JP3123331B2 - Polishing apparatus and semiconductor device manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clean unit for introducing a polishing apparatus used for polishing a semiconductor substrate into a clean room.

[0002] In particular, in the field of wafer processing characterized by microfabrication, there is a demand for high-precision chemical-mechanical polishing of a semiconductor substrate using a chemical polishing liquid in a highly clean atmosphere and high dust resistance.

[0003] Therefore, a clean unit is required to strictly distinguish a contaminated region, which is a scattering range of dust generated from a polishing apparatus, from a clean region in which a semiconductor substrate is processed in the preceding and following steps.

[0004]

2. Description of the Related Art FIG. 5 is an explanatory view of a conventional example. In the figure, 1 is a substrate to be processed, 2 is a polishing section, 3 is a transport section, 5 is a polishing apparatus, 11 is a clean room, 12 is a surface plate, 13 is a delivery robot, 14 is a transport robot, and 15 is a cleaning tank.

Conventionally, as the performance required for semiconductor devices has increased, higher integration and ultrafineness have been promoted. Furthermore, the consciousness of product miniaturization has increased, and semiconductor manufacturing processing technology has become more complicated. For this reason, it is difficult to obtain customer satisfaction with existing technologies without being able to satisfy the degree of perfection.

Against this background, the demands on the semiconductor device side require the most complete flatness and smoothness of each thin film itself in order to design a multilayer three-dimensional stacked wiring.

[0007] Thin films constituting a semiconductor device are roughly divided into a wiring layer and an insulating layer. At present, research and reports pursuing flatness during film formation for forming a thin film are mainly performed. It is the conventional technology that combines each of these technologies to satisfy the flatness of each thin film layer and develop the next-generation device.

When considering a stacked wiring structure, the flatness of an insulating layer for arranging patterned wirings in each layer is important. In the prior art, complete flatness cannot be obtained by one process of film formation, and flattening is performed in complicated and multiple steps.

For the formation of the insulating thin film layer, CVD and spin coating methods are mainly used, but each has a special technique, and when these are formed into a composite film, time and cost are accumulated. In addition, unevenness of the wiring layer other than the insulating layer directly affects the thickness of the insulating layer and the composite process.

For forming the wiring thin film layer, CVD or PVD (P
Hisical Vapor Deposition) method is used,
It is very difficult to form a metal thin film having excellent electrical characteristics by simultaneously filling the small holes and securing the film thickness.

In order to solve these technical problems,
Although a polishing apparatus 5 for a semiconductor substrate to which a chemical mechanical polishing technique is applied is considered, a polishing operation of the polishing apparatus 5 provided in the clean room 11 as shown in FIG. The problem is significant, as shown in FIG.
The atmosphere in the contaminated area passes through the transport unit 3 and is
There is a problem of leaking into the clean area in 11.
On the other hand, a remarkable dust-proof countermeasure device of the chemical mechanical polishing device corresponding to the operation in the clean room has not been performed yet.

[0012]

As the ultra-precision and miniaturization of semiconductor devices progress, the number of steps increases in proportion. It becomes technically difficult to combine processes having complicated control, and time and cost accumulate and increase as the number of processes increases.

However, unless it depends on such a composite technology, it is impossible to supply products desired by users.
Therefore, the present invention aims to reduce the number of steps in the semiconductor substrate manufacturing process and to form a flat and high-quality thin film layer, with the aim of developing a clean unit that adapts a polishing apparatus applying a chemical mechanical polishing technique to a clean room. Was done.

[0014]

FIGS. 1 and 2 are diagrams for explaining the principle of the present invention. In the figure, 1 is a substrate to be processed, 2 is a polishing section, 3 is a transport section, 4 is a clean unit section, 4a is a rinsing chamber, 4b is an oven chamber, 5 is a polishing apparatus, 6 is a sealing member,
Reference numeral 7 denotes a shutter, 8 denotes a high-purity air filter, 9 denotes an intake port, 10 denotes an exhaust port, 11 denotes a clean room, and 12 denotes a surface plate.

Among the methods for solving the complicated forming technology problem in the wiring layer and the insulating layer, a chemical polishing method is the most effective technique. This technique combines mechanical polishing elements with chemical reactions to achieve perfect flatness. The equipment of the chemical mechanical polishing apparatus used in the present flattening technique is greatly affected by the elements of the equipment, and the present invention is also an indispensable element for improving this polishing technique and completing high-precision polishing.

