JP5203102B2 - Operation method of semiconductor processing equipment - Google Patents

Description

  The present invention relates to moving a semiconductor substrate to be processed (hereinafter referred to as “wafer”) between processing chambers of a semiconductor processing apparatus, and more specifically, a vacuum processing method and a vacuum for correcting the position of a wafer. The present invention relates to a transport device.

  In the manufacture of semiconductor devices, it is desirable to connect processing chambers and the like so that wafers can be transferred between the connected processing chambers. Such transfer is performed by a vacuum transfer device that transfers wafers between the chambers through a passage communicating with the inside of the side walls of the vacuum chamber constituting the buffer chamber and the processing chamber, which are vacuum transfer chambers. Vacuum transfer devices are typically used in conjunction with various wafer processing modules, including semiconductor etching systems, material deposition systems, and flat panel display etching systems.

  As demands for cleanliness and high processing accuracy in vacuum processing increase, a vacuum transfer device is employed to continuously perform processing steps and between processing steps under vacuum conditions. The vacuum transfer device is installed between, for example, a port through which a wafer is transferred and a container and a processing chamber in which the wafer is actually processed, for example, a plurality of processing chambers in which the surface is etched or a film is deposited. The A wafer can be transferred and exchanged between these containers and the processing chamber using a robot arm installed in the vacuum transfer device.

On the other hand, in the use of such a robot, several problems have occurred in transferring the wafer. For example, when a wafer is transferred from one chamber such as a load lock chamber to another chamber such as another processing chamber which is a target location, there is a possibility that the wafer may not be properly installed or positioned at a desired position of the target location. There is. For example, Patent Document 1 describes a method of detecting by providing a sensor in the R-axis direction as a system for correcting the position of a wafer when the center of the wafer is not properly installed or positioned.
JP 2007-123556 A

However, the above-described prior art wafer position correction system has the following problems.
(1) When the correction amount Sθ and the correction amount SR deviate from the standard value, the correction operation is performed. However, since the correction amount Sθ and the correction amount SR have only the standard value, all the values out of the standard value are used. The correction operation is performed for the correction amount. Therefore, a correction operation is performed even for an unexpected correction amount due to a sensor output defect or the like.
(2) In the case of a wafer misalignment error, the apparatus stops without any prior warning.
(3) Since the sensor output data after the correction operation is not cleared, if the contraction operation of the vacuum robot is performed after the correction operation and is expanded as it is, the θ-axis sensor output during the previous operation and the R-axis sensor output value during the main expansion are used. Since the calculation is performed, the calculation result is different from the position data for the actual vacuum robot.
(4) The correction calculation is performed even in the case of a sensor abnormality such as a plurality of sensor outputs used for the calculation.

  An object of the present invention is to provide a high-throughput vacuum processing apparatus or vacuum processing method capable of appropriately taking measures against unexpected correction amounts due to sensor output defects and the like, and miscalculation of position data for a vacuum robot. There is to do.

In order to achieve the above object, a method of operating a vacuum processing apparatus according to the present invention includes: a plurality of vacuum containers in which a wafer is connected to the buffer chamber by a vacuum robot disposed inside a buffer chamber that is a vacuum transfer chamber. A vacuum processing method in which the wafer is placed and processed on a sample stage disposed inside the vacuum container, wherein one of the vacuum containers of the wafer by the vacuum robot is provided. Based on the outputs of the θ-axis sensor that detects the light shielding angle of the wafer when the vacuum robot rotates and the R-axis sensor that detects the light shielding distance of the wafer when the vacuum robot expands and contracts. obtain the position correction amount for the vacuum robot wafer, when the position correction amount is out of the range of predetermined value, performs an operation stop of the conveyance of the vacuum robot operation Stop after the retry for transporting the wafer is conveyed to the ascertainable chambers above position was confirmed the position of the wafer on the concatenated the vacuum robot in the buffer chamber from the outside again to one of the vacuum vessel It is characterized by performing an operation.

  According to the present invention, based on the outputs of the θ-axis sensor and the R-axis sensor, the correction amount in the rotation direction and the correction amount in the straight direction of the wafer with respect to the vacuum robot are obtained, and these are out of a predetermined standard value. If the value exceeds the allowable value, the operation can be stopped as a correction amount range over error, and if the correction amount range over error occurs, the correction operation can be retried by clearing the wafer. it can. Further, when the difference in distance data obtained based on the outputs of the θ-axis sensor and the R-axis sensor exceeds a standard value, a warning is issued as a misalignment error, thereby reducing the wafer holding power. Warnings and even appropriate actions can be taken.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows an overall configuration diagram of a semiconductor processing apparatus 100 according to an embodiment of the present invention. The semiconductor processing apparatus 100 can transfer wafers between a plurality (four) of processing chambers 101, 102, 103, and 104 and a plurality (three) of cassette mounting tables 105.

