JP2003229353A - Surface treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface treatment device capable of performing requested surface treatment with precision only at a requested section of a substrate which is to be treated. <P>SOLUTION: A table 2 which supports a semiconductor wafer W, which is a substrate to be treated, is provided inside a vacuum chamber 1. An electron beam irradiating mechanism 6 which generates an electron beam EB is provided to the sealing part of the vacuum chamber 1. An electrode 10 is provided on the table 2, and a mesh-like or porous intermediate electrode 12 is provided between the table 2 and the electron beam irradiating mechanism 6. The intermediate electrode 12 is connected to a DC power source 30 to apply a desired DC voltage. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface processing apparatus for irradiating an object to be processed such as a semiconductor wafer or a glass substrate with electrons in a vacuum atmosphere to modify a resist or an insulating film.

[0002]

2. Description of the Related Art Conventionally, in the field of manufacturing semiconductor devices, etc., a lithography process using a resist is used.
A circuit pattern is transferred to a substrate such as a semiconductor wafer, and in such a lithography process,
After exposure and development, surface treatment using UV is often performed to modify the resist by irradiation with ultraviolet rays (UV) and cure the resist to enhance its mechanical strength.

Therefore, in the field of manufacturing semiconductor devices, surface treatment apparatuses having an ultraviolet irradiation mechanism have been used conventionally.

In recent years, instead of ultraviolet rays,
Using an electron beam (EB) to irradiate electrons,
Attempts have been made to perform surface treatment for modifying a resist or an insulating film.

In such surface treatment using electrons, an object to be treated such as a semiconductor wafer or a glass substrate housed in a vacuum chamber is irradiated with electrons in a vacuum atmosphere, and the action of the electrons modifies a resist or an insulating film. And has a feature that the processing can be performed in a very short time compared with the conventional method.

[0006]

As described above, it has hitherto been attempted to carry out a surface treatment using electrons, which can perform treatment such as resist curing in a shorter time than in the case where ultraviolet rays are used. ing.

The inventors of the present invention have been developing such a surface treatment apparatus, and as a result of many experiments, the surface treatment apparatus using electrons has the following problems. found.

That is, in a surface treatment apparatus using electrons, an EB tube is used to generate an electron beam, and the inside of the EB tube is kept in a high vacuum.
The electron beam is irradiated to the outside through an irradiation window provided in this EB tube. The irradiation window of the EB tube is required to have mechanical strength capable of withstanding the pressure difference between the inside and the outside of the EB tube, and the inside and the outside of the EB tube can be hermetically closed. Is needed.

Therefore, as the constituent member of the irradiation window, one having a certain thickness such as 3 μm is used, and the material thereof is, for example, SiN.

Therefore, in order to extract the electron beam to the outside through the irradiation window as described above, a somewhat high acceleration voltage is required as an electron acceleration voltage in the EB tube, for example, an acceleration voltage of about 15 to 35 KeV is required. And

On the other hand, since the resist film and the like for the EB curing process have a wide variety of materials and thicknesses, when the electron beam emitted with the above-mentioned acceleration voltage is irradiated, depending on the type of the resist film or the like, The electron beam may penetrate into the lower layer of the resist film or the like through the resist film and undesired treatment may be applied to the lower layer, which may change the properties of the device or insulating film provided in the lower layer. There was a problem.

The electron beam interacts with the constituents of the irradiation window when passing through the irradiation window, and further interacts with gas molecules in the vacuum chamber after passing through the irradiation window. For this reason, the energy distribution of the electron beam becomes broad, and the energy of the electron beam becomes uneven, which causes a problem that the accuracy of the EB cure process deteriorates.

The present invention has been made to solve the above problems, and an object thereof is to carry out a surface treatment using electrons capable of precisely performing a desired surface treatment only on a desired portion of a substrate to be processed. To provide a device.

