JP2010034418A - Wafer resistivity measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a work burden of a user and to maintain an environment inside an instrument in mounting a cleaning wafer when cleaning a four-needle probe. <P>SOLUTION: A wafer resistivity measuring instrument includes: a measuring stage on which a wafer is placed; a rotary driving section for rotating the measuring stage; a four-needle probe for measuring the wafer; a driving section for driving the four-needle probe; a feeding section for feeding a wafer for cleaning to the measuring stage; and a control section in which, when it is determined that cleaning of the four-needle probe is required, used coordinates of the cleaning wafer are read from a storage region, cleaning is performed while bringing the four-needle probe into contact with the wafer on coordinates different from the used coordinates, and coordinate information used for the contact is updated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wafer resistivity measuring apparatus using four probe probes, and more particularly to a wafer resistivity measuring apparatus having a function of automatically cleaning four probe probes.

  In recent years, with the widespread use of semiconductors, many problems have been imposed on semiconductor wafer measurement apparatuses. For example, literatures that refer to methods related to cleaning of four-probe probes are known. Since the 4-probe resistivity measuring device in which the 4-probe probe is used is designed to measure the resistivity by bringing the probe into contact with the semiconductor wafer, a part of the semiconductor wafer is attached to the tip of the probe during the measurement. If the deposit or the deposit is oxidized, the contact state between the probe and the semiconductor wafer becomes unstable. Such deposits may affect the reproducibility of measurement values and measurement accuracy, and a cleaning operation for removing such deposits is required.

  Patent Document 1 discloses a technique for improving the efficiency of probe cleaning work. When a cleaning mode is selected, the probe is idled on a cleaning wafer to remove attached foreign matter and perform cleaning. Is disclosed.

JP-A-10-107104.

However, in Patent Document 1, the user must manually clean the cleaning wafer by blanking the probe, and the user has to manage the cleaning position.
An object of the present invention is to provide a wafer resistivity measuring apparatus that automatically manages the cleaning position of a cleaning wafer in cleaning a four-probe probe.

One embodiment for solving the problem is:
A measurement stage on which the wafer is placed;
A rotation drive unit for rotating the measurement stage;
A four-probe probe for measuring the electrical resistivity of the wafer placed on the measurement stage;
A drive unit for driving the four-probe probe;
A transfer unit for transferring a cleaning wafer to the measurement stage;
A controller connected to the drive unit, the rotation drive unit, and the transport unit;
When the cleaning unit is moved to and placed on the measurement stage using the transfer unit, the control unit reads out coordinate information of a position used for cleaning the cleaning wafer from a storage area and uses the cleaning wafer. Cleaning is performed by bringing the four probe probes into contact with the cleaning wafer by the driving unit and the rotation driving unit at coordinates different from the coordinates of the completed positions, and coordinate information used for the contact is stored in the storage area. A wafer resistivity measuring apparatus that is updated.

  Provided is a wafer resistivity measuring apparatus capable of easily improving the cleaning efficiency by automatically managing the cleaning position of a cleaning wafer in cleaning of a four-probe probe used for measuring the four-probe resistivity.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a plan view showing an example of the configuration of a wafer resistivity measuring apparatus according to an embodiment of the present invention, FIG. 2 is a three-dimensional view showing an example of the configuration of a wafer resistivity measuring apparatus, and FIG. It is a block diagram which shows an example of a structure of a rate measuring device.

(First embodiment: With cleaning wafer storage)
-Configuration First, the configuration of a wafer resistivity measuring apparatus according to an embodiment of the present invention will be described below. As shown in FIGS. 1 to 3, the wafer resistivity measuring device 10 includes a measuring device chamber 11 that blocks outside air, an open / close door 20 provided in the measuring device chamber 11, and a FOUP (Front (Opening Unified Pod) 41 and the like, a load port 12, a door 25 provided between the load port 12 and the measuring device chamber 11, and a transfer unit 13 having a transfer arm 14. Here, the transfer unit 13 can transfer a wafer W such as a silicon wafer in the FOUP 41. Further, the load port 12 is a private chamber, and a load port door 25 is provided between the load port 12 and the measuring device chamber 11.

