JPH07283289A - Wafer cassette transferring robot in semiconductor manufacturing device - Google Patents

Abstract

PURPOSE:To prevent generation of fine particles which adversely affect surface processing of a wafer and to enable a change of supply/receive position in relation to a cassette loader to a certain extent, by rotating first and second arms and plate receiving sections in a predetermined direction at a predetermined angle. CONSTITUTION:Since a rotational drive mechanism 33', a second rotation shaft 40' of an arm section 22 and a rotation shaft 23A of a plate receiving section 23 rotate under a rotating condition of 1:2:1+alpha, a wafer cassette 26 carried out by a cassette loader 25 and set on l the plate receiving section 23 can be linearly moved on a carrier line. Also, immediately before the wafer cassette 26 is set on a setting section 20D of a carrier stocker 20, the wafer cassette 26 can be rotationally moved by a predetermined angle beta and set on each shelf 20C of the carrier stocker 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment apparatus for heat-treating a semiconductor wafer, in which a wafer cassette on a cassette loader is conveyed to a carrier stocker in front of a reaction furnace, and vice versa. The present invention relates to a wafer cassette transfer robot used for returning a wafer cassette containing a wafer returned by a wafer transfer robot after being processed in the furnace to the outside of the furnace to a cassette loader. .

[0002]

2. Description of the Related Art FIG. 9 is a schematic perspective view showing a conventional semiconductor wafer surface treatment apparatus. Reference numeral 10 is a vertical reactor, 11 is a shutter arranged directly below the furnace, and 12 is a ball.
It is a toelevator. As shown in FIG. 10, the vertical reactor 10 includes a furnace body 13 in which a side wall and a furnace top are integrated, a heater 14 arranged inside the side wall, a quartz tube 15 and a support flange 16. A processing fluid (a mixed gas of hydrogen gas and nitrogen gas) is supplied to the quartz tube 15 for processing. 17
Is a semiconductor wafer to be surface-treated (hereinafter, simply referred to as a wafer
A boat having a shelf for stacking and accommodating a large number of Ws (hereinafter referred to as “C”) at regular intervals, and a boat support on the lift table 12A of the boat elevator 12 by the transfer device 18. 12B
Moved to. Each of the semiconductor wafers W (hereinafter, simply referred to as a wafer) is a shelf in the wafer cassette 26 having a plurality of shelves 26B arranged in multiple stages at regular intervals as shown in FIGS. The wafer cassette 26 is conveyed to a predetermined position on the cassette loader 25,
It is placed on a predetermined shelf of the carrier stocker 20 by a cassette transfer robot described later.

As shown in FIG. 13 in detail, the carrier stocker 20 is supported by four shelf posts 28 to 31 provided between the top plate 20A and the lower table 20B, and each shelf plate 20C is provided with a wafer. (C) Two mounting portions 20D for limiting the unintentional movement of the cassette 26 are provided side by side, the projections 32 are provided at both ends in the longitudinal direction of the mounting portion 20D, and the opening between both projections is a cassette. Is a passage for loading and unloading. In FIG. 9, reference numeral 21 denotes a wafer cassette transfer robot (abbreviated as a cassette transfer robot), which is a pair of left and right arm portions 22 and a pair of rotary drive mechanisms 33 for rotationally moving the arm portions 22. And a main body 36 having a lifting drive mechanism 35 capable of moving the base 34 up and down along the shelves of the carrier stocker 20.
Each of the first arm 22A and the second arm 2
2B is articulated, and the first arm 22A and the second arm 22B correspond to the human upper arm and lower arm, respectively.
At the tip of the second arm 22B, there is provided a receiving plate portion 23 on which the wafer cassette 26 is placed and conveyed, and the third rotating shaft 2
It is rotatably attached to the second arm 22B by 3A. The cassette transfer robot 21 is controlled by a cassette controller 24 that operates by receiving a command from a sequence controller (not shown) that controls the entire system.

Reference numeral 19 denotes a wafer transfer robot,
19A and a way to rotate and move this arm 19A
(C) A base including a rotation drive mechanism 37 of the transfer robot and a main body including a vertical drive mechanism 38 for moving the base up and down in the rack row direction of the carrier stocker 20.
A robot finger (also referred to as a spatula pencil) 19B for vacuum-adsorbing the wafer W is cantilever-supported at the tip of 9A. The wafer transfer robot 19 is controlled by a wafer controller 27 which operates by receiving a command signal from the sequence controller which controls the entire system. Two wafers juxtaposed on the cassette loader 25
The cassette 26 is simultaneously lifted by the receiving plate portion 23 of the cassette transfer robot 21, is rotationally moved along a predetermined path by the lifting drive mechanism 35 and the rotation drive mechanism 33 of the cassette transfer robot 21, and is conveyed to the carrier stocker 20 side. The carrier stocker 20 shown in FIGS. 9 and 13 is mounted on a mounting portion 20D on a predetermined shelf plate 20C.