[0014]

In order to solve the above-mentioned problems, the invention according to claim 1 provides a vacuum chamber whose inside can be set to a predetermined vacuum atmosphere, and a substrate to be processed which is provided in the vacuum chamber. A mounting table on which a substrate is placed, an electron irradiation mechanism for irradiating the substrate to be processed with electrons, and an energy control means for controlling the energy of electrons emitted from the electron irradiation mechanism to irradiate the substrate to be processed. And is provided.

According to a second aspect of the invention, in the surface treatment apparatus according to the first aspect, the energy control means controls the energy of electrons by forming an electric field.

The invention of claim 3 is the surface treatment apparatus according to claim 1 or 2, wherein the energy control means comprises an electrode provided on the mounting table.

According to a fourth aspect of the present invention, in the surface treatment apparatus according to the third aspect, the energy control means includes a voltage applying means for applying a desired voltage to the electrodes.

According to a fifth aspect of the present invention, in the surface treatment apparatus according to any one of the first to fourth aspects, the energy control means is in the form of a mesh provided between the mounting table and the electron irradiation mechanism. It is characterized by having a porous intermediate electrode.

According to a sixth aspect of the present invention, in the surface treatment apparatus according to the fifth aspect, the energy control means includes a voltage applying means for applying a desired voltage to the intermediate electrode.

According to a seventh aspect of the present invention, in the surface treatment apparatus according to any one of the first to sixth aspects, the energy control means controls the energy of the electrons emitted from the electron irradiation mechanism to be lowered. It is characterized by being configured as follows.

According to an eighth aspect of the present invention, in the surface treatment apparatus according to any one of the first to seventh aspects, the electron irradiation mechanism irradiates electrons into the vacuum chamber through an irradiation window having a predetermined thickness. It is characterized by being configured.

According to a ninth aspect of the present invention, in the surface treatment apparatus according to any one of the first to eighth aspects, the energy control means causes electrons other than a desired energy among the electrons emitted from the electron irradiation mechanism. It is characterized by having an electron energy filtering function for removing.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The details of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows the present invention in which a semiconductor wafer or the like is irradiated with electrons (electron beam (EB)) to surface-treat an insulating film (for example, a Low-K film), a resist or the like (surface modification treatment). FIG. 2 is a diagram schematically showing a schematic configuration of an embodiment applied to a surface treatment apparatus that performs
Reference numeral 1 denotes a cylindrical vacuum chamber which is made of, for example, aluminum and has a structure capable of hermetically closing the inside thereof and which constitutes a processing chamber.

Inside the vacuum chamber 1, there is provided a mounting table 2 for supporting a semiconductor wafer W as a substrate to be processed substantially horizontally with the surface to be processed facing upward.

The mounting table 2 is vertically movable by an elevating device 3 including a ball screw and a motor for rotating the ball screw. A cylindrical bellows 4 which is made of a material such as stainless steel (SUS) and is expandable and contractible and keeps the inside of the vacuum chamber 1 airtight is provided below the mounting table 2, and the bellows 4 is provided outside the bellows 4. A cover 5 is provided.

On the other hand, an electron beam irradiation mechanism 6 for generating an electron beam EB is provided on the ceiling of the vacuum chamber 1, and an electron beam is applied to the semiconductor wafer W provided on the mounting table 2. EB
Is configured to illuminate. Here, the electron beam EB emitted from the EB tube 6a of the electron beam irradiation mechanism 6 repeatedly collides and diffuses with the inert molecules in the processing space in the vacuum chamber 1, and as shown in FIG.
It becomes a radial electron flow with some spread. In the present embodiment, the “electron beam EB” means such an electron flow.

The distance between the electron beam irradiation mechanism 6 and the semiconductor wafer W when the electron beam EB is irradiated can be adjusted by moving the mounting table 2 up and down by the elevating device 3.

The electron beam irradiation mechanism 6 has an E
It is configured by arranging a plurality of B tubes 6a, and in the present embodiment, as shown in FIG. 2, a total of 19 EB tubes 6a are provided.
The semiconductor wafers W are arranged side by side so as to occupy a circular region having substantially the same shape as the semiconductor wafer W provided on the mounting table 2 and to be arranged concentrically. In FIG. 2, 6
Reference numeral b indicates an irradiation window configured to hermetically close the inside of the EB tube 6a to the outside and to emit the electron beam EB. As described above, the irradiation window 6b is made of, for example, SiN having a thickness of about 3 μm.

