JPS6057224B2 - Semiconductor wafer visual inspection equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for visually inspecting semiconductor wafers, and more particularly to an apparatus equipped with a mechanism for positioning and rotationally precessing a semiconductor wafer.

In the manufacturing process of semiconductor wafers (hereinafter referred to as wafers), the condition of the wafer surface after cleaning, the condition of the substance applied to the wafer surface, the surface condition of the oxide film or nitrogen film formed on the surface, and the wafer manufacturing process. Visually inspects the appearance of scratches that occur during the process, the state of adhering dust, etc., and microscopically inspects the shape of fine patterns formed by photosensitive resin films, oxide films, and other substances on wafers. It will be done.

Conventionally, among these inspections, for microscopic inspection, automated equipment, such as automatic wafer supply and automatic pass/fail selection, has been put into practical use. However, in visual inspection, the surface condition of the wafer cannot be determined depending on the angle of the light beam, the position of the eye, etc. Therefore, the wafer is held in place with tweezers, etc., and the surface angle is changed by hand while observing.
As a result, inspection efficiency has been poor and has been an obstacle to automation of a series of wafer manufacturing processes. The present invention relates to a visual inspection device equipped with a mechanism for efficiently and effectively performing a visual visual inspection among the above-mentioned inspections, and aims to automate manual operations using tweezers or the like.

The present invention will be described in detail below with reference to the embodiments shown in FIGS. 1 and 2.

FIG. 1 is a plan view of an embodiment showing the mechanism of the device of the present invention, and FIG.
The figure is a partially sectional side view.

In the figure, a rotating shaft 1 is vertically held rotatably via upper and lower bearings 20, and the lower end of a vacuum suction hole 18 provided through the interior of the rotating shaft 1 is connected to a bearing support portion 3.
A cavity 15 provided therein is opened on the axial surface of the portion through which the rotating shaft 1 passes, and the cavity 15 is connected to an external reduced pressure source through a vacuum suction hole 17. The rotating shaft 1 and the bearing support member 3 are fitted with a very small gap, and the upper and lower ends of the cavity 15 are sealed with O-rings 24 to form a rotating seal, so that the rotating shaft 1 does not come out even while rotating. The reduced pressure state can be transmitted to the vacuum suction hole 18 through the vacuum suction hole 17 and the cavity 5. The rotating shaft 1 has a joint in the part protruding from the bearing support member 3, and the rotating shaft 2 is connected to the upper part of the rotating shaft 1 via a pin provided at this joint, and the rotating shaft 2 can be folded freely around the pin. Can be bent.

A vacuum suction hole 16 is provided in the rotary shaft 2, and the lower external connection end is opened near the pin of the rotary shaft 2, and the vacuum suction hole 18 of the rotary shaft 1 is connected by a flexible hose 5 across the joint. It is connected to the.

A vacuum chuck 4 that holds the surface of the wafer 23 at right angles to the rotation shaft 2 is fixed to the upper end of the rotation shaft 2, and a groove 19 for sucking and fixing the wafer provided on the upper surface of the vacuum chuck 4 is It is connected to the upper connection end of the vacuum suction hole 6. An arm 6 is fixed to the rotating shaft 2 in a direction perpendicular to the axis, and a roller 7 is attached to the tip of the arm 6. In addition, a coil spring 8 is fixed to the arm 6 in order to constantly apply force to the rotating shaft 2 to bend it around the pin of the joint.
is fixed to a spring fixing member 9 whose other end is fixed to the rotating shaft 1 in a tensioned state. The cylindrical cam 25 is arranged in a guide portion on the bearing support member 3 so as to slide and rotate concentrically with the rotating shafts 1 and 2, and slides and rotates with the cylindrical cam 25 provided on the bearing support member 3. A groove 21 for suctioning and fixing the cam is provided on the surface of the cam, and the air hole 22 connected to the groove connects to an external depressurization source and a pressurization source. By doing so, the cylindrical cam 25 is held by suction on the bearing support member 3, and the holding is released by applying pressure.

The cam surface at the upper end of the cylindrical cam 25 has unevenness.
While the roller 7 is in contact with this cam surface, the rotating shaft 1,
2 is designed to rotate. The height of the unevenness on the cam surface is set so that the semiconductor wafer 2 is vertical when the roller 7 contacts the cam surface at a certain portion and supports the rotating shaft 2. In this state, the roller 7 and the cylindrical cam 25 are erected perpendicularly to the cam surface so as to contact the pin 10 force aligner 73. To explain the detailed movement of this part, when the rotating shafts 1 and 2 rotate in a direction in which the roller 7 does not hit the pin 10 in a state where the cylindrical cam 25 is suctioned and fixed by the bearing support member 3, the roller 7 force is applied to the cam surface. The upper surface of the vacuum chuck 4 performs rotational precession because the rotating shaft 2 rotates along the four unevennesses while being inclined. On the other hand, when the bearing support member 3 releases the suction holding of the cylindrical cam 25, the cylindrical cam 25 is freely rotatable and the roller 7
pushes the pin 10, and with the rotating shaft 2 being vertical, the rotating shaft 2 and the cylindrical cam 25 rotate together, and the upper surface of the vacuum chuck 4 performs a planar rotational motion.

