JPH1050640A - Precise grinding device and manufacture of semiconductor device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detain a precise grinding device which is provided with a system for reproducing defective products. SOLUTION: Wafers carried by a transfer robot 10e via a opening and closing means are transferred to a grinding unit 10a and a cleaning unit 10d in sequence defective products are selected by a detecting unit 10c and remaining ones are picked up as products by the opening and closing means 20d. The defective products are classified, depending on the kinds of failures and in case of having a scratch on a grinded surface, these are returned to the grinding unit 10a. In the case of failure of defective products being discriminated as having grinding dust or slurry attached, those are returned to the cleaning unit 10b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates, in a manufacturing process of a semiconductor device, precision polishing for polishing a wafer or the like surface of a substrate formed by laminating dielectric layers such as SiO ₂ or the like with high precision device and this The present invention relates to a method for manufacturing a semiconductor device used.

[0002]

2. Description of the Related Art In recent years, high definition of semiconductor devices has progressed.
Submicron-order accuracy is required for the line width of a fine pattern. Along with this, a technique for flattening the surface of a substrate such as a wafer on which wiring and a dielectric layer are laminated with extremely high precision is required. Mechano-chemical polishing (chemical mechanical polishing or mechano-polishing) which is said to involve a chemical reaction on a processed surface is required. A precision polishing apparatus employing a polishing method such as chemical lapping has been developed.

FIG. 11 shows a conventional precision polishing apparatus, which comprises a polishing head 102 which sucks and holds a pair of wafers W _{0 so} that a polishing surface faces downward and conveys them along a guide 101. And the loading unit 103 and the wafer centering unit 10 arranged in series in the transport direction.
4. It has a polishing section 105 for rotating the polishing pad 105a on the surface plate, a wafer cleaning section 106, a wafer reversing section 107, an unloading section 108, and the like.

The wafers W ₀ stored in the loading cassette G ₁ and carried in from the preceding process are taken out of the loading cassette G ₁ in the loading section 103, and after being centered in the centering section 104, are attracted to the polishing head 102. And is conveyed to the polishing unit 105. In the polishing unit 105, the lower surface (surface to be polished) of each wafer W ₀ is traversed along the diameter of the polishing pad 105a by lightly pressing each wafer W ₀ against the surface of the rotating polishing pad 105a. Grind. Polishing head 1 across polishing pad 105a
02 reaches the wafer cleaning unit 106 moves along the continuing guide 101, wherein, to remove the side products of the polishing by spraying a cleaning liquid from the nozzles 106a to the surface to be polished of the wafer W _0. The wafer reversing unit 107 reverses the washed wafer W ₀ and transfers it to the unloading unit 108. In unloading unit 108, it sends accommodating the wafer W ₀ to unloading cassette G ₂ to the next step.

The polishing head 102 is suspended from a top frame 102a that moves above the wafer centering unit 104, the polishing unit 105, the wafer cleaning unit 106, and the like. One end of the top frame 102a follows the guide 101. It is supported so as to be able to reciprocate, and the other end is connected to the drive unit 102b. The top frame 102a on which the polishing head 102 is suspended moves the guide 10
Reciprocate along 1. The polishing unit 105 includes a brushing device 1 for cleaning the surface of the polishing pad 105a.
05b and a hand shower 105c.

Thus, the polishing of the wafer W ₀ continuously fed from the previous step and the subsequent cleaning step are automatically performed and sent to the next step. In addition, the operation of cleaning the surface of the polishing pad 105a can be efficiently performed before the polishing head 102 moves in the direction opposite to the above direction and returns from the unloading section 108 to the loading section 103.

FIG. 12 is a flowchart showing a polishing process disclosed in Japanese Patent Application Laid-Open No. 2-257629. This is because, after cleaning and drying a semiconductor substrate (bare silicon wafer) which has been subjected to primary polishing, which is rough polishing, a polishing state is measured to determine whether or not the semiconductor substrate has irregularities of a predetermined value or more. Only the semiconductor substrate is sent to secondary polishing as final polishing, and the semiconductor substrate having irregularities is subjected to partial polishing described later.

That is, a semiconductor substrate that has undergone primary polishing is
The surface usually has some irregularities due to the properties of the polishing cloth, the properties of the semiconductor substrate itself, or the unevenness of the pressing force. If the degree of the irregularities is such that the secondary polishing can be performed normally, there is no support even if the irregularities are sent to the secondary polishing step. However, if the unacceptable unevenness state is not changed even after the secondary polishing, or if it is expected that the state becomes more unacceptable, some measures should be taken before sending to the secondary polishing. Therefore, in this conventional example, it is determined whether or not there is an unacceptable unevenness, and if so, partial polishing is performed as described above.

Here, in the above-mentioned measurement of the polishing state, when there are irregularities on the polished surface of the semiconductor substrate, the position, area, height and the like of the convexes are determined to form, for example, interference fringes by laser. , Analyzing this interference fringe to determine the position, area,
In addition to detecting the height, the polishing pad is controlled based on the height or contour lines are generated by image processing or the like. Specifically, the measurement is performed such that the surface shape accuracy of the semiconductor substrate is measured on the basis of the back surface.

[0010] Thus, the above-mentioned measurement of the polishing state is performed, and the semiconductor substrate having unacceptable polishing accuracy is sent to the partial polishing step described below.

In this partial polishing, when the convex portion has an unacceptable height, only the convex portion is partially polished to an allowable height.