As shown in FIG. 1, the EB tube 6a is arranged so that the emission side end of the electron beam EB (irradiation window 6b side) faces downward. And the irradiation window 6b
The semiconductor wafer W in the vacuum chamber 1 is irradiated with the electron beam EB via the.

Further, in the vacuum chamber 1, each EB pipe 6
A grid-shaped detection mechanism 6c for detecting the amount of the electron beam EB is provided for each a.

The detection mechanism 6c detects the amount of the electron beam EB from the current flowing due to the collision of the electron beam EB. The detection signals of these detection mechanisms 6c are input to the output control device 20, respectively. It is supposed to be done. Then, the output control device 20
Uses these detection signals as reference signals for each EB tube 6a.
However, each has a predetermined electron beam EB
Is configured to electrically control each EB tube 6a.

Further, as shown in FIG. 1, the vacuum chamber 1
Is a gas introduction pipe 7 connected to a gas supply source (not shown).
Further, an exhaust pipe 8 connected to a vacuum exhaust device (not shown) is provided so that the inside of the vacuum chamber 1 can be made a predetermined gas atmosphere having a predetermined degree of vacuum.

A heater 9 is provided on the mounting surface of the mounting table 2 so that the semiconductor wafer W can be heated to a predetermined temperature. The side wall of the vacuum chamber 1 is provided with an opening 1a for loading and unloading the semiconductor wafer W, and the opening 1a is provided with a gate valve 11 for opening the semiconductor wafer W. At the time of loading and unloading, the gate valve 11 is opened and closed to load and unload the semiconductor wafer W from the opening 1a.

Further, in this embodiment, in order to configure the energy control means for controlling the energy of the electron beam EB, the mounting table 2 is provided with the electrode 10, and the mounting table 2 and the electron beam irradiation mechanism 6 are provided. The intermediate electrode 12 is provided between them.

The intermediate electrode 12 has a mesh shape or a porous shape so that the electron beam EB can pass therethrough. A DC power supply 30 is connected to the intermediate electrode 12 so that a desired DC voltage can be applied to the intermediate electrode 12. On the other hand, the electrode 10 provided on the mounting table 2 is set to the ground potential in the example shown in FIG.

Then, for example, by applying a desired negative voltage from the DC power source 30 to the intermediate electrode 12, as shown in FIG.
As shown in FIG. 5, it becomes possible to form an electric field in which the value (absolute value) of the negative voltage becomes maximum at the position of the intermediate electrode 12 and becomes zero at the irradiation window 6b and the semiconductor wafer W (electrode 10). There is.

As a result, the irradiation window 6b of each EB tube 6a
From the electron beam EB electrons emitted from
The semiconductor wafer W can be irradiated with the filtered electron beam EB except for the low energy electron beam EB that cannot pass through the intermediate electrode 12.

When the electrode 10 is set to the ground potential, the electron beam EB that has passed through the intermediate electrode 12 is accelerated to the original energy due to the potential difference between the intermediate electrode 12 and the semiconductor wafer W (electrode 10). However, by applying a negative voltage to the electrode 10 to reduce the potential difference between the intermediate electrode 12 and the semiconductor wafer W (electrode 10),
The energy of the electron beam EB can also be reduced.

With the above structure, the interaction with the irradiation window 6b when passing through the irradiation window 6b and the interaction with gas molecules in the vacuum chamber 1 after passing through the irradiation window 6b
The electron beam EB having a broad energy distribution is removed from the electron beam EB having a low energy, and the semiconductor wafer W can be irradiated with the electron beam EB having a narrower energy distribution and more uniform energy. .

That is, the intermediate electrode 12 and the DC power source 30 are
It also functions as an electron energy filtering mechanism for removing electrons other than the desired energy from the electrons in the electron beam EB.

