JPH07122619A - Method for transferring semiconductor wafer - Google Patents

Abstract

PURPOSE:To allow easy discrimination of a wafer in a container not subjected to normal processing by adjusting the orientation of the wafer not subjected to normal processing through a position matching mechanism thereby discriminating the wafer based on the orientation thereof when the wafer is set in the container. CONSTITUTION:When normal processing is not conducted, a control section selects an abnormal mode and controls the driving section of a transfer means 21 such that a wafer 1 is transferred onto the rotary stage 61 of a position matching mechanism 6. The control section selects a containment identification mode for the position matching mechanism 6 and rotates the rotary stage 61 such that the wafer 3 is contained in a cassette C in the direction different from the orientation flat of a normal wafer 1 thus transferring the wafer 1 into a cassette C in a cassette chamber 3B. Since the direction of orientation flat is different by 180 deg. between a normally processed wafer 1 and a wafer 1 not processed normally, the wafer 1 not processed normally can be discriminated at a glance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer transfer method.

[0002]

2. Description of the Related Art A semiconductor device is manufactured through many processes such as film forming process, etching process, ion implantation process and ashing process. This kind of process is performed in a vacuum atmosphere or air-tightly sealed atmosphere or a normal atmosphere. It is performed in a pressure atmosphere. For this reason, semiconductor processing stations, such as vacuum processing stations, use semiconductor wafers (hereinafter "wafers").
Wafer) is loaded into the vacuum processing chamber from the input / output port through the load lock chamber and the vacuum processing chamber and the load lock chamber, and vice versa. The transfer means is configured to be carried out along the path, and a wafer orientation flat (hereinafter referred to as “orientation flat”) provided in the transfer path and a positioning mechanism for aligning the center of the wafer.

By the way, when some abnormality occurs in the vacuum processing chamber, for example, when process conditions such as gas flow rate and electric power deviate from predetermined values, an alarm is issued and the processing is stopped. At this time, the operator performs a reset process to restart the apparatus, and if the abnormality is released after that, the canceled wafer is returned to the cassette,
Normal processing is performed from the next wafer. Therefore, in such a case, the wafers returned to the cassette also include wafers that have not been subjected to normal processing. However, regarding the wafers, for example, based on the data sheet of the upper computer, the operator The cassette containing the wafer is identified, the wafer is removed from the cassette, and the wafer is discarded.

[0004]

However, in a manual operation in which an operator searches a cassette by relying on a data sheet or the like and finds a wafer in the cassette, the cassettes have the same shape and the wafers are arranged in the same array in each cassette. Since 25 sheets are stored, the work is complicated and the reliability is not absolutely absolute. If the operator mistakenly removes another wafer, the wafer that is not normally processed flows through the line, causing unnecessary confusion such as investigating the cause in the subsequent inspection process and temporarily stopping the line. May invite.

The present invention has been made under such circumstances, and an object thereof is to provide a wafer transfer method capable of easily identifying a wafer in a container which has not been normally processed. To do.

[0006]

According to a first aspect of the present invention, there is provided a step of transferring a semiconductor wafer to an alignment mechanism to align the semiconductor wafer, a step of transferring the semiconductor wafer into a processing chamber, and the processing chamber. In the step of transferring the semiconductor wafer that has been normally processed in the container into the container, the semiconductor wafer that has not been normally processed in the processing chamber is transferred to the alignment mechanism, and the orientation of the semiconductor wafer is changed. A step of adjusting the orientation of the semiconductor wafer so that the orientation of the semiconductor wafer is different from the orientation of the semiconductor wafer that has been normally processed when stored in the vessel; and a step of transporting the semiconductor wafer with the orientation of the semiconductor wafer adjusted into the vessel. , Is provided.