In order to transfer the wafer W housed in the wafer cassette 26 mounted on the mounting portion 20D of the carrier stocker 20 to the boat 17, the wafer transfer robot 19 is used. , By its slide drive mechanism 39,
9 to the wafer loading / unloading direction of the carrier stocker 20 shown in FIG.
It is reciprocated in the direction of arrow a. Next, by the vertical drive mechanism 38 of the wafer transfer robot 19, among the plurality of wafer cassettes 26 placed on the carrier stocker 20,
The wafer cassette 26 in the order of transfer by the robot finger 19B is moved up and down to a position corresponding to the side opening surface 26A shown in FIGS. 11 and 12, and further the wafer transfer robot. The wafer W is horizontally taken out one by one from the wafer cassette 26 by using the fingers of FIG.
7 is used and transferred to the boat 17. Instead of the transfer method described above, the carrier transfer stocker 20 is moved by a slide drive mechanism so that the wafer transfer robot 19 is moved to the carrier transfer stocker 20.
The wafer loading / unloading direction may be matched. Way
The boat 17 on which the wafer W is transferred is mounted on the boat support base 12 on the lift base 12A shown in FIG.
The furnace body 1 is set on B, is lifted by the boat elevator 12, and is placed upright in the bottom opening of the furnace body 13.
A quartz tube 15 coaxially arranged in the quartz tube 3 is fed to a predetermined position in the quartz tube 15 through an opening at the bottom. Next, the wafer W is shielded from the atmosphere by the shutter 11 and sealed in the furnace body 13 to be processed in a high-temperature processing atmosphere.

[0006]

In the conventional cassette transfer robot 21 described above, the wafer transfer robot fingers 19B are used from the wafer cassettes 26 mounted on the respective shelves of the carrier stocker 20. In order to take out the wafer, the wafer transfer robot 19 or the carrier stocker 20 is moved by using the vertical drive mechanism 38, and the robot finger 19 is attached to the opening surface of the wafer cassette.
The height of B is made to coincide with each other, and the direction of the robot fingers 19B is made to coincide with the opening surface 26A of the wafer cassette 26 on each shelf plate by the rotation driving mechanism 37 of the wafer transfer robot. Since the wafer is transferred, fine particles are generated in the vicinity of the wafer cassette 26 on the carrier stocker at the friction parts of the rotary drive mechanism and the vertical drive mechanism, and the receiving plate of the cassette transfer robot. Between the bottom of the wafer cassette and the bottom of the wafer cassette, or between the bottom of the wafer cassette and the shelf 20C of the carrier stocker 20, fine particles are generated by friction, which adversely affects the surface treatment of the semiconductor wafer. there were.

In order to cope with such a problem, the applicant of the present application has found that the fingers of the wafer transfer robot 19 have a turning angle of 2β, and the fingers 1 on both sides (upper and lower in the figure) symmetrical to the carrier line.
When the cassette transfer robots 21A are arranged one by one and the inclination angle of the fingers of the wafer transfer robot 19 at the transfer position with respect to the carrier line is β, the arm portion of the cassette transfer robot is set to the cassette. Two arms, a first arm rotating about the rotation axis of the transfer robot and a second arm rotatably attached to the tip of the first arm and having the same length. When the first arm is rotated clockwise by an angle, for example, θ, the second arm rotates 2θ in the opposite direction, and the tip of the second arm is The second arm always moves linearly on the transfer path, and at the end of the transfer, the second arm has the same inclination angle β with respect to the transfer line as the finger 19B of the wafer transfer robot 19, and the tip of the second arm is on the receiving plate portion. The opening surface of the placed cassette was made to face the conveyance path at a right angle. Invented set transfer system and patent application (Japanese Patent Application No. 4-91035). FIG. 6 is a plan view showing the structure of the arm section 22 of the cassette transfer system of this prior application. The arm section 22 includes a first arm 22A and a second arm 22B. And the one end of the first arm 22A has a first rotating shaft 33 driven by a motor or the like.
This first arm 22 is swiveled around A and is swung
A second arm 22B is rotatably connected to the other end of A, and a receiving plate portion 23 for mounting a wafer cassette is provided at the tip of the second arm 22B. 9 is the same as the conventional wafer cassette transfer robot, but in the invention of this prior application, as shown in FIGS. 7 and 8, the lengths of the first arm 22A and the second arm 22B are long. When the first arm 22A is rotated about the first rotation axis 33A and the second arm 22B is made equal, the second arm 22B is rotated by the first arm 22A.
A second arm which is rotated about the rotation axis of the tip of A in the opposite direction by a double angle and moves with the backing plate portion mounted thereon.
The leading end of the frame 22B is designed to always go straight on the conveying line.
Further, when the inclination angle of the wafer transfer robot 19 with respect to the conveyance path of the fingers is β as described above, as shown in FIG. 8, the first arm 22A has the first rotation shaft 33.
It is rotated by a predetermined angle θ ₂ around A, and the inclination angles of the first and second arms with respect to the conveying path at the transfer position with the cassette stocker are both β, and the receiving position on the second arm is The opening surface of the wafer cassette placed on the plate portion is also made to face the tip of the finger of the wafer transfer robot 19 at a right angle.

