Wafer carrying device and control method thereof

Abstract

The wafer carrying device comprises a platform for carrying wafers and is characterized by further comprising a base for supporting the platform, a groove position for installing the platform is formed in the base, the platform is supported and suspended in the groove position through a supporting body, and the base is provided with a vacuum generator and communicated with the groove position. A distance sensor facing upwards is arranged on the base and electrically connected with the vacuum generator through a controller. According to the invention, redundant gas generated by wafer descending can be extracted, so that the wafer descending is free from gas obstruction, and the wafer can smoothly fall onto a wafer platform; according to the invention, the falling deflection angle of the wafer can be adjusted, so that the wafer can always fall on the platform horizontally when falling, and the damage risk is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and particularly relates to a wafer placement device and a control method thereof. Background Art

[0002] In semiconductor equipment, the placement of wafers requires a certain degree of precision. The wafers need to be placed at specific positions so that the lithography machine can produce a standard number of chips during lithography. When the wafers are offset, it may cause waste of wafers, resulting in an insufficient number of chips produced from a single wafer and increasing costs. When placing wafers on a wafer placement platform, generally a robotic arm is used for placement, or PIN needles are used for adsorption and placement. After the wafers approach the platform at a short distance, they need to be separated from the robotic arm or the adsorption device, and then the wafers freely fall onto the corresponding positions on the platform. When the wafers fall, since there is a gap between the wafer platform, the air in the gap will be compressed as the wafers descend, and the air will push the wafers away from the platform. Therefore, it may cause the wafers to deviate from the predetermined positions, affecting the precision of wafer manufacturing. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a wafer placement device and a control method thereof to solve the problem that it is difficult for wafers to fall into the target positions.

[0004] Based on the technical problems existing in the background art, the present invention proposes a wafer placement device, including a platform for placing wafers and a base for supporting the platform. The base is provided with a slot for installing the platform, and the platform is supported by a support body and suspended in the slot. The base is provided with a vacuum generator and is connected to the slot, and a distance sensor facing upward is arranged on the base. The distance sensor and the vacuum generator are electrically connected through a controller.

[0005] Preferably, there are a plurality of the vacuum generators and they are circumferentially distributed in the slot, and the number of the vacuum generators is an even number.

[0006] Preferably, every two of the vacuum generators form a group, and the distances of the two vacuum generators in each group from the center of the platform are the same, and the connection line of the two vacuum generators in each group coincides with the diameter of the platform.

[0007] Preferably, the vacuum generators are located below the platform, and the suction ports of the vacuum generators penetrate through the platform to the upper surface of the platform and are in the same plane as the upper surface of the platform.

[0008] Preferably, there are a plurality of the distance sensors, and one distance sensor is correspondingly installed on the side of each suction device, and the distances of each distance sensor from the center of the platform are the same.

[0009] Preferably, all the distance sensors are electrically connected to a controller, and the controller is electrically connected to a vacuum generator. Each distance sensor can control the opening and closing of the corresponding vacuum emission device through the controller.

[0010] Preferably, the upper surface of the platform and the emission point of the distance sensor are in the same plane.

[0011] A control method for a wafer carrier device includes the following steps:

[0012] S1: Set the longitudinal critical distance between the wafer distance sensors as h;

[0013] S2: Set the actual distance between the wafer and the sensor as H;

[0014] S3: When the sensor detects that 0 < H < h, the vacuum generator starts;

[0015] S4: When H = 0, the vacuum generator reduces the operating power.

[0016] Preferably, it includes the following steps:

[0017] S11: Set the volume of air extruded per unit time when the wafer descends as V 压 , the radius of the wafer is r, the landing speed of the wafer is V 压 , the landing time is t, then it can be obtained that V 压 = πr 2 V 晶 t;

[0018] S12: Set the volume of air exhausted per unit time directly below the wafer as V 排 , then it can be obtained that V 排 = 2πrH;

[0019] S13: When V 压 = V 排 , H is at the critical value, then it can be obtained that H = V 晶 tr / 2.

[0020] Preferably, it includes the following steps:

[0021] S21: The distance sensors corresponding to two vacuum generators in the same group respectively detect the distances from the two wafers;

[0022] S22: Adjust the power of the two vacuum generators in the same group through the two distance sensors in the same group;

[0023] S23: When the distances from the wafer measured by two distance sensors in the same group are equal, the starting powers of the two vacuum generators in the same group are the same. When the distances from the wafer measured by the two distance sensors are not equal, the two vacuum generators in the same group adjust different powers to adjust the skew direction of the wafer.