[0007]

The wafer in the container is taken out by the transfer means, and after the orientation mechanism adjusts the orientation of the orientation flat to a predetermined orientation, for example, it is transported into the vacuum processing chamber. Then, after a predetermined vacuum process (however, a normal pressure process may be performed), the wafer is returned to, for example, the original container or another container, but for a wafer that has not been normally processed, the alignment mechanism is used. The orientation of the wafer is adjusted by, and when the wafer is accommodated in the container, it is in a state of being distinguished from the orientation of the wafer which has been normally processed.

[0008]

1 is a schematic perspective view showing the overall construction of an example of an apparatus used in an embodiment of the present invention. In the figure, 2 is an airtight rectangular parallelepiped transfer chamber, and a wafer cassette (hereinafter simply referred to as a cassette) which is a container for storing 25 wafers 1 is placed around the transfer chamber 2. As shown in FIG. 2, two cassette chambers 3A, 3B having an airtight structure and three vacuum processing chambers 4A to 4C are connected to the transfer chamber 2 in a gastight manner through gate valves G, respectively. ing.

Of the cassette chambers 3A and 3B, for example, one (3A) is used for carrying in and the other (3B) is used for carrying out, a lid portion 31 is formed on the upper portion, and the cassette C is raised and lowered inside. An elevating mechanism 32 is provided. Further, as shown in FIG. 2, an exhaust pipe 33 is connected to the bottoms of the cassette chambers 3A and 3B, and the exhaust pipe 33 is connected to a vacuum pump 33a, for example, a dry pump via a valve V1.

The vacuum processing chamber 4A (4B, 4C) is configured to perform plasma etching using a magnet, for example, and is provided with a lower electrode 41 and an upper electrode 42 which also serve as susceptors and a processing gas supply pipe. 43
And the exhaust pipe 44 is connected. Process gas supply pipe 43
A gas box 5 that houses a control device for controlling the gas flow rate and the gas pressure is provided on the proximal end side of the. A magnet unit 45 is provided above the upper electrode 42 so as to be separated from the vacuum processing chamber. The magnet unit 45 is provided inside the housing 45a in the vacuum processing chamber 4A (4B, 4B,
C) A magnet 46 for forming a magnetic field, a magnet 47 for preventing magnetic field leakage formed so that magnetic poles opposite to the magnetic poles of the magnet 46 are vertically overlapped with each other, and a motor 48 for rotating them are housed in C). Has been done.

In the transfer chamber 2, cassette chambers 3A, 3A
A transfer means 21 is provided for transferring the wafer between the B and the vacuum processing chambers 4A to 4C. The transfer means 21 is, for example, an articulated arm having three independently rotatable horizontal transfer arms. The drive unit 22 of the transfer means 21 is provided in an airtight case part 23 below the bottom wall of the transfer chamber 2,
The inside of the case portion 23 is evacuated to the vacuum pump 3 via the exhaust pipe 35.
4 Particles are prevented from scattering from the bearing portion by evacuation using a turbo molecular pump, for example.
V2 is a valve. An exhaust pipe 36 having a valve V3 is connected to the transfer chamber 2, and the vacuum pump 34 is connected to the exhaust pipe 36.

In the transfer chamber 2, a buffer stage 24, which can be raised and lowered, for temporarily mounting a wafer,
An alignment mechanism 6 for aligning the orientation and center position of a wafer orientation flat (hereinafter referred to as “orientation flat”) is arranged. As shown in FIGS. 1 and 3, the alignment mechanism 6 has a small-diameter stage 61 having a chucking function for chucking the wafer 1 and a drive unit 62 for driving the stage 61 in the X, Y, Z, and θ directions. And a light emitting / receiving unit 63 including a light emitting unit 63a and a light receiving unit 63b above and below the moving path of the peripheral edge of the wafer 1 so as to optically detect the peripheral edge of the wafer 1.

