JPH1187458A - Semiconductor manufacturing apparatus with foreign matter removal function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a semiconductor manufacturing apparatus in which a foreign matter existing in a part coming into contact with the backside of a wafer is transferred to a sheetlike member and in which a foreign matter to be stuck to the backside of the wafer is reduced by a method wherein the sheetlike member having an area capable of covering the part coming into contact with the backside of the wafer in an ordinary operation is used and the same operation as an in an ordinary treatment is performed. SOLUTION: A sheetlike member 10 having an area capable of covering a part coming into contact with the backside of a wafer 9 is conveyed in the same manner as an ordinary wafer to be treated, and a foreign matter in the part coming into contact with the backside of the wafer 9 is transferred to the side of the sheetlike member 10 so as to be removed. That is to say, the sheetlike member 10 is installed inside a load lock chamber 2. While the wafer 9 is being treated so as not to exist inside the load lock chamber 2, an electrostatic attraction and conveyance arm 6 is raised, the sheetlike member 10 is attracted and fixed, and the foreign matter which is stuck onto the electrostatic attraction and conveyance arm 6 is removed. When the wafer 9 is situated inside a main chamber, the above operation is performed, and the foreign matter can be removed without lowering the throughput of an apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing apparatus and an inspection apparatus having a function of removing foreign substances adhering to the back surface of a wafer during wafer processing in a semiconductor device manufacturing process.

[0002]

2. Description of the Related Art As semiconductor elements become more highly integrated, foreign matter (dust) adheres not only to the front surface of a wafer but also to the back surface in the manufacturing and inspection processes of semiconductor devices.
This is because the transfer of foreign matter from the back surface of the wafer to the front surface in the cleaning process and the defocus due to the back surface foreign material in the photolithography process are caused. In addition, in a wafer processing process such as etching and sputtering, temperature control in the wafer surface is performed in order to ensure uniformity in the wafer surface. It becomes uniform, and sufficient temperature control becomes impossible.

Particularly, in recent years, electrostatic force has been used for holding a wafer. However, since the presence of foreign matter causes the electrostatic force to be significantly attenuated, adhesion of foreign matter on the back surface of the wafer is an important problem. I have.

Conventionally, as a method for reducing such foreign matter on the back surface of a wafer, there is, for example, Japanese Patent Application Laid-Open No. 8-321414.

[0005]

2. Description of the Related Art In a wafer processing apparatus, an electrostatic attraction apparatus is often used for transferring and fixing a wafer in a vacuum and during processing. The electrostatic attraction device has advantages such as being able to correct the warpage of the wafer during processing, improving thermal conductivity for temperature control, and reducing foreign matter generated from the mechanical contact portion.

However, even in a processing apparatus utilizing electrostatic attraction, foreign matter is generated at this portion because the back surface of the wafer is in contact with the electrostatic attraction device. As described above, the adhered foreign matter on the back surface of the wafer becomes an important problem in the manufacturing and inspection processes of the semiconductor device.

[0007] However, in the above-mentioned conventional example, although consideration is given to the removal of foreign matter adhering to the member that comes into contact with the foreign matter on the back surface, the installation of a plate-like member used for removing foreign matter and the method for removing foreign matter are not considered. Lack of consideration,
As a means for positively reducing the number of foreign substances itself, it was still insufficient.

A first object of the present invention is to provide a semiconductor manufacturing apparatus and an inspection apparatus having a function of positively removing foreign matter generated in a contact portion with a back surface of a wafer in a processing apparatus or foreign matter brought in by a processed wafer. Is to do.

A second object of the present invention is to provide a semiconductor manufacturing apparatus with a foreign matter reduction function capable of efficiently removing foreign matter that may adhere to the back surface of a wafer in a processing apparatus using a plate-like member. And an inspection device.

[0010]

In order to achieve the first object, in a wafer processing apparatus having a function of transporting, fixing, or processing a wafer, an area capable of covering a portion which comes into contact with the back surface of the wafer during a normal operation. The same operation as during normal processing is performed using the plate-like member having the same, foreign matter existing in a portion that comes into contact with the back surface of the wafer is removed by transferring the foreign matter to the plate-like member. To reduce.

Alternatively, only the operation of carrying or fixing is carried out while holding the above-mentioned plate-like member, foreign matters are removed from the contact surface with the backside of the wafer by the same foreign matter transfer effect, and foreign matter adhering to the backside of the wafer is removed. Reduce.

In order to achieve the second object, the above-described plate-like member is set in an arbitrary wafer transfer path, and an operation of transferring or fixing the plate-like member is performed. By placing the plate-shaped member in an arbitrary wafer transfer path, the operation of transferring or fixing the plate-shaped member can be performed during the processing time of the product wafer, thereby efficiently removing foreign matter on the contact surface with the back surface of the wafer. It can be removed.

The effect of removing foreign substances can be further enhanced by repeating the above-described operation of transporting or fixing the plate-shaped member twice or more continuously, so that foreign substances at the contact portion with the back surface of the wafer can be efficiently removed. It is possible to remove them, and as a result, it is possible to reduce foreign substances adhering to the back surface of the wafer.

Further, the above-mentioned plate-shaped member may be a silicon wafer, a polymer material, or ceramics, and the object is achieved by periodically replacing them.

Further, the object is achieved by providing a cassette, a loader chamber, and an unloader chamber dedicated to the plate-shaped member separately from the cassette, the loader chamber, and the unloader chamber for the actual processing wafer.

Further, the sequence when using the plate-shaped member is incorporated in the sequence at the time of ordinary wafer processing, and the object can be achieved because the sequence using the plate-shaped member can be used independently. Is done.

[0017]

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

FIG. 1 shows a first embodiment of the present invention. An example in which the present invention is applied to a transport section of a semiconductor inspection apparatus will be described. In FIG. 1, reference numeral 1 denotes a main chamber for inspection, and reference numeral 2 denotes a load lock chamber for exchanging a sample, which is partitioned by a gate valve 3 and each is kept in a vacuum atmosphere. 4 is a wafer cassette, 5 is a transfer arm for transferring a wafer to the load lock chamber 2 in the atmosphere, 6 is an electrostatic suction transfer arm for transferring a wafer in a vacuum, 7 is a wafer holder on which a silicon wafer is placed, and 8 is a main chamber. A wafer stage that holds a wafer holder inside.

Normally, the wafer 9 is taken out of the cassette 4 and transported to the load lock chamber 2 and placed on the wafer holder 7 by the electrostatic attraction arm 6, and after the evacuation is completed, passes through the gate valve 3 and passes through the main chamber. The wafer holder 8 is transferred to the wafer stage 8 in the inside.

In this example of the apparatus, the wafer comes into contact with the respective transfer arms and the wafer holder in the atmosphere and in vacuum while the wafer is being transferred. When the wafer is fixed and transported, it is conceivable that these foreign substances adhere to the back surface of the wafer, causing a reduction in the yield in subsequent steps, and contaminating the manufacturing apparatus. Further, it may be a cause that the wafer cannot be reliably held.

Therefore, as proposed in the present invention, by transporting the plate-like member covering the contacting portion of the back surface of the wafer in the same manner as a normal processing wafer, the foreign matter at the contact portion of the wafer back surface is reduced to the plate-like member side. Transferred and removed.

Next, a second embodiment of the present invention will be described with reference to FIGS.
This will be described below. FIG. 2 is a top view of the load lock chamber 2 of the inspection device similar to FIG. FIG. 3 is a cross-sectional view showing a structure in which the plate member 10 can be installed in the load lock chamber 2. When the wafer is being processed, and is not in the load lock chamber, the electrostatic suction transfer arm 6 is raised to fix the plate-shaped member 10 by suction, and foreign substances adhering to the transfer arm 6 are removed. By performing this operation when the processing wafer is in the main chamber, foreign substances can be removed without reducing the throughput of the apparatus.

In this embodiment, emphasis is placed on the removal of foreign matter in the portion of the electrostatic attraction device, which has a large contact area with the wafer and is particularly problematic with respect to the adhesion of foreign matter to the back surface of the wafer. Is installed. However, the place where the plate-shaped member is to be installed is set in an arbitrary wafer transfer path that is effective and does not affect the throughput of the apparatus in accordance with the situation of the component from which the foreign matter is to be removed, and a part of the wafer back surface contact portion in the apparatus is used. By mainly removing foreign matter, the entire apparatus can be efficiently kept in a clean state.

Next, the principle of holding a wafer by electrostatic attraction and the removal of foreign matter adhering to the attracted portion will be described with reference to FIG. Electrostatic suction is employed in various apparatuses for the purpose of holding a wafer stage in a processing step such as etching or sputtering, in addition to the above-described wafer transfer in a load lock chamber. In FIG. 4, 9 is a wafer, 11 is a dielectric,
Reference numeral 12 is an electrode, and 13 is a power supply. The electrostatic attraction device applies a voltage between the electrode 12 and the wafer 9 by the power supply 13 via the dielectric 11, and generates an electrostatic force between the electrodes 12 and the wafer 9.
Is to be adsorbed.

FIG. 4 shows what is called a monopolar type, in which one electrode is used.
1 shows an electrostatic chuck having a structure for grounding the wafer. As shown in FIG. 4, a foreign substance 14 is generated on the surface of the dielectric 11 due to contact with the processing wafer, or is brought into the processing apparatus or brought in. It is conceivable that these foreign particles are charged for some reason. For example, foreign matter generated by destruction due to mechanical contact is charged by friction on the destruction surface. Also, if contact occurs between different materials, charging occurs due to the difference in the energy order of electrons between the materials.

In addition to charging due to exposure to an electric field, in a device utilizing plasma, charging also occurs due to incidence of electrons and ions. When the foreign matter 14 comes into contact with the wafer, the foreign matter 14 is attached to the wafer side by physical contact or electrostatically attached due to charging caused by a potential difference between the foreign matter and the wafer, thereby removing the foreign matter 14 from the dielectric surface which is the contact surface with the wafer. Is done.

FIG. 5 shows a third embodiment of the present invention.
1 shows an overall configuration of a semiconductor manufacturing apparatus and a flow of a wafer. In FIG. 5, reference numerals 15 and 16 denote processing chambers for processing a wafer, and reference numeral 10 denotes a plate-like member used for removing foreign matter. Reference numeral 17 denotes a transfer robot for loading and unloading a wafer into and from the processing chamber, and is installed in a buffer chamber 18 kept at a vacuum. Reference numerals 19, 20, and 21 denote cassettes into which wafers are taken in and out.

In normal wafer processing, the wafer 22 is transferred from the load cassette 19 to the processing chambers 15 and 16 by the transfer robot 17 through the buffer chamber 18.
After the processing, the process returns to the unload cassette 21. The present invention is characterized in that, in addition to the normal load and unload cassettes, a cassette 20 dedicated to a plate-like member for removing foreign substances is provided.

After the normal processing, the plate-like member 10 for removing foreign matter is loaded from the cassette 20 into the processing chamber to remove foreign matter from the wafer back surface contact member. After being transferred, fixed, and held in the same manner as the processing wafer, the plate member 10 is unloaded and returned to the cassette 20 again, and normal etching processing is started.

By providing the special cassette for removing foreign matter as described above, since a cassette for processing wafers is not used, it is not necessary to replace the substrate at the time of removing foreign matter, and the workability can be improved.

Further, since the plate-like member after the foreign matter removing operation can be separated from the actual processed wafer, there is no fear of contaminating the processed wafer. Further, by providing a dedicated loader chamber and an unloader chamber in addition to the cassette dedicated to the plate-like member 8 for removing foreign substances, it is possible to further prevent a decrease in throughput.

The plate-like member used here may be any member having an area larger than the area of the portion in contact with the wafer in the processing apparatus, such as a silicon dummy wafer having a clean surface, a polymer material, a ceramic material, or the like. Various materials other than those that cause heavy metal contamination can be used.

Regarding the frequency of using the plate-like member for removing foreign matter, there is a method that is performed when a foreign matter is increased by an inspection apparatus, in addition to a method of performing a sequence such that the plate-like member is used for every certain number of sheets in advance. Is also effective.
Further, a higher effect can be obtained by performing the operation a plurality of times using one or two or more plate members for removing foreign matter at a time. Furthermore, foreign substances can be removed using both surfaces of the plate-like member.

In the embodiments of the present invention described above, the inspection apparatus and the semiconductor manufacturing apparatus are provided with the plate-like members for removing foreign substances. However, the present invention is directed to various apparatuses for semiconductor processing,
For example, the present invention can be effectively applied to devices such as an etching device, an ion implantation device, a drawing device, and a CVD device.

[0035]

As described above, according to the present invention, a plate-like member having an area capable of covering a portion that comes into contact with the back surface of a wafer during normal operations in a wafer processing apparatus, for example, operations such as transfer, fixing, and processing, is used. Thus, foreign matter present on the contact surface on the back surface of the wafer in the apparatus can be removed by transferring the foreign matter to the plate member. As a result, it is a clean device that reduces foreign matter on the back side of the processing wafer, and the operation rate is higher,
A device with a high yield can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a semiconductor inspection apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a semiconductor inspection apparatus according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing a second embodiment of the present invention.

FIG. 4 is a view showing the principle of foreign matter removal by a plate-like member.

FIG. 5 is a diagram showing a third embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Main chamber, 2 ... Load lock chamber, 3 ... Gate valve, 4 ... Wafer cassette, 5 ... Transfer arm, 6 ...
Electrostatic suction arm, 7: Wafer holder, 8: Wafer stage, 9, 22: Wafer, 10: Plate member, 11: Dielectric, 12: Electrode, 13: Power supply, 14: Foreign matter, 15, 16
... Processing room, 17 ... Transfer robot, 18 ... Buffer room,
19: Load cassette, 20, 21: Cassette.

Claims (1)

[Claims] In a wafer processing apparatus having at least one of a function of transferring the wafer while holding the wafer, a function of fixing the wafer, and a function of processing the wafer in a fixed state, Before or after, using a plate-shaped member having an area capable of covering a portion that comes into contact with the back surface of the wafer during normal wafer processing, performs the same operation as during normal wafer processing and adheres to a portion that comes into contact with the back surface of the wafer. A semiconductor manufacturing apparatus with a foreign matter removing function, which removes foreign matter.