[0024] S24: The sum of the suction volumes of all the vacuum generators is V 吸 = V 压 - V 排 。

[0025] Compared with the prior art, a wafer placement device and its control method proposed by the present invention adopt the above technical solutions and achieve the following technical effects:

[0026] The present invention can extract the excess gas generated by the descent of the wafer, so that the wafer can descend without gas obstruction and can smoothly fall onto the wafer platform; the present invention can adjust the angle of deflection of the wafer during the fall, so that the wafer can always fall horizontally on the platform when it drops, reducing the risk of damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0028] Figure 2 is a schematic diagram of the wafer dropping process of the present invention Figure 1 ;

[0029] Figure 3 is a schematic diagram of the wafer dropping process of the present invention Figure 2 。

[0030] In the figure: 1, platform; 2, base; 21, slot; 3, support; 4, distance sensor; 5, vacuum generator; 6, controller. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] In the present invention, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected", "fixed" and other terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, or electrically connected or communicable with each other through a controller; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0032] In the present invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply indicates that the horizontal height of the first feature is less than that of the second feature.

[0033] Embodiment

[0034] Please refer to Figures 1 - 3 , the present invention provides a wafer placement device, including a platform 1 for placing a wafer, a base 2 for supporting the platform 1. The base 2 is provided with a slot 21 for installing the platform 1. The platform 1 is supported by a support 3 and suspended in the slot 21. The base 2 is provided with a vacuum generator 5 which communicates with the slot 21. A distance sensor 4 facing upward is arranged on the base 2. The distance sensor 4 and the vacuum generator 5 are electrically connected through a controller 6. In this solution, the volume excluded by the wafer during descent is related to the area. The height of the wafer descending per unit area is the volume of the wafer discharged per unit time. There is a space between the wafer and the platform 11, and its opening is the lateral area of the cylinder between the wafer and the projection of the wafer. Then the size of the exhaust opening is the circumference of the wafer multiplied by the height of the wafer from the platform 11. During the descent process, the volume of the wafer extruded per unit time is only related to the descending height, and the volume of the wafer extruded per unit time is continuously increasing or remaining balanced. However, due to the height, the exhaust space will continuously decrease. When the volume of the air extruded by the wafer is equal to the volume of the air exhausted, the height between the wafer and the platform 11 will reach a critical value. At this time, when the wafer descends, due to the untimely exhaustion of the air, the exhausted air will increase its speed and escape from under the wafer, which will generate a push on the wafer. Therefore, as long as the air extracted by the vacuum generator 55 plus the gas exhausted from the bottom of the wafer is equal to the gas extruded by the wafer, there will be no horizontal pushing force of the air on the wafer, and the stable landing of the wafer can be achieved.

[0035] In a specific embodiment, referring to Figure 2 , Figure 3 , there are multiple vacuum generators 5 which are circumferentially distributed in the slot 21. The number of the vacuum generators 5 is an even number. Every two vacuum generators 5 form a group. The distances of the two vacuum generators 5 in each group from the center of the circle of the platform 1 are the same. The connection line of the two vacuum generators 5 in each group coincides with the diameter of the platform 1. In this solution, multiple vacuum generators are adopted. It is also possible to use a total vacuum generator to suck air and achieve the technical effects in this solution through multiple controllable suction ports.

[0036] In a specific embodiment, refer to Figure 2 , Figure 3 . The vacuum generator 5 is located below the platform 1. The suction port of the vacuum generator 5 penetrates through the platform 1 to the upper surface of the platform 1 and is in the same plane as the upper surface of the platform 1. The distance error between the vacuum generator 5 and the wafer may cause unstable wafer control. Therefore, it is necessary to ensure that the distance between each vacuum generator 5 and the wafer is equal.

[0037] In a specific embodiment, refer to Figure 2 , Figure 3 . There are multiple distance sensors 4. One distance sensor 4 is correspondingly installed on the side of each suction device. The central distance of each distance sensor 4 from the platform 1 is the same. In this solution, the points projected by the distance sensors 4 in the same group on the wafer are at two balance points, which can accurately judge whether the wafer has flipped and adjust it in time through the vacuum generator 5.

[0038] In a specific embodiment, refer to Figure 2 , Figure 3 . All the distance sensors 4 are electrically connected to the controller 6, and the controller 6 is electrically connected to the vacuum generator 5. Each distance sensor 4 can control the opening and closing of the corresponding vacuum emission device through the controller 6. When the distances from the wafer measured by the two distance sensors 4 in the same group are equal, the starting powers of the two vacuum generators 5 in the same group are the same. When the distances from the wafer measured by the two distance sensors 4 are not equal, the two vacuum generators 5 in the same group adjust different powers to adjust the skew direction of the wafer. Multiple groups of vacuum generators 5 can adjust in multiple directions of the wafer to make the wafer in a horizontal state.

[0039] In a specific embodiment, refer to Figure 2 , Figure 3 . The upper surface of the platform 1 and the emission point of the distance sensor 4 are in the same plane. The distance sensor 4 can detect the distance from the wafer to the platform 1. The monitoring points of each distance sensor 4 are on the same horizontal plane.