The light receiving portion 63b is connected to the control portion 7, which detects the center position of the wafer 1 and the orientation of the orientation flat based on the light receiving signal of the light receiving portion 63b.
It has a function of controlling the drive unit 62 of the stage 61 (hereinafter referred to as “rotary stage 61”) so that the center position of the wafer 1 becomes a predetermined position and the orientation flat direction becomes the predetermined direction. The control unit 7 includes a vacuum processing chamber 4A (4B, 4B,
The processing mode for designating the orientation of the orientation flat determined in C) and the orientation of the orientation flat different from the orientation of the orientation flat of the wafer 1 when the wafer 1 that has undergone normal processing is stored in the cassette C. For example, the storage identification mode in which the orientation different by 180 degrees is designated can be selected. Further, the control unit 7 controls the drive unit 22 of the transfer means 21, and when the vacuum processing chamber 4A (4B, 4C) is normal, a normal mode for carrying out a normal transfer is performed. It is provided with a function of selecting an abnormal mode when a wafer 1 which has been detected to be abnormal and which has not been subjected to normal processing is transferred.

Next, an embodiment of the method of the present invention using the above apparatus will be described.

First, the lids 31 of the cassette chambers 3A and 3B are opened, and a cassette C as a container for storing 25 wafers 1 is provided.
The wafer 1 is placed in a horizontal position, for example, on the elevating mechanism 32 in one of the cassette chambers 3A (carrying-in cassette chamber 3A) by, for example, an operator, and in the other cassette chamber 3B (carrying-out cassette chamber 3B). An empty cassette C is placed on the cassette chamber, the lid 31 is closed, and the interiors of the cassette chambers 3A and 3B are evacuated to the same degree of vacuum as the interior of the transfer chamber 2 that has been evacuated. Open the gate valve G of. Then, the transfer arm of the transfer means 21 enters the cassette C in the cassette chamber 3A to receive the wafer 1. In this case, the elevating mechanism 32 is intermittently lowered and the wafers 1 are unloaded from the cassette C one by one, and the wafers 1 are held by the tip of the transfer arm.

The transfer means 21 places the wafer W received from the cassette C on the rotary stage 61 of the alignment mechanism 6, detects the peripheral edge of the wafer 1 by, for example, the light emitting and receiving section 63, and based on the result, the rotary stage. 6 is moved to align the orientation and center of the orientation flat of the wafer 1. Then, the wafer 1 is carried into the vacuum processing chamber 4A, for example, by the carrying means 21. In the vacuum processing chamber 4A, the wafer is placed on the susceptor 41 through the elevating operation of the elevating pins (not shown) combined with the susceptor 41.
Etching is performed by the plasma obtained by the energy of the high frequency power between the first and upper electrodes 42 and the energy of the magnetic field of the magnet 46.

The wafer 1 in the cassette C is distributed to, for example, the respective vacuum processing chambers 3A to 3C by the above-described transfer process, and vacuum processing, for example, plasma etching is performed in parallel. The processed wafer 1 is transferred, for example, into the cassette C of the other cassette chamber 3B by the transfer means 21, and the next wafer W to be processed is the vacuum processing chambers 3A to 3A.
Positioning is performed while the process is being performed in 3C, and the process is waiting on the buffer stage 24.

When the vacuum processing chamber is operating normally in this way, the control mode of the drive unit 22 of the transfer means 21 is set to the normal mode, and the control mode of the drive unit 62 of the alignment mechanism 7 is set to the processing mode. The steps as described above are performed. Here, in the embodiment of the present invention, the vacuum processing chamber 4A (4B-4
The transfer process varies depending on whether or not the normal processing is performed on the wafer in C). Figure 4 for this process
Describing with reference to the process chart of FIG. 1, when the wafer 1 is loaded into the vacuum processing chamber and subjected to the normal processing, the wafer 1 is transferred into the cassette C as described above, but the normal processing is performed. If not, for example, process conditions such as the flow rate of processing gas, temperature, pressure, and electric power become abnormal values,
An abnormal signal is sent from the host computer (see FIG. 3) to the control unit 7.
Is output to the wafer 1, the control unit 7 selects the abnormal mode and controls the drive unit 22 of the transfer means 21.
Are conveyed to the rotary stage 61 of the alignment mechanism 6.
Further, the control unit 7 selects the storage identification mode for the alignment mechanism 6, whereby the rotary stage 61 is rotated so that the wafer 1 is stored in the cassette C in a direction different from the orientation flat of the normal wafer 1. To move. Thereafter, the wafer 1 is transferred from the rotary stage 61 to the cassette C in the cassette chamber 3B.
Be transported inside.

