JPH0666730A - Wafer surface inspecting device for dust-free chamber - Google Patents

Abstract

PURPOSE:To improve productivity by shortening an inspecting time even in a dustfree chamber having small floated foreign matter fine particles and small side with high cleanness in a wafer surface inspecting device for a dustfree chamber for inspecting the particles adhered to a surface of the wafer in the chamber. CONSTITUTION:A wafer surface inspecting device for a dustfree chamber comprises a measuring.evaluating unit 11 for measuring and evaluating number and size of foreign matter fine particles adhered to a surface of a semiconductor wafer in the chamber, an output unit 12 for outputting obtained data, a controller 13' and an operation unit 14' connected thereto to manage dusts of the chamber. The unit 11 has a wafer placing plate 21a having means for blowing the air in the chamber to a surface of the wafer 17 placed planely, purifying the air and discharging it and means for applying a predetermined potential to the wafer 17 to provide a fine particle adhering unit 21 connected to the units 13', 14' between the chamber and the unit 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a semiconductor wafer (hereinafter referred to as a wafer) in a dust-free room (clean room).
Dust-free chamber that inspects the state of adhesion of foreign particles on the surface.Concerning the structure of the wafer surface inspection device, it is possible to shorten the inspection time even in a special high-cleanness dust-free room where floating particles are particularly small and small. The present invention relates to a wafer surface inspection device for a dust-free chamber, which improves productivity.

In the field of semiconductor devices in recent years, high integration,
Although densification is progressing, for example, foreign particles (hereinafter simply referred to as “fine particles”) adhering to the surface of a silicon wafer, which is a base material of semiconductor devices, are a direct cause of lowering the yield in the manufacturing process of semiconductor devices. Therefore, in the wafer process as a manufacturing process of the wafer, it is usual that all of them are performed in a dust-free chamber.

In the dust-free chamber in this case, the number of suspended fine particles decreases as the level of air cleaning increases.
However, since the size of the problematic fine particles becomes smaller with the progress of pattern miniaturization accompanying the higher integration and higher density of the semiconductor device, the problematic fine particles may temporarily increase.

Therefore, how to efficiently control the dust level in the dust-free chamber when the number of suspended fine particles is decreasing is a major issue. One of the dust-level controlling methods in the dust-free chamber is There is a wafer surface inspection device that measures and evaluates the state of adhesion of fine particles to the wafer surface at required measurement points in a dust-free chamber.

[0005]

2. Description of the Related Art FIG. 3 is a block diagram conceptually illustrating a conventional wafer surface inspection device, and FIG. 4 is a diagram illustrating a configuration example of a conventional wafer surface inspection device.

In FIG. 3, the conventional wafer surface inspection apparatus 1 is mainly composed of a measurement / evaluation unit 11, an output unit 12, a control unit 13 and an operation unit 14. Therefore, first, the wafer to be measured is left flat in the dust-free chamber where measurement is required, for example, for one day, and fine particles are attached to the surface thereof, and then the wafer is connected to the control unit 13 by manual handling. Set it on the measurement / evaluation unit 11, and then the operation unit 14
The number of fine particles adhering to the wafer and the respective sizes, that is, particle diameters are measured by the above operation, and at the same time, the data is displayed on the screen and printed out from the output section 12 to inspect the wafer.

In FIG. 4 showing a concrete configuration example of a wafer surface inspection apparatus set in the dust-free chamber A,
The evaluation unit 11 includes a turntable 11a which can move up and down and in the X direction, a laser beam light source 11b which is arranged downward on a vertical axis of movement of the table 11a, and a projection lens 11c which is arranged on the optical axis thereof. The photomultiplier tube 11f is attached to the analyzer 11e so that the phototube 11d is located near the convergence point of the laser beam, and the output unit 12 uses the monitor picture tube 12a and its monitor picture as data. It consists of a printer 12b that prints out.

The control unit 13 can control each component of the measurement / evaluation unit 11 and the output unit 12, and the operation unit 14 has each component of the measurement / evaluation unit 11 and the output unit 12. The parts can be operated according to the purpose.