However, the aforementioned cassette transfer system of the prior application has the following problems. 1) As is clear from FIG. 6, the arm section 22 has a mode
The first rotating shaft 33A of the first arm 22A driven by a motor and the like, and the first arm 22A at the tip of the first arm 22A.
A gear train 41 including a large number of gears 41a is connected between the second rotary shaft 40A that connects the second arm 22B and the second arm 22B. Further, from the second rotary shaft 40A to the third rotary shaft 23A of the receiving plate portion at the tip of the second arm 22B.
Similarly, the gear train 42 including a large number of gears 42a
Since a large number of gears are required for the entire arm portion 22 and the positions of the rotary shafts and teeth of each of these gears must be precisely machined, the entire gear will be smooth. There was a problem in construction that it did not work. 2) Further, the transfer position of the second arm 22B with respect to the cassette loader is limited to one point at which the inclination angle between the second arm 22B and the conveying line becomes the same as β, or Whether or not it can be variably selected to some extent has not been disclosed at the time of application, and even if it is variable, the first
It was also not disclosed how to specifically set the second arm and the relative rotation angle of the receiving plate portion with respect to the second arm. From this point of view, a solution that addresses the above problems has been desired. The present invention aims to solve this problem.

[0009]

In order to achieve the above object, the cassette transfer robot of the present invention has been solved by employing the following two motion mechanisms. For convenience of explanation, the cassette transfer robot will be described by selecting the right arm (upper side in FIG. 1) toward the cassette loader. The present invention has been solved by adopting the following two movement mechanisms described below. 1) Regarding the two arms of the cassette transfer robot,
As in the previous application, the characteristic of the isosceles triangle is utilized, and the rotation connecting the rotary shaft of the first arm driven by the rotary drive mechanism, the tip of the first arm and the second arm. Instead of the many gear trains in the invention of the prior application, the shaft and the shaft are rotatably connected via a gear and a timing belt, and when the first arm is rotated by a predetermined angle, the first arm is rotated. The second arm at the tip of the arm is rotated by a double angle so as to be pulled back in the direction opposite to the rotational movement of the first arm by the gear and the timing belt, and the second arm is rotated. -The tip of the frame always moves linearly on the line connecting the start point and the end point of the transport path. Therefore, the transfer position of the second arm with respect to the cassette loader is selected as an intermediate position between the rotation axis of the first arm on the cassette loader and the first arm on the cassette transfer robot within a range that does not hinder the movement. Set to enable the second route to the transport path at that time.
The variable tilt angle of the frame is α. In this state, the first arm, which is the other side of the isosceles triangle, is also inclined by the angle α in the opposite direction with respect to the transport path.
Rotate the arm of 2R- (α + β) clockwise,
In conjunction with this, if the second arm is rotated counterclockwise by a double angle in the opposite direction to the first arm, the first arm will rotate with the fixed shaft as the rotation shaft. The wafer transfer robot is tilted counterclockwise by β with respect to the carrier line, and the second arm linearly moves on the carrier line to reach a position tilted clockwise by β with respect to the carrier line. Corresponds to the finger tilt angle β. 2) A third rotating shaft is provided at the tip of the second arm opposite to the connecting point with the first arm, and a receiving plate for transferring the wafer cassette to and from the third rotating shaft. The part is fixed and is rotatably supported by the second arm, and is rotatably supported by the second arm via a gear and a timing belt, and is rotatably supported in the opposite direction to the second arm. That is, in the same direction as the first arm, it is further rotated by a predetermined angle, and at the end of the transfer, the opening surface of the wafer placed on the receiving plate is at the wafer receiving position. The fingers of the wafer transfer robot are inclined at an angle β with respect to the transfer line so that they are perpendicular to each other. 3) Specifically, in conjunction with the rotation of the second arm, the receiving plate portion at the tip of the second arm is rotated by 2R-α around the third rotation axis.
The rotation angle of the first arm in this case is 2R- (α + β), and the ratio of the rotation angles is 2R- (α + β): 2R-α = 1: 1 + δ, When the rotation angle of the first arm is 1, the problem is solved by rotating the rotation angle of the receiving plate by 1 + δ in the same direction.

