TW202027227A - Method for positioning test substrate, probes and inspection unit relative to one another, and tester for carrying out the method - Google Patents

Abstract

The invention relates to a method and a tester (1) for positioning the test substrate (5), probes (6) and inspection unit (9) relative to one another, in which the test substrate (5) and the probes (6) are oriented into a desired position relative to one another at least in the X-Y plane, and the inspection unit (9) is moved in a Z position over the relative position in which the focus of the inspection unit (9) is set onto an observation point on the test substrate (5). In order to make tracking of the inspection unit (9) simpler and faster, the test substrate (5) and the inspection unit (9) are moved synchronously from this starting position in the Z direction such that the focal plane is maintained.

Description

Method for positioning test substrate, probe and inspection unit relative to each other, and detector for performing the method

The invention relates to a method for positioning a test substrate, a probe, and an inspection unit relative to each other, wherein the test substrate and the probe are at least in a required relative position on the XY plane, and the inspection unit is at the Z position above the relative position. Move, wherein the focus of the inspection unit is adjusted to an observation point of the test substrate at the Z position. In addition, the present invention also relates to a detector for performing this method.

Many different electronic components (usually called test substrates) have different characteristics that need to be tested or require special tests. The test substrate under test may be in different manufacturing and integration stages. That is to say, the test objects may be hybrid components, micro-mechanical and micro-optical components, or other similar components of semiconductor wafers that are still on the wafer, have been cut into single components, or have been assembled into simple or complex circuits.

The inspection station for inspecting and inspecting the test substrate is usually also called a detector. The detector has a chuck on which the test substrate can be placed on a surface. The chuck is a accommodating device designed to fix the test substrate, the contact of the test substrate and the inspection conditions, and usually a moving unit is used to make the chuck move in the X, Y, and Z directions.

The detector also includes a plurality of probes fixed on the probe holder. Depending on the test substrate and the test state, a single probe or a probe card with multiple probe tips can be used. The probe holder usually includes a probe fixing plate, wherein the probe fixing plate is arranged above the chuck and carries a single probe fixed by the probe head or a probe card. The probe fixing plate and/or the probe head can also be equipped with a moving unit, which enables the probes to move together or individually at least in the Z direction.

The detector also has an inspection unit whose function is to display the test substrate and the probe tip in an image mode. The inspection unit includes a microscope and/or camera, through which the surface of the test substrate can be viewed in the Z direction. The inspection unit usually also has a moving unit, whose function is to move the objective lens for viewing the test substrate in the Z direction, so as to adjust the focus of the inspection unit to a specific observation point of the test substrate, that is to say, make this observation point clear Imaging, and re-moving to a sufficient distance, such as when the probe is to be replaced.

The moving unit can generally move the aforementioned components independently, for example, the inspection unit can bring the probe tip, the test substrate, or the Z position into focus. The mobile unit usually has a driving device to electrically drive the chuck and/or probe fixing disk or a single probe and/or inspection unit. The electric movement of the components mentioned in the previous sentence is achieved through a correspondingly set control unit.

During the inspection process, the focus of the observation point must be repeated multiple times, including repeated contact of one or more points of the test substrate to complete the required movement in the X, Y, and Z directions. In this process, each new movement will make the required inspection time longer.

In order to form electrical contact, in addition to the mobility on the XY plane, it also needs to be able to move between the probe and the test substrate in the Z direction. The XY plane is defined as the plane where the chuck's receiving surface is located, and usually It is realized through the moving unit of the chuck.

First, at least one moving unit is used to position the probe and the test substrate relative to each other on the X-Y plane, so the probe and the test substrate are separated by a certain height difference from each other. The next movement in the Z direction (hereinafter referred to as Z movement) brings the two into contact. This Z position is called the contact position. After the inspection, a movement in the Z direction makes this contact disappear, and then moves to the next contact position on the X-Y plane.

The Z movement to the contact position can be achieved through the movement of the probe or the movement of the test substrate. The advantage of the probe movement is that it does not change the relative position of the inspection unit lifting the test substrate, so that the focus can be maintained on the contact surface, so even the smallest deviation of the probe tip in the XY direction can be observed continuously The minimum deflection movement of the probe tip mentioned here is caused by putting the probe on, and it is also the movement required to form a stable electrical contact.