Further, outside the measuring apparatus room 11, a storage place 42 (stocker or the like) for storing a plurality of FOUPs 41 and an automatic transfer system 43 in the factory for transferring the FOUP 41 between the load port 12 and the storage place 42 are provided. ing.
Further, the wafer resistivity measuring apparatus 10 includes a measurement stage 16 for placing a wafer, a four-probe probe 17 for applying a current and detecting a voltage value, for example, to measure the electrical characteristics of the wafer, and a later-described probe probe 17. A position sensor 27 for positioning by detecting a notch portion of the wafer mounted on the measurement stage 16 connected to the control unit 30 and a cleaning wafer CW for cleaning the four probe probes 17 are mounted. It has a cleaning wafer place 15 which is a place for placing and storing. Further, a cover-shaped measuring instrument door 26 is provided for dust protection covering the measurement stage, the four-probe probe 17, the probe horizontal drive unit 18, and the probe vertical drive unit 19.

  Further, the electrical connection will be mainly described with reference to the block diagram of FIG. 3. The wafer resistivity measuring apparatus 10 includes a control unit 30 that controls the overall mechanical operation and measurement processing, and a power source that supplies power to each unit. A display unit 21 connected to the control unit 30 and displaying operation information and measurement information on a display screen; and a rotation drive unit 24 connected to the control unit 30 and rotating the measurement stage 16.

  Further, the wafer resistivity measuring apparatus 10 is connected to the control unit 30 to drive the four-probe probe 17 in the vertical direction, and connected to the control unit 30 to drive the four-probe probe 17 in the horizontal direction. Measurement processing by supplying a measurement current to the probe horizontal drive unit 18 to be operated, an operation unit 22 for supplying an operation signal to the control unit 30 according to an operation from a user, and detecting a measurement voltage by supplying a measurement current to the four-probe probe 17 And an I / F unit 31 connected to the control unit 30 and communicating with the host computer H shown in FIG.

Cleaning Process The operation of the automatic cleaning process in the wafer resistivity measuring apparatus 10 will be described in detail with reference to the flowcharts of FIGS. FIG. 4 is a flowchart showing an example of the cleaning process of the wafer resistivity measuring apparatus, and FIG. 5 is a flowchart showing an example of a subroutine of the cleaning process.

  Such a wafer resistivity measuring apparatus 10 transfers the FOUP 41 from the storage location 42 to the load port 12 by the automatic transfer system 43 in the factory in accordance with an operation signal from the operation unit 22 under the control of the control unit 30 (step). S11). Furthermore, the door 25 of the load port is opened under the control of the control unit 30, the wafer W is transferred from the FOUP 41 using the transfer unit 13, the door 26 of the measuring instrument is opened, and it is placed on the measurement stage 16 (step) S12). At this time, the control unit 30 detects the notch portion of the wafer by the position sensor 27 and performs alignment by the rotation drive unit 24 and the like. Further, under the control of the control unit 30, the four-probe probe 17 is moved onto the wafer W by the probe horizontal driving unit 18 and the probe vertical driving unit 19. Then, under the control of the control unit 30, a measurement process is performed by supplying a measurement current from the resistivity measurement unit 23 via the four-probe probe 17 and detecting a measurement voltage (step S13). The measurement result of the wafer W is displayed on the display unit 21 together with the operation information. Under the control of the control unit 30, the measuring device door 26 is opened, the wafer W is taken out from the measurement stage 16, the door 25 of the load port 12 is opened, and the transfer unit 13 is used for transfer to the FOUP 41 (step S14).

  Next, when the control unit 30 confirms that the probe cleaning conditions (probe contact count, number of wafers, etc.) registered in the measurement recipe have been reached in advance, it determines that cleaning is required (step). S15). At this time, the control unit 30 displays a warning on the display unit 21 that automatic cleaning is necessary because the number of times the four-probe probe has been used reaches a predetermined number. It is also preferable to notify the host computer H or the like connected to the I / F unit 31. The control unit 30 opens the door 26 of the measuring instrument, and transfers the cleaning wafer CW from the cleaning wafer place 15 to the measurement stage 16 using the transfer unit 13 (step S16). The control unit 30 detects the cutout portion of the cleaning wafer CW with the position sensor 27 and performs alignment with the rotation drive unit 24 and the like. The control unit 30 changes the position of the four-probe probe 17 with the probe horizontal drive unit 18, the probe vertical drive unit 19, and the rotation drive unit 24, and brings the four-probe probe 17 into contact with the cleaning wafer CW, thereby making the four-probe probe. The deposit on the tip 17 is automatically cleaned, and details will be described later with reference to the flowchart of FIG. 5 (step S17).

When cleaning is completed, the controller 30 opens the door 26 of the measuring instrument, and transports the cleaning wafer CW from the measurement stage 16 to the cleaning wafer storage 15 using the transport unit 13 (step S18). Finally, the control unit 30 unloads the FOUP 41 from the load port 12 to the storage location 42 by the automatic transfer system 43 in the factory and ends the process.
Here, the details of the cleaning process will be described in detail with reference to the subroutine of FIG. First, the control unit 30 detects the notch portion of the cleaning wafer CW by the position sensor 27 and performs alignment by the rotation drive unit 24 and the like. The control unit 30 obtains the cleaning start coordinates (R, θ) from the memory provided in the control unit 30 (step S21). The control unit 30 recognizes and manages the management information of the plurality of cleaning wafers CW in the memory, and updates the already used coordinate information (R, θ) of each cleaning wafer CW. When a new cleaning is started, a new start coordinate (R, θ) is determined so as not to use the same coordinate. Thus, the cleaning sheet CS of the cleaning wafer CW is managed so as not to be contaminated.

  And the control part 30 moves to the starting coordinate of cleaning by changing the position of the 4-probe probe 17 with the probe horizontal drive part 18 and the rotation drive part 24 (step S22). The control unit 30 performs cleaning by lowering the four-probe probe 17 by the probe vertical drive unit 19 and bringing it into contact with the cleaning sheet (step S23). Next, the control unit 30 raises the four-probe probe 17 by the probe vertical drive unit 19 (step S24).

  Next, the control unit 30 updates the four-probe probe 17 by 0.1 degrees in the θ direction by the rotation driving unit 24 (step S25). Here, if the control unit 30 determines that the measurement stage 16 has already been rotated 360 degrees in the θ direction (step S26), the probe horizontal drive unit 18 moves the 4-probe probe 17 by 0.1 mm in the R direction. The contact portion is not updated to be repeated (step S27). Next, in order to avoid the cleaning process at the same location on the cleaning wafer, the control unit 30 updates and stores the probe start coordinates (R, θ) previously performed in the memory as history information (step S28). .

  Then, the control unit 30 determines whether or not the number of cleaning processes has reached the specified number (step S29), and if not, returns to step S21 and continues cleaning. As described above, the cleaning wafer CW is brought into contact with the cleaning sheet by moving the four probe probes up and down in the same manner as in the measurement using the four probe probes, and the contact with the cleaning sheet is about 50 times as an example. is there. If the number of times of contact has reached the predetermined number, the control unit 30 moves the four-probe probe 17 to the HOME position and ends the cleaning (step S30).

  As shown in FIG. 6, this cleaning wafer CW has, as an example, a circular cleaning sheet CS having a diameter of 50 mm attached to the wafer. Here, an effective area α indicated by diagonal lines effective for cleaning is an area having an inner diameter of 5 mm to an inner diameter of 15 mm as an example. The reason is that overlapping of dents frequently occurs in the vicinity of the center, and it is assumed that the damage to the cleaning sheet CS is large. Therefore, the start position of the effective area α is set to 5.0 mm. In addition, since the cleaning area CS is manually pasted on the cleaning wafer CW at the end position of the effective area α, it is considered that there is an error in the pasting position (about ± 2 mm). About 10.0 mm.

  Further, the control unit 30 registers management information of the cleaning wafer CW for managing the cleaning sheet CS in the memory. The control unit 30 manages a plurality of cleaning wafers CW for each name, and updates and manages the usage status of each cleaning sheet CS by using coordinates before use, thereby avoiding duplicate use of the same location. Yes.

Since the cleaning process in the first embodiment can be performed in the measurement process that involves loading and unloading of the FOUP 41, the cleaning conditions (the number of probe contacts, the number of wafers, etc.) are registered in the measurement recipe. Is preferred.
In the cleaning process in the second embodiment to be described later, it is necessary to carry in / out the dedicated FOUP 41-2 to / from the cleaning wafer CW independently of the measurement process. Therefore, it is preferable to provide a dedicated cleaning recipe. is there.

(Second Embodiment: No Cleaning Wafer Place)
In the second embodiment, as shown in FIG. 7, since the cleaning wafer storage 15 cannot be provided by providing the notch aligner 44 as a configuration of the wafer resistivity measuring apparatus 10, at least one cleaning wafer CW is stored. The case where the cleaning process is performed using the dedicated FOUP 41-2 is specified.

  The configuration of the wafer resistivity measuring apparatus specified by the second embodiment will be described below with reference to FIG. Although the configuration of the wafer resistivity measuring apparatus 10 is basically the same as that shown in FIG. 1, the cleaning wafer place 15 cannot be provided by providing the notch aligner 44. The notch aligner 44 has a function of automatically detecting the groove of the wafer and recognizing the direction of the wafer.

  Therefore, a dedicated FOUP 41-2 for storing the cleaning wafer CW must be prepared in, for example, the storage location 42 as shown in FIG. Further, as shown in FIG. 9, the control unit 30 manages which FOUP is a dedicated FOUP 41-2 for the cleaning wafer, and at what level of the dedicated FOUP 41-2 the cleaning wafer CW is stored. It is necessary to store information in a memory or the like.

Operation The cleaning process of the wafer resistivity measuring apparatus 10 according to the second embodiment will be described in detail with reference to the flowchart of FIG. FIG. 8 is a flowchart showing an example of a cleaning process performed in another configuration (with a notch aligner) of the wafer resistivity measuring apparatus.

  In the cleaning process of the second embodiment, a dedicated FOUP 41-2 for storing the cleaning wafer CW must be used. Therefore, basically, it is necessary to start the cleaning process by unloading the normal FOUP 41 for the wafer W and loading the dedicated FOUP 41-2 for the cleaning wafer. Therefore, it is more convenient to perform processing with a dedicated cleaning recipe than to include the cleaning processing in the measurement recipe as in the cleaning processing of the first embodiment.

  That is, in the flowchart of FIG. 8, the wafer resistivity measuring apparatus 10 firstly, the control unit 30 determines that the current usage status of the wafer resistivity measuring apparatus 10 is a pre-registered probe cleaning condition (probe of probe). It is determined whether or not cleaning has been performed (step S40). In the case of the second embodiment, this cleaning condition is desirably managed by an independent cleaning recipe rather than being a part of the measurement recipe. At this time, the control unit 30 displays a warning on the display unit 21 that automatic cleaning is necessary because the number of times the four-probe probe has been used reaches a predetermined number. It is also preferable to notify the host computer H or the like connected to the control unit 30. If the control unit 30 determines that it should be cleaned, the process proceeds to step S47.

  If the controller 30 determines that it should not be cleaned, cleaning is not performed, and if there is an instruction signal to be measured, normal measurement processing is performed. Under the control of the control unit 30, the FOUP 41 is transported from the storage location 42 to the load port 12 by the automatic transport system 43 in the factory in accordance with the operation signal from the operation unit 22 (step S41). Further, under the control of the control unit 30, the door 25 of the load port 12 is opened, the wafer W is taken out from the FOUP 41 by the transfer unit 13, the measuring device door 26 is opened, and the wafer W is placed on the notch aligner 44. After aligning the orientation, the sample is conveyed and placed on the measurement stage 16 (step S42). Further, under the control of the control unit 30, the four-probe probe 17 is moved onto the wafer W by the probe horizontal driving unit 18 and the probe vertical driving unit 19. Then, under the control of the control unit 30, a measurement process is performed by supplying a measurement current from the resistivity measurement unit 23 via the four-probe probe 17 and detecting a measurement voltage (step S43). The measurement result of the wafer W is displayed on the display unit 21 together with the operation information. Under the control of the control unit 30, the measuring device door 26 is opened, the wafer W is taken out from the measurement stage 16, the door 25 of the load port 12 is opened, and the wafer is transferred to the FOUP 41 using the transfer unit 13 (step S44). . Further, the FOUP 41 is carried out from the load port 12 to the storage place 42 by the automatic transfer system 43 in the factory (step S45).

  Next, the control unit 30 again checks whether the current usage status of the wafer resistivity measuring apparatus 10 has reached the previously registered probe cleaning conditions (the number of probe contacts, the number of wafers, etc.). Judgment is made (step S46). If it is determined that there is no need for cleaning, the process is terminated. If it is determined that cleaning is necessary, the control unit 30 displays a warning on the display unit 21 that automatic cleaning is necessary, for example, when the number of times the four-probe probe has been used has reached a predetermined number. It is also preferable to notify the host computer H or the like connected to the control unit 30.

  Then, the control unit 30 carries the dedicated FOUP 41-2 for storing the cleaning wafer CW from the storage location 42 to the load port 12 by the automatic transfer system 43 in the factory (step S47). Then, the control unit 30 opens the door 25 of the load port 12 by the transfer unit 13 and takes out the cleaning wafer CW from the FOUP 41-2, opens the door 26 of the measuring instrument, and places the cleaning wafer CW on the notch aligner 44 to clean the cleaning wafer. After aligning the CW direction, the cleaning wafer CW is transferred to the measurement stage 16 (step S48). The control unit 30 changes the position of the four-probe probe 17 with the probe horizontal driving unit 18, the probe vertical driving unit 19, and the rotation driving unit 24, thereby bringing the four-probe probe 17 into contact with the cleaning wafer CW and four probes. The probe is cleaned (step S49). The details of this cleaning process are shown in the flowchart of FIG.

  When cleaning is completed, the control unit 30 opens the door 26 of the measuring instrument, takes out the cleaning wafer CW from the measurement stage 16 by the transport unit 13, opens the door 25 of the load port 12, and transports it to the FOUP 41-2 ( Step S50). And the control part 30 carries out FOUP 41-2 from the load port 12 to the storage place 42 by the automatic conveyance system 43 in a factory, and complete | finishes a process (step S51).

  As described above, in the second embodiment, the cleaning process for the four-probe probe 17 is performed using the cleaning wafer CW stored in the dedicated FOUP 41-2. For each cleaning wafer CW of the dedicated FOUP 41-2, the control unit 30 reliably updates to the memory how each coordinate of the cleaning wafer CW was used for cleaning. Thus, it is preferable that the coordinate information is easily and automatically managed so that the four-probe probe 17 does not contact the same location a plurality of times when performing the cleaning process.

  As described above, according to the embodiment of the present invention, the automatic cleaning process of the four-probe probe 17 makes it possible to reduce the work burden on the operator and maintain the internal environment (cleanness, differential pressure, etc.). The probe 17 can be realized. In addition, it is possible to handle a 300 mm automated line. In addition, good measurement accuracy is possible by reducing the burden on the operator and preventing human error.

  With the various embodiments described above, those skilled in the art can realize the present invention. However, it is easy for those skilled in the art to come up with various modifications of these embodiments, and have the inventive ability. It is possible to apply to various embodiments at least. Therefore, the present invention covers a wide range consistent with the disclosed principle and novel features, and is not limited to the above-described embodiments.

The top view which shows an example of a structure of the wafer resistivity measuring apparatus which concerns on one Embodiment of this invention. Similarly, a three-dimensional view showing an example of the configuration of a wafer resistivity measuring apparatus. The block diagram which similarly shows an example of a structure of a wafer resistivity measuring apparatus. The flowchart which similarly shows an example of the cleaning process of a wafer resistivity measuring apparatus. The flowchart which shows an example of the subroutine of the cleaning process of a wafer resistivity measuring apparatus similarly. Explanatory drawing which shows an example of the cleaning wafer similarly used by the cleaning process of a wafer resistivity measuring apparatus. The top view which similarly shows an example of the other structure (no cleaning wafer place) of a wafer resistivity measuring apparatus. The flowchart which shows an example of the cleaning process similarly performed with the other structure (no cleaning wafer place) of a wafer resistivity measuring apparatus. The side view which shows the example of FOUP in an example of the other structure (no cleaning wafer place) of a wafer resistivity measuring apparatus similarly.

Explanation of symbols

  W ... wafer, 10 ... wafer resistivity measuring device, 11 ... measuring device room, 12 ... load port, 13 ... conveying unit, 14 ... conveying arm, 15 ... cleaning wafer place, 16 ... measuring stage, 17 ... 4 probe probe 18 ... probe vertical drive unit, 19 ... probe horizontal drive unit, 21 ... display unit, 22 ... operation unit, 23 ... resistivity measurement unit, 24 ... rotation drive unit, 25 ... load port door, 26 ... measuring instrument Door, 30 ... control unit, 41 ... FOUP (Front Opening Unified Pod), 41-2 ... cleaning wafer, 43 ... automatic transfer system, 44 ... notch aligner.

Claims (1)

A measurement stage on which the wafer is placed;
A rotation drive unit for rotating the measurement stage;
A four-probe probe for measuring the electrical resistivity of the wafer placed on the measurement stage;
A drive unit for driving the four-probe probe;
A transfer unit for transferring a cleaning wafer to the measurement stage;
A controller connected to the drive unit, the rotation drive unit, and the transport unit;
When the cleaning unit is moved to and placed on the measurement stage using the transfer unit, the control unit reads out coordinate information of a position used for cleaning the cleaning wafer from a storage area and uses the cleaning wafer. Cleaning is performed by bringing the four probe probes into contact with the cleaning wafer by the driving unit and the rotation driving unit at coordinates different from the coordinates of the completed positions, and coordinate information used for the contact is stored in the storage area. A wafer resistivity measuring apparatus that is updated.

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