More specifically, as shown in FIG. 13, the result of the accuracy measurement and the actual semiconductor substrate are made to correspond to each other on a 1: 1 basis.
The semiconductor substrate 301 is held and fixed on the surface plate 305, and the small polishing tool 304 is controlled and operated by the NC control method according to the result of the accuracy measurement. Here, the shape of the polishing pad 303 attached to the lower surface of the polishing tool 304 is preferably a circle whose diameter is 1/10 to 1/20 of the diameter of the semiconductor substrate. Move forward, backward, left and right. Here, the partial polishing is preferably performed with the polished surface down in order to prevent the semiconductor substrate 301 from being attacked by a polishing liquid (slurry). Thus, the convex portion on the semiconductor substrate 301 is removed by a predetermined amount and washed,
The above accuracy measurement is performed. Only semiconductor substrates having surface polishing accuracy that is acceptable in this accuracy measurement are sent to secondary polishing,
On the other hand, a semiconductor substrate having a surface polishing accuracy that cannot be tolerated even by the partial polishing is sent to the partial polishing again.

[0013]

However, according to the above-mentioned prior art, the surface of a workpiece having relatively large irregularities, such as when a semiconductor wafer is polished before a semiconductor device is manufactured, is referred to as a back surface. It may be convenient if the projections are polished and flattened by the method, but in the case of polishing after forming a metal film or an interlayer insulating film to be wiring on the surface of the wafer, the back surface of the wafer may be advantageous. It does not mean that the surface only needs to be flat by reference. Rather, polishing may be desired to have the same film thickness in accordance with the underlying wiring pattern and the unevenness of the transistor portion. When such polishing is performed, minute irregularities are generated on the entire wafer surface. Therefore, as in the conventional example, whether the partial polishing is performed after the surface state is determined or the secondary polishing is performed, the two choices are suitable for polishing a substrate such as a wafer on which semiconductor elements such as transistors are formed. I can't say.

[0014] In addition, during the secondary polishing and the tertiary polishing, new scratches may be generated due to hard foreign substances or the like attached to the polishing pad. Therefore, the present inventors manually return the wafer in which the defect is found, return to the primary polishing unit and repeat the above all steps, or, or add a wafer defect removal device downstream of the tertiary polishing unit, An attempt was made to regenerate a defective wafer by re-polishing or cleaning the wafer.

[0015] However, the defects of the wafer found by the inspection include the scratches on the surface to be polished which require repolishing,
There are many cases where dirt due to polishing by-products such as abrasive powders adhered, and drying in the final step is insufficient and only the cleaning liquid remains, and it is not always necessary to re-polish. found.

If the wafer that does not require repolishing is returned to the primary polishing section of the precision polishing apparatus, or is manually sent to a wafer defect removing apparatus separate from the precision polishing apparatus and repolished, unnecessary polishing is performed. In addition to the reduction in throughput due to the additional steps, there are also problems such as the occurrence of new defects in the repolishing step, and as a result, the manufacturing costs of semiconductor devices and the like increase.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned unsolved problems of the prior art, and has a high-throughput precision polishing apparatus capable of reducing the manufacturing cost of a semiconductor device. It is an object of the present invention to provide a method for manufacturing a semiconductor device using a semiconductor device.

Another object of the present invention is to continuously and automatically perform polishing and cleaning of a workpiece such as a wafer, detect a defect of a product inside the apparatus, and select a process required for reproduction. An object of the present invention is to provide a highly productive precision polishing apparatus that can automatically return to the process and a method for manufacturing a semiconductor device using the same.

[0019]

In order to achieve the above object, a precision polishing apparatus according to the present invention comprises a polishing unit having polishing means for polishing a workpiece, and a workpiece transferred from the polishing unit. A cleaning unit for cleaning the workpiece, a detecting unit for detecting a surface state of a polished surface of the workpiece cleaned by the cleaning unit, and a detection result of the workpiece by the detecting unit. And a selective return means for selectively returning the polishing unit or the cleaning unit based on the return.

Also, a polishing unit having polishing means for polishing a workpiece, a cleaning unit for cleaning the workpiece transferred from the polishing unit, and a workpiece transferred from the cleaning unit A drying unit for drying, and a detecting means for detecting the surface state of the polished surface of the workpiece dried by the drying unit,
The precision polishing apparatus may include a selective return means for selectively returning the workpiece by the detection means to the polishing unit or the cleaning unit based on the detection result of the surface condition.

Alternatively, a second unit provided with polishing means for polishing the workpiece transferred from the first unit, and a third unit for cleaning the workpiece transferred from the second unit. A fourth unit for drying the workpiece transferred from the third unit, and a detecting unit for detecting a surface state of a polished surface of the workpiece transferred from the fourth unit; The workpiece is detected by the detecting means based on the detection result of the surface state of the workpiece.
The precision polishing apparatus may further comprise a selective return means for selectively returning to any of the units.

[0022]

The surface condition of the polished surface of the workpiece such as a wafer after the drying step is inspected for defects such as scratches and dirt, and only those having no defects are taken out of the apparatus as products. The defective product in which a defect is found is determined as to whether the defect is a scratch on the surface to be polished, stains due to polishing powder, or, if necessary, stains in which only the cleaning liquid remains. If the surface to be polished is flawed, it is returned to the polishing unit, if it is contaminated by polishing powder or the like, it is returned to the cleaning unit, and if necessary, if the cleaning liquid remains, it is returned to the drying unit.

As described above, the defective product is returned to a necessary step according to the type of the defect, the defect is removed, and the product is reproduced as a product.

Since there is no possibility that a defective product is included in a product produced from the precision polishing apparatus, automation of the next process of the workpiece is easy. That is, it can greatly contribute to the full automation of the manufacturing process of semiconductor devices and the like.

In addition, when a defective product is not reclaimed, a polishing step or the like can be omitted if unnecessary, so that the productivity of the precision polishing apparatus can be improved and the average unit price of products such as semiconductor devices can be reduced. It can be greatly reduced.

If a sealing means for individually sealing the atmosphere of each unit and an atmosphere pressure control means for controlling the atmosphere pressure of each unit to a value lower than the outside atmosphere pressure are provided, foreign matter in the precision polishing apparatus can be cleaned in a clean room. It can be prevented from spreading inside.