Under different circumstances, it is an advantageous practice to move the probe tip in the Z direction to an intermediate position above the test substrate. In this intermediate position, there is a sufficiently large distance between the probe tip and the test substrate. For example, in this case, correction can be made on the X-Y plane, and the probe tip will not be damaged. This intermediate position also allows the X-Y position to be checked and the contact position to be reached manually.

Moving in the Z direction through the chuck is usually an advantageous practice, or due to the way the probe is fixed, it can only be moved in the Z direction through the chuck. But to do so, the inspection unit must be used as an aid, for example, to identify the contact surface of the test substrate. If it is necessary to move to an intermediate position, due to the need for intermediate correction of the second component, chuck, and inspection unit, the time required will accumulate to an unacceptable level with continuously increasing cost-effectiveness and partial or fully automated inspection requirements.

Therefore, it is necessary to simplify and speed up the movement of the inspection unit in the Z direction

At the same time, it is also necessary to maintain the moving speed of the inspection unit on the X-Y plane.

In addition, another requirement is that the final contact position can also be reached by manual control, at least from the intermediate position to the final position.

In order to meet the above requirements, the present invention uses the chuck and the inspection unit to simulate the following effects: when the contact between the test substrate and the probe tip is formed and eliminated, the probe fixing plate and the probe are lifted and lowered, while testing The substrate and inspection unit are not moved. In order to achieve this effect, the idea of the present invention is to start from an initial position, that is, from the position where the focus of the inspection unit is adjusted to an observation point of the test substrate (for example, a contact surface on the test substrate), the test substrate And the inspection unit moves synchronously in the Z direction, so that the test substrate reaches the required final position relative to the probe tip, such as the contact position.

The method of synchronous movement is to maintain the focus plane at least during the Z movement (and also during the elimination of contact if necessary), so that the observation point can be clearly imaged on the test substrate, just like the movement of the probe known from the prior art. This operation mode can be regarded as a virtual movement of the probe fixing plate, and it can be applied to occasions where the probe fixing plate is fixed or its movement is negligible during the inspection process.

The so-called "one" movement in the Z direction includes the entire movement process that needs to be passed in order to reach a sufficient distance in the Z direction, such as the distance between the tip of the contact probe and the test substrate, and a certain section of the entire movement process. For example, this moving segment may be a movement to or from the aforementioned intermediate position, or a movement to or from the test substrate.

The following will describe the features of the concept of the present invention. Those familiar with the art can combine these features in different ways in different implementations, as long as these combinations are reasonable and appropriate for the application to be used.

In the following description of the X, Y, and Z directions, the X and Y directions refer to the horizontal direction, and the Z direction refers to the vertical direction.

The synchronized movement in which the focus plane remains unchanged includes the length and time components of the movement in the Z direction.

The so-called "synchronization" here refers to the movement at the same time, and it also includes the delay caused by the control unit and/or the delay achievable with the conventional computing technology, but the premise is that the commonly used algorithm causes the focus to move (including Automatic movement), and start a corresponding compensation movement.

The test results show that with the current measuring instrument technology, the waiting time (that is, the delay between the start of real movement (such as the movement of the chuck) and the movement following this real movement (such as the movement of the inspection unit) Time) As long as there is 300ms, it is enough to identify the focal plane in time.

For example, the so-called "in time" refers to the detection of the deviation movement caused by the probe tip being placed on the test substrate at a point in time. The time point referred to here means that the probe tip is still in the contact area and/or has not yet caused damage or reached Other unfavorable relative positions in time. The waiting time should be less than 200ms, less than 100ms, less than 50ms, less than 40ms, less than 30ms, less than 20ms, less than 10ms, or preferably less than 5ms. With the larger the size of the electronic components and the greater the performance of the arithmetic, the allowable deviation and the achievable waiting time can be further reduced.

For example, the movement of the chuck and the inspection unit can be performed by the synchronous control signal to realize the synchronous movement of the test substrate and the inspection unit, wherein the aforementioned waiting time can be applied to the time interval of the control signal.

Since the chuck is located on the horizontal receiving surface of the test substrate, the movement of the chuck mentioned below has the same meaning as the movement of the test substrate.

