JPH0449907B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a surface inspection device for inspecting the surface of a test object such as a wafer for scratches, dust, etc.

Conventional technology Conventionally, a laser beam is irradiated onto the surface of a test object such as a wafer (the wafer will be explained as an example below), and the reflected beam is detected to remove scratches, dirt, etc. on the wafer surface. Surface inspection equipment for inspection is well known.

In this type of surface inspection device, a large number of wafers are set in advance in a storage case such as a carrier or a cassette, and each wafer is taken out from the storage case one after another, with the wafers fixed in the chuck. The wafers are sequentially transported to the measurement section of the inspection equipment main body, and the wafers are rotated and moved in a horizontal plane. At this time, the surface of the wafer is inspected in the measurement section, and the inspected wafers are sequentially transferred to another It was designed to be transported and stored in the storage case section.

Problems to be Solved by the Invention However, such inspection equipment must be installed in a high-level complete clean room. However, as the number of wafers increases significantly and the size of the wafers also tends to increase in size, there has been a demand for a surface inspection device that can be used even in a non-high-level clean room.

Another problem is the installation location of a display device such as a cathode ray tube for displaying the results of measurement and inspection of each wafer.

Purpose of the invention The purpose of the invention is to
To provide a surface inspection device which can be used with a measurement part of the inspection device kept sufficiently clean even in a generally clean room, and in which cathode ray tubes are skillfully arranged.

SUMMARY OF THE INVENTION The present invention provides a surface inspection device for automatically measuring the surface of a test object by irradiating the surface of the test object with a laser beam and using the reflected light. The surface inspection apparatus is characterized in that a clean space is formed in a measuring section, a clean unit is provided above the clean space, and a display is provided on the clean unit to display measurement results.

Embodiment FIG. 1 is a schematic diagram of an inspection device that is equipped with a transfer device, and is used to transfer a test object such as a wafer (hereinafter, the wafer will be simply explained as an example) and inspect it along the way. It shows.

The measurement unit 10 of the inspection device includes a light source 11 as is well known.
The wafer 14 is irradiated with a laser beam from the wafer 14, and the scattered reflected light caused by the abnormality on the surface is received by the photoelectric conversion element 12 such as a photomultiplier tube and extracted as an electrical signal, and the electrical signal is sent to the control device 13. Then, after performing the specified data processing,
Scratches, dust, dirt, etc. on the surface of the wafer 14 are measured and output to a display device such as a cathode ray tube (CTR) 15 or a printer 16.

In the measurement state shown in FIG. 1, the wafer 14 is fixed to a turntable type chuck portion 17 by vacuum action. The vacuum hole 17a of the chuck portion 17 is connected to a vacuum source 18, so that the wafer 14 can be fixed and held by the vacuum as necessary.

First storage case section 20 and second storage case section 23
are provided on the departure side and the destination side, respectively.
A large number of wafers 14 are stored in a first storage case section 20, and the wafers 14 are transported one by one from the storage case section 20 within a horizontal plane by a first transport section 21. Then, each wafer 14 is transferred to the chuck section 17 via a first test object holder section 29, which will be described later, and is fixedly held there by a vacuum chamber. The chuck section 17 passes through the measuring section 10 and is transferred to the second transport section 22 on the opposite side via a second test object holder section 42, which will be described later. The wafers 14 are transported by the second transport section 22 and sequentially stored in the second storage case section 23 .

As shown in detail in FIGS. 2 and 3, the first conveying section 21 is in the form of a conveyor with flexible endless conveying members 26 and 27 on both sides of a frame 25, respectively.
6 and 27 support the peripheral edge of the wafer 14, and transport the wafer 14 from the first storage case section 20 to the first test object holder section 29. The driving force for the conveying members 26 and 27 is transmitted from the motor 19 via the belt 28.

The elevator 30 is arranged at one end side of the transport members 26, 27, and the first storage case part 20 can be detachably set at a predetermined position above the elevator 30. The entire upper part of the elevator 30 is approximately H-shaped, and the first
The storage case portion 20 can be moved vertically by a predetermined amount. This elevator 30 has a female threaded portion (not shown) that engages with a vertical threaded rod 31, and the threaded rod 31 is further connected to a gear on the motor 33 side via a gear 32. has been done. That is, the driving force of the motor 33 is transmitted to the threaded rod 31 to move the elevator 30 in the vertical direction.

On the other hand, the transport members 26, 2 of the first transport section 21
A first test object holder 29 is provided on the other end side of the test object 7 . A circular hole is formed in the center of the first test object holder 29, and a stepped holder 29a having a size corresponding to the size of the wafer is formed at the edge of the hole. ing.