When the process abnormality in the vacuum processing chamber 4A (4B, 4C) is canceled by, for example, the reset process, the remaining wafers 1 in the cassette C in the cassette chamber 3A.
Are sequentially processed. FIG. 5 is a view showing the cassette C in the cassette chamber 3B in which the wafer 1 has been transferred after the above-described steps, and the wafer 1 that has been subjected to the normal processing and the wafer that has not been subjected to the normal processing. The orientation of the orientation flat 10 differs from that of 1 by 180 degrees, for example.

Therefore, by looking at the inside of the cassette C, the operator can identify at a glance a wafer that has not been subjected to normal processing, and can reliably remove the wafer without mistakenly performing a wafer that has been processed normally. , It is not necessary to do unnecessary examination or stop the line in the subsequent process. In the above, for a wafer having a semi-circular cutout called a notch instead of the orientation flat, the orientation of the wafer is determined based on the notch.

The present invention can be applied to the case where the transfer means and the alignment mechanism are provided in the atmosphere, for example. In addition to plasma etching, CVD, ashing,
It can also be applied to the case of performing vacuum processing such as ion implantation and sputtering, or to the case of performing normal pressure or high pressure processing not limited to the vacuum processing chamber.

A preferred method of supplying the processing gas will be described with reference to FIG. For example, n gas supply systems (gas lines) L1 to Ln are provided in the gas box 5, and control devices such as valves, flow meters, and pressure gauges are incorporated in the respective gas supply systems L1 to Ln. There is. In FIG. 6, these control devices are schematically omitted and shown as Va.
~ Vc is a valve, MFC is a mass flow controller. It is assumed that the gas supply systems L1 to L3 are for supplying nitrogen gas, the first processing gas, and the second processing gas (gas different from the first processing gas), respectively. Suppose that the second processing gas is processed, the valves Vb of the gas supply systems L1 to Ln are first used.
Closed, Va and Vc opened, and the processing gas supply pipe 43
The valve 50 is opened, and the inside of the vacuum processing chamber 4 is evacuated by the exhaust pipe 44. Then, for example, the valve Vb of the gas supply system L1 is opened to supply the nitrogen gas at a predetermined flow rate. As a result, the control equipment such as the valves of the gas supply systems L1 to Ln, the mass flow controller and the like and the inside of the pipe are evacuated to evacuate the nitrogen gas. Such a process 1
The residual gas in the control equipment and the pipes is surely removed by repeating the operation once or a plurality of times. Therefore, when the second processing gas is flown, mixing of other gas components into this gas can be suppressed, so that unintended mixing of components into the wafer 1 can be prevented. In this case, other inert gas may be used instead of nitrogen gas.

Next, a preferred example of the hinge mechanism of the lid of the vacuum chamber such as the above-mentioned transfer chamber or cassette chamber will be described with reference to FIG.
Will be described with reference to. In the figure, 8 is a part of an upper wall forming the upper surface of the vacuum chamber, 81 is a lid portion that opens and closes the upper surface of the vacuum chamber, and the lid portion 81 is configured to be opened and closed by hinges 82 on both left and right sides. Leaf spring mechanisms 9 are provided on the left and right sides between the lid portion 81 and the upper wall 8 of the vacuum chamber. This leaf spring mechanism 9 fixes, for example, a drum portion 91 having a shape obtained by dividing a cylinder into four equal parts in the circumferential direction on the upper wall 8 with the circumferential surface facing the lid portion 81 side, while the drum portion 91 side is fixed. Roller base 9
2 is fixed and a roller 94 is rotatably attached thereto via a horizontal roller shaft 93. A leaf spring 95 is wound around the roller 94 and the tip end of the leaf spring 95 is pulled out from the lower side of the roller 94. It is configured by mounting and fixing along the circumferential surface of the drum portion 91.