By thus irradiating the semiconductor wafer W with the electron beam EB having a narrow energy distribution and uniform energy, a desired depth region such as a resist film formed on the semiconductor wafer W is accurately and uniformly distributed. Surface treatment can be performed. Further, as described above, the output of the DC power supply can be controlled to control the energy of the electron beam EB. Therefore, by controlling the DC power supply according to the surface state of the resist film and the progress of processing, the accuracy can be improved. Good surface treatment is possible.

Next, using the surface treatment apparatus having the above-mentioned structure,
A procedure for performing the surface treatment of the semiconductor wafer W will be described.

First, the gate valve 11 provided on the side wall of the vacuum chamber 1 is opened, the semiconductor wafer W is loaded into the vacuum chamber 1 from the opening 1a by a transfer mechanism (not shown), and the semiconductor wafer W is moved to a predetermined position in advance. It is mounted on the mounting table 2 that has been lowered.

Next, after the transfer mechanism is evacuated to the outside of the vacuum chamber 1, the gate valve 11 is closed to hermetically close the inside of the vacuum chamber 1.

Then, the mounting table 2 is raised to a predetermined position as shown in FIG. 1 so that the distance between the semiconductor wafer W and the electron beam irradiation mechanism 6 becomes a desired distance.
Set.

Then, the vacuum chamber 1 is passed through the exhaust pipe 8.
The inside of the vacuum chamber 1 is evacuated, and a predetermined atmosphere gas such as nitrogen gas is introduced from the gas introduction pipe 7 so that the inside of the vacuum chamber 1 has a predetermined pressure, for example, 1.33 to 66.5 KPa (10 to 500).
Torr).

Then, the semiconductor wafer W is heated by the heater 9.
While heating the semiconductor wafer W to a predetermined temperature, the semiconductor wafer W is irradiated with the electron beam EB from the EB tube 6a.
The surface treatment of the resist or the like formed on the substrate is performed.

At this time, as described above, the intermediate electrode 12
In addition, a desired negative voltage (for example, -2 to -1) from the DC power supply 30 is obtained.
3KV) is applied to form an electric field as shown in FIG. 3 to control the electron beam EB, and the electron beam E having a narrower energy distribution and more uniform energy.
The semiconductor wafer W is irradiated with B. The acceleration voltage in the EB tube 6a is, for example, about 15 to 35 KeV.

When the irradiation time of the electron beam EB to the semiconductor wafer W reaches a predetermined time, the EB tube 6
The irradiation of the electron beam EB by a is stopped, the surface treatment is completed, and the semiconductor wafer W is carried out of the vacuum chamber 1 by the procedure reverse to the above procedure.

FIG. 4 shows the structure of another embodiment of the present invention. In this embodiment, both the intermediate electrode 12 and the electrode 10 described above are connected to a DC power supply 30. Then, as shown in FIG. 5, the intermediate electrode 12 and the electrode 10 have the same potential, and the intermediate electrode 12 and the semiconductor wafer W (electrode 1
It is possible to form an electric field so that a space having no potential difference is formed between the electric field and the electric field.

In the embodiment shown in FIGS. 4 and 5, the electron beam EB in the filtered state is removed, except for the electron beam EB of low energy which cannot pass through the intermediate electrode 12, as in the above-described embodiment.
Can be irradiated onto the semiconductor wafer W, and the energy of the electron beam EB can be reduced overall,
The semiconductor wafer W is irradiated.

Therefore, the electron beam EB having an energy lower than the minimum acceleration voltage (for example, about 15 KeV) required in the EB tube 6a is supplied to the semiconductor wafer W.
Since the electron beam EB can be prevented from reaching the device or the insulating film below the resist film even when the resist film or the like subjected to the EB curing treatment is thin, it is possible to prevent undesired irradiation in the lower layer. It is possible to prevent the processing from proceeding.