[0010]

To facilitate understanding, referring to FIG. 3, the first arm 22A and the second arm 22B at the starting point of conveyance are indicated by the line segment AC ₁ and the line segment B ₁ C ₁ , respectively. Three line segments AC ₁ and C ₁ B
₁ and B ₁ A are isosceles triangles AC ₁ B ₁ (hereinafter ΔAC ₁ B ₁
), And ∠C ₁ B ₁ A = ∠C ₁ AB ₁ . Assuming that the second arm B ₁ C ₁ at the starting point of the conveyance has a bottom angle, that is, an inclination with respect to the conveyance path, ∠C ₁ B ₁ A = ∠C ₁ AB ₁
= Α and the extension of AC ₁ is CX, △ AC ₁ B
External angle B ₁ C ₁ X at the apex C _{1 1} is 2.alpha. Next, side A
When C ₁ (22A) rotates clockwise by an angle θ and vertex C ₁ moves to vertex C ₂ , the second arm (22B) also rotates counterclockwise about C ₁ by an angle 2θ. , Second
Assuming that the arm has not rotated, ΔAC ₁
B ₁ moves to ΔAC ₂ B ₂ indicated by the one-dot chain line. Actually, the side B ₂ C ₂ corresponding to the _second arm is rotated counterclockwise by ∠2θ around C ₂ , so the extension line of AC ₂ is C ₂ Y and B ₂ C _If the point where ₂ is rotated and intersects AB ₁ is B ₂ ′, then ∠B ₂ ′ C ₂ Y = 2α + 2θ. The first arm 22A indicated by AC ₁ rotates by θ to AC ₂ and ∠C ₂ AB ₂ ′ = ∠ (α + θ) = ∠α ₃ , so ∠C ₂ B ₂ ′ A = ∠ (α + θ) = ∠α ₃
Since ΔAC ₂ B ₂ ′ is an isosceles triangle, AC ₂
= B ₂ 'C _2, and the second A has moved - arm B _2' point B ₂ of C ₂ 'is the side B _2' becomes the tip of C _2.

As described above, the AC which is the first arm 22A.
With the rotation of ₁ , the second arm 22B rotates twice in the opposite direction, and its tip B is always on the line segment BA from B to A.
It will move in a straight line toward. Line segment AC ₁ (first
Arm 22A) of the second arm further rotates to a position perpendicular to the base BA to become AC, and the second arm is the line segment B ₁
C ₁ overlaps AC. When the line segment AC (first arm) is further rotated by an angle γ to become AC ₃ , the line segment B ₂ ′ C ₂
(Second A - arm) is rotated by an angle 2γ about the C _3, C ₃ B ₃ and since _{∠C 3 AB 3 = ∠C 3 B} 3 A next point B ₃ also extended line BA Be on the line. In this way, if the first arm 22A rotates clockwise by the angle .theta. And at the same time the second arm rotates counterclockwise by the angle 2.theta., The tip of the second arm will be the cassette. The transfer robot linearly moves on an extension line of the line AB connecting the point B, which is the transfer start point of the second arm, and the center A of the fixed rotation axis of the first arm. In the above description, the start point of conveyance is B ₁ and the second
Showed arm 22B as a line segment B ₁ C _1, Kasettoro - on the relationship between such arrangement Da, cassette transfer robot of the second A - even when the arm 22B is necessary to extend the left side of the conveying path in FIG occur is there. In that case, if the starting point of conveyance is B ₀ and the second arm 22B is a line segment B ₀ C ₀ , the arms 22A and 22A are
The B and the conveyance path △ AC ₀ B ₀ is formed, ∠C ₀ B ₀
A = α ₁ . In this case, with respect to the above-mentioned relational expression and the rotation angle of the receiving plate portion described below, it is sufficient to replace α with α ₁ .

