JP5553062B2 - Positioning device and positioning method - Google Patents

Description

  The present invention relates to a positioning apparatus and a positioning method used for positioning a wafer in a stepper apparatus, for example.

  Patent Document 1 discloses a positioning device having a notch pin movably attached to a stage and a positioning pin fixed to the stage. This positioning apparatus presses a wafer against positioning pins by pressing the wafer with a notch pin applied to a notch (V-shaped notch) of the wafer. The wafer is positioned at a predetermined position on the stage by the notch pins and the positioning pins.

JP-A-9-219437

  An epitaxial layer is formed on the wafer to obtain the desired characteristics. The wafer on which the epitaxial layer is formed has a certain warpage. In addition, a convex portion having an acute angle may be formed on the edge of the wafer on which the epitaxial layer is formed.

  When the above-described wafer is positioned at a predetermined position on the stage, the convex portion may be stuck in the positioning pins while the wafer is warped. If the convex portion pierces the positioning pin, the warpage of the wafer cannot be suppressed, and an error of the positioning device may occur or the wafer processing may be hindered.

  SUMMARY An advantage of some aspects of the invention is that it provides a positioning device and a positioning method capable of positioning a wafer at a predetermined position while suppressing warpage of the wafer.

  A positioning apparatus according to the present invention includes a stage for placing a wafer, suction means for sucking the wafer to the stage, positioning pins attached to the stage for positioning the wafer at a predetermined position on the stage, A notch pin formed in a shape corresponding to the notch of the wafer so as to be movable in a direction of pressing the wafer against the positioning pin, and a retracting means for retracting the positioning pin in a direction away from the wafer. And

  Another positioning apparatus according to the present invention includes a stage on which a wafer is placed, a suction means for sucking the wafer to the stage, and a positioning attached to the stage for positioning the wafer at a predetermined position on the stage. A pin and a notch pin formed in a shape corresponding to the notch of the wafer so as to be movable in a direction of pressing the wafer against the positioning pin. The positioning pin is attached to the stage so as to avoid a position that forms an odd multiple of 45 ° with respect to the direction of the notch pin from the center position of the wafer.

  Another positioning apparatus according to the present invention includes a stage on which a wafer is placed, suction means for sucking the wafer to the stage, and a recess formed in a direction toward the center of the stage, and is placed at a predetermined position on the stage. A positioning pin attached to the stage for positioning the wafer, and a notch pin formed in a shape that hits the notch of the wafer and movable in a direction of pressing the wafer against the positioning pin. .

  The positioning method according to the present invention includes a step of placing a wafer on which a notch is formed on a stage, a step of pressing a notch pin against the notch, pressing the wafer against a positioning pin attached to the stage, and A step of attracting the wafer to the stage after being pressed against the positioning pin; and a step of retracting the positioning pin in a direction away from the wafer after the wafer is attracted to the stage. Features.

  According to the present invention, the wafer can be positioned at a predetermined position while suppressing the warpage of the wafer.

It is a top view of the positioning device which concerns on Embodiment 1 of this invention. It is a figure which shows the positioning method by the positioning device which concerns on Embodiment 1 of this invention. It is sectional drawing in the 3-3 broken line of FIG. It is a figure which shows retracting | locating a positioning pin. It is sectional drawing in the 5-5 broken line of FIG. It is a top view of the positioning device which concerns on Embodiment 2 of this invention. It is sectional drawing which shows the positioning pin which concerns on Embodiment 3 of this invention. It is sectional drawing which shows that the curvature of the wafer was suppressed. It is sectional drawing which shows the positioning pin which concerns on Embodiment 4 of this invention. It is sectional drawing which shows that the curvature of the wafer was suppressed.

Embodiment 1 FIG.
FIG. 1 is a plan view of a positioning device according to Embodiment 1 of the present invention. The positioning device 10 has a stage 14 on a disc placed on a base 12. The stage 14 is formed for mounting a wafer. The stage 14 is formed with suction means 16 for sucking the wafer onto the stage 14. The adsorbing means 16 has an intake port 16a and an intake port 16b. These intake ports 16a and 16b are formed in order to vacuum-suck the wafer to the stage 14.

  The positioning device 10 has positioning pins 30 and 34 attached to the stage 14. The positioning pins 30 and 34 position the wafer at a predetermined position on the stage 14. The positioning pins 30 and 34 can be retracted away from the wafer by retracting means 32 and 36, respectively. The retracting means 32 and 36 are configured to move the positioning pins 30 and 34 in the outer peripheral direction of the stage 14 according to an instruction from the operator, for example.

  A notch pin 20 is formed in a shape corresponding to a notch of a wafer placed on the stage 14. The notch pins 20 are formed so as to be movable in a direction in which the wafer is pressed against the positioning pins 30 and 32.

  Hereinafter, a wafer positioning method using the positioning apparatus 10 will be described. FIG. 2 is a diagram showing a positioning method by the positioning device according to Embodiment 1 of the present invention. The wafer 40 on which the notch 42 is formed is placed on the stage 14. Next, the wafer 40 is pressed against the positioning pins 30 and 34 by moving the notch pin 20 in the arrow direction of FIG. Thus, the wafer 40 is positioned at a predetermined position.