If an intermediate defect inspection means and an intermediate return means are provided between the polishing unit and the cleaning unit, or between the cleaning unit and the drying unit, a wasteful cleaning step and drying can be performed by early detection of defective products. By omitting the process, the productivity of the precision polishing apparatus can be further improved. As a result, manufacturing costs of semiconductor devices and the like can be further reduced.

[0028]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram showing a precision polishing apparatus according to one embodiment, which comprises a polishing unit 10a having polishing means for polishing a workpiece such as a wafer,
A cleaning unit 10b for cleaning the workpiece transferred from the polishing unit 10a, and a detection unit 10c having a detecting unit for detecting a surface state of a polished surface of the workpiece cleaned by the cleaning unit 10b; And a transfer robot 10e for selectively returning the workpiece to the polishing unit 10a or the cleaning unit 10b based on the result of detecting the surface condition of the polished surface of the workpiece by the detection unit 10c. Transfer room 10d
Having.

The transfer chamber 10d has three wall surfaces, which are respectively opened and closed by the opening and closing means 20a, 20b and 20c.
0a, a cleaning unit 10b, and a rectangular sealed chamber adjacent to the detection unit 10c.
It faces the atmosphere of a clean room where a precision polishing apparatus is installed through d. Transfer robot 10 in transfer chamber 10d
e has a robot arm 10g that can move forward and backward in the radial direction on the rotating plate 10f, and under the control of the controller 21,
The loading / unloading of the workpiece to / from the transfer chamber 10d and the transfer chamber 10d
The transfer of the workpiece to / from each of the units 10a to 10c from d, the transport of the workpiece between the units 10a to 10c, and the like are performed.

The controller 21 continuously controls the transfer robot 10e and the drive units of the units 10a to 10c at a predetermined timing according to a preset program.

The polishing unit 10a includes the polishing unit 1
It is preferable to provide an exhaust means for exhausting the inside of Oa. Further, if necessary, the cleaning unit 10b and the detection unit 10c may be provided with exhaust means for exhausting the inside thereof.

If the inside of the polishing unit 10a is evacuated and the inside of the polishing unit 10a is maintained at a slightly lower pressure than the inside of the transfer chamber 10c, the opening / closing means 20a can be omitted. Similarly, the opening / closing means 20b, 20c, 20d can be omitted if necessary. For example, the conductance of the communicating part between the polishing unit 10a and the transfer chamber 10d, the cleaning unit 10b
If the conductance of the communicating portion between the polishing unit 10d and the transfer chamber 10d is properly determined, the pressure Pa in the polishing unit 10a and the pressure Pd in the transfer chamber 10d can be reduced with respect to the pressure Po in the clean room simply by exhausting the inside of the polishing unit 10a. And Pa <P
d <Po can be set. If possible, exhaust means is also provided in the cleaning unit 10b, and the pressure Pd is set to P
It is desirable to set b <Pd <Po.

FIG. 2 is a flowchart illustrating the basic steps of the polishing method using the apparatus of FIG.

First, a cassette accommodating a wafer (workpiece) is arranged on the front surface of the opening / closing means 20d, and the controller 21 is operated to start the polishing operation of the polishing unit 10a.

The transfer robot 10e takes in one wafer from the cassette into the transfer chamber 10d. Opening / closing means 20a
To open the wafer in the polishing unit 10a and close the opening / closing means 20a. Thus, the wafer is polished in the polishing unit 10a (S10).
1).

Next, when polishing is completed, the opening / closing means 20a is opened, and the transfer robot 10e takes out the polished wafer from the polishing unit 10a into the transfer chamber 10d once. Next, the opening / closing means 20b is opened, the polished wafer is transferred into the cleaning unit 10b, and the opening / closing means 20b is closed. Thus, the cleaning is performed in the cleaning unit 10b (S10).
2).

After completion of the cleaning, the opening / closing means 20b is opened to take out the cleaned wafer into the transfer chamber 10d, and the opening / closing means 20c is opened to transfer the wafer into the detection unit 10c. The state is detected (S103).

In accordance with the detection result, it is determined whether or not the surface to be polished of the wafer is flawed. If it is determined that there is a flaw, the wafer is transferred to the polishing unit 10a to return to the polishing step of step S101. It is transported (S104).

If it is determined that there is no flaw, it is determined whether there is any other adhesion of slurry or the like. If it is determined that there is adhesion, the wafer is transferred to the cleaning unit 10b in order to return to the cleaning step S102 without returning to the polishing step (S
105).

Thus, only the wafer that has passed through step S105 is returned from the transfer chamber 10d to the cassette. Opening / closing means 20a
It is needless to say that these opening / closing operations become unnecessary when 〜20c is omitted.

FIG. 3 is a diagram showing a main part of the polishing means used in the polishing unit 10a. Wafer W as a workpiece is arranged on the rotation can platen M _1, rotates with the platen M _1. Polishing pad M ₂ is the vibration of the rotation and the horizontal direction is fixed to the lower surface of the polishing tool M ₃ is freely. At the time of polishing, the polishing tool M ₃ descends, and while the lower surface of the polishing pad M ₂ and the upper surface (polished surface) of the wafer W are in pressure contact with each other, the polishing tool M ₃ Reciprocate along the surface to be polished. Polishing the upper surface of the wafer W by performing the above operation is performed while supplying the slurry as a polishing agent from the nozzle M ₄ between the upper surface of the lower surface and the wafer W of the polishing pad M _2.