Next, referring to FIG. 4, the receiving plate portion 23 mounted on the third rotating shaft 23A at the tip portion of the second arm 22B.
However, when the wafer cassette 26 is received with the opening surface facing forward, the wafer cassette 26 relatively rotates as the second arm 22B rotates and reaches the cassette stocker, the opening surface 26A of the wafer cassette 26 is opened. C. The angular relationship for rotating the transfer robot 19 to an angle facing the robot finger 19B at a right angle will be described. For the sake of convenience, the entire receiving plate portion 23 is considered as a square EFGH, and the third rotating shaft 2
3A is indicated by O, the wafer cassette placed on the receiving plate portion 23 is defined as an opening surface (open circle) 26A indicated by a chain line, and the second arm 22B is indicated by a line segment BC. When the opening surface 26A of the wafer cassette 26 placed on the receiving plate portion at the beginning of conveyance is placed parallel to the side EF of the square EFGH which is the receiving plate portion, EF indicates OK indicating the conveying line. Although perpendicular, it intersects with the side BC which is the second arm at an angle γ, and the arm BC is inclined by ∠α which is the complement of the angle γ with respect to the carrier line. The edge EF of the receiving plate portion, which was obliquely intersected with the second arm BC at an angle γ at the beginning of conveyance, becomes a right angle with respect to the second arm BC at the end point of conveyance, and the cassette transfer robot. In order to face the arm part of the armature at a right angle, it is necessary to rotate the side EF of the receiving plate part with respect to the second arm BC by a certain predetermined angle. Separated from the rotation angle of the arm BC with respect to the first arm AC, treat as a ratio of the rotation angle of the first arm AC with respect to the rotation axis A to the rotation angle of the receiving plate portion. You can

In order to make it easier to understand this rotating state, ΔF as a part of ΔEOK, which is 1/8 of the whole receiving plate portion.
Considering OK as a rotating body of a right triangle, the side OF of ΔFOK is an angle α (∠α) with respect to the second arm line BC.
Just lean. When the second arm 22B reaches the final position with respect to the cassette loader, that is, when it reaches B ₀ C ₀ in FIG. 3, the side FK is perpendicular to the second arm 22B (BC). In order to do so, it is necessary to rotate clockwise up to ΔOF ₁ K _{1 in} FIG. In this rotation, △ FOK rotates 180 ° and △
In the state of reaching OF ₂ K ₂ , the state has been over-rotated by ∠α, so it is necessary to return ∠α in reverse, that is, rotate by 2R−α. The second arm is ∠ to the carrier line
The rotation angle of the first arm required to reach the final transport position from the initial position inclined by α is 2R- from FIG.
In the case of (α + β), the rotation angle of the receiving plate corresponding to this is 2R−α, which is larger by β.
The gear ratio between the rotary shaft of the drum and the rotary shaft of the receiving plate is 2
The problem can be solved by setting R- (α + β): 2R-α = 1: 1 + δ. Here, the angle β is a fixed value determined by the turning angle of the fingers of the wafer transfer robot,
On the other hand, α is a variable angle determined by the transfer position when the transfer position with the cassette loader is selected within a certain range.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1, 2 and 5. FIG. 1 is a top view of essential parts showing peripheral equipment of a surface treatment system in which a cassette transfer robot 21 'according to the present invention is arranged. FIGS. 2A and 2B are cassettes according to the present invention. FIG. 2 is an enlarged top view of an upper arm part of FIG. 1 in a pair of arm parts 22 in a transfer robot 21 ′ and a side sectional view corresponding thereto. Arm part 22
Is a first arm 22A and a second arm 22 having the same length.
B, and the right end of the first arm 22A in the drawing is fixed to the rotary shaft 33'A of the rotary drive mechanism 33 '.
The second rotary shaft 4 is provided at the other (far) end of the arm 22A.
The second arm 22B is rotatably connected to the second arm 22B via 0'A. In FIG. 1, the rotary drive mechanism 33 'is connected to the cassette controller 24, and the first arm 22A is rotated by a command signal from this controller. 2A is a plan view of the arm portion 22, and FIG. 2B is a side view. In this embodiment, the rotary drive mechanism 33 'is a gear drive, motor - lower gear G ₁ fixed in the gear G ₁ and G ₂ which is fixed on top around the drive shaft S of the motor drive, the first The first rotation shaft 33′A meshes with the gear G ₃ fixed to the first rotation shaft 33′A to rotate the first rotation shaft 33′A by half, while the upper gear G ₂ is fixed to the outer circumference of the tubular rotation shaft 33B. meshing with the gear G ₄ of the number of teeth, the tubular rotary shaft 33B to the rotation of the drive shaft S is the angle rotated twice in the same direction as the first rotational shaft 33'a. Therefore, the drive shaft causes the first rotary shaft 33 'to rotate.
When A and the first arm 22A rotate integrally by an angle θ as shown in FIG. 3, the gear 33'a moves in the same direction by 2θ.
Since it rotates, the gear 33'a further rotates .theta. With respect to the first rotating shaft 33'A and the first arm 22A which rotate by .theta ..