According to this structure, the restoring force of the leaf spring 95 exerts a force in the opening direction on the lid portion 81. Therefore, when the lid portion 81 is opened and closed, the weight of the lid portion 81 corresponds to its own weight. It can be opened and closed with a force obtained by subtracting the force corresponding to the restoring force of the leaf spring 95 from the force, and the opening and closing of the otherwise heavy lid 81, which is thick enough to withstand the vacuum, is light, and safety is high.

As shown in FIG. 8, the leaf spring mechanism 9 has a structure in which a drum portion 91 is formed at a base end portion of a lid portion 81 and a roller 94 is provided at a side portion of the upper wall 8 of the vacuum chamber. As shown in FIG. 9, the drum portion 91 may be provided on the upper wall 8 side and the roller 94 may be provided on the side portion of the lid portion 81. P is hinge 8
Is the center of rotation. Further, the leaf spring mechanism 9 includes a roller 94 on the side wall 83 of the vacuum chamber, as shown in FIGS.
A configuration in which the drum portion 91 is provided at the base end portion of the lid portion 81, and FIG.
As shown in FIG. 2, the protruding piece portion 84 may be formed vertically on the upper surface of the vacuum chamber, and the drum portion 91 may be provided on this.

[0026]

According to the present invention, a wafer that has not been normally processed can be identified at a glance from among the wafers in the container. Can be reliably removed.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an overall configuration of an example of a vacuum processing apparatus used in a method of the present invention.

FIG. 2 is a sectional view showing a vacuum processing apparatus.

FIG. 3 is a configuration diagram showing a main part of a vacuum processing apparatus.

FIG. 4 is a process drawing showing an example of the method of the present invention.

FIG. 5 is an explanatory diagram for explaining an embodiment of the method of the present invention.

FIG. 6 is an explanatory view showing a gas box.

FIG. 7 is a perspective view showing a hinge mechanism of a lid portion of a vacuum chamber.

FIG. 8 is an explanatory view showing another example of the leaf spring mechanism.

FIG. 9 is an explanatory view showing another example of the leaf spring mechanism.

FIG. 10 is an explanatory view showing another example of the leaf spring mechanism.

FIG. 11 is an explanatory view showing another example of the leaf spring mechanism.

FIG. 12 is an explanatory diagram showing another example of the leaf spring mechanism.

[Explanation of reference numerals] 1 wafer 2 transfer chamber 21 transfer means 22 drive unit of transfer means 3A, 3B cassette chamber C cassette 5 gas box 6 alignment mechanism 61 rotating stage 7 control unit 8 vacuum chamber upper wall 81 lid 9 plate Spring mechanism 95 Leaf spring

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Koji Suzuki, 2381 Kitashitajo, Fujii-cho, Nirasaki-shi, Yamanashi Prefecture, Tokyo Electron Yamanashi Co., Ltd. 1 Tokyo Electron Yamanashi Co., Ltd. (72) Inventor Masato Kajiwara 1 2381 Kitashitajo, Fujii-cho, Nirasaki-shi, Yamanashi Tokyo Electron Yamanashi Co., Ltd.

Claims (1)

[Claims] 1. A step of transporting a semiconductor wafer to an alignment mechanism to align the orientation of the semiconductor wafer, a step of transporting this semiconductor wafer into a processing chamber, and a semiconductor wafer which has undergone normal processing in the processing chamber. The step of transporting the semiconductor wafer into the container, and transporting the semiconductor wafer that has not been normally processed in the processing chamber to the alignment mechanism so that the orientation of the semiconductor wafer is the normal processing when stored in the container. And a step of transporting the semiconductor wafer in which the orientation of the semiconductor wafer has been adjusted into the container. Wafer transfer method.