The respective components are housed in predetermined positions of the housing 15 to form the wafer surface inspection apparatus 1. Therefore, the wafer 17 set in a plane on the table 16 located at the measurement required place in the dust-free chamber is manually handled by the turntable 11a as shown by an arrow B in the figure.
After placing on top, operate the operation unit 14 to operate the laser beam light source.
When the laser beam light L is focused on the surface of the wafer 17 by moving the table 11a up and down while turning on 11b, the reflected light from the wafer surface received by the photo detector tube 11d is amplified by the photomultiplier tube 11f. It can be analyzed by the analyzer 11e.

Since the reflectance of the light reflected from the wafer surface varies depending on the state of the wafer surface, that is, the presence or absence of fine particles on the surface, the presence or absence of fine particles can be determined from the difference in the reflectance.

Therefore, since the laser beam L is scanned on the wafer 17 by moving the wafer 17 and then the turntable 11a in the X direction while rotating, the number of fine particles on the entire surface of the wafer 17 and the size thereof. The distribution including its distribution state can be displayed on the monitor image tube 12a as shown in the drawing and can be output from the printer 12b at the same time.

Therefore, it is possible to perform inspection of the wafer 17 to be inspected and eventually control the degree of dust as a dust-free chamber from the image displayed on the monitor image tube 12a and its data.

[0013]

However, in the above-described wafer surface inspection apparatus for the purpose of controlling the degree of dust in the dust-free chamber, the wafer must be left in the measurement-required location in advance for a long time such as one day. There is a problem that the inspection result cannot be obtained immediately when the required measurement points are added or changed, and the number of floating particles on the wafer is further reduced in the dust-free chamber with improved cleanliness. However, there is a problem that the leaving time for adhering fine particles to the above becomes longer and the productivity improvement of the dust degree control work as a dust-free chamber cannot be expected.

[0014]

Means for Solving the Problems The above-mentioned problem is a measuring / evaluating section for measuring and evaluating the number and size of foreign particle adhering to the surface of a semiconductor wafer in a dust-free chamber placed on a plane. A wafer surface inspection apparatus for a dust-free chamber that is used to manage the dust level of a dust-free chamber, including an output unit that outputs the data obtained by the evaluation unit, and a control unit and an operation unit that are connected to both of them. The measuring / evaluating unit has means for spraying the dust-free chamber air on the surface of the semiconductor wafer placed on a plane and then for cleaning and discharging the air and means for applying a predetermined potential to the semiconductor wafer. A wafer mounting plate that has a fine particle deposition area connected to the control section and the operation section
This is solved by a wafer surface inspection device for a dust-free chamber, which is configured at least between the dust-free chamber and the measurement / evaluation unit.

[0015]

When the adhesion of the particles floating in the dust-free chamber to the wafer surface is replaced by the adhesion of particles by blowing the dust-free indoor air onto the wafer, the amount of air in the dust-free chamber contacting the wafer surface and thus the air Since it is possible to increase the amount of fine particles scattered therein, it is possible to shorten the time for leaving the dust-free room.

Therefore, in the present invention, the wafer can be set in the air flow path, and at the same time, the fine particle adhesion portion region constituted by applying a potential to the wafer itself so that the fine particles in the air are adsorbed, and the wafer is removed. A transfer robot for transferring the particles from the dust chamber to the conventional measurement / evaluation unit through the area where the particles are adhered is added to the conventional wafer surface inspection apparatus to configure a required wafer surface inspection apparatus.

This means that it is possible to inspect the particle adhesion state on the wafer surface as needed in a dust-free chamber having any cleanliness. Therefore, it is possible to realize a wafer surface inspection apparatus capable of performing a dust degree control operation in a dust-free chamber in a short time without providing a long-time wafer leaving time unlike the conventional case.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram for conceptually explaining a wafer surface inspection device according to the present invention, and FIG. 2 is a diagram for explaining a configuration example of a wafer surface inspection device according to the present invention.