The surface to be polished as described above may be an insulating film (dielectric film) such as silicon oxide, silicon nitride, tantalum oxide, or aluminum oxide, or aluminum, copper, tungsten, molybdenum, aluminum silicon, or aluminum. A metal film such as silicon copper, a surface where an insulator and a metal are mixed, and the like can be given. As an abrasive (slurry), 1 to 1000 n of silicon oxide, aluminum oxide, cerium oxide, manganese dioxide, etc.
A liquid having m-diameter fine particles is used. As this liquid, an aqueous solution of KOH, NaOH, NH ₄ , isocyanocyanuric acid, or the like can be used. Even though it is called chemical mechanical polishing, there are many unclear points about its chemical action, so here we do not exclude the case where polishing is performed only by physical action (mechanical action) without chemical action. Absent.

FIG. 4 is a view showing a cleaning means used in the cleaning unit 10b. Figure. 4 (a), has a tank M ₅ for containing a cleaning liquid such as pure water, the wafer W is immersed in the cleaning solution by using the transfer arm M ₆ by applying ultrasonic wave or the like performing wet cleaning liquid Tank cleaning means.

FIG. 4B shows one step of the wet cleaning apparatus, in which the wafer W is attached to the rotatable wafer holding means M _7.
It mounted, while rotating the the wafer W, a nozzle cleaning unit for supplying a cleaning liquid from the nozzles M _8.

FIG. 4C shows scrub cleaning means for scrubbing the upper surface (surface to be polished) of the wafer W placed on the wafer holding means M ₉ with a scrub means M ₁₀ such as a nylon brush. The cleaning unit 10b is configured as shown in FIGS.
And at least one of the devices shown in FIG.

When performing wet cleaning using a cleaning liquid, a drying unit for supplying hot air or cold air may be provided integrally with the cleaning unit 10b or as a separate unit.

FIG. 5 shows detection means for detecting the surface condition of the surface to be polished in the detection unit 10c. In the upper surface to be polished to the wafer W is mounted on the table M _11. And
By scanning the line sensor M ₁₂ of the light source and the plurality of photoelectric conversion elements and a sensor array disposed in a row in the direction of arrow A, to detect the fine pattern on the surface to be polished by a difference in contrast.

When the slurry or the like has adhered to the surface to be polished of the wafer W, the shape of the adhered dirt has an aspect ratio of 1 to 1.
It is often a square or circle close to. On the other hand, wafer W
The scratches on the surface to be polished are often elongated lines, and the aspect ratio of the scratches is sufficiently larger than 1. Therefore, it is possible to determine such as slurry or scratches from the shape of the fine pattern detected by the line sensor M _12.

That is, as shown in FIG. 5B, the length of the detected minute patterns P ₁ and P _{2 in} the longitudinal direction is represented by L.
_{1. When} the length in the width direction is L ₂ , if L ₁ / L ₂ <2 (fine pattern P ₂ ), this is determined to be contamination by slurry or the like, and L ₁ / L ₂ ≧ 2. In a certain case (small pattern P ₁ ), this is determined as a flaw. Based on this determination, the wafer W is removed from the polishing unit 10a and the cleaning unit 1a.
0b.

If necessary, it is possible to detect the case where the cleaning liquid has adhered to the wafer W by using a known wafer inspection apparatus.

Next, a method for manufacturing a semiconductor device employing the above-described polishing method will be described. The substrate (wafer) as a workpiece is a silicon wafer having an insulating film or a metal film on the upper surface, a compound semiconductor wafer, an SOI wafer, an insulating substrate having a semiconductor layer, or the like.

As an example, a wafer W using a silicon wafer as a substrate material will be described. As shown in FIG.
A semiconductor layer is formed on the surface of a silicon wafer 71 by vapor phase epitaxial growth, and an N well 80, a P well 77, an N ⁺ buried layer 72, and a collector region 7 are formed by ion implantation.
Form 3 Further, a P-type base region 74 is formed. After forming the gate insulating film, a polysilicon gate electrode 7 is formed.
9, 82 are formed. N ⁺ type source / drain 78,
An emitter 75 and a collector contact 76 are formed, and P ⁺
A mold source / drain 81 is formed. When the insulating film 84 is C
A contact hole is formed by reactive ion etching. Sputtering or C
When a metal film such as aluminum silicon is formed by the VD method and patterned into a wiring shape, a wiring 83 is obtained (S301).

Next, as shown in FIG. 6B, a relatively thick oxide film 85 serving as an interlayer insulating film is formed by a CVD method. Then, the wafer W is put into the precision polishing apparatus shown in FIG. 1, and the oxide film 85 is polished. The oxide film 85 is removed by polishing to the position shown by the line B so that the concave portion 86 on the surface disappears (S302).

The wafer W is taken out of the precision polishing apparatus through the cleaning and detecting steps shown in FIG. The wafer W whose surface is polished is put into a sputtering apparatus to form a metal film such as aluminum silicon serving as a wiring, and is patterned into a wiring shape. As a result, a wiring 88 is obtained as shown in FIG. 6C. . By repeating the above steps S302 and S303, a flat multilayer wiring structure can be formed. In the above, the polishing of the oxide film 85 has been described, but it goes without saying that the metal film serving as the wiring may be polished.

The structure of the above-described polishing means, cleaning means, detection means and the like can be appropriately replaced with the polishing means, cleaning means and detection means of each embodiment described later.

Next, an embodiment will be described.

(Embodiment 1) FIG. 7 shows a precision polishing apparatus according to a first embodiment, which comprises a loading unit 1, a wafer stocker unit 2, a polishing unit 3, first and second polishing units. It has cleaning units 4 and 5, a dehydration unit 6, a drying unit 7, and an unloading unit 8. 9. The loading unit 1 and the wafer stocker unit 2 according to claim 8.
, The second unit corresponds to the polishing unit 3, the third unit corresponds to at least one of the first cleaning unit 4 and the second cleaning unit 5, and the fourth unit corresponds to the dry unit. It corresponds to the unit 7. Detecting means for detecting a polishing state of the wafer W ₁ is in this embodiment provided in the unloading unit 8.