This step-shaped receiving part 29a supports the wafer 14 transported by the transport member 26 in a fixed position, and also supports the chuck part 17, which will be described later.
The shaft 45 joined to the shaft 45 is configured to have a shape that does not interfere with the shaft 45. The peripheral edge of the wafer 14 is adapted to be inserted into a receiving portion 29a and supported.

The first test object holder 29 is replaceable depending on the size of the wafer to be measured.
If the wafer is large, a pedestal portion having a pedestal size indicated by the dotted line N is attached.

The above-mentioned first conveyance section 21 is also on the side of the second conveyance section 22.
A transport mechanism similar to that shown in FIG.

As shown in FIGS. 4 and 5, the first test object holder 29 is removably fixed to the upper ends of two vertically arranged connecting rods 35 with a nut 36. These connecting rods 35 are movable up and down while being guided by a guide 37. The lower end of the connecting rod 35 is fixed to a flat plate-shaped driven member 38, as shown in FIG. Rotating shaft 40 of motor 39
is fixed to an eccentric cam 41, and the eccentric cam 41 engages with the aforementioned driven body 38. Therefore, as the motor 39 rotates, the eccentric cam 41 moves the connecting rod 35 and the first test object holder 29.
can be moved up and down together.

The second test object holder 42 is the first test object 29 described above.
Since it has the same vertical movement mechanism as , the same reference numerals will be used and the explanation thereof will be omitted.

To explain in detail the operating mechanism of the measuring section 10, a vacuum hole 17a is formed in the center of the table-type chuck section 17, and this vacuum hole 17a is connected to the vacuum source 18 as described above. The chuck portion 17 is connected to the shaft 45 of a motor 46, and an encoder 47 is provided adjacent to the motor 46. With this configuration, the rotational force of the motor 46 is transmitted to the chuck portion 17 so that it rotates at a predetermined speed. The chuck portion 17, the motor 46, and the like are fixed as a unit to the frame 52, and the whole is movable in the left-right direction in FIG. 4 along guide rails 50, 51. A threaded rod 53 disposed laterally engages with a female threaded portion (not shown) on the frame 52 side, and the threaded rod 53
3 is adapted to be rotated by a motor 55 via a belt 54.

In this embodiment, the chuck section 17 is configured to rotate the wafer and simultaneously transport it in a horizontal plane; however, if the chuck section 17 is configured to scan the laser beam irradiated onto the wafer, the chuck section 17 can rotate. There's no need to do it.

As shown in FIGS. 2 and 6, the first conveyance section 21
A shape detecting means for the storage case part is provided in the second conveyance part 22, particularly in the part of the elevator 30 where the storage case is installed. That is, elevator 30
There are three holes 30a on the top surface of the storage case installation part,
30b, 30c are formed, and the respective holes 30a,
Micro switches 50 are set at 30b and 30c so that the shape (particularly the dimensions) of the first storage case section 20 set there can be detected.
For example, when three types of storage case parts 20 are used, when a large one is set, the outer hole 30a
When a medium-sized object is set, the micro-switch 50 provided in the inner hole 30b is activated, and when a small-sized object is set, the micro-switch 50 in the inner hole 30c is activated. It's starting to work. These micro switches 50 are connected to the control device 13 (first
(Figure).

Also, the shapes of the first test object holder 29 and the second test object holder 42, especially the receivers 29a and 42, are different from each other.
Means are provided for detecting the dimension of a. That is, as shown in FIG. 7, three holes 29b (only one is shown in the figure, but there are actually three holes) are formed on the back surfaces of these test object holders 29 and 42, respectively. A micro switch 52 is set accordingly. Depending on which microswitch 52 out of the three microswitches 52 is activated, the shapes of the first test object holder 29 and the second test object 42 actually mounted are detected. be. These microswitches 52 are also connected to the control device 13.

The first and second storage case parts 20, 23 and the first
The control device 13 (FIG. 1) is set in advance so that the entire inspection apparatus becomes operable only when the shapes of the second test object holders 29 and 42 match.

FIG. 8 shows an example of the appearance of a surface inspection apparatus equipped with the above-mentioned conveyance device. An inspection device main body 60 is arranged in the lower part of the surface inspection device, and inside the inspection device main body 60, a control device 13, a printer 16, and other main components are arranged.
An elevator 30, a first conveyance section 21, a second conveyance section 22, and a chuck section 17 are provided on the top of the inspection device main body 60.
The measuring section 10 covered by the above-mentioned cover section 65 is disposed at the chuck section 17 thereof. This measuring section 10
A clean unit 62 is provided on the top of the screen. A narrow clean space 63 is formed between the clean unit 62 and the inspection device main body 60. The measuring section 10 is arranged in the clean space 63, so that the measuring section 10 can be used in an extremely clean state. The clean unit 62 is equipped with a well-known air cleaning mechanism for cleaning the air within the clean space 63, and sends clean air downward. The cover part 65 is
The measuring section 10 is configured in a shape that prevents harmful external light from entering the measuring section 10 and prevents air turbulence from occurring in the clean space 63 from above that would hinder measurement. The clean space 63 is formed by transparent plates on three or four sides.
Of course, when the room is kept sealed by the four transparent plates, the front transparent plate can be opened and closed as needed.