Since the drawings are based on the case of the wafer surface inspection apparatus described in FIGS. 3 and 4, the same target components as those in FIGS. 3 and 4 are designated by the same reference numerals. A duplicate description will be omitted.

The wafer surface inspection apparatus 2 according to the present invention shown in FIG. 1 includes the measurement / evaluation unit 11, the output unit 12, the fine particle deposition region 21, the transfer robot 22 and the control unit 13 shown in FIG.
A control unit 1 which has the same configuration as the operation unit 14 and can control or operate including the particulate adhesion region 21 and the transfer robot 22.
The main part is composed of 3'and an operating part 14 '.

Therefore, first, a wafer to be measured is placed on the holding jig of the transfer robot 22 by manual handling, and then the transfer robot 22 is operated by operating the operation unit 14 'connected to the control unit 13'. 3 is transferred to the particle adhering part region 21 in which the descending flow path of the air in the dust-free chamber is formed, and after being positioned within the region 21 for about 30 minutes, the wafer is again explained by the operation of the transfer robot 22 with reference to FIG. Measurement and evaluation section
The wafer is inspected by setting it to 11 and then following the same procedure as in FIG.

A concrete example of the structure of the wafer surface inspection apparatus set in the dust-free chamber A is shown in FIG.
In the wafer surface inspection apparatus 2, the measurement / evaluation unit 11 and the output unit 12 described in FIG. 4 and the fine particle adhesion region 21 disposed adjacent to the lateral side of the measurement / evaluation unit 11, A transfer robot 22 disposed on the lateral side, and a control unit 13 'for controlling the particle adhesion part region 21 and the transfer robot 22 together with the measurement / evaluation part 11 and the output part 12, the particle adhesion part region. 21, the transfer robot 22 and the above measurement and evaluation unit
11 and an operation unit 14 'configured to be operable together with the output unit 12 are main components, and each component is housed in a predetermined position of the housing 23 and held in a wafer. The surface inspection device 2 is configured.

The robot arm 22a of the transfer robot 22 is surrounded only by the wall surface that surrounds the inside of the housing 23 and on the line connecting the transfer robot 22 and the turntable 11a of the measurement / evaluation unit 11. Wafer 17 described in FIG.
The fine particle adhering area 21 is provided with partition windows 23a and 23b of such a size that it can penetrate with a margin while holding it together with the holding jig made of a conductor. A wafer mounting plate 21a made of a conductive ceramic, which is held and fixed while maintaining insulation from the plate) 23c, is fitted as a floor plate.

Further, a through hole 23d communicating with an external dust-free chamber is formed on the ceiling wall surface in the fine particle adhesion region 21, and the wafer mounting plate 21a forming the floor plate is provided with an exhaust gas having a filter 21b. A pump 21c is connected and arranged by a pipe 21d so that it can be discharged to the outside of the casing.

The wafer mounting plate 21a has a plurality of protrusions 21a 'protruding from the upper surface thereof so that the wafer 17 can be positioned and mounted in a plane with the holding jig thereof. Even in the state, the air in the fine particle adhesion region can be exhausted to the outside of the housing through the pipe 21d, and the wafer mounting plate 21a itself is connected to the power supply unit 21e, so that the mounted wafer is The potential can be set to the same as that of the mounting plate 21a.

On the other hand, the transfer robot 22 in this case having the robot arm 22a capable of expanding and contracting to the position of the above-mentioned turntable 11a by the operation of the operation section 14 'connected to the control section 13', has the above-mentioned robot arm 22a at the tip thereof. The chuck 17 has a chuck hand 22a 'capable of gripping the wafer 17 around its holding jig.

Therefore, after the wafer 17 stored in a stocker (not shown) in the dust-free chamber A is held by the robot arm 22a of the transfer robot 22 by manual handling together with its holding jig, only the partition window 23a is opened. In this state, the robot arm 22a is extended to mount the wafer 17 on the wafer mounting plate 21a together with the holding jig.