The processing chambers 101, 102, 103, 104 may be processing chambers for performing plasma etching, layer deposition, and / or sputtering. These processing chambers 101, 102, 103, and 104 are configured by a vacuum processing container having a sample stage on which a sample such as a wafer is placed in an internal space that is depressurized to a predetermined pressure (vacuum pressure). While supplying a processing gas to the space, an electric field or magnetic field is applied from an electric field or magnetic field supply means (not shown) to form plasma in the space above the wafer in the processing chamber, thereby forming a processing container for processing the surface of the sample. Yes.

  The buffer chamber 110 of the semiconductor processing apparatus 100, which is a vacuum processing apparatus, is composed of a vacuum container whose inside can be adjusted to the same pressure as the inside of the processing chamber 101 and the like, and is mounted to introduce the wafer to the vacuum side. A plurality of load lock chambers 106 and 107 are connected. The processing chambers 101, 102, 103, 104, the buffer chamber 110, and the load lock chambers 106, 107 constitute a vacuum side block that transports and processes the sample under reduced pressure conditions.

  The plurality of load lock chambers 106 and 107 are connected to an atmospheric transfer chamber 109 in which an atmospheric robot 108 is disposed in an internal space, and a cassette for storing wafers is placed on the upper surface of the atmospheric transfer chamber 109. A cassette mounting table 105 is provided on the front side. The load lock chambers 106 and 107 are opening / closing mechanisms for taking out and delivering the wafer between the atmospheric transfer chamber 109 to which the cassette is connected and the vacuum side block, and also function as a variable pressure interface.

  The atmospheric robot 108 takes out the wafer from the cassette placed on the cassette placing table 105 to be placed, carries the wafer to the atmospheric transfer chamber 109, performs wafer centering and notch alignment in the atmospheric transfer chamber 109, and then again. Then, it is carried into the load lock chamber 106 or 107.

  The wafer carried into the load dock chamber or 107 is placed on a sample stage disposed inside the load dock chamber or 107. After the inside is depressurized, the hand at the tip of the arm of the vacuum robot 111 is moved down the wafer while being lifted by a plurality of pin-shaped wafer pushers arranged in the sample table, and the wafer is transferred onto the hand. Is done. When the delivery of the wafer is completed, the arm of the vacuum robot 111 contracts, and the wafer placed on the hand is carried into the buffer chamber 110.

  In the buffer chamber 110, the direction is changed in the direction of the processing chambers 101, 102, 103, and 104 by the rotation operation of the vacuum robot 111, and the wafer is processed into the processing chambers 101, 102, and 102 by the extension operation of the arm of the vacuum robot 111. In the processing chamber, processing such as plasma etching, layer deposition, and / or sputtering is performed.

  These processes are performed in a sealed processing chamber. For example, the wafer transferred to the inside of the processing chamber 101 is placed on a sample table (not shown). At this time, similarly to the configuration inside the load lock chamber 106 or 107, a plurality of pusher pins that move up and down and move the wafer up and down arranged inside the sample stage are provided.

  With these pusher pins moving upward, a wafer placed on the arm tip side hand of the vacuum robot 111 positioned above the pusher pins is placed on the pusher pins as the arm descends, and then the arm is moved to the buffer chamber. The wafer is moved into 110 and the wafer is delivered to the sample stage. After the movement of the arm, the pusher pin is moved downward and stored in the sample table, and the wafer is placed on the wafer mounting surface covered with the dielectric film on the upper surface of the sample table.

  Thereafter, a processing gas is introduced into the processing chamber 101, and the processing chamber 101 is evacuated and adjusted to a predetermined pressure (vacuum pressure) by an operation of a vacuum pump (not shown). In addition, the wafer is placed on the sample stage by the electrostatic adsorption force between the wafer and the dielectric film generated by applying electric power to the electrode for electrostatic adsorption arranged in the dielectric film. The wafer is sucked and held on the mounting surface.

  In addition, a heat transfer gas such as He is introduced between the front surface of the wafer mounting surface and the back surface of the wafer, and the heat transfer between the wafer and the sample table is adjusted so that the temperature of the front surface of the wafer is increased. Adjust to the desired range. In this state, an electric field or a magnetic field is supplied to the space above the wafer in the processing chamber 101 to turn the processing gas into plasma, and the wafer surface is processed using this plasma.

  After this process is completed, the power applied to the electrostatic chucking electrode is removed to reduce the electrostatic chucking force, and then the pusher pin is raised to lift the wafer upward from the wafer mounting surface. After the gate valve sealed in the processing chamber 101 is opened, the arm of the vacuum robot 111 is extended so that the hand on the tip side is positioned below the wafer. By the downward movement of the pusher pin, the wafer is placed on the holding surface on the hand and transferred to the arm. The pusher pin is then stored again inside the sample stage.

  As described above, after the processing in the processing chambers 101, 102, 103, and 104 is performed, the processed wafer is transferred to the vacuum robot 111, and the arm of the vacuum robot 111 is contracted, the vacuum robot 111 is rotated, The wafer is transferred between the processing chambers or between the processing chamber and the load lock chamber by a combination of the extending operations of the arms of the vacuum robot 111.