Further, a cathode ray tube 15 for displaying the measurement results of the wafer 14 is built into the clean unit 62. This cathode ray tube 15 is housed so as to be folded downward so that it can be easily observed by the measurer without being subjected to reflection of external light.

FIG. 9 is an explanatory diagram showing the operation of the conveying device shown in FIGS. 1 to 7. First, the first and second
When the storage case parts 20 and 23 are set in the elevator 30 and the start button of the surface inspection apparatus is pressed, the initial setting state shown in FIG. 2 is entered. That is, both the storage case parts 20 and 23 are arranged on the upper surface of the elevator 30 in the most raised state. Thereafter, the first storage case section 20 on the departure side is lowered by one storage stage, and in parallel therewith, the second storage case section 23 on the end point side is lowered to the lowest position.

After that, the first storage case section 20 on the departure side is lowered by one step, and one wafer 14 is placed on the transfer members 26 and 27 of the first transfer section 21, thereby being transferred in the direction of arrow 1. . When the wafer 14 reaches the first test object holder 29, the first test object holder 29 moves up in the direction of arrow 2, and the wafer 14 is moved from the first transport section 21 to the first test object holder 29.
The specimen is transferred to the specimen holder section 29. and wafer 1
4 is held by the first test object holder 29 and further rises in the direction of arrow 2. Thereafter, the chuck section 17 moves below the wafer 14 in the direction of arrow 3 and stops. Thereafter, the first test object holder 29 descends in the direction of arrow 4. The wafer 14 is transferred from the first test object holder 29 to the chuck part 17.
and is fixed by the chuck portion 17 by vacuum action. Then, the chuck section 17 rotates and moves in the direction of the arrow 5, during which time the measuring section 10 performs a predetermined measurement. When the chuck part 17 comes to the second test object holder part 42,
The vacuum action of the chuck portion 17 is stopped and the wafer 14 is released. Thereafter, the second test object holder section 42 moves up in the direction of arrow 6 to receive the wafer 14 from the chuck section 17. The chuck 17 then moves in the direction of arrows 7,3. During this time, the second test object holder 42 descends again in the direction of the arrow 8. The wafer 14 is thus transferred from the second test object holder 42 to the second transport section 22, and is transported by the second transport section 22 in the direction of arrow 9. Finally, it is stored in an appropriate position at the top of the second storage case section 23 on the terminal side from the second transport section 22.

The above-mentioned transport and measurement operations are carried out on each wafer 14.
Repeat each time, and remove the first storage case part 2 on the departure side.
Each of the 0 wafers 14 is sequentially stored in a predetermined stage of the second storage case section 23 on the end point side from the upper stage downward.

[Brief explanation of the drawing]

Fig. 1 is a block diagram schematically showing an inspection device equipped with a transport device, Fig. 2 is a perspective view schematically showing the transport device, and Fig. 3 is a schematic perspective view showing the first transport section of the transport device. Fig. 4 is a schematic perspective view showing the related mechanism of the chuck part of the transport device, Fig. 5 is a schematic front view showing a part of the drive mechanism of the specimen holder, and Fig. 6 is the storage case installation part of the transport device. FIG. 7 is a schematic sectional view showing the type detection means of the test object holder, FIG. 8 is a schematic perspective view showing the external appearance of the test object surface inspection device, and FIG. 9 FIG. 2 is a schematic explanatory diagram showing a transport route of a test object. 10... Measuring section, 21... First transport section, 22...
...Second transport section, 20, 23...Storage case section, 1
4... Test object (wafer), 30... Elevator, 29, 42... Test object pedestal section, 17... Chack section, 13... Control device, 15... Braun tube, 60... Inspection device main body , 62...Clean unit, 63...Clean space.

Claims (1)

[Claims] 1. In a surface inspection device that irradiates the surface of a test object with a laser beam and automatically measures the surface of the test object using the reflected light, a clean space is formed in the measurement section of the main body of the test device, and the clean space is A surface inspection device characterized in that a clean unit is provided in the upper part of the space, and a display device is provided on the clean unit to display measurement results.