[0059] The loading unit 1 receives the wafer W ₁ is a workpiece each cassette from the conveyor or the like (not shown). The wafer stocker unit 2, which is temporarily waits by performing centering of the wafer W ₁ taken out of the loading unit 1. Polishing unit 3
Holds the wafer W ₁ to the polished surface faces upward, polishing the surface of the wafer W ₁ by the polishing pad 3a is a downward polishing means while supplying the slurry from the slurry supply device 3b. The first cleaning unit of the cleaning unit 4 and 5 4 are prewashing unit 4 to perform preliminary washing by spraying a cleaning liquid to the wafer W ₁ after polishing. The second cleaning unit 5 includes first and second cleaning tanks 5.
a, in order to clean the wafer W ₁ by 5b. Dehydrating unit 6 is a spin dehydration unit to remove the washing liquid adhered to the wafer W ₁ is rotated. Drying unit 7 is a unit to completely dry by blowing cool air or warm air or the like to the wafer W _1. Unloading unit 8 sends out the dried wafer W ₁ to the next step. Each unit 1-8 constitutes a sealed chamber inside the atmosphere sealed by the sealing means, to a position for loading and unloading the wafer W ₁ between the units, the opening and closing means such as a gate valve 20
Is provided.

The polishing unit 3 is provided with a plurality of downward-facing polishing pads 3a as described above. These pads are alternately regenerated by the hand dresser 9, and when regeneration is impossible, the polishing pad exchange unit 9a Is replaced with a new polishing pad.

A first transfer robot chamber 11 is provided between the loading unit 1 and the wafer stocker unit 2, and a rotary first transfer robot 11a is disposed therein. Similarly, a second transfer robot chamber 12 is provided between the dehydration unit 6 and the drying unit 7, and a rotary second transfer robot 12 a is provided therein, and the drying unit 7 and the unloading unit are provided. 8, a third transfer robot chamber 13 is provided, in which a rotary third transfer robot 13a is disposed. The transfer robots 11a to 13a take out the wafer W1 from _one unit and carry it into another unit by expanding and contracting the arm and moving it up and down.

First to third transfer robot chambers 11 to 1
3 are each a sealed chamber inside the atmosphere sealed, loading of the wafer W _1, switching means 20, such as a gate valve is provided in the outlet port.

The polishing unit 3 has a fourth transfer robot 14a that reciprocates along the guide 14 and transfers the wafer. Second cleaning unit 5 includes a cleaning robot 15a for transferring the wafer W ₁ forward as soon as 1, the second cleaning tank 5a, and 5b along the guides 15.

Each of the units 1 to 8 and the transfer robot chambers 11 to
All the sealed chambers such as 13 are isolated from the atmosphere around the precision polishing apparatus, and the opening and closing means 20 between the adjacent sealed chambers is opened and closed as follows.

For example, the opening / closing means 20 between the loading unit 1 on the upstream side of the polishing unit 3 and the first transfer robot chamber 11 and the wafer stocker unit 2 is sequentially opened / closed to transfer the wafer W ₁ toward the polishing unit 3. First, the atmospheric pressure P ₁ in the loading unit ₁
Working delivers the wafer W ₁ to the transfer robot 11a by opening the loading unit 1 and the closing means 20 between the first transfer robot chamber 11 at a state in which higher than the ambient pressure P ₂ in the first transfer robot chamber 11 And the opening / closing means 20 is closed. Subsequently, the atmosphere pressure P ₂ of the transfer robot chamber 11 is carried to the wafer W ₁ by opening the closing means 20 between them in higher than ambient pressure P ₃ in the wafer stocker unit 2 to the wafer stocker unit 2 Perform centering and the like.

When the wafer W ₁ is carried into the polishing unit 3 from the wafer stocker unit 2, the polishing unit 3
Towards atmospheric pressure opens the closing means 20 in lower than the atmospheric pressure in the wafer stocker unit 2, delivers the wafer W ₁ to the fourth transfer robot 14a.

As described above, when the opening / closing means 20 of the sealing chambers adjacent to each other is opened, the pressure of each sealing chamber is set so that the atmospheric pressure of the sealing chamber far from the polishing unit 3 becomes high. In addition, it is possible to prevent a large amount of dust such as polishing powder generated in the polishing unit 3 from entering the wafer stocker unit 2, the loading unit 1, the transfer robot chamber 11, and the like.

The opening / closing means 20 disposed downstream of the polishing unit 3 is controlled in such a manner as to increase the atmospheric pressure in the sealed chamber far from the polishing unit 3 in the same manner as described above. the carry out the transfer of the wafer W ₁ is open.

In order to control the atmospheric pressure of each sealed chamber, a supply / exhaust port serving as an atmospheric pressure control means is provided in each sealed chamber, and when the opening / closing means 20 is opened, the supply / exhaust port of one sealed chamber is opened. By supplying clean air and exhausting the air supply / exhaust port of the other sealed chamber, a pressure difference is provided in the atmosphere of each sealed chamber.

If a slit-shaped opening or the like is provided in each of the opening / closing means 20 and the polishing unit 3 is continuously evacuated, clean air around the precision polishing apparatus is sequentially sucked into each sealed chamber, and the polishing is performed. A pressure gradient occurs in which the closer to the unit 3, the lower the atmospheric pressure. As described above, if it is set that the state in which the atmospheric pressure becomes higher as the sealed chamber is farther from the polishing unit 3 is always maintained, it is not necessary to control the atmospheric pressure of each sealed chamber every time the opening / closing means 20 is opened and closed.

