Hand and Method for Verifying Wafer Alignment using Hand

Abstract

The present invention relates to a return hand, a return device using the same, and a method for verifying the alignment of a wafer. More specifically, it relates to a return hand with an improved structure that can verify whether multiple stacked wafers are properly aligned, a return device using the same, and a method for verifying the alignment of a wafer. The present invention provides a conveying hand for conveying a wafer mounted on an upper surface, comprising a plurality of load sensors formed on the upper surface and a control unit that measures the load by the load sensors.

Description

Technology Field

[0001] The present invention relates to a return hand, a return device using the same, and a method for verifying the alignment of a wafer. More specifically, it relates to a return hand with an improved structure that can verify whether multiple stacked wafers are properly aligned, a return device using the same, and a method for verifying the alignment of a wafer. Background Technology

[0003] In semiconductor manufacturing processes, a return hand is used to return wafers or ring carriers. When two or more wafers are returned in stacked layers using methods such as C2C (Chip to Chip), C2W (Chip to Wafer), or W2W (Wafer to Wafer), the wafer placed at the very bottom, which comes into direct contact with the return hand, is temporarily fixed to the return hand by vacuum suction, thereby maintaining its initial alignment. However, wafers placed on top of the wafer at the very bottom may move during return without maintaining their initial alignment.

[0004] If the alignment of the stacked wafers is not maintained in this way, damage to the wafers may occur during the transport process. The problem to be solved

[0006] The present invention was devised to solve the problems of the background technology, and the problem to be solved by the present invention is to provide a return hand, a return device using the same, and a method for verifying wafer alignment that can prevent wafer damage caused by a problem with wafer alignment during the wafer return process by verifying the alignment of multiple stacked wafers. means of solving the problem

[0008] As a means of solving the aforementioned problem, the present invention is,

[0009] In a conveying hand for mounting and conveying a wafer on an upper surface,

[0010] A return hand is provided that includes a plurality of load sensors formed on the upper surface and a control unit that measures the load by the load sensors.

[0011] It is desirable to verify the alignment of the wafers by utilizing the load change measured by each load sensor during the transport process of the wafers stacked on the upper surface.

[0012] It is preferable that the above load sensors be arranged symmetrically.

[0013] It is desirable that the above control unit controls the wafer transport to stop if an abnormality in the alignment of the wafer is detected during the wafer transport process.

[0014] The present invention, in a second form,

[0015] In a wafer transport device,

[0016] A conveying hand for mounting and conveying a wafer on an upper surface, comprising a plurality of load sensors formed on the upper surface and a control unit that measures the load by the load sensors;

[0017] A wafer transport device is provided that includes a drive arm for driving the above-mentioned transport hand.

[0018] The present invention, in its third form,

[0019] A step of providing a conveying hand comprising a plurality of load sensors formed on the upper surface and a control unit that measures the load by the load sensors, for mounting and conveying a wafer on the upper surface;

[0020] A mounting step of mounting a wafer stacked in multiple sheets on the upper surface of the above-mentioned return hand;

[0021] A first measurement step in which, after the above mounting step, each of the load sensors measures the load and inputs the result to a control unit;

[0022] A second measurement step in which, during the process of transporting the above-mentioned wafers stacked in multiple layers, each load sensor measures the load and inputs the result to a control unit;

[0023] A method for verifying the alignment of a wafer is provided, comprising: a comparison step of periodically repeating the second measurement step and comparing the measurement value of the first measurement step with the measurement value of the second measurement step.

[0024] It is desirable to further include a stop step in the comparison step above to stop the return if there is a difference between the measurement value of the first measurement step and the measurement value of the second measurement step. Effects of the invention

[0026] According to the present invention, a return hand, a return device using the same, and a method for verifying wafer alignment can be provided to prevent damage to the wafer caused by a problem with wafer alignment during the wafer return process by verifying the alignment of multiple stacked wafers. Brief explanation of the drawing

[0028] FIG. 1 is a drawing for explaining a return hand and a return device according to one embodiment of the present invention. FIG. 2 is a block diagram illustrating a load sensor and a control unit. FIG. 3 is a block diagram according to one embodiment of a method for verifying wafer alignment. Specific details for implementing the invention

[0029] Hereinafter, specific details for implementing the present invention will be provided by describing preferred embodiments of the present invention with reference to the drawings.