  The operation of the vacuum robot 111 or the atmospheric robot 108 is adjusted by each control device (not shown). Such a control device may be connected to a control device that controls the operation of the entire vacuum processing apparatus 100 so as to be able to exchange commands, or may be integrated therewith.

  When the wafer is transferred or transferred by the vacuum robot 111, the vacuum robot 111 whose operation is controlled or the wafer placed on the arm of the vacuum robot 111 is shifted away from the intended position. Therefore, there is a possibility that it cannot be accurately positioned and placed at the target position of the transport destination.

  In other words, there is a problem that when the wafer is delivered, there is a gap between the wafer and a predetermined position on the arm or the hand on the tip side, or the position of the wafer moves on the arm or the hand during transfer. Arise. For example, even if the wafer is lifted by the pusher pin and the arm of the vacuum robot 111 is controlled to move and the hand on the tip side of the arm is placed at a predetermined position below the wafer, the position where the wafer is lifted by the pusher pin is When the position is different from the reference position when the wafer is placed on the arm or hand, the above-described deviation occurs. This is likely to occur when the electrostatic attraction force remains at a specific level or higher when the wafer is lifted, or when there is an uneven arrangement, shape, or position of the pusher pins. In addition, even when the wafer is placed on the wafer placement surface and is displaced from the reference position for the placement, a deviation from the reference position at the delivery occurs.

  If there is such a variation in the position of the wafer, the positioning of the wafer with respect to the wafer mounting surface at a target location such as a sample stage in the processing chamber becomes unstable, and the suction force for holding the wafer is not uniform on the wafer surface. Or non-uniformity of processing, and the processing yield is reduced. In addition, there was a problem that the wafer could not be stably placed on the arm or hand when the wafer was delivered, and the wafer dropped during transportation or contacted with the surface inside the apparatus, resulting in an accident or contamination. . For this reason, it is required to accurately place or deliver the wafer to a target position on the upper surface of the arm or hand or the placement surface on the sample table.

  Further, the operation of the vacuum robot 111 when transferring the wafer may cause the wafer to move its position on the upper surface of the arm. In order to suppress this, it is conceivable that pins for holding the wafer in contact with the outer end edge thereof are arranged on the arm in accordance with the outer shape and diameter of the wafer to fix the position of the wafer. However, in this case, since the outer periphery of the wafer cannot be contacted or supported by a plurality of pins unless the arm position is controlled with high precision, the wafer cannot be properly supported and the wafer may be dropped or transported to the target location. The number of accidents that cannot be properly placed increases and the processing efficiency decreases. Or the problem that the cost of the vacuum robot 111 increases and the manufacturing cost of the whole apparatus increases arises. Alternatively, the contact between the pins and the outer peripheral edge of the wafer causes dust to become foreign matter, contaminating the inside of the apparatus such as the wafer and the processing chamber to reduce the processing yield, and increasing the frequency of cleaning to increase the processing efficiency. Will fall.

For this reason, in this embodiment, a technique is adopted in which the back surface of the wafer is supported by a surface or a plurality of points on the hand on the tip side of the arm and a gap is formed around the outer periphery of the wafer.
In the configuration of this embodiment, when there is a possibility that the movement of the wafer position during the wafer transfer may occur due to the stop or movement of the vacuum robot 111, the movement (deviation) of the generated wafer is detected. Correspondingly, the operation of the vacuum processing apparatus is adjusted.

  FIG. 2 shows a sensor mounting position in the vacuum transfer device 200 (buffer chamber 110) of the semiconductor processing apparatus 100. A plurality of processing chambers 101, 102, 103, 104 and a plurality of load lock chambers 106, 107 are connected to the side surface of the vacuum vessel that constitutes the vacuum transfer device 200, via a passage that communicates the inside thereof. Thus, wafers can be transferred between the processing chamber and the load lock chamber.

  In the present embodiment, the vacuum robot 111 has a center 203 disposed in the vicinity of the center of the buffer chamber 110, and can rotate at a predetermined angle θ about the center 203 as an axis. The rotation operation of the vacuum robot 111 or its arm with the center 203 as the central axis is called the θ-axis operation or the θ-axis (around) rotation.

  Furthermore, the vacuum robot 111 can extend and contract its arm in a direction connecting the center 203 side and the outer peripheral side (processing chamber side) of the buffer chamber 110 at a predetermined rotational angle position of the θ axis, and mount the wafer on the tip portion thereof. The position of the placing hand can be moved back and forth between the buffer chamber 110 and the processing chamber. This expansion / contraction operation is called an R-axis (direction) operation.

In the present invention, in the vacuum transfer apparatus 200 (buffer chamber 110) of the semiconductor processing apparatus 100, each of the θ axis and the R axis, which are the operation directions of the vacuum robot 111, are provided. A θ-axis sensor 201 and an R-axis sensor 202 are provided. (In the case of an apparatus configuration with two load lock chambers and four processing chambers, there are six for the θ axis and six for the R axis.)
A plurality of θ-axis sensors 201 (at least the number of processing chambers and load lock chambers) are arranged on the circumference centered on the center 203 of the vacuum robot 111. In this embodiment, the θ-axis sensors 201 are arranged above and below the buffer chamber 110, respectively. This is a highly directional optical sensor with one pair as a single sensor that detects the amount of light traveling from one of the upper and lower sides to the other, and the wafer between the sensor pair at the mounting position of the upper and lower sensors. Presence / absence or passage thereof is detected by shielding the wafer. By arranging such a pair of sensors at a radial position through which the wafer passes during the rotation of the vacuum robot 111, the wafer from the center of the vacuum robot can be obtained using the output of the θ-axis sensor 201 during the rotation of the vacuum robot 111. The distance to the center can be calculated.

  The R-axis sensor 202 is arranged on a line along the direction of expansion / contraction of the arm of the vacuum robot 111, that is, the direction connecting each processing chamber or load lock chamber and the center 203. In this embodiment, the R-axis sensor 202 Similarly, it is a highly directional optical sensor, and the passage at the sensor mounting position or the presence / absence of the wafer is detected by shielding the wafer during the extension operation of the arm on which the wafer is placed. In this embodiment, the optical sensor is highly directional like the θ-axis sensor 201, and the passage of the sensor at the attachment position or the presence / absence of the wafer is determined by the shielding of the wafer during the extension operation of the arm on which the wafer is placed. Detected. The distance between the hand center of the vacuum robot 111 and the wafer center can be calculated using the output of the R-axis sensor 202 when the arm is extended and contracted.

  The θ-axis sensor 201 and the R-axis sensor 202 are arranged at positions where the wafer is positioned between these pairs and the presence / absence of the wafer is not detected when the wafer, which will be described later, is in the processing chamber retracted position or the standby position. . That is, in the present embodiment, the θ-axis sensor 201 and the R-axis sensor 202 are for detecting the passage and time of the wafer, and are not for detecting the presence or absence of the wafer.

  The displacement amount obtained from the θ-axis sensor 201 and the R-axis sensor 202 is calculated, and the position is corrected only when there is a displacement amount equal to or greater than a predetermined standard value. Note that this displacement amount is obtained by setting the value at teaching to an absolute value and obtaining the displacement amount by the difference from the absolute value.

  Teaching is performed on the atmosphere robot 108 side and the vacuum robot 111 side, respectively. What is performed on the side of the vacuum robot 111 is the adjustment of the rotation angle from the operation origin of the vacuum robot 111 to each processing chamber and the distance from the retreat position before loading to each processing chamber. In other words, for the vacuum robot 111 or its control device that can freely adjust the position of the arm or hand within a movable range, a specific position or processing chamber of the wafer on which the position serving as a reference for the operation can be placed. The information is stored and set as information on a relative position with respect to a specific position of a target location in a device such as a sample stage 101 in the apparatus.

  For example, the position of the arm where the specific position of the wafer placed at a specific position on the hand of the arm and the specific position on the sample stage in the processing chamber 101 are arranged at a predetermined distance is set as reference position information. To do. Based on the reference position information, the arm position is adjusted by the rotation of the vacuum robot 111 in the θ-axis direction and the expansion and contraction in the R-axis direction. These adjustments are performed using a jig so that the center of the hand matches the center of each processing chamber.

  FIG. 3 schematically shows a procedure for detecting information on the position of the vacuum robot 111 or the wafer using the θ-axis sensor 201 in the teaching.

The light shielding angle θ1 is obtained by reading ON / OFF of the θ-axis sensor 201.
θ1 = θon−θoff (deg) (1)
From this calculated θ1, the distance A is
A = cos (θ1 / 2) × L1 (mm) (2)
It becomes.
Further, from the attachment distance Ll of the θ-axis sensor 201 and the obtained distance A, the distance B is
B = √ (L12−A2) (mm) (3)
It becomes.
From the wafer radius r and the obtained distance B, the distance C is
C = √ (r2−B2) (mm) (4)
It becomes.

  In the above detection, the distance L1 between the center 203 and the θ-axis sensor 201 whose amount is not easily changed by the operation of the apparatus is used. With such a configuration, it is possible to improve the accuracy of position detection during teaching or operation during processing of the apparatus.

From the above, the distance D from the vacuum robot center 203 to the wafer center is
D = A−C (mm) (5)
It becomes.

FIG. 4 shows the detection procedure of the R-axis sensor 202 during teaching.
In the present invention, the distance of the sensor mounting position L2 is obtained by reading the interval at which the R-axis sensor 202 is shielded by the wafer when the arm is extended.
The light shielding distance E is obtained by reading ON / OFF of the R axis sensor 202.
E = Ron-Roff (mm) (6)
From the obtained E and the wafer radius r, the distance F is
F = √ ((r2− (E / 2) 2) (mm) (7)
It becomes.

Since this distance F and the R-axis sensor mounting position L2 at the time of teaching must be the same,
L2 = F (mm) (8)
It becomes.
Also, since the displacement G during teaching is 0,
G = L2-F = 0 (mm) (9)
It becomes.

Therefore, from the position of the center of the wafer (hereinafter referred to as the processing chamber retreat position) in a state where the vacuum robot 111 holds the wafer on the hand outside the processing chamber and can rotate in the θ-axis direction during teaching. The distance J to the vacuum robot center 203 is
J = √ (D2-G2) (mm) (10)
It becomes.

In addition, when the vacuum robot 111 extends its arm and moves the wafer to above the sample stage in the processing chamber, the center of the sample stage and the center of the wafer substantially coincide with each other on the hand at a specific position of the wafer. The distance K to the center position of the wafer (hereinafter referred to as the processing chamber transfer position) is
K = J + TR (mm) (11)
It becomes. Note that TR is the difference between the distance K and the distance J in teaching, and is the distance between the processing chamber retracted position and the processing chamber transfer position.

  The position correction is performed by obtaining and calculating D and G obtained by teaching and the displacement amounts of D and G obtained during normal operation. The operation during normal operation will be described below as an example.

  The wafers loaded into the load lock chambers 106 and 107 are delivered to the hand of the vacuum robot 111 by the wafer pusher. When the delivery is completed, the arm of the vacuum robot 111 is contracted and the wafer is carried into the buffer chamber 110. . At this time, when the arm of the vacuum robot 111 is contracted, the sensor 202 is shielded from light by the wafer. It is possible to compare the position of the wafer by reading the shielded interval.

FIG. 5 shows the detection procedure of the R-axis sensor 202 during normal operation.
If the shielded distance is E ′,
E ′ = R ′ reduction on-R ′ reduction off (mm) (12)
It becomes.
Next, the vacuum robot 111 enters a rotation operation for carrying it into a predetermined processing chamber, and here again, the R-axis sensor 202 is shielded from light by the wafer. Here, the shielded angle θ1 is read out, and the distance D from the vacuum robot center 203 to the wafer center can be calculated.

The detection procedure of the θ-axis sensor 201 during normal operation is the same as the detection procedure of the θ-axis sensor shown in FIG.
The light shielding angle θ1 ′ is obtained by reading the θ-axis sensor 201.
θ1 ′ = θ′on−θ1′off (deg) (13)
From this calculated θ1 ′, the distance A ′ is
A ′ = cos (θ1 ′ / 2) × L1 (mm) (14)
It becomes.
Further, from A ′ obtained as the sensor distance Ll, the distance B ′ is
B ′ = √ (L12−A′2) (mm) (15)
From the wafer radius r and the obtained distance B ′, the distance C ′ is
C ′ = √ (r2−B′2) (mm) (16)
It becomes.
From the above, the distance D ′ from the vacuum robot center 203 to the wafer center during normal operation is
D ′ = A′−C ′ (mm) (17)
It becomes.

  The vacuum robot 111 rotates by a predetermined angle in the direction of the target processing chamber or load lock chamber by a predetermined angle and stops. This position is in front of the gate that opens between the target chamber and the buffer chamber 110 and is opened and closed by the gate valve (on the buffer chamber 110 side). The sensor detects whether or not the wafer is mounted on the arm hand. If the mounting of the wafer is not confirmed from the output of the sensor, it is determined that the wafer has dropped or the position is greatly shifted, an error is notified as a conveyance failure, and the processing operation in the apparatus is stopped. The operation proceeds to the operation of extending the arm of the vacuum robot 111 to the position determined by teaching. During the extending operation, the R-axis sensor 202 is shielded from light by the wafer, and by reading the shielded distance E, the amount of displacement from teaching can be obtained by calculation.

The detection distance E ′ is obtained by reading ON / OFF of the R-axis sensor 202.
E ′ = R ′ extension on−R ′ extension off (mm) (18)
From the obtained E ′ and the wafer radius r, the distance F ′ is
F ′ = √ ((r2− (E ′ / 2) 2) (mm) (19)
It becomes.
Displacement amount G 'when teaching is based on R-axis sensor mounting positions L2 and F' G '= L2-F' (mm) (20)
It becomes. The distance J ′ from the processing chamber retreat position to the vacuum robot center 203 is:
J ′ = √ (D′ 2-G′2) (mm) (21)
The distance K ′ from the center of the vacuum robot 111 to the processing chamber is
K ′ = J ′ + TR (mm) (22)
It becomes.

Accordingly, the correction amount Sθ in the rotation direction is
Sθ = tan−1 ((G′−G) / K ′) (deg) (23)
The correction amount SR in the straight direction is
SR = K−K ′ (mm) (24)
It becomes.

  As described above, when the obtained Sθ, SR is larger than the predetermined value, the position data changing operation of the vacuum robot 111 is performed, and the operation is adjusted to reduce the values of Sθ, SR to 0. The position of the wafer is adjusted so that it is closer. That is, the wafer position is corrected. This corrects the deviation of the position of the wafer detected during transfer in actual processing, and brings the specific position of the mounting surface of the sample table, which is the target position of transfer, and the center of the wafer to be transferred as close as possible. Thus, the wafer can be mounted on the mounting surface of the sample table with high accuracy.

  In addition, when the difference in distance read from (12) and (18) is out of the allowable value and when the difference in the following expressions (27) and (28) is out of a predetermined standard value, “wafer” “Position shift warning” and report the warning to the host device. If the tolerance is not met, it is considered that the wafer has been misaligned on the hand after sensor detection. This is reported as a “wafer misalignment error” to the user of the apparatus by a display or buzzer. Then, the transfer operation or the wafer processing operation in the apparatus is stopped. Such comparison of detection results will be described with reference to FIG. 6 showing information of distance and position necessary for this.

The distance M from the vacuum robot center 203 to the wafer center required during teaching is:
M = L3-E / 2-Ron (mm) (25)
M 'during normal operation is
M ′ = L3-E ′ / 2-R′on (mm) (26)
It becomes.
This difference P is
P = MM− (′) (<27>)
It becomes. Further, the difference Q between the distances J and J ′ from the processing chamber retracted position obtained from the equations (10) and (21) to the vacuum robot center 203 is:
Q = J−J ′ (mm) (28)
It becomes.

  If the difference between P and Q deviates from a predetermined standard value, a “wafer position deviation warning” is set and a warning is reported to the host device. Also, if it exceeds the allowable value, it is considered as “wafer misalignment error”, and it is considered that the wafer has misaligned on the hand after sensor detection. A notification is given by a display, a buzzer or the like, and the transfer operation or the wafer processing operation in the apparatus is stopped.

  7 to 9 show an example of a wafer transfer operation flow in the semiconductor processing apparatus. First, in the wafer transfer operation flow of FIG. 7, the wafer transfer operation flow is started in step S601, and in step S602, a wafer transfer pattern is selected.

  Next, in step S603, the vacuum robot 111 is rotated in the θ-axis direction so as to face the load lock chamber or the processing chamber where the wafer is taken out according to the selected transfer pattern.

  In step S604, the arm of the vacuum robot 111 is extended in the R-axis direction to take out the wafer. In step S605, the vacuum robot 111 that has transferred the wafer on the sample table to the upper surface of the hand on the tip side of the arm in the processing chamber performs a contraction operation in the R-axis direction of the arm.

  When the arm of the vacuum robot 111 is contracted in the R-axis direction, in step S606, the light-shielding distance E is detected by the R-axis sensor 202 and the detected distance is read (corresponding to Expression 12). Next, in step S607, the vacuum robot 111 rotates in the θ-axis direction. When the vacuum robot 111 rotates in the θ-axis direction, in step S608, the θ-axis sensor 201 detects and reads the light shielding angle θ1 ′ (corresponding to Equation 13).

  After the vacuum robot 111 rotates in the θ-axis direction and faces the processing chamber or the load lock chamber of the selected transfer pattern, in step S609, the arm of the vacuum robot 111 extends in the R-axis direction. .

  When the arm of the vacuum robot 111 is extended in the R-axis direction, in step S610, the R-axis sensor 202 detects the light shielding distance E 'and reads the detected distance (corresponding to Expression 18).

  Next, the wafer transfer operation flow (continued) in FIG. 8 will be described. In step S615, position correction calculation is performed using the light shielding angle θ and the light shielding distances E and E ′ detected and read by the θ-axis sensor 201 and the R-axis sensor 204. Sensors that output information used for calculating these positions include an R-axis sensor 202 corresponding to the processing chamber from which the wafer is taken out, an R-axis sensor 202 corresponding to the processing chamber into which the wafer is loaded, These are the three sensors (three pairs) of the θ-axis sensor 201 that detects the passage of the wafer during the rotation in the θ-axis direction performed by the vacuum robot 111 during the transfer of the wafer. The amount of deviation at each position is determined by three sensors.

  The calculation of the distances A ′, B ′, C ′, and D ′ using the light shielding angle θ1 ′ (corresponding to the equations 14, 15, 16, and 17) is a stage where necessary data are prepared prior to step S615. You can calculate early. If the output value of the θ-axis sensor 201 is equal to or smaller than the allowable value in step S611, a “abnormal correction calculation error” is reported to the host device as a wafer abnormality in step S613, and the operation is stopped in step S614.

  The allowable value of the θ-axis sensor 201 here means a light shielding width determined by the size of the wafer diameter and the sensor mounting position, and is separated from the case where light is shielded by an object other than the wafer such as the arm of the vacuum robot 111, for example. is there. In addition, it is possible to detect abnormalities such as the presence / absence of a wafer and a crack of the wafer based on the allowable value.

  If it is determined in step S611 that the operation is normal, the process proceeds to step S612, and the θ-axis sensor 201 and the R-axis sensor 202 used for the calculation are not output a plurality of times, or the θ-axis sensor 201 and the R-axis sensor 202 are If it is determined that there is both outputs and it is determined that there is an abnormality, a wafer abnormality is reported as a “correction calculation impossible error” in step S613, and the operation is stopped in step S614. If it is not determined as abnormal, the process proceeds to step S615.

  Next, in step S616, it is determined whether or not the difference between the detected distance when the R-axis contracts in step S606 and the detected distance (E, E ′) when the R-axis is expanded in step S610 is within the standard. . If the difference in detection distance is out of the standard value, it is checked in step S617 whether it is within the allowable value. If it is out of the standard value but within the allowable value, in step S622, a “wafer misalignment warning” is displayed. Is reported to the host device, and the process proceeds to step S620.

  If the allowable value is not satisfied in step S617, a “wafer misalignment error” is reported to the host device in step S618, and the operation is stopped in step S619. At this time, if a “wafer misalignment error” occurs during transfer, this is notified to the apparatus user or the like by a display or buzzer.

  If it is determined in step S616 that the difference in detection distance is within the allowable value, the process proceeds to step S620. Next, in step S620, the difference Q between the processing chamber retracted position and the vacuum robot center 203 obtained from the light shielding distance when the R-axis contracts in step S606 and the detected angle when rotating in the θ-axis direction in step S608 (formula 28) And a difference P (corresponding to Expression 27) of the distance M from the vacuum robot center to the wafer center obtained from the detected distance when the R-axis is extended in step S610, and the difference between P and Q is predetermined. It is determined whether the value is within the standard value.

  If the difference between P and Q is out of the range of the standard value, it is checked in step S621 whether it is within the allowable value. If it is out of the standard value but within the allowable value, in step S622, “ A “wafer displacement warning” is reported to the host device, and the process proceeds to step S623. If the allowable value is not satisfied in step S621, a “wafer position error” is reported to the host device in step S618, and the operation is stopped in step S619. At this time, if a “wafer misalignment error” occurs during transfer, this is notified to the apparatus user or the like by a display or buzzer.

  Next, the wafer transfer operation flow (continued) in FIG. 8 will be described. In step S623, a position correction amount (rotation direction correction amount Sθ, straight-ahead direction correction amount SR calculated from the detection angle during rotation in the θ-axis direction in step S608 and the detection distance during extension of the R-axis in step S610. , Corresponding to Equations 23 and 24) is determined to be within a predetermined standard value.

  If the position correction amount (Sθ, SR) is within a predetermined standard value, that is, if the position correction amount is small and the position data does not need to be changed, the position data is not changed, and the process proceeds to step S635. Then, the position correction of the vacuum robot 111 is finished, and the data of the θ-axis sensor and the R-axis sensor are cleared.

  If the position correction amount (Sθ, SR) is out of the predetermined standard value, it is determined in step S624 whether it is within the allowable value. If it is out of the standard value, but within the allowable value. In step S633, the position data is changed to adjust the position of the wafer or the arm of the vacuum robot 111. Then, the process proceeds to step S635 to complete the position correction of the vacuum robot, and the θ axis sensor and the R axis Clear the sensor data.

  On the other hand, if it is outside the allowable value, it is determined as “correction amount range over-error” in step S625, and the operation is stopped in step S626. If the operation is stopped in step S626, the wafer clear operation is performed in step S627, and the arm of the vacuum robot 111 is extended to the load lock chamber in step S628.

  By the expansion operation of the vacuum robot 111, the “correction amount range over-error” in step S629 occurs, the process proceeds to step S630, the operation is stopped again, and the process proceeds to step S631. In step S631, the positional relationship between the vacuum robot hand and the wafer is confirmed in the load lock chamber. If a wafer is placed in the vacuum robot hand, a retry operation is performed in step S634 to change the position data. After the adjustment of the position of the wafer or the arm of the vacuum robot 111 is completed, the process proceeds to step S635, the position correction of the vacuum robot is terminated, and the data of the θ-axis sensor and the R-axis sensor are cleared. If the wafer is not normally placed in the vacuum robot hand, the operation is stopped in step S632.

  Note that the load lock chamber extended in step S628 may be either the load lock chamber 106 or the load lock chamber 107. The load lock chamber 106 and the load lock chamber 107 can be seen from above so that the wafer and the vacuum robot hand can be confirmed. The viewing window 112 and the viewing window 113 are preferably made of a transparent material that can withstand external pressure and has good visibility.

  If the position data is changed in steps S633 and S634 and the correction is completed, the sensor data is cleared. Therefore, even if the vacuum robot is extended again, there is no data for the θ-axis sensor. Since the condition is not satisfied, a “correction calculation impossible error” is reported and the operation is stopped.

  In the first embodiment, four processing chambers, two load lock chambers, and three cassette mounting tables are shown in the semiconductor processing apparatus. However, the processing chamber, the load lock chamber, and the cassette mounting table are provided. The number is not limited to this, and an arbitrary number of devices can be configured. Further, as the treatment performed in the treatment chamber, treatments such as plasma etching, layer deposition, and / or sputtering are illustrated, but the treatment is not limited thereto.

  In addition, as the position correction amounts determined in step S616, the rotation direction correction amount Sθ and the straight direction correction amount SR corresponding to Equations 23 and 24 are exemplified, but based on the outputs of the θ-axis sensor and the R-axis sensor. As the calculated position correction amount, other position correction amounts can be used besides the rotation direction correction amount Sθ and the straight direction correction amount SR corresponding to the equations 23 and 24.

  Further, in the operation flow of FIG. 6, whether or not it is within the allowable value or within the standard value is determined by the order of step S612, step S613, and step S616. The number of S may be changed.

  In addition, the predetermined allowable value and the predetermined standard value used in step S612, step S613, and step S616 are relatively small values, and are used to determine whether or not position data needs to be changed. The allowable value is a relatively large value and is used to determine whether or not it is necessary to stop the operation.

  As these allowable values and standard values, optimum predetermined values are set so as to perform the wafer transfer operation quickly and reliably in the semiconductor processing apparatus. The predetermined permissible values used in steps S612 and S613 do not have to be the same value, and differ according to other distance data used to determine the wafer misalignment error on the hand. A value can be set.

FIG. 1 is a diagram showing an overall configuration of a semiconductor processing apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing sensor mounting positions in the vacuum transfer device (buffer chamber) of the semiconductor processing apparatus. FIG. 3 is a diagram illustrating a detection procedure of the θ-axis sensor. FIG. 4 is a diagram illustrating a detection procedure of the R-axis sensor during teaching. FIG. 5 is a diagram illustrating the detection procedure of the R-axis sensor during normal operation. FIG. 6 is a diagram illustrating distance and position information necessary for detecting a wafer position shift. FIG. 7 is a diagram illustrating a wafer transfer operation flow. FIG. 8 is a diagram showing a wafer transfer operation flow (continued). FIG. 9 is a diagram showing a wafer transfer operation flow (continued).

Explanation of symbols

100 Semiconductor processing apparatus 101 Processing chamber 1
102 Processing chamber 2
103 Processing chamber 3
104 Processing chamber 4
105 cassette mounting table 106 load lock chamber 107 load lock chamber 108 atmospheric robot 109 atmospheric transfer chamber 110 buffer chamber 111 vacuum robot 112 viewing window 113 viewing window 200 vacuum transfer device 201 θ-axis sensor 202 R-axis sensor 203 center of vacuum robot

Claims (4)

A wafer stage is transferred to at least one of a plurality of vacuum vessels connected to the buffer chamber by a vacuum robot arranged inside a buffer chamber which is a vacuum transfer chamber, and a sample stage is arranged inside the vacuum vessel. A vacuum processing method for mounting and processing the wafer on the top,
During transfer of the wafer to one of the vacuum containers by the vacuum robot, a θ-axis sensor that detects a light shielding angle of the wafer when the vacuum robot rotates, and a light shielding distance of the wafer when the vacuum robot extends and contracts. Based on the output from the detected R axis sensor, the position correction amount of the wafer relative to the vacuum robot is obtained,
When the position correction amount exceeds a predetermined value range , the transfer operation of the vacuum robot is stopped,
After the operation is stopped, the wafer is connected to the buffer chamber and transferred to a chamber where the position of the wafer on the vacuum robot can be confirmed from the outside, and the wafer whose position is confirmed is transferred again to one of the vacuum containers. A method of operating a semiconductor processing apparatus , wherein a retry operation is performed . A method of operating a semiconductor processing apparatus according to claim 1 ,
The output of the θ-axis sensor is an allowable value in the output of the θ-axis sensor that detects the light shielding angle of the wafer when the vacuum robot rotates and the R-axis sensor that detects the light shielding distance of the wafer when the vacuum robot extends and contracts. In the following cases, when the output of the θ-axis sensor and the R-axis sensor is detected a plurality of times, or when the output of the θ-axis sensor or the R-axis sensor is only one, a correction calculation error how the operation of a semiconductor processing device and performing output to stop operating. A method of operating a semiconductor manufacturing apparatus according to claim 1 or 2 ,
Based on the output of the θ-axis sensor that detects the light shielding angle of the wafer when the vacuum robot rotates and / or the R-axis sensor that detects the light shielding distance of the wafer when the vacuum robot expands and contracts, the wafer with respect to the vacuum robot If distance data is obtained and the position correction amount obtained from the distance data exceeds a predetermined standard value smaller than the predetermined value and smaller than the predetermined value , a positional deviation warning is reported to the host device,
When the position correction amount is further beyond the predetermined value, the method operation of a semiconductor processing device and performing an operation stop as a position deviation error. A method for operating a semiconductor processing apparatus according to any one of claims 1 to 3,
After obtaining the position correction amount, the position of the wafer or the vacuum robot is adjusted, and after the position correction operation of the wafer with respect to the vacuum robot is completed, the data of the R-axis sensor and the θ-axis sensor are cleared. A method for operating a semiconductor processing apparatus.

Images