In FIG. 2B, reference numeral 51 is a first timing belt, which rotates the tubular rotary shaft 33B of the rotary drive mechanism 33 'by rotating the gear 33'a, the intermediate gears 34c, 3 and 3.
It transmits to the 2nd rotating shaft 40'A via 4b, and rotates the 2nd arm 22B. The first rotating shaft 33'A and the second
The intermediate shaft 34B is mounted between the rotary shaft 40'A and the rotary shaft 40'A so as to be rotatable relative to the first arm 22A, and the timing belt 51 is fixed to the tubular rotary shaft 33B.
3'a and the intermediate gear 3 in the two intermediate gears 34b and 34c which have the same number of teeth and are coaxially overlapped with each other and whose rotation directions are opposite to each other.
The rotation of 4b is transmitted to the gear 40a, and the gear 40a is fixed to the second rotating shaft 40'A connecting the second arm 22B and the first arm 22A. Since this is done, the rotation angle of the second arm 22B with respect to the rotation axis 40'A is 2 relative to the rotation angle with respect to the first rotation axis 33'A.
That is, the rotation ratio of the rotation shaft 33'A of the first arm 22A and the rotation shaft 40'A of the second arm 22B rotates in the opposite directions at a ratio of 1: 2.

In FIG. 2A and FIG. 2B, reference numeral 52 is a second timing belt, which rotates the gear 40b mounted on the second rotary shaft 40'A to the third rotation. It transmits to the gear 52a mounted on the shaft 23A and rotates the receiving plate portion 23 rotatably supported by the tip of the second arm 22B so as to rotate. The rotation of the tubular rotary shaft 33B of the rotary drive mechanism 33 'is transmitted to the rotary shaft 23A of the second arm 22B by the second timing belt. The above-mentioned first timing belt 51 and gear 4
0a, 40'a, 40'b, 40b and the gear ratio of the gear 52a are the receiving plate 2 fixed to the third rotating shaft 23A.
3 is (1 + δ) for one rotation of the first rotating shaft 33′A.
Set to rotate. With reference to FIGS. 1, 2 and 5, the rotary drive mechanism 33 ′ of each of the pair of arm portions 22 is connected to the cassette control device 24, from which the rotation control mechanism 33 ′ rotates. When the rotation command signal including the conditions of the direction and the rotation angle is input, the first arm 22A and the first rotation shaft 33'A are integrated with each other by rotating based on the input rotation command signal. Turn in the direction. To transfer the wafer cassette 26 by moving the receiving plate portion 23 on which the wafer cassette 26 is placed and the second arm 22B supporting the same to the carrier stocker side, first, the first rotating shaft 33 ′ A is the first arm 22A
And rotate it in the clockwise direction.

