JPH07263388A - Method and device for polishing wafer - Google Patents

Abstract

PURPOSE:To improve the quality of a wafer and reduce the facility cost by preventing the scattering of fine powder, etc., of abrasive produced by the polishing of a wafer. CONSTITUTION:The drying of the abrasive supplied between a polishing face 3a and a wafer 5 is prevented by partitioning off at least, a region including a polishing face 3a and a wafer 5 from the outside, and polishing it while maintaining the inside of its division in enough wet condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer polishing method and a polishing apparatus for polishing the surface of a semiconductor wafer or the like forming an integrated circuit.

[0002]

2. Description of the Related Art In recent years, semiconductor wafers for manufacturing integrated circuits such as LSIs (hereinafter simply referred to as "wafers") have been polished to have a highly accurate and defect-free surface in accordance with miniaturization of devices. Has come to be required. This polishing mechanism is based on a mechano-chemical polishing method that combines a mechanical element such as fine particle silica and an etching element with an alkaline solution.

That is, a wafer is placed in pressure contact with the polishing surface of a polishing disk and rubbed against the polishing surface, and fine particle silica and an alkaline liquid such as potassium hydroxide supplied between the polishing surface and the polishing surface are mixed. It is polished by the slurry-like polishing agent. As a result, the surface of the wafer to be polished can be accurately finished. However, the polishing agent will remain on the polished wafer, so if this is left unattended, the etching of the wafer surface will proceed, and the dry polishing agent will stick to the wafer surface and be removed. It is difficult to do this.

In order to avoid such inconvenience, it is necessary to wash and remove the polishing agent adhering to the surface of the wafer before it is dried. Immediately after polishing, it is put into a cleaning machine such as a double-sided scrubber. However, it has been performed conventionally. In this cleaning machine, while polishing wafers are circulated one by one, pure water is sprayed while rubbing both sides with a brush or the like to clean and remove the polishing agent, and then dried.

[0005]

By the way, since a high degree of cleanliness is required for a wafer which has been inserted through the cleaning machine, the cleaning machine is installed in a clean room of class 10 to 100. It On the other hand, in a polishing apparatus for polishing a wafer, the polishing agent supplied to the polishing surface is scattered around due to the relative movement of the wafer and the polishing surface. And
The scattered polishing agent dries and floats in the air due to the flow of air in the room, so that the cleanliness of the room where the polishing apparatus is arranged is about class 1000.

Therefore, the polishing apparatus and the washing machine cannot be placed in the same room, and must be installed in separate completely isolated rooms. However, as described above, the polishing apparatus and the cleaning machine are preferably arranged adjacent to each other because it is necessary to immediately clean the wafer after polishing, and when they are installed in separate completely isolated rooms,
There is an inconvenience that the polishing process and the cleaning process cannot be continued. Moreover, in order to transfer wafers between rooms having different cleanliness, it is necessary to provide auxiliary equipment such as a cleaning room for removing dust adhering to clothes by an air shower, which causes a problem that the equipment area is increased. .

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a wafer polishing method and a wafer polishing apparatus which prevent scattering of fine particles of the polishing agent generated by polishing the wafer. There is.

[0008]

In order to achieve the above object, a method of polishing a wafer according to a first aspect of the present invention is a method of polishing a wafer while relatively moving a polishing surface of a polishing disk and a wafer pressed against the polishing surface. In a polishing method of supplying a polishing agent between a polishing surface and a wafer, at least while partitioning a region including the polishing surface and the wafer with respect to the outside thereof,
It is characterized in that the inside of the partition is polished while being filled with moist air having a saturation degree of 1 or more.

According to a second aspect of the present invention, there is provided a method for polishing a wafer, in which an abrasive is supplied between the wafer and the polishing surface while relatively moving the polishing surface of the polishing disk and the wafer pressed against the polishing surface. In a polishing method for polishing a wafer, at least:
It is characterized in that a region including the polishing surface and the wafer is partitioned from the outside thereof, and pure water is sprayed and polished inside the partition.

Further, in the method of polishing a wafer having the above structure, it is effective to set the pressure inside the compartment lower than that outside the compartment.

According to a fourth aspect of the present invention, there is provided a wafer polishing apparatus having a polishing plate having a polishing surface, a head for supporting the wafer in a pressure contact state with the polishing surface and moving the head relative to the polishing surface. A partitioning means for partitioning a region including at least the polishing surface and the wafer with respect to the outside, and a polishing agent supply means for supplying a polishing agent between the polishing surface and the wafer. A humidifying means for supplying moist air having a saturation degree of 1 or more is provided inside.

According to a fifth aspect of the present invention, there is provided a wafer polishing apparatus comprising: a polishing plate having a polishing surface; and a head for supporting the wafer in pressure contact with the polishing surface and moving the wafer relative to the polishing surface. Polishing means for supplying a polishing agent between the polishing surface and the wafer, and partitioning means for partitioning at least an area including the polishing surface and the wafer with respect to the outside thereof, and the partitioning means. And a water sprinkling means for spraying pure water inside the means.

Further, in the above polishing apparatus, it is effective if the partition means is provided with suction means for making the inside of the partition a lower pressure state than the outside thereof.

[0014]

According to the wafer polishing method of the first aspect, the region including the wafer and the polishing surface of the polishing plate is divided.
The abrasive supplied between the polishing surface and the wafer is prevented from scattering outside the compartment and is retained in the compartment. Moreover, since the inside of the compartment is constantly humidified by the moist air having a saturation of 1 or more, the abrasive is kept dry,
Floating around is avoided.

According to the wafer polishing method of the second aspect, the polishing agent held in the compartment is constantly wetted by the pure water to be sprayed as in the polishing method of the first aspect. Become. Further, in the above method, if the pressure inside the compartment is set lower than the outside, the flow of air will be from the outside to the inside of the compartment even if the compartment is not a completely airtight structure. This prevents the dust from leaking to the outside.

According to the wafer polishing apparatus of the fourth aspect, the partitioning means partitions the region including the polishing surface and the wafer with respect to the outside thereof, and the humidifying means operates to saturate the partitioning means. One or more humid air is provided. In this state, relative movement between the polishing platen and the head occurs inside the partitioning means, and the polishing agent supply means is operated to polish the wafer while supplying the polishing agent, thereby adhering to the wafer and this. The polishing agent is always kept in a humidified state, which prevents the wafer surface from being dried and prevented from becoming fine powder and floating in the air.

Also in the wafer polishing apparatus according to the fifth aspect, as in the polishing apparatus according to the fourth aspect, the partitioning means partitions the region including the polishing surface and the wafer from the outside. Then, by the operation of the water sprinkling means, pure water is sprinkled into the compartment, so that the wafer and the polishing agent adhering thereto are constantly moistened.

Further, in the wafer polishing apparatus according to the sixth aspect, the inside of the partitioning means is kept at a lower pressure state than the outside by the operation of the suction means, and the air in the partitioning means is held so as not to leak to the outside. To be done. This prevents the fine dust of the abrasive from scattering to the outside of the partitioning means even when the partitioning means is not required to have high airtightness and the operation of the humidifying means or the water sprinkling means is stopped. It becomes possible.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a wafer polishing method and a polishing apparatus according to the present invention will be described below with reference to FIGS. The wafer polishing method according to the present embodiment is performed by moving a wafer pressed against the polishing surface of a polishing platen such as a platen that is rotationally driven, while relatively moving the wafer relative to the polishing surface while adding fine particle silica to potassium hydroxide. This is common to the conventional polishing method in that a wafer is polished by supplying a slurry-like polishing agent mixed with an alkaline solution such as. However, in the wafer polishing method of this embodiment, at least the region including the polishing surface and the wafer is partitioned from the outside, and the wafer is polished while the inside of the partition is sufficiently humidified. The point is different from the conventional example.

This polishing method is realized by the polishing apparatus 1 shown in FIGS. That is, the polishing apparatus 1 includes a platen (polishing plate) 3 that has a horizontal polishing surface 3a that is arranged in an exposed state on the upper surface of the housing 2 and is horizontally rotated by a drive mechanism (not shown) in the housing 2. The platen 3 is supported by the support member 4 on the top of the housing 3.
A plurality of heads 6 arranged above the wafer and supporting the wafer 5.
And a head moving mechanism 7 that presses these heads 6 against the polishing surface 3a of the platen 3 and moves horizontally within the polishing surface 3a, and an abrasive supply means for supplying an abrasive between the wafer 5 and the polishing surface 3a. 8 is the basic configuration.

Further, the polishing apparatus 1 of the present embodiment comprises a partition means 9 such as a fence for covering the polishing surface 3a of the platen 3, the head 6, the head moving mechanism 7 and the abrasive supply means 8,
A sprinkling means 10 for spraying pure water inside the partition means 9;
The partition means 9 has a suction means 11 for making the inside of the partition means 9 in a lower pressure state than the outside. In these drawings, reference numeral 12 is an operation panel, 13 is a control panel, and 14 is a table on which a cassette (not shown) for storing the wafer 5 before and after polishing in a water-immersed state is placed.

The partitioning means 9 is not particularly limited in material, shape, etc. as long as it can partition the inside and outside with a certain degree of airtightness. It may be configured in a box shape by a transparent glass plate or the like that can be used. Also, the sprinkling means 10
Is a plurality of nozzles 15 arranged on the side wall of the partition means 9.
And a pure water supply means 16 for supplying pure water to the nozzle 15. The nozzle is provided with a plurality of jet holes having a small diameter, and the pure water supplied from the pure water supply means 16 is sprayed inside the partition means 9 like a shower.

The suction means 11 is, for example, a suction pump 18 connected to an exhaust port 17 provided in the partition means 9.
By sucking the air inside the partition means 9, the pressure can be made lower than the outside. The discharge port of the suction pump 18 is communicated with the outside of a clean room (not shown) by a duct 19 so as to remove the dust-containing air sucked from the inside of the partitioning means 9 from the inside of the clean room.

The operation of the wafer polishing apparatus 1 thus constructed will be described below. In order to polish the surface of the wafer 5 by the polishing apparatus 1 of the present embodiment, first, the pure water supply means 16 is operated to supply the pure water to the nozzles 15, and the pure water is supplied to the inside partitioned by the partitioning means 9. While spraying, the inside of the compartment defined by operating the suction means 11 is brought into a low pressure state.

In this state, the platen 3 is rotationally driven, and the head moving mechanism 7 is operated to move the wafer 5 relative to the polishing surface 3a of the platen 3 while pressing it. At the same time, the polishing agent supply means 8 is operated to supply a slurry-like polishing agent between the wafer 5 and the polishing surface 3a, whereby the surface of the wafer 5 is polished.

In this case, when polishing the wafer 5,
With the relative movement between the wafer 5 and the polishing surface 3a, the supplied polishing agent is repelled and tends to scatter around. However, in the polishing apparatus 1 of this embodiment, since the region including the wafer 5 and the polishing surface 3a of the platen 3 is partitioned by the partitioning means 9, it is possible to prevent the polishing agent from scattering outside the partitioning means 9. To be done.

Further, since pure water is sprayed inside the partition means 9 in a shower shape, the abrasive adhering to the wafer 5 and the abrasive scattered toward the partition means 9 are always wet. Maintained in a state. As a result, it is possible to prevent the abrasive from sticking to the wafer 5 due to drying, and to prevent the particulate silica contained in the abrasive from floating in the air.

Moreover, the inside of the partition means 9 is the suction means 1
Since the low pressure state is set by 1, when the partitioning means 9 is not a completely airtight structure, an air flow that passes through the partitioning means 9 and goes from the outside to the inside is generated based on the pressure difference between the partition means 9 and the outside. . Therefore, the abrasive is securely held inside the partitioning means 9, and, for example, the water sprinkling means 10 is used.
Even if the defective operation of No. 2 occurs and the abrasive in the partitioning means 9 becomes dry and easily floats in the air, leakage to the outside of the partitioning means 9 is reliably prevented.

As described above, according to the polishing apparatus 1 for the wafer 5 of the present embodiment, the inside partitioned by the partitioning means 9 is constantly moistened by the operation of the water spraying means 10 to prevent the polishing agent from being dried, and Since the fine particle silica is sucked into the low pressure state to prevent the fine particle silica from floating in the air, it is possible to prevent the dust such as the polishing agent from leaking to the outside of the polishing apparatus 1, and maintain the cleanliness of the surroundings high. It becomes possible.

As a result, it becomes possible to install the polishing apparatus 1 in the same clean room as a cleaning machine or the like which requires high cleanliness, and the polishing process and the cleaning process are continuously performed to polish the polished wafer 5. The washing can be carried out immediately. As a result, the efficiency of the manufacturing process of the wafers 5 can be improved, high quality wafers 5 can be supplied, and the installation area of equipment can be reduced.

In this embodiment, a box-shaped fence made of a glass plate is used as the partitioning means 9, but any material and shape can be used. Further, although the region partitioned by the partitioning means 9 is the entire region on the housing 2 including the head moving mechanism 7 and the like, instead of this, at least a region including only the polishing surface 3a of the platen 3 and the wafer 5. The partitioning means 9 for partitioning may be adopted.

Further, in the present embodiment, the water spraying means 10 for spraying pure water in a shower shape is adopted inside the partition means 9, but instead of this, for example, pure water is supplied as mist-like fine particles. A humidifying means such as a humidifier may be employed to fill the inside of the partitioning means 9 with moist air having a saturation level of 1 or more. That is, as long as the inside of the partitioning means 9 is excessively humidified and pure water is condensed to prevent the abrasive from drying, any configuration may be used.

[0033]

As described in detail above, according to the wafer polishing method of the present invention, the polishing agent supplied between the polishing surface and the wafer is prevented from being dried, and the polishing agent is fixed to the wafer. The effect that it is possible to avoid scattering to the surroundings. As a result, the wafer can be polished in the clean room. Further, by setting a low pressure state in the area partitioned so as to include the polishing surface and the wafer, it is possible to more effectively prevent the scattering of the polishing agent to the outside of the partition.

Further, according to the wafer polishing apparatus of the present invention, at least the area including the polishing surface and the wafer is partitioned by the partitioning means with respect to the outside thereof, and the moisturizing means or water sprinkling means is operated. Since it is possible to prevent the polishing agent from drying, it is possible to prevent the polishing agent from sticking to the wafer and scattering to the surroundings and to be installed in a clean room. As a result, it can be placed adjacent to equipment such as a cleaning machine, which should be placed in a clean room, and can improve wafer manufacturing efficiency, and at the same time, ancillary equipment accompanying the reduction of equipment area and separation of clean rooms. Can be eliminated, and the equipment cost can be significantly reduced.

Further, if the inside of the partitioning means is maintained at a low pressure by the suction means, even if the abrasive is dried and the particulate silica contained therein tends to float, This has the effect of preventing leakage to the outside of the partition means and ensuring the cleanliness of the surroundings. As a result, the quality of the manufactured wafer can be improved.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a wafer polishing apparatus according to the present invention.

FIG. 2 is a plan view showing a polishing apparatus for the wafer of FIG.

[Explanation of symbols]

 1 Polishing Device 3 Platen (Polishing Plate) 3a Polishing Surface 5 Wafer 6 Head 8 Abrasive Supplying Means 9 Partitioning Means 10 Water Sprinkling Means 11 Suction Pump (Suctioning Means)

Claims (6)

[Claims] 1. A polishing method of polishing a wafer by supplying a polishing agent between the wafer and the polishing surface while relatively moving the polishing surface of the polishing disk and the wafer pressed against the polishing surface. A method of polishing a wafer, characterized in that a region including a polishing surface and a wafer is partitioned from the outside thereof, and the inside of the partition is filled with moist air having a saturation degree of 1 or more and polished. 2. A polishing method for polishing a wafer by supplying a polishing agent between the wafer and the polishing surface while relatively moving the polishing surface of the polishing plate and the wafer pressed against the polishing surface. A method of polishing a wafer, characterized in that a region including a polishing surface and a wafer is partitioned with respect to the outside, and pure water is sprayed inside the partition. 3. The method for polishing a wafer according to claim 1, wherein the pressure inside the compartment is set lower than the pressure outside the compartment. 4. A polishing plate having a polishing surface, a head for supporting the wafer in pressure contact with the polishing surface and moving the head relative to the polishing surface, and polishing between the polishing surface and the wafer. And a partitioning means for partitioning at least an area including the polishing surface and the wafer with respect to the outside thereof, and a wetting agent having a saturation degree of 1 or more. A wafer polishing apparatus, comprising: a humidifying unit that supplies air. 5. A polishing plate having a polishing surface, a head for supporting the wafer in a pressed state on the polishing surface and moving the wafer relative to the polishing surface, and polishing between the polishing surface and the wafer. A partitioning means for partitioning a region including at least the polishing surface and the wafer with respect to the outside, and a sprinkling means for spraying pure water into the partitioning means. A wafer polishing apparatus comprising: 6. The wafer polishing apparatus according to claim 5, wherein the partition means is provided with a suction means for making the inside of the partition a lower pressure state than the outside thereof.