JPH07312356A - Chemical and mechanical polishing apparatus - Google Patents

Abstract

PURPOSE:To prevent mutual contamination between treatments by a method wherein a conveyance means is provided with a plurality of clamps which are used selectively according to the contamination degree of a substrate to be treated. CONSTITUTION:A head part 22 is installed at the free end of a conveyanc means 21, and three each of claws 23A, 23B, 23C as clamps which can sink into, and rise from, the rear surface of the head part 22 are installed at the peripheral edge part. The claws are arranged so as to be deviated by an angle of about 120 deg. each from the center of the head part 22, and three groups of one each of the claws 23A, 23B, 23C are arranged. Then, the claws 23A, 23B, 23C rise and sink selectively by a rising and sinking drive means. The operation of the claws is set in such a way that the claws 23A are used when a wafer 1 is conveyed to a polishing plate from, e.g. a loader-side stage, that the claws 23B are used when the polished wafer 1 on the polishing plate is conveyed to a rough removal plate and that the claws 23C are used when the roughly removed wafer 1 is conveyed to an unloader-side stage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical mechanical polishing apparatus used for manufacturing a semiconductor device or the like, and more particularly to a chemical mechanical polishing apparatus which is free from mutual contamination during processing when a substrate is transported.

[0002]

2. Description of the Related Art With the increase in device densities, wiring technologies are becoming finer and more multilayered. On the other hand, however, high integration may cause a decrease in device reliability. This is because the step of the interlayer insulating film becomes large and steep due to the miniaturization of wiring and the progress of multi-layering, and the processing accuracy and reliability of the wiring formed thereon are lowered. For this reason, it is necessary to improve the flatness of the interlayer insulating film at present when the step coverage of the Al wiring cannot be significantly improved. This is becoming important from the viewpoint of a decrease in the depth of focus due to the shortening of the wavelength of lithography.

Until now, various insulating film forming techniques and flattening techniques have been developed. However, in the case of fine and multi-layered wiring, insufficient flattening when the wiring interval is wide and the interlayer film between the wirings are insufficient. Due to the occurrence of "su", connection failure between wirings has become an important issue.

Therefore, as a means for improving this problem,
Recently, a method called a chemical mechanical polishing method has been proposed in which mirror polishing of a silicon wafer is applied.
This technique has attracted attention as a technique capable of surely flattening in a flattening process accompanying the high integration of LSI. In the LSI process, this technique has been studied for flattening of the interlayer insulating film, embedding of multi-layer metal, etc., and is expected to be applied in a wide range. In this chemical mechanical polishing, as shown in FIG. 3, the carrier rotating part 2 on which the wafer 1 is mounted is set so that the wafer 1 faces the polishing plate 3 called a platen, and the slurry supply port of the slurry supply system 4 is set. Slurry 6 supplied from No. 5 is supplied onto a polishing cloth 7 called a pad attached to the surface of polishing plate 3, and rotation speed of polishing plate rotating shaft 8 and rotation speed of carrier rotating shaft 9 of carrier rotating portion 2 are supplied. Also, polishing is performed by adjusting the pressure of a polishing pressure adjuster (not shown). At this time, in order to etch the insulating film on the wafer surface, KOH or the like is added and the etching is performed in a basic atmosphere.

This chemical mechanical polishing apparatus has a structure as shown in the plan view of FIG. 4, and the handling of the wafer between the stations is carried out by an arm-shaped transfer means for holding the wafer as shown in FIG. Done by Referring to FIG. 4, the wafer 1 stored in the cassette 11 on the loader side is transferred to the stage 12 on the loader side, and the wafer 1 is held by the head portion 13 of the transfer means indicated by the broken line in the figure to hold the polishing plate. Carry on 3. Conventionally, the head portion 13 of the transfer means holds the wafer 1 by a vacuum chuck or a claw 13A as shown in FIG. Next, after the polishing is completed, the wafer 1 is carried by the same head portion 13 onto the rough cleaning plate 14, and the slurry attached to the wafer is rinsed by the rough cleaning pad 15 attached on the rough cleaning plate 14 to perform the rough cleaning. I am supposed to do it. By this rough removal step, the slurry can be reduced to 1,000 or less. In FIG. 4, 16 is a rinse liquid supply system, and 17 is a rinse supply port. Next, the head portion 13 of the same conveying means
Or the same claw 13A is used to carry the wafer 1 to the unload-side stage 18, and the wafer 1 is loaded into the unload cassette 1
It is designed to be stored in 9.

[0006] The problem to be solved by the present invention is to obtain a chemical mechanical polishing apparatus free from cross contamination of the slurry.
The point is what kind of measures should be taken.

[0007]

Therefore, the present invention comprises a carry-out means for carrying in and carrying out a substrate to be processed, and in a chemical mechanical polishing apparatus for chemically mechanically polishing the substrate to be processed, the carrying out means is The solution is to provide a plurality of clamps that are selectively used according to the contamination level of the processed substrate. The clamp is characterized by being constituted by a plurality of claw members capable of holding the substrate to be processed by contacting the peripheral portion of the substrate to be processed. Further, it is possible to solve the above problem by making it possible to select different clamps for the transporting means before and after the chemical mechanical polishing treatment.

[0008]

In the present invention, the transfer means for transferring the substrate (wafer) to be processed before polishing can select and use the clamp according to the degree of contamination of the substrate to be processed. It is possible to hold the substrate with different clamps. Therefore, there is an effect of preventing the slurry, particles generated by polishing, other metal contamination, and the like from mutually contaminating each process.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The chemical mechanical polishing apparatus according to the present invention will be described in detail below with reference to the embodiments shown in the drawings. It should be noted that the same parts as those of the related art will be described with the same reference numerals.

The chemical mechanical polishing apparatus of this embodiment has the same structure as that shown in FIG. 4 except for the conveying means. Therefore, in FIG.
The configuration of the transport unit 21 will be described with reference to (A) and (B). This transfer means is operated by a drive control means (not shown) to loader side stage 12, unload side stage 18,
The wafer 1 is carried in and out of the polishing plate 3 and the rough cleaning plate 14. And the transport means 2
A head portion 22 is provided at the free end of No. 1 as in the conventional case. Claws 23A, 23B, 23C as clamps, which can be retracted from the lower surface, are provided on the peripheral edge of the head portion 22.
As shown in FIG. 1A, three sheets are provided. These claws are arranged so as to be offset from the center of the head portion 22 by an angle of approximately 120 degrees, and the claws 23A, 23B,
Three groups of 23C are arranged. Then, these claws 23A, 23B, 23C are selectively projected and retracted by a retracting drive means (not shown).

FIG. 1B shows the head portion 2 of the conveying means 21.
3 shows a state in which three claws 23A project from the lower surface of 2 and hold the wafer 1. Such a claw operation is performed, for example, when the wafer 1 is transferred from the loader stage 12 to the polishing plate 3 by using the claw 23A and when the wafer 1 on the polished polishing plate 3 is transferred to the rough drop plate 14. The claws 23B are used for the claws 23C, and the claws 23C are used for transporting the roughly dropped wafer 1 to the unload-side stage 18.

Next, an example of the polishing method will be described with reference to FIG. First, the carrier rotating unit 2 on which the wafer 1 is set is set so that the wafer 1 faces the polishing plate 3 called a platen, and the slurry 6 stored in the slurry supply system 4 is placed on the polishing plate 3 from the slurry supply port 5. It is supplied onto a polishing cloth 7 called a pad, and the polishing speed is adjusted by adjusting the rotation speed of the polishing plate rotation shaft 8, the rotation speed of the carrier rotation shaft 9 of the carrier rotation unit 2, and the pressure of a polishing pressure adjuster (not shown). I do. The method of placing the wafer, the number and structure of the platen, the carrier rotating portion, the type of the pad, and the slurry are not particularly limited.

(Embodiment 1) In this embodiment, an insulating film is formed on an Al wiring layer formed with a space by using a transporting means as shown in FIG. 1, and the insulating film is flattened. This is the case. As shown in FIG. 2A, the first interlayer insulating film 32 made of silicon oxide or the like is formed on the surface of the semiconductor substrate 31 made of silicon or the like, and the Al wiring layer 33 is patterned.

Next, the substrate (wafer 1) on which the second interlayer insulating film 34 is deposited as shown in FIG. 2B is transferred from the loader stage 12 shown in FIG. The sheet is conveyed using the conveying means 21 shown. At this time, the head portion 22 of the transfer means 21 holds only the claw 23A so that the wafer 1 is gripped by protruding from the lower surface. Then, chemical mechanical polishing was performed under the following conditions.

Polishing plate rotation speed: 50 rpm Carrier rotation speed: 17 rpm Polishing pressure: 8 psi Polishing pad temperature: 30 to 40 ° C. Slurry flow rate: 225 ml / min These polishing conditions are general polishing conditions for insulating films. Here, since the polishing is performed in a basic atmosphere, a slurry prepared by suspending the slurry in KOH / water / alcohol was used.

After such polishing, the flat shape of the insulating film as shown in FIG. 2C was obtained, and then the wafer 1 was transferred to the rough cleaning plate 14 by using the claw 23B. Next, after the rough removal step, the wafer 1 was transferred to the unload-side stage 18 by using the claw 23C.

In this embodiment, the mutual attachment of the slurry between the processed wafers can be reduced to almost zero by selectively using the plurality of claws.

(Embodiment 2) This embodiment is also a case in which the insulating film is flattened by using the transfer means 21 shown in FIG. 1 as an example between the Al wiring layers. However, here, the contamination level of the wafer is divided into two stages, and only the polished wafer 1 is 23A.
All the claws other than the above claws were used to grab the wafer 1. As shown in FIG. 2A, a wafer was prepared in which a first interlayer insulating film 32 made of silicon oxide and an Al wiring layer 33 were formed and patterned on a semiconductor substrate 31 made of silicon. All this was done in the usual way. Next, chemical mechanical polishing was performed under the following conditions using the polishing apparatus shown in FIG.

Polishing plate rotation speed: 50 rpm Carrier rotation speed: 17 rpm Polishing pressure: 10 psi Polishing pad temperature: 30 to 40 ° C. Slurry flow rate: 225 ml / min These polishing conditions are common as film polishing conditions. Here, since the polishing is performed in a basic atmosphere, a slurry prepared by suspending the slurry in diluted hydrofluoric acid / water / alcohol was used.

Although such polishing was performed, since the chemical mechanical polishing apparatus having a plurality of claws of the present invention was used, FIG.
After the flat shape as shown in (C) was obtained, the mutual adhesion of the slurry between the wafers could be reduced to a level at which there was practically no problem. Further, the present embodiment enables simplification of the device.

Although the embodiments have been described above, the present invention can be modified in various ways, and the clamp of the transfer means has a structure in which the wafer is held by the claws, and a plurality of vacuum suctions which can be retracted from the lower surface of the head portion. Various locking means such as a structure having a mouth can be applied.

Although the wafer 1 is transferred to the unload-side stage 18 after the rough cleaning step in the above embodiment, other post-cleaning steps and the like may be provided.

[0023]

As described above, according to the present invention,
Cross contamination of the wafer due to the slurry, which has been a bottleneck in the conventional method, can be reduced, and the insulating film can be planarized by chemical mechanical polishing.

Therefore, the VLSI can be manufactured with a high yield by a highly reliable process.

[Brief description of drawings]

FIG. 1A is a cross-sectional view of a main part of a conveying unit showing an embodiment of the present invention, and FIG. 1B is a front view of the same.

2A to 2C are cross-sectional views showing a step of flattening an insulating film according to this embodiment.

FIG. 3 is an explanatory view showing a polishing process section of the chemical mechanical polishing apparatus.

FIG. 4 is an explanatory plan view of a chemical mechanical polishing device.

FIG. 5 is an explanatory view showing a conveying means of a conventional polishing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Wafer 2 ... Carrier rotating part 3 ... Polishing stage 21 ... Conveying means 22 ... Head part 23A, 23B, 23C ... Claw

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H01L 21/306 21/68 A

Claims (3)

[Claims] 1. A chemical mechanical polishing apparatus comprising: a carry-out means for carrying in and carrying out a substrate to be processed, the chemical mechanical polishing apparatus for chemically mechanically polishing the substrate to be processed, wherein the carrying out means is in accordance with a degree of contamination of the substrate to be processed. A chemical mechanical polishing apparatus comprising a plurality of clamps that are selectively used. 2. The chemical mechanical polishing apparatus according to claim 1, wherein the clamp is composed of a plurality of claw members that can hold the substrate to be processed by contacting the peripheral edge of the substrate to be processed. 3. The transport means can select different clamps before and after the chemical mechanical polishing process.
The chemical mechanical polishing apparatus described.