According to an embodiment of the present invention, the movement of the test substrate and the inspection unit in the Z direction can be activated through a manipulator body, which is a component of the manipulator of the probe used. The manipulator body is moved manually, and the movement mode is clearly defined by a movement direction and a movement amount (such as length or angle). An appropriate movement value sensor can be used to measure the movement direction and amount of the manipulator body, so that the movement direction of the chuck and/or inspection unit in the Z direction can be obtained from the movement direction of the manipulator body, and from the manipulator body The amount of movement of the main body calculates the movement length of the chuck and/or the inspection unit in the Z direction.

The chuck or inspection unit moves according to the measured value and the control signal generated from the measured value. At the same time, other detector elements are connected through the control unit according to the arithmetic technology of the two moving units and move synchronously with this initial movement. Depending on the configuration of the inspection device, other methods can also be used to connect the two movements together, as long as these methods allow simultaneous movements. For example, the initial movement can be performed by the chuck, and then the inspection unit moves accordingly. It is also possible to determine the other movement sequence or the movement of the two components according to the control signal generated from the measured value.

In order to realize the synchronous movement of the test substrate and the inspection unit, the manipulator can be connected with the two mobile units, so that when the manipulator is moved electrically, the manipulator can be driven by the two mobile units, and control is generated according to the measurement value of the movement sensor of the manipulator Signal to control the mobile unit.

Another way is that the manipulator only has a direct function relationship with one of the two mobile units. In this way, the second moving unit performs a compensation movement in the Z direction.

Another embodiment is to move the manipulator body manually. Another way is to move the manipulator body through an appropriate manipulator control device.

One possible way of movement of the manipulator body is to rotate around a rotation axis. The rotation direction of the manipulator body (clockwise or counterclockwise) determines the direction of movement in the Z direction (upward or downward movement), and the angle of rotation determines whether the stroke (that is, the movement in the Z direction) is positive or negative.

According to another embodiment, one or more stops can be used to limit the movement of the manipulator body. The stop can limit the amount of movement, and the amount of movement can be defined by the contact position. Similarly, as with the minimum interval position, the stop position can also be used to define the frequently used starting position, intermediate position and final position.

The moving axes of the chuck and the inspection unit in the Z direction are not always completely parallel to each other. According to one method, in order to compensate for the resulting change in the X-Y relative position between the observation point of the test substrate and the focus of the inspection unit, the deviation caused by the Z movement should be calculated and compensated through the movement unit. This method also applies to the waiting time described above with respect to synchronized movement.

The X-Y deviation (herein referred to as linear compensation) can be compensated through an additional movement of at least one of the two elements in the X-Y direction according to the moving direction and the degree of deviation during or after the execution of the Z-direction movement. For example, when the test substrate moves in the X-Y direction, it is best to compensate during the movement and before the probe tip is placed on the test substrate to avoid damage to the contact surface afterwards.

Another way is to compensate after the Z movement. As long as the inspection unit is moved, it will not affect the relative position between the test substrate and the probe holder.

The amount of deviation can be obtained from the distance between the two components that are still in contact during the Z movement. When the Z movement is not performed in a parallel manner, this distance will cause a deviation of the field of view relative to the test substrate. This deviation can be seen from the top view. The same as the deviation during the synchronous Z movement, the deviation can be calculated on-site by known methods (such as the mode recognition method or observing the spatial position of the two components or other appropriate measures).

Another method is to find the Z-axis position from previous movement or detector analysis. In any case, linear compensation can be compensated by reverse movement during or after Z movement.

In addition to the aforementioned chuck, probe and related fixing device and inspection unit, the detector used to perform the method of the present invention also has a positioning device. The positioning device has a moving unit, and at least one of the moving units is For the chuck, the other moving unit is used for the inspection unit to perform at least the movement of the chuck and the inspection unit in the Z direction. In addition, there is at least one control unit, whose function is to control the two moving units so that the movement of the chuck and the inspection unit can be synchronized in the manner described above. Another way is that each mobile unit is equipped with a control unit, and these control units are communicatively connected with each other to perform synchronous movement.