The wafer W ₁ carried into the loading unit 1 by a conveyor or the like (not shown) is transferred to the wafer stocker unit 2 by the transfer robot 11a, where it is centered and stored in a storage shelf or the like. 4 is transferred to the polishing unit 3 by the transfer robot 14a. Fourth transfer robot 14a
Holds the wafer W _{1 so} that the surface to be polished faces upward, transports the wafer, and places the wafer W ₁ on a wafer chuck in the polishing unit 3. Wafer chuck is wafer W ₁
Is held by suction. In this case downward polishing pad 3a is moved above the wafer W _1. The polishing pad 3a on the surface to be polished of the wafer W ₁ contact, by rotating the polishing pad 3a by applying pressure to polish the wafer W _1.

The polished wafer W ₁ is transferred to the first cleaning unit 4 and is subjected to preliminary cleaning. Next, the wafer W ₁ is transferred to the second cleaning unit 5 for cleaning. Thereafter, the wafer W ₁ is dehydrated in the dehydration unit 6, and is subsequently transferred to the drying unit 7, where the wafer W ₁ is dried.

The precision polishing apparatus according to the present embodiment
Steps ₁ and 2 such as loading, polishing, washing and drying are continuously and automatically performed. However, by performing the defect inspection of the wafer W ₁ taken in the unloading unit 8, when a defect such as scratches on the polished surface is found,
Than described above was repeated for the entire process again send back the wafer W ₁ to the loading unit 1, the wafer W with a defective
_The time spent on regeneration of ₁ is long, and the productivity is low. Further, since all the transfer robot chambers 11 to 13 and the opening / closing operation of each opening / closing means 20 are required, the number of times of driving these may increase, which may lead to shortening of the life of the apparatus.

[0074] Therefore, during or unloading uni bets in 8 of the drying unit 7 and the unloading unit 8, and the defect inspection apparatus 31a which inspects the polished surface scratches and dirt of the wafer W ₁ fractionating defective wafer defect W ₁ is either a flaw remaining on the polished surface, or a stain for remaining byproducts or slurry polishing, or dry it is determined whether a stain for leaving insufficient cleaning liquid determination Inspection discriminating unit 3 as detecting means provided with device 31b
1 is provided.

Defect inspection device 31 of inspection discrimination unit 31
In a, examines whether there is a scratch or dirt of the polished surface of the wafer W _1, feeds only those without such defects from the unloading unit 8 to the outside of the device.
Wafer W ₁ including a defect is transported to the determination unit 31b, whether the defect is a scratch of the polished surface, or a soiled by residual slurry and polishing byproducts on the polished surface of the wafer W _1, or pre-washed Ya Inspect whether the cleaning liquid used in the cleaning process is dirty due to remaining. Wafer W ₁ which has been determined to be defective through such detailed defect inspection, the drying unit 7 through the return duct 32 is selectively returning means, the cleaning unit 5 or the wafer stocker unit 2
Etc. are selectively returned.

The return duct 32 is composed of units 2, 5, 7,
Comprises a closing means 20 to the opening for 31 and the like, when the defect of the wafer W ₁ detected in the inspection determination unit 31 is a flaw of the surface to be polished, the wafer W ₁ wafer stocker unit to repeat the polishing a first return passage 32a for returning to 2, defects of the wafer W ₁ is, when it is determined that the stain for leaving a slurry and polishing byproducts, to return the wafer W ₁ to the cleaning unit 5 a second return passage 32b, the defect of the wafer W ₁ is, when it is determined that the stain for remaining cleaning liquid, a third return path 32c for returning the wafer W ₁ to the drying unit 7
When defects of the wafer W ₁ is, if it is determined that none of the above has a fourth return path 32d to return the wafer W ₁ to the defect inspection apparatus 31a to perform a re-inspection, the wafer depending on the type of defect of W _1, it is configured to return the wafer W ₁ to step necessary for reproducing the wafer W _1.

Incidentally, instead of connecting the first return path 32a to the wafer stocker unit 2, it may be directly connected to the polishing unit 3.

According to the present embodiment, before the wafer is taken out of the unloading unit, the wafer is inspected for defects and automatically returned to the step for removing the defects. Is taken out of the unloading unit as a product, and there is no possibility that a defective product is contained in the wafer taken out of the precision polishing apparatus and sent to the next step.

In addition, wafers that do not require repolishing, such as scratches on the surface to be polished, such as scratches on the surface to be polished, are returned to the cleaning step and drying step downstream of the polishing step. There is no trouble such as lowering the throughput of the precision polishing apparatus due to a complicated polishing process, or generating new scratches or stains on the surface to be polished of the wafer, and performing re-polishing many times.

By efficiently regenerating defective products in this manner, the throughput of the wafer polishing step can be greatly improved. In addition, it is possible to prevent defective products from being included in products sent to the next process, thereby contributing to automation of the manufacturing process of semiconductor devices and the like. As a result, the productivity of semiconductor devices and the like can be greatly improved.

(Embodiment 2) FIG. 8 shows a second embodiment.
This consists of a drying unit 7 and an unloading unit 8
The second and third inspection discriminating units 41 and 5 which are intermediate detecting means, similar to the inspection discriminating unit 31 provided between
1 is a second cleaning unit 5 and a drying unit 7
And between the polishing unit 3 and the first cleaning unit 4. Loading unit 1, wafer stocker unit 2, polishing unit 3, cleaning units 4 and 5, drying unit 7, unloading unit 8
Since these are the same as in the first embodiment, they are denoted by the same reference numerals and description thereof is omitted.

[0082] The second inspection discrimination unit 41, a defect inspection apparatus 41a for detecting defects of the wafer W ₂ after cleaning, wafer defects W ₂ is an intermediate defective products in scratches the polished surface of the wafer W ₂ Discriminating device 41 for discriminating whether or not there is contamination or contamination due to slurry or polishing powder remaining on the surface to be polished
b, and if the defect of the wafer W _{2 is} a flaw in the surface to be polished, the wafer W ₂ is returned to the wafer stocker unit 2 through the first return path 42 a which is an intermediate return means in the return duct 32. , defects of the wafer W ₂ is to return the wafer W ₂ to the cleaning unit 5 through the second return passage 42b, if contamination by the polishing powder or the like. Also, if not its either is to return the wafer W ₂ through the third return passage 42c to the defect inspection apparatus 41a.