A plate 26 is fixed to the side surface of the cylindrical cam 25, and a detector 4 is provided to detect this plate. or,
A disc 12 is attached to the part of the rotating shaft 1 that protrudes from the lower end of the bearing support member 3, and a large number of openings are provided on the circumference near the outer periphery of the disc. A detector 13 is provided to detect the amount of rotation of the rotating shaft 1.

Further, a rotation transmitting member 11 such as a gear is attached near the disc 12 of the rotating shaft 1 to transmit the rotation of an external rotating shaft source to the rotating shaft 1. According to the mechanism configured as described above, first, in order to create an initial state, the holding between the bearing support member 3 and the cylindrical cam 25 is released, and the rotating shafts 1 and 2 are rotated by an external rotation source.

The rotating shafts 1 and 2 rotate and the roller 7 hits the pin 10,
The rotating shaft 2 becomes vertical and rotates together with the cylindrical cam 25, and stops when the detector 14 senses the plate 26. This is the initial state. The wafer is transferred onto the vacuum chuck 4 by an external transfer mechanism, the center of the wafer 23 is aligned with the center of the vacuum chuck 4 by an external positioning mechanism such as a stopper, and then the wafer is sucked into the vacuum chuck. Next, while releasing the holding between the bearing support member 3 and the cylindrical cam 25, the roller 7 pushes the pin 10, and the rotating shaft 1,
2 and the cylindrical cam 25 are rotated together to rotate the wafer 23 on the vacuum chuck 4, and the wafer rotates at the point where a detector using external optical means detects a notch (orientation flat) provided in the wafer. stops.
This completes the positioning of the wafer. Thereafter, the bearing support member 3 attracts and fixes the cylindrical cam 25, and the roller 7 moves the pin 1 while the detector 13 detects the opening in the disk 12.
The rotating shafts 1 and 2 are rotated in a direction that does not hit zero.

Since the roller 7 performs a rotational precession motion along the uneven surface of the cylindrical cam 25, the wafer surface on the vacuum chuck 4 performs a rotational precession motion while having an inclination. At this time, if the wafer surface is illuminated and observed with the naked eye, dust, scratches, etc. on the wafer can be observed very clearly because the angle of the light reflecting surface changes in various ways. The cylindrical cam stops attracting the cylindrical cam before it rolls on the roller cam surface and hits the pins, and when the roller pushes the pins and the wafer has rotated correctly 3600 times, the detector 13 stops the rotation. In this state, the position of the notch in the wafer that was initially positioned does not change. If necessary, it is also possible to perform rotational precession by further rotating 360 degrees in the opposite direction. After the external visual inspection by rotational precession is completed, it is easy to move the wafer under the microscope for the next step of microscopic inspection without changing the position of the wafer notch using an external transport mechanism. The arrangement according to the invention as described above can be provided as a very effective and efficient arrangement in a small space as part of an apparatus for surface visual inspection of wafers, which is often carried out during the wafer manufacturing process.

[Brief explanation of drawings]

FIG. 1 is a plan view of an embodiment of the mechanism of the apparatus according to the present invention, and FIG. 2 is a side view showing a part of the mechanism shown in FIG. 1 in cross section. 1, 2...Rotating shaft, 3...Bearing support member, 4...Vacuum chuck, 5...Flexible hose, 6...Arm , 7111 shares - Rani, 8◆◆●
●●Coil spring, 90●●●●Spring fixing member, 10...
...Pin, 11...Rotation transmission member, 12.
... Disc, 13, 14 ... Detector, 15
...Cavity, 16, 17, 18...Vacuum suction hole, 19...Wafer suction and fixing groove, 20...
...Bearing, 21...Cam suction fixing groove, 2
2...Air hole, 23...Wafer, 24...
...O-ring, 25...Cylindrical cam, 26.
...board.

Claims (1)

[Claims] 1 A rotating shaft that holds a semiconductor wafer at one end and is attached to swing from side to side using the other end as a fulcrum, an arm that protrudes from a part of the side of the rotating shaft, and a rotating shaft that is attached to this arm. 1. A semiconductor wafer appearance inspection apparatus comprising a roller, and providing rotational precession to the semiconductor wafer by providing unevenness on the surface on which the roller rolls.