Synchronous movement keeps the focus plane unchanged, so the observation point can maintain a clear image on the test substrate.

According to one embodiment, the positioning device of the detector includes a manipulator whose function is to move the chuck or the inspection unit.

The manipulator includes a manipulator body, an operating element for moving the manipulator body, and a movement value sensor. A movement direction and movement amount can be clearly measured from the movement of the manipulator body.

According to a configuration of the manipulator, if the manipulator has exactly one degree of freedom of movement, it can be ensured that the manipulator has a clear direction of movement.

According to another configuration of the manipulator, the manipulator body is a rotating body that can rotate about its rotation axis.

The manipulator can be operated through an appropriate operating element, wherein the operating element matches the operating mode (manual or machine operation) and movement mode (for example, rotation or offset) of the manipulator body.

The movement direction and amount of movement can be obtained through the movement sensor of the manipulator. According to the form of the movement sensor and the required movement, the relative position of the movement sensor and the manipulator body is determined. Taking the rotating body as an example, the movement value sensor is a rotation value sensor whose function is to measure the direction of rotation and the angle of rotation. For example, in this case, the rotation value sensor can be arranged on the axis of the rotating body. Another way is to use more than one movement sensor to find the required measurement value. These measured values (pre-processed if necessary) are transmitted to at least one control unit.

The control unit generates a control signal according to the measured value to control the movement of the chuck or the inspection unit (or the chuck and the inspection unit) in the Z direction in the manner described above. To achieve this goal, the movement value sensor and the control unit are connected in communication with each other.

According to another embodiment of the detector, the manipulator has at least one stop to limit the movement of the manipulator body. According to an advantageous manner, the stop is variable and/or can be adjusted to a specific distance in the Z direction. Since the stop gear can be adjusted, the stop gear can be manually moved to different final positions and intermediate positions. The at least one stop may be a piece of hardware on the manipulator, or it may be a piece of software (for example, a piece of software installed in the control unit).

According to the method of the present invention, it may be necessary to linearly compensate the relative position of the chuck and the inspection unit in the X-Y direction to ensure that the required image segment can always be obtained. To achieve this goal, the detector with linear compensation has at least one moving unit that can enter and exit the chuck or inspection unit, and its function is to move its components in X and Y directions in addition to Z movement. Another way is that both components can be selectively connected to the mobile unit. In addition, a hardware or software control unit can be installed, which is used to control at least one moving unit in the X, Y, and Z directions.

The detector 1 in FIG. 1 includes a chuck 2 with a moving unit 3. The chuck 2 can move in the X, Y, and Z directions. These directions are shown in Figure 1 for a standard system. There is a test substrate 5, such as a wafer, on the horizontal receiving surface 4 above the detector. The probe head 7 fixed on the probe 6 will touch the wafer. The probe head is arranged on a fixed needle control disk 8.

When the inspection unit 9 (such as a camera) looks in the Z direction from above, the test substrate 5 can be seen, that is, an observation point that can be clearly imaged can be seen. The inspection unit 9 also has a moving unit 10, and the moving unit 10 enables the inspection unit 9 to also move in the X, Y, and Z directions, or at least in the Z direction.

In order to explain the dynamic stability of the movable element and its moving element or bracket (in this example, the chuck 2 and the inspection element 9 and its moving units 3, 10, and the probe head 7 and its probe fixing plate 8, Figure 1 shows that these elements are Fixed, that is, statically determinate to a common coordinate system (horizontal hatching).

For example, a feasible (but not necessarily) way is to communicate with the two mobile units 3, 10 and a common control unit 11, where the control unit 11 can be a piece of hardware or software.

As shown in Fig. 1, the probe 6 is in contact with the test substrate 5, and the chuck 2 is moved to a contact position K _C. The inspection unit 9 is also located at its contact position K _I. The focus of the inspection unit 9 is located on the surface of the wafer 5, that is, adjusted to the tip of the probe 6 located thereon.