FIG. 6 shows the structure of another embodiment of the present invention. In this embodiment, a DC power source 30 is connected to the electrode 10 without using the intermediate electrode 12 described above, and only the electrode 10 is used. , And is configured to control the energy of the electron beam EB. Then, as shown in FIG. 7, the semiconductor wafer W (electrode 1
It is possible to form an electric field in which the potential changes linearly toward 0).

Also in the embodiment configured as described above, as in the above-described embodiments, the electron beam in the filtered state is removed except for the electron beam EB having a low energy that cannot reach the semiconductor wafer W (electrode 10). It is possible to irradiate the semiconductor wafer W with EB and to irradiate the semiconductor wafer W with the energy of the electron beam EB being lowered overall, and it is possible to obtain the same effect.

In the above embodiment, the case where the present invention is applied to the surface treatment apparatus for treating the surface of a semiconductor wafer or the like has been described, but the present invention is not limited to such a case. For example, the same can be applied to the case of processing a glass substrate or the like for a liquid crystal display device other than a semiconductor wafer. Further, the present invention is not limited to the surface treatment of the resist, and can be applied to the surface treatment of an insulating film or the like.

[0057]

As described above, according to the surface treatment apparatus of the present invention, the desired surface treatment can be accurately performed only on the desired portion of the substrate to be processed.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an embodiment of a surface treatment apparatus of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a main part of the surface treatment apparatus of FIG.

FIG. 3 is a diagram showing a state of an electric field of the surface treatment apparatus of FIG.

FIG. 4 is a diagram showing a schematic configuration of another embodiment of the surface treatment apparatus of the present invention.

5 is a diagram showing a state of an electric field of the surface treatment apparatus of FIG.

FIG. 6 is a diagram showing a schematic configuration of still another embodiment of the surface treatment apparatus of the present invention.

7 is a diagram showing a state of an electric field of the surface treatment apparatus of FIG.

[Explanation of symbols]

W ... Wafer, 1 ... Vacuum chamber, 2 ... Mounting table, 6
...... Electron beam irradiation mechanism, 6a …… EB tube, 6
B ... Irradiation window, 10 ... Electrode, 12 ... Intermediate electrode, 30
...... DC power supply.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Koichi Murakami             TBS release, 5-3-6 Akasaka, Minato-ku, Tokyo             Sending Center Tokyo Electron Limited F-term (reference) 5F046 KA01 LA18

Claims (9)

[Claims] 1. A vacuum chamber whose inside can be set to a predetermined vacuum atmosphere, a mounting table provided in the vacuum chamber for mounting a substrate to be processed, and the substrate to be processed is irradiated with electrons. A surface treatment apparatus comprising: an electron irradiation mechanism; and an energy control unit for controlling the energy of electrons emitted from the electron irradiation mechanism to irradiate the substrate to be processed. 2. The surface treatment apparatus according to claim 1, wherein the energy control unit controls the energy of electrons by forming an electric field. 3. The surface treatment apparatus according to claim 1 or 2, wherein the energy control means includes an electrode provided on the mounting table. 4. The surface treatment apparatus according to claim 3, wherein the energy control unit includes a voltage applying unit that applies a desired voltage to the electrode. 5. The surface treatment apparatus according to claim 1, wherein the energy control unit is a mesh-shaped or porous intermediate electrode provided between the mounting table and the electron irradiation mechanism. A surface treatment apparatus comprising: 6. The surface treatment apparatus according to claim 5, wherein the energy control unit includes a voltage applying unit that applies a desired voltage to the intermediate electrode. 7. The surface treatment apparatus according to claim 1, wherein the energy control unit is configured to control the energy of electrons emitted from the electron irradiation mechanism so as to be reduced. A surface treatment device. 8. The surface treatment apparatus according to claim 1, wherein the electron irradiation mechanism is configured to irradiate electrons into the vacuum chamber through an irradiation window having a predetermined thickness. A characteristic surface treatment device. 9. The surface treatment apparatus according to claim 1, wherein the energy control unit removes electrons other than a desired energy from the electrons emitted from the electron irradiation mechanism. A surface treatment device having a filtering function.