[0083] The third inspection discrimination unit 51, a defect inspection apparatus for detecting defects in the polished surface of the wafer W ₂ after polishing 5
1a and the defect of the wafer W ₂ which is an intermediate defective
Discriminating device discriminates whether the flaw of the polished surface of the ₂ 5
Has 1b, if defects of the wafer W ₂ is a flaw of the surface to be polished, to return the wafer W ₂ to the wafer stocker unit 2 through the first return passage 52a, which is an intermediate return means in the return duct 32 Otherwise, the second return path 52b
To return the wafer W ₂ in the defect inspection apparatus 51a through.

As described above, if the wafer defect is detected after the polishing step and the cleaning step and returned to the necessary preceding step, the wafer defect can be found earlier. The number of drying and cleaning steps per product until the wafer is taken out of the precision polishing apparatus is different from the case where the wafer is inspected for defects after all the steps are completed as in the first embodiment. Average value can be significantly reduced. This can further contribute to lowering the price of semiconductor devices and the like.

(Embodiment 3) FIG. 9 shows a precision polishing apparatus according to a third embodiment, which comprises a wafer stocker unit 62, a polishing unit 63, and a cleaning unit 65.
, A drying unit 67, a detection unit 71 serving as a detection unit, and a transfer chamber 72. Opening / closing means 80a to 80e are provided between the transfer chamber 72 and each unit. An opening / closing means 80f is provided at the opening of the transfer chamber 72 which opens to the atmosphere of the clean room in which the precision polishing apparatus is provided.

The polishing unit 63 comprises a processing chamber (sealed chamber) which can be sealed by opening / closing means 80a, and has a large-diameter polishing tool 63a to which a polishing pad is attached, a slurry feeder 63b, a wafer holder 63c, and a wafer holder. Holder 6
And an arm 63d for reciprocating the 3c.

FIG. 10 is a flowchart showing the operation of the precision polishing apparatus according to this embodiment.

The opening / closing means 80f controlled by the controller 73 is opened, and the wafer is taken into the transfer chamber 72 by the transfer robot 72a.

The wafer is held by the wafer holder 63c in the polishing unit 63 from the transfer chamber 72 via the opening / closing means 80a with the surface to be polished facing upward. Closing the opening / closing means 80a, while rotating the polishing tool 63a, the wafer holder 6
3c is lowered. At this time, the slurry is supplied to the slurry feeder 6.
3b, the wafer is supplied onto the polishing pad on the polishing tool 63a, and the surface to be polished of the wafer is pressed against the upper surface of the polishing pad. Then, the arm 63d reciprocates to polish the surface to be polished of the wafer (S201).

When the polishing is completed, the opening / closing means 80a is opened, the wafer is taken out into the transfer chamber 72, and the opening / closing means 80a is closed. The polished wafer is transferred to the cleaning unit 65 by opening the opening / closing means 80b, and the opening / closing means 80b is closed.
In the cleaning unit 65, the surface to be polished of the wafer is cleaned, and the slurry and polishing debris on the wafer are removed by wet cleaning (S202).

The cleaned wafer is once taken out into the transfer chamber 72 by opening the opening / closing means 80b, and is sent into the drying unit 67 by opening the opening / closing means 80d. The opening / closing means 80d is closed, and the polished surface of the wafer is dried in the drying unit 67. Drying is performed by blowing cool air from a nozzle onto the wafer surface (S203).

The dried wafer is opened in the opening / closing means 80d and is once taken out into the transfer chamber 72.
c is opened and transferred to the detection unit 71. The detection unit 71 detects whether a flaw, slurry, or the like exists on the surface to be polished using the above-described line sensor (S204). For a wafer determined to have no scratches, no slurry, or the like, the wafer inspection device arranged in the detection unit 71 determines whether the cleaning liquid is attached. This device irradiates a laser beam, detects its regular reflection,
The determination is made based on whether or not the average value of the detection levels is within a predetermined range. Since the detection level of the specular reflection light is different between the portion where the cleaning liquid is attached and the surface of the wafer without the cleaning liquid, the two can be distinguished by checking the values of the two in advance.

The wafer determined to have a flaw in step S205 is returned to polishing step S201. Step S2
At 06, the wafer determined to have the adhesion of the slurry or the like is returned to the cleaning step S202 without going through the polishing step S201.

In step S207, the wafer judged to have the cleaning liquid attached thereto is returned to step S203 without going through steps S201 and S202.

In this manner, only the wafer judged to be free of any of the cleaning liquid such as scratches, slurry, etc., is once taken out into the transfer chamber 72 by opening the opening / closing means 80c, and opened and closed by opening the opening / closing means 80e. 62.

According to the above embodiment, polishing and cleaning of a workpiece such as a wafer are performed continuously and automatically.
By providing a system that detects a defect of a product inside the apparatus and automatically returns to a step required for reproduction, a precision polishing apparatus with extremely high productivity can be realized. Further, since there is no possibility that a defective product is included in the product of the precision polishing apparatus, it can contribute to the automation of the manufacturing process of semiconductor devices and the like.
This can greatly contribute to lowering the price of semiconductor devices and the like.

[0097]

Since the present invention is configured as described above, it has the following effects.

Polishing or cleaning can be selectively performed again according to the surface condition of the surface to be polished of the workpiece such as a wafer which has been cleaned after polishing. In other words, if it is determined that there is a flaw, polishing is performed again, and if it is determined that only slurry or the like is adhered, the cleaning step and the subsequent steps are repeated without returning to the polishing unit. Thereby, unnecessary re-polishing processing steps can be omitted. As a result, high-precision and high-precision precision polishing can be performed without lowering the throughput.