The biggest obstacles that occur when this polishing technique is implemented in an apparatus are polishing abrasive grains and contaminants generated by chemical polishing, which may cause atmospheric contamination due to polishing processing or adhere to a semiconductor substrate or a device or jig. The contaminants may adversely affect the entire clean room and the next process, such as contamination and dust generation.

In order to solve this problem, it is conceived that the contaminated area and the clean area are clearly distinguished from each other in a facility or an apparatus intended for the work by polishing. Learn how to discharge substances.

That is, an object of the present invention is to provide a polishing apparatus 5 provided in a clean room 11 air-conditioned by using a high-cleanliness air filter 8, and as shown in FIG. By providing a clean unit 4 connectable to the polishing section 2 and the transport section 3 between the polishing section 2 and the transport section 3 for transporting the substrate 1 to be processed to the outside or the polishing section 2, Then, the polishing section 2 performs chemical mechanical polishing, and as shown in FIG. 1B, the clean unit section 4 seals the passage boundary between the clean area and the contaminated area of the polishing apparatus 5 with a seal. A shutter 7 capable of maintaining airtightness by using a member 6 is provided, and an intake port 9 for taking in air using a high-purity air filter 8 and an exhaust port 10 for exhausting from the clean unit unit 4 are further provided. , The clean unit section As shown in FIG. 2, polishing is performed in a clean room 11, which is air-conditioned by using a high-purity air filter 8, as shown in FIG. The processed substrate 1 is transferred from the polishing section 2 of the polishing apparatus 5 to the polishing section 2 and the transport section 3.
This is achieved by transporting to the transport unit 3 via the clean unit unit 4 that can be connected to the printer.

[0019]

As described above, according to the present invention, a chemical mechanical polishing apparatus corresponding to a polishing operation in a clean room can be introduced into an existing clean room at low cost.

The introduction of this equipment makes it possible to perform ultra-precision processing, which greatly contributes to the flattening of the semiconductor substrate, and further to the development of highly integrated and miniaturized semiconductor devices. As a result, energy costs required for cooling and heating these cleaning liquids can be reduced, and the time required for regeneration can be reduced.

That is, in the present invention, the operation of collecting the waste liquid is eliminated, and the regenerating process is also performed simultaneously in one cleaning apparatus. The cleaning liquid discharged at a high temperature is simply additionally heated and returned to the cleaning tank. good.

[0022]

3 and 4 are explanatory views of an embodiment of the present invention. In the figure, 1 is a substrate to be processed, 2 is a polishing section, 3 is a transport section, 4 is a clean unit section, 4a is a rinsing chamber, 4b is an oven chamber, 4c is an exhaust chamber, 5 is a polishing apparatus, 8 is high cleanliness. An air filter, 12 is a surface plate, 13 is a delivery robot, 14 is a transfer robot, 15 is a cleaning tank, 16 is a filter, 17 is a handling chuck, 18 is a rinsing liquid, and 19 is a spray nozzle.

An embodiment of the present invention will be described with reference to FIGS. Generally, the polishing unit 2 for performing chemical mechanical polishing includes a platen 12 in which a polishing cloth is attached to a fixing unit that holds a semiconductor wafer as the substrate 1 to be processed. The surface plate 12 rotates, and the substrate 1 to be processed, which is held on the fixed portion side, rotates while receiving pressure.

The wafer is moved on a wide platen 12 while drawing an arbitrary trajectory, and is polished through a chemical solution containing abrasive grains. Since the substrate 1 after the polishing process is contaminated with the abrasive grains, the fixed part holding the substrate 1 moves away from the surface plate 12 to the delivery robot 13, and from there the transfer robot 13
14 and enters the clean unit section 4 composed of a unit assembly such as the rinsing chamber 4a, the oven chamber 4b, and the exhaust chamber 4c of the present invention.

The clean unit 4 includes the substrate 1 to be processed.
The operation of the shutter 7 for loading and unloading and the basic operation of the exhaust procedure for the polluted atmosphere are common to the following contents. As shown in FIG. 1B, each of the clean units 4 is hermetically sealed by a shutter 7a on the boundary with the contaminated area and a shutter 7b on the clean area. Is managed. When the substrate 1 contaminated by the polishing process is transported to the clean unit section 4 of the present invention via the shutter 7a, the atmosphere of the polishing section 2 on the contaminated area side flows in. Here, the operation of the exhaust port 10 is stopped during the opening operation of the shutter 7a. Shutter 7
When the closed state is formed again by the closing operation of a, the forced exhaust port 10 having the high cleanness air filter (HEPA) 8 is formed.
Thus, the polluted atmosphere in the clean unit 4 is discharged.