  3 is a cross-sectional view taken along a broken line 3-3 in FIG. The wafer 40 is obtained by forming an epitaxial layer 40b on a <100> substrate 40a formed of a low-resistance CZ single crystal mirror wafer. The substrate 40a is formed to have a p-type conductivity type. The edge of the substrate 40a is chamfered over the entire circumference in order to prevent chipping and the like from occurring during handling. Therefore, surfaces having various plane orientations other than the <100> plane appear at the edge of the substrate 40a.

  The epitaxial layer 40b is obtained by forming an n + buffer layer and an n− high resistance layer in this order on a substrate 40a. The layer thickness of the n-high resistance layer is 120 μm. The entire thickness of the wafer 40 reaches about 500 to 700 μm. Therefore, the wafer 40 has a certain warp. In addition, since the growth of the epitaxial layer 40b has crystal plane dependency, a convex portion 40c having a sharp point is formed at the edge of the wafer 40. For example, an element such as an IGBT is formed on the wafer 40.

  When the wafer 40 is pressed against the positioning pins 30 by the notch pins 20, the convex portions 40 c are stuck in the positioning pins 30 while the wafer 40 is warped. Similarly, the convex portion 40 c is also stuck in the positioning pin 34.

  Next, the wafer 40 is attracted to the stage 14. By sucking air from the suction ports 16 a and 16 b of the suction means 16, the wafer 40 is vacuum-sucked to the stage 14.

  Next, the positioning pins 30 and 34 are retracted away from the wafer 40 by the retracting means 32 and 36. FIG. 4 is a diagram illustrating retracting the positioning pins. The positioning pins 30 and 34 are retracted in the direction of the arrow in FIG. 5 is a cross-sectional view taken along a broken line 5-5 in FIG. When the positioning pins 30 and 34 are separated from the wafer 40, the warpage of the wafer 40 is suppressed by the suction means 16, and the wafer 40 is sucked to the stage 14 over the entire surface.

  According to the positioning device 10 according to the first embodiment of the present invention, after positioning the wafer 40 with the positioning pins 30 and 34 and the notch pins 20, the positioning pins 30 and 34 are moved by the retracting means 32 and 36. Move away from. Therefore, the state where the convex portion 40 c of the wafer 40 is stuck in the positioning pins 30 and 34 is eliminated, and the warp of the wafer 40 is suppressed by the suction means 16. That is, the wafer can be positioned at a predetermined position while suppressing the warpage of the wafer. The positioning device 10 according to Embodiment 1 of the present invention is particularly suitable for positioning with a stepper or the like that requires high-precision positioning.

  The wafer positioned by the positioning device 10 according to the first embodiment of the present invention is not limited to the above-described configuration. For example, the thickness of the n − high resistance layer is about 120 μm in the case of an IGBT compatible with 1200 V, but the thickness is about 60 μm in the case of an IGBT compatible with 600 V. As described above, the total thickness of the wafer varies depending on the specifications of the element, but at least if the wafer is warped due to the formation of the epitaxial layer and has a convex portion on the edge, An effect can be obtained.

Embodiment 2. FIG.
The positioning device according to Embodiment 2 of the present invention has many common points with the positioning device according to Embodiment 1 of the present invention. Therefore, differences from the positioning device according to Embodiment 1 will be described. The positioning device according to Embodiment 2 of the present invention is characterized by the position where the positioning pin is attached.

  FIG. 6 is a plan view of a positioning device according to Embodiment 2 of the present invention. The positioning pins 42, 44, 46, and 48 are attached to the stage 14 while avoiding positions that form an odd multiple of 45 ° with respect to the direction of the notch pins 20 from the center position P of the wafer. In FIG. 6, a position that forms an odd multiple of 45 ° with respect to the direction of the notch pin 20 from the center position P is indicated by a broken line.

  Various crystal planes appear on the edge portion of the wafer, and the growth rate of epitaxial growth differs for each crystal plane. Therefore, a convex part is not formed over the entire periphery of the edge part of the wafer. The direction in which the convex portion appears in the <100> substrate widely used for industrial use is the <110> direction. That is, when the notch is set at 6 o'clock when the wafer is viewed from directly above, convex portions are formed in the direction of 1:30, 4:30, 7:30, and 10:30. In other words, the convex portion is formed at a position that forms an odd multiple of 45 ° with respect to the direction of the notch pin 20 from the center position P of the wafer.

  According to the positioning device according to the second embodiment of the present invention, since the positioning pins 42, 44, 46, and 48 are formed at positions that do not hit the convex portions, the convex portions of the wafer are positioned at the positioning pins 42, 44, 46 and 48 are not stabbed. Therefore, it can be avoided that the convex portion is stuck in the positioning pins while the wafer is warped.

