chuck 16 and the stage member 50 are configured separately from each other, the conventional wafer chuck 16 can be reused, and It is possible to shorten the period and the manufacturing process, reduce the design labor, reduce the cost, and the like.

(Second embodiment)
Next, a second embodiment will be described.

  FIG. 10 is a schematic configuration diagram illustrating a wafer test system 100A according to the second embodiment. 10, the same reference numerals are given to the components common or similar to those in FIG. 1, and the description thereof will be omitted.

  In the second embodiment, as shown in FIG. 10, the conductive contact 70 is attached to (separated from) the head stage 22 independently of the wafer alignment camera 19, and a contact lift mechanism ( It is configured to be movable in the Z direction (vertical direction) by a second elevating mechanism (78). Specifically, the head stage 22 is provided with a Z table 72 that can be moved in the Z direction (vertical direction) by a contact elevating mechanism 78, and the Z table 72 holds and fixes the conductive contact 70. A holder 74 is mounted. Thus, the conductive contact 70 is configured to be movable in the Z direction independently of the wafer alignment camera 19 by the contact lift mechanism 78. The contact lifting mechanism 78 is configured by a known linear moving mechanism such as a linear guide mechanism and a ball screw mechanism, as in the first embodiment.

  Next, a wafer level inspection performed by the wafer test system 100A according to the second embodiment will be described with reference to FIGS. FIG. 11 is a flowchart showing the flow of the wafer level inspection. In FIG. 11, processes common to those in FIG. 3 are denoted by the same reference numerals. FIGS. 12 to 16 are views for explaining the respective steps shown in FIG. FIGS. 12 to 16 show only the main parts of the wafer test system 100A. The position of the conductive contact 70 relative to the head stage 22 can be moved between the retracted position (upper end position) and the contact position (lower end position) by the contact elevating mechanism 78. It is assumed that the tip of the conductive contact 70 (the tip on the side of the stage member 50) is adjusted in advance so as to coincide with the height of the focal position (alignment height) of the wafer alignment camera 19 when moving to the contact position. . Hereinafter, although the description partially overlaps with that of the first embodiment, it will be described again.

(Step S10: Probing height detection step)
First, as shown in FIG. 12, the probe position detecting camera 18 is moved together with the wafer chuck 16 so that the probe position detecting camera 18 is positioned below the probe card 24, and the probe position detecting camera 18 moves the probe position detecting camera 18 to the height of the tip of the probe 25. (Probing height) h0 is detected. The detection result by the probe position detection camera 18 is input to the control unit 60.

(Step S12: wafer transfer step)
Next, the wafer W to be inspected is loaded on the wafer chuck 16 by a wafer loading mechanism (not shown), and the wafer chuck 16 holds the wafer W.

(Step S14A: alignment height adjustment step)
Next, as shown in FIG. 13, after moving the wafer chuck 16 so that the wafer W is positioned below the wafer alignment camera 19 while holding the wafer W on the wafer chuck 16, the control unit 60 When the height (alignment height) of the focal position of the wafer alignment camera 19 is h1, the camera elevating mechanism 40 of the wafer alignment camera 19 is controlled to set the wafer alignment camera 19 by Δh (= h1−h0). Is moved in the Z direction. As a result, as shown in FIG. 14, the probing height h0 and the alignment height h1 become the same.

  Further, the control unit 60 controls the contact lift mechanism 78 to move the conductive contact 70 in the same movement direction and movement amount (Δh) as the wafer alignment camera 19. Thereby, even after the wafer alignment camera 19 moves in the Z direction, the height (contact height) of the tip of the conductive contact 70 (tip on the side of the stage member 50) is the alignment height (that is, the probing height). Will be matched.

  Subsequently, as shown in FIG. 15, the control unit 60 controls the wafer chuck so that the wafer W held by the wafer chuck 16 is positioned at the alignment height (that is, the height of the focal position of the wafer alignment camera 19). 16 is moved in the Z direction. At this time, in order to prevent interference with the wafer W held on the wafer chuck 16 or its upper surface (support surface 16a), the control unit 60 moves the Z table 72 in the Z direction by the contact lift mechanism 78, and controls the conductive member. The sex contact 70 is moved to a retreat position where it does not contact the wafer chuck 16 or the wafer W.

(Step S18: Probing process)
Next, the control unit 60 temporarily lowers the wafer chuck 16 slightly in the Z direction, and then moves the wafer W held by the wafer chuck 16 under the probe card 24 as shown in FIG. Then, the wafer chuck 16 is moved. Thereafter, the wafer chuck 16 is raised in the Z direction to the height immediately before lowering the wafer chuck 16 in the Z direction, that is, the height of the tip of the probe 25 (probing height) which is the same height as the alignment height, and the chip to be inspected on the wafer W Is brought into contact with the probe 25.

  At this time, the stage member 50 arranged adjacent to the wafer chuck 16 moves to a position facing the conductive contact 70 integrally with the wafer chuck 16. Further, the control unit 60 controls the contact lift mechanism 78 in conjunction with (synchronous with) the movement of the wafer chuck 16 so that the conductive contact 70 relative to the head stage 22 becomes a contact position. The contact 70 is moved. As a result, the conductive contact 70 comes into contact with the stage surface 50a of the stage member 50 at a predetermined contact pressure, and the chip back surface electrode formed on the back surface of the wafer W includes the wafer chuck 16 (support surface 16a), the wiring 64, The stage member 50 (stage surface 50 a), the conductive contacts 70, and the cable 76 are electrically connected to the tester main body 31. Then, a current or voltage is applied to the chip from the tester main body 31 to measure the characteristics.

  When the inspection of the chip is completed, the wafer W and the probe 25 are once separated, and the other chips are moved so as to be located under the probe 25, and the same operation is performed. Hereinafter, each chip is sequentially selected and inspected. When the inspection of all the specified chips on the wafer W is completed, the inspection of one wafer W is completed.

  When the inspection of all the chips on the wafer W is completed in this manner, the inspection of the wafer W is completed, the inspected wafer W is unloaded, the next wafer W to be inspected is loaded, and the above operation is performed. I do.

  Next, effects of the second embodiment will be described.

  In the second embodiment, the same effects as those of the first embodiment can be obtained, and the conductive contact 70 is attached to the head stage 22 independently (separated) from the wafer alignment camera 19, so that the conductive contact 70 is provided. The wiring length of the wiring (cable 76) connecting between the sex contact 70 and the tester main body 31 can be shortened.

  That is, the head stage 22 is mounted so as to be openable and closable with the back side of the paper surface of FIG. 10 as a fulcrum, and the tester body 31 fixed (mounted) to the head stage 22 also opens and closes integrally with the head stage 22. However, in the case of the configuration in which the conductive contact 70 is attached to the wafer alignment camera 19 as in the first embodiment, the movement of the tester main body 31 accompanying opening and closing of the head stage 22 is also taken into consideration. It is necessary to provide an extra length for the wiring connecting between the conductive contact 70 and the tester main body 31. On the other hand, in the second embodiment, since the conductive contact 70 is attached to the head stage 22, the wiring length of the wiring connecting between the conductive contact 70 and the tester main body 31 can be reduced. The effect described above can be obtained.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above examples, and various improvements and modifications may be made without departing from the spirit of the present invention. . Hereinafter, some modified examples will be described.

[Modification 1]
In each of the above-described embodiments, the stage member 50 is configured separately from the wafer chuck 16, but the stage member 50 may be configured integrally with the wafer chuck 16.

  For example, in the modification shown in FIG. 17, the stage member 50 is integrated with the wafer chuck 16. Further, in this modification, the stage member 50 is configured to be rotatable around a rotation shaft 54 provided at an end thereof (an end on the wafer chuck side). That is, the stage member 50 is configured to be rotatable around the Y axis (the direction perpendicular to the paper surface), and the stage surface 50a is arranged in parallel to the support surface 16a of the wafer chuck 16 (FIG. 10). , And a state of being vertically arranged (shown by a broken line in FIG. 10).

  According to the aspect in which the stage member 50 is configured to be foldable, the same operation and effect as those of the above-described embodiments can be obtained, and the stage member 50 can be folded at the time of loading or unloading or alignment of the wafer W. The operable range of the wafer chuck 16 can be enlarged by moving the wafer chuck 16 in a state where the wafer chuck 16 is in a folded state (shown by a broken line in FIG. 17). In addition, a larger wafer chuck 16 can be mounted, and a wafer level inspection can be performed on a large-diameter wafer W.

[Modification 2]
In each of the above-described embodiments, as shown in FIG. 2, the stage surface 50a of the stage member 50 has the same shape and the same area as the support surface 16a of the wafer chuck 16, but at least in the movable range of the wafer chuck 16. The conductive contact 70 may have a different shape or area as long as it has a stage surface 50a that can always contact. For example, the stage surface 50a of the stage member 50 may have the same planar shape (circular shape) as the support surface 16a of the wafer chuck 16, and may have an area larger than the support surface 16a. In addition, as shown in FIG. 18, the side surface of the stage member 50 on the wafer chuck 16 side may be formed in a concave shape along the side surface of the wafer chuck 16. In any of the aspects, the conductive contact 70 has the stage surface 50a with which the conductive contact 70 can always contact at least in the movable range of the wafer chuck 16, and the same effects as those of the above-described embodiments can be obtained.

[Modification 3]
In each of the above-described embodiments, the spring pin is used as the conductive contact 70 that can contact the stage surface 50a of the stage member 50. However, the present invention is not limited to this. For example, a probe card-like contact such as a cantilever type or a vertical needle type is used. A child may be used.

[Modification 4]
In each of the above-described embodiments, the configuration in which the probe card 24 is provided as the probe holding unit has been described. However, the configuration is not limited thereto, and for example, a manipulator-type probe head may be provided.

  Reference Signs List 10: prober, 11: base, 12: moving base, 13: Y-axis moving table, 14: X-axis moving table, 15: Z-axis moving / rotating unit, 16: wafer chuck, 16a: support surface, 18: probe Position detection camera, 19: alignment camera, 22: head stage, 23: card holder, 24: probe card, 25: probe, 30: tester, 31: tester body, 32: contact ring, 40: camera lifting mechanism, 50: Stage member, 50a Stage surface, 52 Connection member, 60 Control part, 64 Wiring, 70 Conductive contact, 72 Z table, 74 Holder, 76 Cable, 78 Contact lift mechanism, 100 ... Wafer test system, 100A ... Wafer test system

Claims (6)

A wafer chuck that holds a wafer on which a plurality of chips having electrodes on both sides are formed, and a wafer chuck having a conductive support surface that contacts a chip back surface electrode formed on the back surface of the wafer.
A moving and rotating mechanism for moving and rotating the wafer chuck,
A probe holder having a probe that contacts the chip surface electrode formed on the surface of the wafer and connects the chip surface electrode to a terminal of a tester;
A probe position detection camera that detects the height of the tip of the probe of the probe holding unit,
A wafer alignment camera for detecting a position of the chip surface electrode of the wafer held by the wafer chuck,
A first elevating mechanism for vertically elevating the wafer alignment camera,
A control unit that controls the first elevating mechanism so that the height of the tip of the probe and the focal position of the wafer alignment camera are the same, based on the detection result of the probe position detection camera;
A stage member formed parallel to the support surface and having a conductive stage surface electrically connected to the support surface, and integrally moving with the wafer chuck;
A conductive contact configured to be movable integrally with the wafer alignment camera and electrically connecting the chip rear surface electrode to the tester by contacting the stage surface;
A prober with   The prober according to claim 1, further comprising a second lifting mechanism that changes a height of the conductive contact relative to the wafer alignment camera. A wafer chuck that holds a wafer on which a plurality of chips having electrodes on both sides are formed, and a wafer chuck having a conductive support surface that contacts a chip back surface electrode formed on the back surface of the wafer.
A moving and rotating mechanism for moving and rotating the wafer chuck,
A probe holder having a probe that contacts the chip surface electrode formed on the surface of the wafer and connects the chip surface electrode to a terminal of a tester;
A probe position detection camera that detects the height of the tip of the probe of the probe holding unit,
A wafer alignment camera for detecting a position of the chip surface electrode of the wafer held by the wafer chuck,
A first elevating mechanism for vertically elevating the wafer alignment camera,
A control unit that controls the first elevating mechanism so that the height of the tip of the probe and the focal position of the wafer alignment camera are the same, based on the detection result of the probe position detection camera;
A stage member formed parallel to the support surface and having a conductive stage surface electrically connected to the support surface, and integrally moving with the wafer chuck;
A head stage on which the probe holding unit is mounted,
A conductive contact that is provided movably in the up-down direction on the head stage and contacts the stage surface to electrically connect the chip back surface electrode to the tester;
A second elevating mechanism for vertically elevating the conductive contact,
A prober with   The prober according to any one of claims 1 to 3, wherein the stage member is configured separately from the wafer chuck, and the stage surface and the support surface are electrically connected via a wiring member. .   The prober according to claim 1, wherein the stage member is configured integrally with the wafer chuck.   6. The stage member according to claim 1, wherein the conductive contact is always in contact with the stage surface when the probe contacts the chip surface electrode in a movable range of the wafer chuck. The prober according to claim 1.

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