After the removal of the contaminated atmosphere, the operation of the exhaust port 10 is stopped, the intake port 9 is operated, the shutter 7b is opened, and the substrate 1 is carried out. The shutters 7a and 7b have independent O- and O- ports at the entrance / exit in the transport direction of the substrate to be processed.
A sealing member 6 made of a ring seal plate is provided. The transfer procedure / exhaust method for loading / unloading the substrate to be processed 1 is the same as the operation of the clean unit unit 4.

Here, polishing was performed using a 4 to 8 inch Si wafer or a ceramic substrate for LCD as a semiconductor substrate according to the following specifications. Polishing conditions are such that milky silica having a particle size of 0.2 μm is polished at 100 rpm on a 300 mm bottom plate. Polishing pressure is 7 ~ 15Pa, polishing cloth thickness is 1.5
Each of the substrates 1 to be processed was polished for 30 minutes.

Thereafter, the substrate 1 to be processed is transferred to the rinsing chamber 4a, and scrubber cleaning is performed by discharging in the order of pure water, a chemical solution, and pure water while increasing the number of revolutions in five stages from 30 rpm to 3,000 rpm. As another cleaning method, a rinsing liquid 18 of a cleaning layer as shown in FIG. 4 is circulated, and an immersion method shown in FIG.
Alternatively, a cleaning method using high frequency cleaning or ultrasonic cleaning by the spray method shown in FIG. 4B is also used.

After that, the substrate 1 is subjected to spin drying, infrared drying or hot air drying in the connected oven chamber 4b.
After that, it is carried out to the clean area of the clean room 11.

[0030]

An assembly of a clean unit having the above functions and a shutter for carrying in and out is installed between the contaminated area and the clean area, and the above-described exhausting method and cleaning method are performed, whereby the polishing area is cleaned. Contaminants can be prevented from flowing to the clean area.

As described above, if the present invention is applied, a sufficient cleaning effect on the substrate to be processed can be obtained, and the manufacturing technology which has been difficult to introduce into a clean room can be adapted to a clean room. It is possible to inject a new wind into the processing technology in the saturated state, which has been developed until now, and can greatly contribute / contribute to the cost reduction of the manufacturing process and the cost reduction of the product by shortening the process.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention (part 1).

FIG. 2 is a diagram illustrating the principle of the present invention (part 2).

FIG. 3 is an explanatory view of one embodiment of the present invention (part 1).

FIG. 4 is an explanatory view of an embodiment of the present invention (part 2).

FIG. 5 is an explanatory view of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate to be processed 2 Polishing part 3 Conveying part 4 Clean unit part 4a Rinse chamber 4b Oven chamber 4c Exhaust chamber 5 Polishing device 6 Sealing member 7 Shutter 8 High cleanness air filter 9 Intake port 10 Exhaust port 11 Clean room 12 Surface plate 13 Delivery robot 14 Transfer robot 15 Cleaning tank 16 Filter 17 Handling chuck 18 Rinse liquid 19 Spray nozzle

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-135192 (JP, A) JP-A-6-45309 (JP, A) JP-A-1-276713 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01L 21/304 621 H01L 21/304 622 H01L 21/02

Claims (5)

(57) [Claims] A polishing apparatus (5) in a clean room (11) air-conditioned using a high cleanness air filter (8), comprising: a polishing section (2) of a substrate (1) to be processed; Between the polishing section (2) or the transfer section (3) for transferring the processing substrate (1) to the outside,
A polishing apparatus comprising a clean unit (4) connectable to the polishing section (2) and the transport section (3). 2. The polishing apparatus according to claim 1, wherein said polishing section (2) performs chemical mechanical polishing. 3. The cleaning unit (4) includes a shutter (7) that can be kept airtight by using a sealing member (6) at a boundary between a clean area and a contaminated area of the polishing apparatus (5). A clean air filter (8) and an exhaust port (9) for taking in outside air, and an exhaust port (10) for exhausting the room atmosphere from the clean unit (4) to the outside. The polishing apparatus according to claim 1, wherein the polishing apparatus is a polishing apparatus. 4. A polishing apparatus according to claim 1, wherein a plurality of said clean unit portions are provided in series. 5. A polished substrate (1) is polished in a polishing unit (2) of a polishing apparatus (5) in a clean room (11) air-conditioned by using a high-cleanliness air filter (8).
From the polishing section (2) and the transfer section (3) via a clean unit section (4) connectable to the transfer section (3).