As a result, the first timing belt 51
Through the tubular rotary shaft 33B of the rotary drive mechanism 33 '.
The rotary motion of the first rotary shaft 33′A transmitted to the second rotary shaft 40′A so that the rotation angle is doubled,
The rotation angle of the rotation shaft 23A of the receiving plate portion 23 at the tip of the arm 22B is converted into a predetermined rotation angle and transmitted, and the receiving plate portion 23 of the wafer cassette 26 is additionally rotated by a predetermined angle. Wafer cassette 26 transferred to receiving plate 23
However, the second arm 22B of each cassette transfer robot 21A has an angle .beta. With respect to the linear movement path of the wafer cassette in the state where it reaches the predetermined mounting portion 20D of the carrier stocker 20 by the above linear movement. The opening surface 26A of the wafer cassette 26 on the receiving plate 23 is inclined at right angles to the second arm 22B, and at the same time the first arm 2 is tilted.
2A is also inclined by an angle β with respect to the transport path. In a state in which the pencil 19B of the wafer transfer robot 19 is also inclined by the angle β with respect to the linear movement path on the extension line of the second arm 22B and vertically faces the opening surface 26A of the wafer cassette 26. The wafer W is taken out from the wafer cassette 26 placed on the carrier stocker 20. According to the wafer cassette transfer robot of the present invention, the first arm 22A and the second arm 22B are always formed into an isosceles triangle by simply rotating the tubular rotary shaft 33B of the rotary drive mechanism 33 '. By forming two sides and changing the shape, the second arm 22B puts the wafer cassette 26 on the receiving plate portion 23 at the tip thereof and moves in a straight line from the start position to the end position of the conveyance. Therefore, the transfer speed is much higher than that of a wafer transfer robot that transfers wafers one by one. Therefore, as described with reference to FIGS. It is not necessary to arrange a carrier stocker having a plurality of different shelves, and the wafer cassette 2
It may be as simple as placing 6 on it. Others are the same as the configuration shown in the related art.

In such a structure, the operation procedure for placing the wafer cassette 26 from the cassette loader 25 to each shelf plate 20C of the carrier stocker 20 by the cassette transfer robot 21 'is the same as that of the prior art, so that it will be described. Is omitted.

As described above, according to the cassette transfer robot of this embodiment, the wafer transferred by the cassette loader 25 is used.
The cassette 26 is used as a rotary drive mechanism 33 ', a second rotary shaft 40'A of the arm portion 22, and a rotary shaft 23A of the receiving plate portion 23.
Are rotated under the rotation condition of 1: 2: 1 + δ, the wafer cassette 26 mounted on the receiving plate portion 23 is rotated.
Can be linearly moved on the carrier line, and the wafer cassette 26 can be mounted on the mounting portion 2 of the carrier stocker 20.
In a state immediately before being placed on 0D, it can be rotationally moved by a predetermined angle β and placed on each shelf plate 20C of the carrier stocker 20.

[0020]

As described in detail above, according to the cassette transfer robot of the present invention, the rotation drive mechanism, the rotation shaft of the arm portion, and the rotation shaft of the receiving plate portion are rotated by 1: 2: 1 + δ. Since each is rotated under the conditions, the following effects are achieved. 1) The transfer position of the cassette transfer robot with respect to the cassette loader can be changed and set within a certain range on the transfer line,
If the tilt angle of the second arm with respect to the carrier line is designated as α and the tilt angle of the wafer transfer robot with respect to the carrier line is designated as β at the set position, the above α and β are known values. From the relational expression, the rotation angle of the first arm and the rotation angle of the receiving plate at the tip of the second arm with respect to this rotation angle can be calculated and dealt with. 2) Instead of the rotation transmission system by the gear train adopted in the applicant's prior invention, the transmission system by gears and timing belts is adopted, so that the machining that requires precision of a large number of gears and a rotary shaft supporting the gears is reduced. it can.

[Brief description of drawings]

FIG. 1 is a top view showing a semiconductor surface treatment system in which a cassette transfer robot of the present invention is arranged.

FIG. 2A is an enlarged top view of an arm portion of the cassette transfer robot of the present invention, and FIG. 2B is a side view of FIG. 2A.

FIG. 3 is an explanatory diagram showing a movement operation of an arm portion of the cassette transfer robot in FIGS. 1 and 2.

FIG. 4 is an explanatory diagram showing a required rotation angle of a receiving plate portion of the cassette transfer robot in FIGS. 1 and 2 with respect to a second arm.

FIG. 5 is a schematic side view of a cassette transfer system using an embodiment of the present invention.

FIG. 6 is an enlarged top view of an arm portion in the surface treatment apparatus of the prior invention.

FIG. 7 is a top view showing a part of the movement of the arm part in the surface treatment apparatus of the prior invention.

FIG. 8 is a top view showing the movement of the arm portion in the surface treatment apparatus of the prior invention.

FIG. 9 is a perspective view showing an entire wafer surface treatment apparatus according to a conventional technique.

FIG. 10 is a vertical sectional view of a surface treatment furnace.

FIG. 11 is a vertical sectional view showing the structure of a wafer cassette.

FIG. 12 is a top view showing the structure of the wafer cassette.

FIG. 13 is a perspective view showing details of the carrier stocker in FIG. 9.