[0031] FIG. 1 is a drawing for explaining a return hand and a return device according to one embodiment of the present invention, FIG. 2 is a block diagram for explaining a load sensor and a control unit, and FIG. 3 is a block diagram according to one embodiment of a method for verifying the alignment of a wafer.

[0033] First, we will describe an embodiment of the return hand, which is the first form of the present invention.

[0034] The conveying hand (100) according to the present embodiment conveys a wafer (W) by placing it on its upper surface, and is configured to include a load sensor (10) and a control unit (20).

[0035] The upper surface of the above-mentioned return hand (100) does not literally mean a surface placed on the top, but rather a surface on which a wafer (W) is placed. A vacuum hole (210) and a support pad (220) are installed on the upper surface, and the wafer (W) is temporarily fixed during the return process by the vacuum suction force acting on the vacuum hole (210) while placed on the support pad (220). To this end, the vacuum hole (210) is connected to a vacuum pump (not shown) by a pipe (not shown).

[0036] The above load sensor (10) is also called a load cell and refers to a sensor capable of electrically extracting an output as a converter for measuring force or load.

[0037] It consists of a primary conversion element that converts a load (force) as a measurement target into a quantity that is easy to convert into an electrical signal, such as displacement or deformation, and a secondary conversion element that converts the primary conversion output (displacement / deformation) into a quantity that can be output as an electrical signal, such as a change in inductance, a change in capacitance, a change in resistance, etc. When a load sensor receives weight, it undergoes deformation such as compression or elongation; the load is measured by a deformation measuring device detecting this amount of deformation as an electrical signal and then converting it into a digital signal by a computer device.

[0038] The load sensor (10) is arranged symmetrically with respect to a virtual line (L) passing through the center of the return hand (100) as shown in FIG. 1. Through this arrangement, the change in weight on both sides with respect to the virtual line can be determined more precisely.

[0039] The control unit (20) is electrically connected to the load sensor (10) as briefly illustrated in FIG. 2, measures the load by the load sensor (10), receives the measured value, and performs control to stop the transport if an abnormality is detected in the alignment of the wafer. FIG. 1 does not show the electrical connection between the load sensor (10) and the control unit (20) or the control unit, but this is for convenience of illustration.

[0040] The above control unit (20) detects an abnormality in the alignment of the wafer by utilizing the change in load measured by each load sensor (10) during the transport process.

[0041] As shown in FIG. 1, when three wafers (W) are stacked and placed on the conveyor hand (100), the load is measured by the load sensor (10) and the measured value is stored in the control unit. During the conveying process, the load is repeatedly measured by the load sensor (10), and if the load value measured by the load sensor (10) differs from the load value measured when the wafers (W) were initially stacked, it is determined that there is an alignment error, and if necessary, the conveying is stopped.

[0042] During the return process, if the load value measured by the load sensor (10) changes from the load value measured when the wafer (W) was initially stacked, it means that the wafer (W) has moved. For example, if the load value measured by the load sensor (10) placed to the left of the virtual line (L) shown in Fig. 1 has increased, it means that the wafer has moved to the left of the virtual line (L). As explained in the background art, the wafer placed at the very bottom is fixed by suction through the vacuum hole (210) formed in the support pad (220), so it does not move. However, the remaining wafers are supported only by frictional force and can move. The alignment of the wafer is checked by utilizing the principle that if the wafer placed second or third from the bottom moves even slightly to the left of the virtual line (L), the load value measured by the load sensor (10) placed to the left of the virtual line (L) increases due to that slight movement.

[0044] Hereinafter, an embodiment of a conveying device, which is the second form of the present invention, will be described.