[0040] A control method for a wafer carrier device includes the following steps:

[0041] S1: Set the longitudinal critical distance between the wafer distance sensors 4 as h;

[0042] S2: Set the actual distance between the wafer and the sensor as H; In this solution, H is used to detect the distance with the wafer as the reference point. It can also be calculated with a point on the PIN pins that hold the wafer or are in contact with the wafer as the reference point;

[0043] S3: When the sensor detects 0 < H < h, the vacuum generator 5 starts;

[0044] S4: When H = 0, the vacuum generator 5 reduces its operating power.

[0045] In a specific embodiment, the following steps are included.

[0046] S11: Set the volume of air squeezed per unit time when the wafer descends to be V 压 , the radius of the wafer is r, the descending speed of the wafer is V 压 , and the descending time is t, then V 压 = πr 2 V 晶 t;

[0047] S12: Set the volume of air exhausted per unit time directly below the wafer to be V 排 , then V 排 = 2πrH;

[0048] S13: When V 压 = V 排 , H is at the critical value, then H = V 晶 tr / 2.

[0049] In a specific embodiment, the following steps are included.

[0050] S21: The distance sensors 4 corresponding to two vacuum generators 5 in the same group respectively detect the distances from the two sensors to the wafer.

[0051] S22: Adjust the power of the two vacuum generators 5 in the same group through the two distance sensors 4 in the same group.

[0052] S23: When the distances from the two distance sensors 4 in the same group to the wafer are equal, the starting powers of the two vacuum generators 5 in the same group are the same. When the distances from the two distance sensors 4 to the wafer are not equal, the two vacuum generators 5 in the same group adjust different powers to adjust the skew direction of the wafer.

[0053] S24: The total suction volume of all vacuum generators (5) is V 吸 = V 压 - V 排 .

[0054] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A wafer loading device, comprising a platform (1) for loading wafers, characterized in that: The invention also comprises a base (2) supporting the platform (1), the base (2) being provided with a slot (21) for mounting the platform (1), the platform (1) being supported by a support body (3) and suspended in the slot (21), the base (2) being provided with a vacuum generator (5) and being connected to the slot (21), the base (2) being provided with a distance sensor (4) facing upward, the distance sensor (4) being electrically connected to the vacuum generator (5) via a controller (6).

2. The wafer mounting device according to claim 1, characterized in that: The vacuum generators (5) are in plurality and are circumferentially distributed in the slots (21), and the number of the vacuum generators (5) is an even number.

3. The wafer mounting device according to claim 1, characterized in that: Every two vacuum generators (5) form a group, the two vacuum generators (5) in each group are at the same distance from the center of the platform (1), and the connecting line of the two vacuum generators (5) in each group coincides with the diameter of the platform (1).

4. The wafer mounting device according to claim 1, characterized in that: The vacuum generator (5) is located below the platform (1); the air suction port of the vacuum generator (5) penetrates the platform (1) to the upper surface of the platform (1) and is in the same plane as the upper surface of the platform (1).

5. The wafer mounting device according to claim 1, characterized in that: There are a plurality of distance sensors (4), one distance sensor (4) being correspondingly mounted on the side of each air suction device, and each distance sensor (4) being at the same distance from the center of the platform (1).

6. The wafer mounting device according to claim 1, characterized in that: All the distance sensors (4) are electrically connected to a controller (6), and the controller (6) is electrically connected to a vacuum generator (5). Each distance sensor (4) can control the opening and closing of a corresponding vacuum emission device through the controller (6).

7. The wafer mounting device according to claim 1, characterized in that: The upper surface of the platform (1) and the emission point of the distance sensor (4) are in the same plane.

8. A control method for a wafer carrier device, used for the wafer loading device according to any one of claims 1 to 7, the method comprising the following steps: S1: setting the longitudinal critical distance between the wafer distance sensors (4) to h; S2: Set the actual distance between the wafer and the sensor to H; S3: When the sensor detects 0<H<h, the vacuum generator (5) starts; S4: When H=0, the vacuum generator (5) reduces the operating power.

9. The control method of the wafer carrier device according to claim 8, comprising the following steps: S11: Set the volume of air squeezed per unit time when the wafer descends to V 压 , the radius of the wafer is r, and the falling speed of the wafer is V 压 , the landing time is t, then V 压 =πr 2 V 晶 t; S12: Set the exhaust volume per unit time directly below the wafer to V 排 , then V 排 =2πrH; S13: When V 压 =V 排 When H is at the critical value, we can get H=V 晶 tr / 2.

10. The control method of the wafer carrier device according to claim 9, comprising the following steps: S21: the distance sensors (4) corresponding to the two vacuum generators (5) in the same group respectively detect the distances between the two distance wafers; S22: adjusting the power of two vacuum generators (5) in the same group through two distance sensors (4) in the same group; S23: When the distances from the wafer measured by the two distance sensors (4) in the same group are equal, the two vacuum generators (5) in the same group are started with the same power; when the distances from the wafer measured by the two distance sensors (4) are not equal, the two vacuum generators (5) in the same group are adjusted to different powers to adjust the skew direction of the wafer. S24: The sum of the suction volumes of all vacuum generators (5) is V 吸 =V 压 -V 排 .

Images