[Explanation of symbols]

19 wafer transfer robot 20 carrier stocker 21A respective wafer cassette transfer robot (cassette transfer robot) 21 'wafer cassette transfer robot (cassette transfer robot) 22 arm section 22A first arm Mu 22B 2nd arm 23 Support plate part 23A 3rd rotating shaft 25 Cassette loader 26 Wafer cassette 26A Wafer cassette opening surface 33B Tubular rotating shaft 33'A 1st rotating shaft 34B, 40B Intermediate shaft 35 Lifting / lowering drive mechanism 40'A Second rotating shaft 51 First timing belt 52 Second timing belt

Claims (4)

[Claims] 1. A cassette loader for mounting a wafer cassette in a semiconductor manufacturing apparatus, a carrier stocker arranged as a relay storage area for transferring wafers to and from a wafer transfer robot arranged in front of a surface treatment furnace, A wafer cassette, which is arranged in the middle of the carrier line connecting the carrier stocker and the cassette loader and has a predetermined number of wafers before processing, is received from the cassette loader and placed in the carrier stocker, or vice versa. A wafer cassette transfer system comprising: a pair of wafer cassette transfer robots symmetrically arranged with respect to the transfer line for returning a wafer cassette containing a completed wafer to the cassette loader. A wafer cassette transfer robot, wherein each of the pair of wafer cassette transfer robots has a main body and one end. Serial first of A, which is attached to the body - and no,
One end is articulated to the other end of the first arm, and an arm portion having a second arm having a length equal to that of the first arm, and the second arm. And a receiving plate portion mounted so as to be pivotable around the pivot axis of the arm of the arm for mounting the wafer cassette; rotating the first arm, and interlocking with this rotation, the first arm is rotated. A rotation interlocking mechanism for rotating each of the two arms and the receiving plate portion by a predetermined angle, and an elevating mechanism for elevating the rotation interlocking mechanism and the arm portion; When the arm is rotated about the rotation axis by a predetermined angle, the second arm rotates the rotation angle of the first arm about the rotation axis of the tip of the first arm. Is rotated in the opposite direction by an angle twice as large as that of the first arm, and the tip end thereof is pulled back from the movement of the first arm by the rotation, so that the transfer position with respect to the cassette loader is changed. From the to the transfer position with the carrier stocker section is linearly moved along the transfer trajectory, and is aligned on the extension line of the finger of the wafer transfer robot at a predetermined angle with respect to the transfer line at the transfer position, The receiving plate portion at the tip of the second arm is rotated by a predetermined angle in the same direction as the rotation of the first arm, so that the wafer cassette mounted on the receiving plate portion is rotated. A wafer cassette transfer robot in a semiconductor manufacturing apparatus, the opening surface of which faces the second arm of the wafer cassette transfer robot at a right angle. 2. The wafer cassette transfer robot according to claim 1, wherein the second arm is placed at a transfer position with respect to a set position of a cassette loader that is selectable within a predetermined range. When the tilt angle with respect to the carrier line when the wafer is transferred is α, and the tilt angle of the fingers at the transfer position of the wafer transfer robot with respect to the carrier line is β, the first arm is 2R- (α + β). The second arm is rotated by an angle.
A wafer cassette transfer robot in a semiconductor manufacturing apparatus, wherein the wafer is rotated at an end of the first arm in the opposite direction by an angle twice the above angle. 3. The wafer cassette transfer robot according to claim 1 or 2, wherein the receiving plate portion at the tip of the second arm has a rotation angle 2 of a rotary shaft for rotating the first arm.
2R- (α) with respect to R- (α + β), that is, 1: 1 + δ
A wafer cassette transfer robot in a semiconductor manufacturing apparatus, which is rotated at a ratio of 4. The wafer cassette transfer robot according to any one of claims 1 to 3, wherein a first rotating shaft connecting the main body of the transfer robot and a first arm, and the first rotating shaft. Between a second rotation shaft connecting the first rotation shaft and the tip of the first arm and the second arm, and the second rotation shaft.
Between the rotary shaft of the second rotary arm and the third rotary shaft connecting the receiving plate to the tip of the second arm, gears provided on the rotary shafts, these rotary shafts, and the next rotary shaft. , One intermediate gear and a timing belt, respectively, are gear-coupled to each other with a predetermined gear ratio, and the first and second arms and the receiving plate portion have a predetermined angle and a predetermined direction. A wafer cassette transfer robot in a semiconductor manufacturing apparatus, characterized in that the robot is rotated in a horizontal direction.