Thereafter, by returning the arm 22a to the original position and then closing the partition window 23a, the particle adhering portion region 21 in which the wafer 17 is contained can be almost sealed. Then, the wafer mounting plate 21a
When a potential of about 500 V is applied and the exhaust pump 21c is operated with a suction amount of about 1 Cubic-Feet / min, for example,
It is possible to continuously form the descending flow path of the dustless indoor air passing through the through hole 23d.

Particularly in this case, the particles contained in the air flowing in the particle adhering portion region can be forcibly adhered to the surface of the wafer 17 by collision with the wafer and adsorption by the applied potential.

Therefore, after continuing the descending flow path of the dust-free room air for, for example, about 30 minutes, the operation of the exhaust pump 21c and the application of the potential to the wafer mounting plate 21a, that is, the wafer 17 are stopped, and the partition window 23a, 23b is opened at the same time and the robot arm 22a is extended so that the wafer mounting plate 21a
After the upper wafer 17 is transferred onto the turntable 11a, the arm 22a is returned to its original position and the partition window 23b is closed to obtain the state shown in FIG.

Therefore, by following the procedure described with reference to FIG. 4 below, it is possible to inspect the state of particulate adhesion on the wafer surface. The wafer 17 that has been inspected is
Since the robot arm 22a can be taken out by the expansion and contraction of the robot arm 22a with the 23a and 23b opened, the wafer surface inspection apparatus 2 can be made portable by adding a carrier to the housing 23, for example.
It is possible to move the whole housing 23 to a measurement-required place in the dust-free chamber and repeat the same work, and it is possible to efficiently manage the dust level in the dust-free chamber.

In the case of a dust-free chamber having the same cleanliness, that is, the degree of dust, the conventional wafer surface inspection result obtained by leaving it for one day and night shows that the above-mentioned wafer surface inspection apparatus 2 can cool the air in the dust-free room air for about 30 minutes. It can be obtained with the duration of the lower flow path.

[0033]

As described above, according to the present invention, even in a special high-cleanness dust-free room with a particularly small amount of floating foreign matter particles, the inspection time can be shortened to improve productivity. An indoor wafer surface inspection device can be provided.

[Brief description of drawings]

FIG. 1 is a configuration diagram conceptually explaining a wafer surface inspection apparatus according to the present invention.

FIG. 2 is a diagram illustrating a configuration example of a wafer surface inspection apparatus according to the present invention.

FIG. 3 is a configuration diagram conceptually explaining a conventional wafer surface inspection device.

FIG. 4 is a diagram illustrating a configuration example of a conventional wafer surface inspection device.

[Explanation of symbols]

2 Dust-free chamber wafer surface inspection device 11 Measurement / evaluation unit 11a Turntable 12 Output unit 13 'Control unit 14' Operation unit 17 Semiconductor wafer 21 Fine particle deposition area 21a Wafer mounting plate 21a 'Projection 21b Filter 21c Exhaust pump 21d Pipe 21e Power supply unit 22 Transfer robot 22a Robot arm 22a 'Chuck hand 23 Enclosure 23a, 23b Partition window 23c Floor 23d Through hole

Claims (1)

[Claims] 1. A measurement / evaluation unit (11) for measuring and evaluating the number and size of foreign particle adhering to the surface of a semiconductor wafer in a dust-free chamber placed on a plane, and the measurement / evaluation unit (11). ), The output unit (12) that outputs the data obtained, and the control unit (13 ′) and the operation unit (14 ′) connected to both of them are used for dust-free chamber dust level control. An indoor wafer surface inspection device, in which the measurement / evaluation unit (11) blows dust-free chamber air on the surface of a semiconductor wafer (17) placed on a plane, and then cleans and discharges the air. A fine particle adhering area which is connected to the control section (13 ') and the operating section (14'), including a wafer mounting plate (21a) having means and means for applying a predetermined potential to the semiconductor wafer (17). (21) is provided between at least the dust-free chamber and the measurement / evaluation unit (11), and the wafer surface inspection is performed in the dust-free chamber. Inspection device.