If the contact is released, the chuck 2 will move downward (as indicated by the arrow in the figure). At this time, the inspection unit 9 will synchronously move down the same distance in the Z direction (as shown by the same arrow length in the figure). These two movements may respectively reach an intermediate position Z _C and Z _I (respectively indicated by a dashed line on the receiving surface 4 of the chuck 2 and the lower edge of the inspection unit 9), or reach a final position E _C and E _I respectively (respectively A dash-dotted line indicates the receiving surface 4 of the chuck 2 and the lower edge of the inspection unit 9). Since the chuck 2 and the inspection unit 9 move synchronously, during the movement of the chuck 2, the adjusted observation point on the test substrate 5 (in this example, a contact surface of the wafer currently or previously touched by the probe tip) 12 A deep position is always kept in a clearly visible state.

In the intermediate position Z _C or the final position E _C , the chuck 2 can be moved in the X and/or Y direction to move to another electronic component of the wafer, while still making contact through the probe 6.

For example, in order to contact the next sub-element, the wafer 5 is raised by the chuck 2 to an intermediate position Z _C. The Z coordinate of this intermediate position Z _C may coincide with the Z coordinate of the intermediate position of each electronic component of the wafer 5 before and after. Then the chuck 2 moves to the contact position K _{C again} .

The control unit 11 will synchronously generate the control signal of the moving chuck 2 and the control signal of the moving inspection unit 10, first reaching the intermediate position Z _I analogous to the inspection unit, and then reaching the contact position K _I.

2A and 2B show an example of the manipulator 13 whose function is to move the chuck 2. In these two figures, the same elements of the manipulator are marked with the same element symbols.

The manipulator 13 itself is manually operated and controls the electric movement of the chuck.

The manipulator 13 includes a manipulator body 20 composed of a cylindrical rotating body. The manipulator body is mounted in a housing 21 in a rotatable manner.

The manipulator body 20 is mounted on the operating element 23 via a suitable connector 22 (Figure 2B). In this embodiment, the operating element 23 is a joystick 23. The manipulator body 20 can be manually turned clockwise and counterclockwise through the joystick 23. The hour hand turns. Such a joystick 23 can also be applied to cause other movements of the manipulator body of other embodiments. The joystick 23 is guided into a frame 25, wherein the contour of the joystick 23 and the contour of the frame 25 are adapted to each other.

In addition, through the brake 24, the operating force and the operating torque of the manipulator body 20 can be changed, and the sensitivity of the manipulator body 20 can be changed. In this embodiment, two brakes 24 are provided, which can apply an adjustable force to the outer surface of the cylindrical manipulator body 20.

A movement value sensor 26 aligned with the axis of the manipulator body 20 is provided beside the manipulator body 20. In this embodiment, it is a rotation value sensor, and its function is to measure the rotation direction and the rotation angle. These measured values (optionally pre-processed) are transmitted to the control unit 11 via a signal transmitter 28 (FIG. 1).

The manipulator body 20 and the rotation sensor 26 installed on the detector (FIG. 1) are protected by the outer cover 27 and protected from the outside influence.

Fig. 3 shows another embodiment of the manipulator body 30. According to this embodiment, the manipulator body 30 is composed of a knob 31, wherein the knob 31 can be locked at a specific angular position. The knob 31 can rotate around its own axis 32. There are three radial notches 34 on the outer surface 33 of the knob 31, and the tube needle 35 can be inserted into the three notches 34. The tube needle 35 enters one of the notches 34 through a guiding slit 37 of the guiding plate 36 arranged concentrically with the knob 31, and the rotation range of the knob 31 by the tube needle is limited by the length of the guiding slit 37. If another notch 34 is used, another rotation can be performed, so that the length of movement that can be performed through the moving units 3, 10 can be changed.

Manipulators or stops of other embodiments can also be used. If the detector has a plurality of manipulators with different functions, it can be designed to distinguish different manipulators by the difference in tactile sense.