[0045] The conveying device according to the present embodiment includes a conveying hand (100) and a driving arm (A).

[0046] The above-mentioned return hand (100) is configured to include a load sensor (10) and a control unit (20), but since this has been explained previously, further explanation will be omitted.

[0047] The above driving arm (A) is configured to drive the above-mentioned return hand (100) in combination with the above-mentioned return hand (100), and since it is a configuration commonly used in return devices, a detailed description is omitted.

[0049] Hereinafter, a method for verifying wafer alignment, which is the third embodiment of the present invention, will be described.

[0050] The method for verifying the alignment of a wafer according to the present embodiment includes a preparation step, a placement step, a first measurement step, a second measurement step, a comparison step, and a stopping step.

[0051] The above provisioning step is a step of providing the aforementioned return hand and a return device including the same.

[0052] The above mounting step is a step of mounting a wafer stacked in multiple sheets on the upper surface of the above-mentioned return hand.

[0053] The first measurement step is a step in which, while the wafer is mounted on the return hand (100) during the mounting step, each of the load sensors measures the load and inputs / stores the result to the control unit. The load measured in the first measurement step becomes the reference value for alignment verification.

[0054] The second measurement step above is a step in which, during the process of transporting wafers stacked in multiple layers, each load sensor measures the load and inputs the result to the control unit.

[0055] The above second measurement step is performed repeatedly during the return process, and the comparison step involves comparing the results of the repeatedly performed load measurements with the load results measured in the first measurement step.

[0056] If a difference is found between the load value measured in the first measurement step and the load value measured in the second measurement step during the comparison step, it can be determined that an abnormality has occurred in the wafer alignment, and in this case, a stop step is performed to stop the wafer transport if necessary.

[0058] Although specific details for implementing the present invention have been provided by describing preferred embodiments of the present invention above, the technical concept of the present invention is not limited to the described embodiments and can be embodied in various forms within the technical concept of the present invention. Explanation of the symbols

[0060] 100 : Return Hand 10 : Load Sensor 20 : Control unit

Claims

Claim 1 delete Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 A wafer conveying device for conveying a wafer stacked in multiple layers, comprising: a conveying hand including a plurality of load sensors formed on the upper surface and a control unit that measures a load by the load sensors, for conveying the wafer stacked in multiple layers by vacuum adsorbing the wafer placed at the bottom among the wafers stacked in multiple layers on the upper surface; and a driving arm that drives the conveying hand; wherein the wafer conveying device determines whether there is an abnormality in the alignment of the wafers stacked in multiple layers by utilizing the load change measured by each load sensor during the conveying process of the wafers stacked in multiple layers. Claim 6 delete Claim 7 In paragraph 5, the load sensor is a wafer transport device arranged in a line-symmetric manner. Claim 8 In claim 5, the wafer transport device wherein the control unit controls the wafer transport to stop if an abnormality is detected in the alignment of the multiple stacked wafers during the wafer transport process. Claim 9 A method for verifying wafer alignment, comprising: a step of providing a conveying hand for conveying a wafer by placing it on an upper surface, the conveying hand including a plurality of load sensors formed on the upper surface and a control unit that measures the load by the load sensors; a step of placing a wafer stacked in multiple layers on the upper surface of the conveying hand, wherein the wafer placed at the bottom among the stacked wafers is placed by vacuum suction; a first measurement step in which, after the placing step, each of the plurality of load sensors measures the load and inputs the result to a control unit; a second measurement step in which, during the process of conveying the wafer stacked in multiple layers, each load sensor measures the load and inputs the result to a control unit; and a comparison step of periodically repeating the second measurement step and comparing the measurement value of the first measurement step with the measurement value of the second measurement step to determine whether there is an abnormality in the alignment of the stacked wafers. Claim 10 A method for verifying wafer alignment according to claim 9, further comprising a stopping step for stopping return when there is a difference between the measurement value of the first measurement step and the measurement value of the second measurement step in the comparison step.

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