Embodiment 3 FIG.
The positioning device according to Embodiment 3 of the present invention has many common points with the positioning device according to Embodiment 1 of the present invention. Therefore, differences from the positioning device according to Embodiment 1 will be described. The positioning device according to Embodiment 3 of the present invention is characterized by the shape of the positioning pin.

  FIG. 7 is a cross-sectional view showing a positioning pin according to Embodiment 3 of the present invention. A recess 50a is formed in a direction toward the center of the stage of the positioning pin 50 (the center of the wafer). The positioning pins 50 are attached at predetermined positions on the stage 14 in order to position the wafer 40 at predetermined positions.

  The wafer 40 having the convex portion 40c is pressed by the notch pin and proceeds in the direction of the arrow. The convex portion 40 c hits the positioning pin 50, but the concave portion 50 a is formed in the positioning pin 50, so that the convex portion 40 c does not pierce the positioning pin 50. Then, the pressing of the wafer 40 is continued. FIG. 8 is a cross-sectional view showing that the warpage of the wafer is suppressed. When the pressing of the wafer 40 is advanced, the convex portion 40c of the wafer 40 and the concave portion 50a of the positioning pin 50 come into surface contact.

  According to the positioning device according to the third embodiment of the present invention, since the convex portion 40c of the wafer 40 can be brought into surface contact with the concave portion 50a of the positioning pin 50, it is avoided that the wafer 40 is stuck along the positioning pin. it can.

Embodiment 4 FIG.
The positioning device according to Embodiment 4 of the present invention has many common points with the positioning device according to Embodiment 1 of the present invention. Therefore, differences from the positioning device according to Embodiment 1 will be described. The positioning device according to Embodiment 4 of the present invention is characterized by the material of the positioning pin.

  FIG. 9 is a sectional view showing a positioning pin according to Embodiment 4 of the present invention. The positioning pin 60 is made of a material that is firmer and more slippery than Teflon (registered trademark). The positioning pins 60 are attached to the stage 14 in order to position the wafer 40 at a predetermined position on the stage.

  The wafer 40 having the convex portion 40c is pressed by the notch pin and proceeds in the direction of the arrow. The convex portion 40 c hits the positioning pin 60, but the convex portion 40 c does not pierce the positioning pin 60 because the positioning pin 60 is made of a material that is harder and more slippery than Teflon (registered trademark). FIG. 10 is a cross-sectional view showing that the warpage of the wafer is suppressed. Since the convex portion 40 c is not pierced by the positioning pin 60, the entire surface of the wafer 40 can be attracted to the stage 14 by the attracting means 16.

  By the way, since the positioning pin is often formed of Teflon (registered trademark), the convex portion of the wafer is easily stuck. However, according to the positioning device according to the fourth embodiment of the present invention, since the positioning pin 60 is formed of a material that is harder and slippery than Teflon (registered trademark), the convex portion 40 c of the wafer 40 is stuck in the positioning pin 60. Can be prevented. Since the positioning pins according to the second to fourth embodiments of the present invention are fixed to the stage 14, unlike the first embodiment of the present invention, no retracting means is required. Further, the positioning device according to the second to fourth embodiments of the present invention can be modified at least as much as the positioning device according to the first embodiment of the present invention.

  DESCRIPTION OF SYMBOLS 10 Positioning device, 14 Stage, 16 Adsorption means, 20 Notch pin, 30, 34 Positioning pin, 32, 36 Retraction means, 40 Wafer, 40c Convex part, 50 Positioning pin, 50a Concave part, 60 Positioning pin

Claims (5)

A stage on which the wafer is placed;
Suction means for sucking the wafer onto the stage;
Positioning pins attached to the stage for positioning the wafer at a predetermined position on the stage;
A notch pin formed so as to be movable in a direction in which the wafer is pressed against the positioning pin in a shape corresponding to the notch of the wafer;
A retracting means for retracting the positioning pin in a direction away from the wafer;
A positioning device comprising: A stage on which the wafer is placed;
Suction means for sucking the wafer onto the stage;
Positioning pins attached to the stage for positioning the wafer at a predetermined position on the stage;
A notch pin formed so as to be movable in a direction in which the wafer is pressed against the positioning pin in a shape corresponding to the notch of the wafer,
The positioning apparatus, wherein the positioning pins are attached to the stage while avoiding a position that forms an odd multiple of 45 ° with respect to the direction of the notch pins from the center position of the wafer. A stage on which the wafer is placed;
Suction means for sucking the wafer onto the stage;
A recess formed in a direction toward the center of the stage, and positioning pins attached to the stage for positioning the wafer at a predetermined position on the stage;
A notch pin formed so as to be movable in a direction in which the wafer is pressed against the positioning pin in a shape corresponding to the notch of the wafer;
A positioning device comprising:   The positioning device according to claim 3, wherein the concave portion forms a V-shaped groove. Placing the wafer with the notches on the stage;
Pressing a notch pin against the notch and pressing the wafer against a positioning pin attached to the stage;
After pressing the wafer against the positioning pins, adsorbing the wafer to the stage;
A step of retracting the positioning pins away from the wafer after the wafer is attracted to the stage;
A positioning method comprising:

Images