1: Detector 2: Chuck 3, 10: Moving unit 4: Receiving surface 5: Test substrate, wafer 6: Probe 7: Probe head 8: Probe fixing plate 9: Inspection unit 11: Control unit 12: Observation point 13: Manipulator 20, 30: Manipulator body 21: Housing 22: Connector 23: Operating element, joystick 24: Brake 25: Frame 26: Movement value sensor, rotation value sensor 27: Cover 28: Signal transmitter 31: Knob 32: Shaft 33: Outer surface 34: Notch 35: Tube needle 36: Guide plate 37: Guide gap K _C , K _I : Contact position Z _C , Z _I : Intermediate position E _C , E _I : Final Position X, Y, Z: direction

Hereinafter, the present invention will be further described in conjunction with the drawings and embodiments. among them: Figure 1: A detector with important components of the present invention. Figures 2A and 2B: a three-dimensional perspective detail view of an embodiment of the manipulator, including a complete view and a partial view. Figure 3: A manipulator body with adjustable stops. The above-mentioned drawings only show what is needed to explain the present invention in a schematic manner. The above drawings do not emphasize the completeness of the content, nor are they drawn to scale.

1: detector

2: chuck

3.10: mobile unit

4: containing surface

5: Test substrate, wafer

6: Probe

7: Probe head

8: Probe fixing plate

9: Inspection unit

11: Control unit

12: Observation point

13: Manipulator

K _C , K _I : contact position

Z _C : middle position

E _C , E _I : final position

X, Y, Z: direction

Claims (13)

A method for positioning a test substrate, a probe, and an inspection unit relative to each other, wherein the test substrate and the probe are at least at a required relative position on the XY plane, and the inspection unit is in the relative position The upper Z position moves, where the focus of the inspection unit is adjusted to an observation point of the test substrate at the Z position. The characteristic is that starting from this initial position, the test substrate and the inspection unit move in the Z direction synchronously to Keep the focus plane. Such as the method of claim 1, characterized in that: the movement of a test substrate and an inspection unit in the Z direction is activated through a manipulator body that moves manually, wherein the movement direction and amount of movement of the manipulator body are measured, and the To find the direction of movement in the Z direction and the length of movement in the Z direction. For example, the method of claim 1 or claim 2, which is characterized by: starting a test substrate and an inspection unit to move in the Z direction through a rotating manipulator body, wherein the rotation direction and angle of rotation of the manipulator body are measured, and According to this, the movement direction in the Z direction and the movement length in the Z direction are obtained. The method according to any one of the foregoing claims is characterized in that the movement of the manipulator body is restricted through at least one selectable stop. Such as the method of claim 6, characterized in that the at least one stop is adjusted for the distance to be moved. The method according to any one of the preceding claims, characterized in that: during or after the Z movement of a test substrate and an inspection unit, the deviation of a relative position between the test substrate and the inspection unit in the XY direction is performed Linear compensation. The method according to any one of the preceding claims is characterized by observing the maintenance of the relative position in the X-Y direction between a focusing plane and/or a test substrate and an inspection unit on site, and compensating for the confirmed deviation. A detector for inspecting a test substrate, having a chuck for accommodating and supporting the test substrate, a probe for contacting the test substrate, and an inspection for focusing and imaging an observation point of the test substrate during the inspection process Unit, and a positioning device for a movable chuck and inspection unit, characterized in that: the positioning device has a moving unit and at least one control unit, wherein the function of the moving unit is to move the chuck and the inspection unit at least in the Z direction The function of the control unit is to control the moving unit so that the chuck and the inspection unit move synchronously in the Z direction with the focus plane unchanged. The detector of claim 8, characterized in that: the positioning device has a manipulator including a manipulator body, an operating element for moving the manipulator body, and a movement value sensor, wherein the movement value sensor has a structure and The setting method relative to the manipulator body makes it possible to measure the movement mode and range of the manipulator body. At the same time, the manipulator communicates with a control unit to generate the chuck and/or inspection unit in the Z direction according to the measurement A control signal for value movement. For example, the detector of claim 9 is characterized in that the manipulator body has exactly one degree of freedom of movement. For example, the detector of claim 9 or claim 10 is characterized in that: the manipulator body is a rotating body, and the movement value sensor is a rotation value sensor. For example, the detector of any one of claim 9 to claim 11 is characterized in that the manipulator has at least one stop to restrict the movement of the manipulator body. For example, the detector of any one of claim 8 to claim 12 is characterized in that: the detector has at least one moving unit and a control unit, wherein the function of the moving unit is to make the chuck and/or the inspection unit Moving in the XY direction, the control unit functions to obtain an adjusted XY relative position and/or an adjusted Z relative position deviation between an observation point of the test substrate and the focus of an inspection unit.

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