Further, since the workpiece to which only the slurry or the foreign matter is adhered is returned to the cleaning step without performing the polishing, new scratches due to the foreign matter may be generated on the wafer as in the case where the polishing is performed again. Nor.

[Brief description of the drawings]

FIG. 1 is a schematic view showing one embodiment of a precision polishing apparatus according to the present invention.

FIG. 2 is a flowchart showing basic steps of a polishing method according to the present invention.

FIG. 3 shows an example of a polishing means used in the precision polishing apparatus of the present invention.

FIG. 4 shows a cleaning means used in the precision polishing apparatus of the present invention.

FIG. 5 is a view for explaining a detecting means used in the precision polishing apparatus of the present invention.

FIG. 6 illustrates a method for manufacturing a semiconductor device according to the present invention.

FIG. 7 is a schematic diagram showing the first embodiment.

FIG. 8 is a schematic view showing a second embodiment.

FIG. 9 is a schematic diagram showing a third embodiment.

FIG. 10 is a flowchart of a polishing method using the precision polishing apparatus of FIG. 9;

FIG. 11 is a schematic view showing a precision polishing apparatus according to a conventional example.

FIG. 12 is a flowchart of a conventional polishing method.

FIG. 13 is a view showing a polishing means used in a conventional partial polishing step.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Loading unit 2, 62 Wafer stocker unit 3, 10a, 63 Polishing unit 4, 5, 10b, 65 Cleaning unit 7, 67 Drying unit 8 Unloading unit 10c, 71 Detection unit 10d, 72 Transfer chamber 10e, 11a to 13a, 72a Transfer robot 20, 20a-20d, 80a-80f Opening / closing means 21, 73 Controller 31, 41, 51 Inspection discrimination unit 31a, 41a, 51a Defect inspection device 31b, 41b, 51b Discrimination device 32 Return duct

Claims (13)

[Claims] 1. A polishing unit having polishing means for polishing a workpiece, a cleaning unit for cleaning a workpiece transferred from the polishing unit, and a workpiece cleaned by the cleaning unit Detecting means for detecting the surface condition of the surface to be polished, and selective return for selectively returning the workpiece to the polishing unit or the cleaning unit based on the detection result of the surface condition of the detecting means. Precision polishing apparatus having means. 2. The precision polishing apparatus according to claim 1, wherein the polishing unit is controlled so that the pressure of the atmosphere inside the polishing unit is lower than the pressure of the atmosphere of the cleaning unit. 3. A cleaning unit comprising: a scrub cleaning means;
3. The precision polishing apparatus according to claim 1, further comprising at least one of a nozzle cleaning unit and a liquid tank cleaning unit having a liquid tank containing a cleaning liquid. 4. A polishing unit having polishing means for polishing a workpiece, a cleaning unit for cleaning the workpiece transferred from the polishing unit, and a workpiece transferred from the cleaning unit. A drying unit for drying, a detecting means for detecting a surface state of a polished surface of the workpiece dried by the drying unit, and a detection result of the workpiece by the detecting means. A precision polishing apparatus comprising a selective return means for selectively returning the polishing unit or the cleaning unit based on the return. 5. The selective return means is configured to return a workpiece of the detection means to any one of a polishing unit, a cleaning unit, and a drying unit based on a detection result of a surface state thereof. The precision polishing apparatus according to claim 4, wherein: 6. The polishing unit according to claim 4, wherein the polishing unit is controlled so that the pressure of the atmosphere in the polishing unit is lower than the pressure of the atmosphere in the cleaning unit or the drying unit.
Or the precision polishing apparatus according to 5. 7. A cleaning unit comprising: a scrub cleaning means;
The precision polishing apparatus according to any one of claims 4 to 6, further comprising at least one of a nozzle cleaning means and a liquid tank cleaning means having a liquid tank containing a cleaning liquid. 8. A second unit provided with a polishing means for polishing a workpiece transferred from the first unit,
A third unit for cleaning the workpiece transferred from the third unit, a fourth unit for drying the workpiece transferred from the third unit, and a workpiece transferred from the fourth unit Detecting means for detecting the surface condition of the surface to be polished of the object, and selecting one of the first to fourth units based on the detection result of the surface condition of the workpiece by the detecting means; Precision polishing equipment with selective return means for selective return. 9. Sealing means for individually sealing the atmosphere of each of the first to fourth units, and atmosphere pressure control means for controlling the atmosphere pressure of each unit to a value lower than the atmosphere pressure outside the precision polishing apparatus. The precision polishing apparatus according to claim 8, further comprising: 10. An intermediate detecting means for detecting a surface condition of a polished surface of a workpiece transferred from the second unit is provided between the second unit and the third unit. 10. The precision polishing apparatus according to claim 8, further comprising an intermediate return means for returning the workpiece of the means to the second unit based on a detection result of the surface condition. 11. An intermediate detecting means for detecting a surface condition of a polished surface of a workpiece transferred from the third unit is provided between the third unit and the fourth unit. 12. An apparatus according to claim 8, further comprising an intermediate return means for selectively returning the workpiece of the means to the second unit or the third unit based on the detection result of the surface condition. 2. The precision polishing apparatus according to claim 1. 12. A method for manufacturing a semiconductor device, comprising a step of forming a wiring and an interlayer insulating film on a substrate on which a semiconductor element is formed, after forming the wiring or a film to be the interlayer insulating film. 12. A method for manufacturing a semiconductor device, comprising a step of polishing the film using the precision polishing apparatus according to any one of 1 to 11. 13. A method of manufacturing a semiconductor device, comprising the step of re-polishing a substrate film returned by the selective return means of the precision polishing apparatus according to claim 1. Description: