JP3211535B2 - Manufacturing method of thin film element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a thin film device. More specifically, the present invention relates to a technique for manufacturing a thin film element by performing ion implantation on a semiconductor thin film formed on an insulating substrate. More specifically, the present invention relates to an antistatic technique for an insulating substrate.

[0002]

2. Description of the Related Art The ion implantation technique is a method of irradiating a solid with an ion beam to introduce impurities near the surface thereof. The ion implantation technique is applied to, for example, LSI manufacture and the like, and a transistor element or the like is formed by introducing impurities into a surface region of a silicon wafer. In recent years, ion implantation technology has been actively applied to semiconductor thin films formed on the surface of an insulating substrate, and is used, for example, in the manufacture of active matrix type liquid crystal display panels and line sensors. Use of ion implantation technology improves the performance of thin-film devices,
Various advantages are obtained in terms of yield improvement, process simplification, cost reduction, and the like.

[0003]

When ion implantation is performed on a semiconductor thin film formed on an insulating substrate, charging (charge-up) generated on the substrate has conventionally been a problem. In order to prevent this, an electron shower system is used in which secondary electrons having weak energy are forcibly supplied to the substrate surface to neutralize ions. The principle of the electron shower system will be briefly described with reference to FIG. The figure shows a schematic sectional structure of a conventional ion implantation apparatus. An insulating substrate 102 to be processed is held on the rotating disk 101, and a semiconductor thin film 103 is formed on the surface thereof. An ion beam 104 accelerated by an ion accelerating tube (not shown) irradiates an insulating substrate 102 held on a rotating disk 101. In this process, the ion beam 1
Positive charges contained in 04 are accumulated in the insulating substrate 102.
As a result, a large electrostatic field is formed on the substrate surface, and the ion beam 104 incident toward the insulating substrate 102 blows up, causing a change in current density. Therefore, the in-plane distribution of ions implanted into the substrate becomes non-uniform. or,
The charge potential generated by the charging causes electrostatic breakdown of a thin film element formed on the insulating substrate 102 and deterioration of withstand voltage of an oxide film such as a gate insulating film. To avoid this, secondary electrons of low energy are generated by an electron gun. In this example, the electron gun includes a filament 105 serving as a primary electron irradiation source and a target 10 receiving primary electron irradiation and generating secondary electrons.
6 combinations. The negative charge of the secondary electrons neutralizes the positive charge accumulated on the insulating substrate 102 to reduce the charge.

The charging of the insulating substrate 102 generated during ion implantation can be reduced to a considerable extent by the supply of secondary electrons. However, it is difficult to completely neutralize it, and a certain amount of charge remains on the insulating substrate 102 at the end of the ion implantation. When the insulating substrate is taken out of the chamber and stored in the cassette after the ion implantation, the charge remaining on the insulating substrate is not discharged, so that the transfer arm and the insulating substrate are attracted by the static electricity, which causes a problem of a transfer trouble. Although the electrification that causes element destruction during ion implantation can be reduced by this electron shower, it is difficult to completely remove the electrification to such a degree as to cause a transport trouble.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned problems in the prior art, an object of the present invention is to prevent a transport trouble due to charges remaining on an insulating substrate after ion implantation. The following measures were taken to achieve this purpose. That is, the thin-film element manufacturing method according to the present invention basically carries out the ion implantation process by carrying the insulating substrate into a predetermined chamber after the previous step including the film forming process of the semiconductor thin film using the insulating substrate,
Then, the insulating substrate is carried out of the chamber and sent to the next step to perform post-processing including wiring. In this process, a procedure for reducing the charge on the insulating substrate by adding an electron shower during the ion implantation process, and neutralizing the charge remaining on the insulating substrate by adding an additional electron shower before the removal from the chamber after the ion implantation process is completed. And performing the following procedure.

[0006]

According to the present invention, after the impurities are ionized and injected into the insulating substrate, the charged electric charge is neutralized by applying an electron shower while the substrate is transferred from the chamber to the cassette, and the insulating substrate is transferred to the cassette. Arms are not attracted, preventing transport problems. That is, according to the present invention, even when the ion beam is removed after the completion of the ion implantation, the electron shower is continued to completely neutralize the static electricity remaining on the insulating substrate. As a result, no charge is generated at the time of carrying out the insulating substrate, and the carrying out of the insulating substrate can be carried out smoothly without being affected by electrostatic attraction.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic block diagram showing a basic configuration of an ion implantation apparatus according to the present invention. As shown in the figure, the present ion implantation apparatus includes a chamber 2 in which an insulating substrate 1 to be processed can be loaded and unloaded. An ion gun 3 is attached to the chamber 2 and performs an ion implantation process on the loaded insulating substrate 1.
Further, an electron gun 4 is provided, and before carrying out, an electron shower is applied to the insulating substrate 1 to neutralize the remaining charge. Note that the electron gun 4 applies an electron shower to the insulating substrate 1 even during the ion implantation processing to prevent electrification.

In this embodiment, a disk 5 is mounted in the chamber 2 and holds and fixes the insulating substrate 1. As shown
The disk 5 is movable between a horizontal position and a vertical position. At the vertical position, the insulating substrate 1 held and fixed faces the ion gun 3 and the electron gun 4, and a predetermined ion implantation process is performed. At this time, the disk 5 rotates at a high speed. On the other hand, at the horizontal position, loading or unloading of the insulating substrate 1 is performed.
At this time, handling of the insulating substrate 1 is performed using the transfer arm 6. The transfer arm 6 has a vacuum suction mechanism and is robot-controlled to transfer the insulating substrate 1 between the disk 5 at a horizontal position and an external cassette 7. A pad 8 for preventing slippage is attached to the surface of the transfer arm 6.

Referring to FIG. 1, the method for manufacturing a thin film element according to the present invention will be specifically described. First, a pre-process including a process of forming a semiconductor thin film using the insulating substrate 1 is performed. The insulating substrate 1 having passed through the preceding process is temporarily
Is stored in. Next, the transfer arm 6 is operated to load the insulating substrate 1 from the cassette 7 into the chamber 2. The loaded insulating substrate 1 is held and fixed to the disk 5 at the horizontal position. Thereafter, the disk 5 is moved to a vertical position, and the ion gun 3 is driven to perform an ion implantation process. At this time, the electron gun 4 is simultaneously operated to reduce the charging of the insulating substrate 1. However, it is difficult to completely neutralize the resin, and a considerable amount of positive charges remain on the insulating substrate 1 when the ion implantation process is completed as shown in the figure. Next, the rotation of the disk 5 is stopped and the disk 5 is moved from the vertical position to the horizontal position. As a characteristic feature of the present invention, an additional electron shower is added to neutralize the charge remaining on the insulating substrate 1 before the transfer from the chamber 2 after the ion implantation process is completed. Therefore, at the time of unloading from the chamber 2, no charge exists on the insulating substrate 1. Here, the transfer arm 6 is operated to carry out the insulating substrate 1 from the chamber 2 and store it in the cassette 7. The stored insulating substrate 1 is sent together with the cassette 7 to the next step, and is subjected to post-processing including wiring to complete the thin film element. As understood from the above description, according to the present invention, the charge remaining on the insulating substrate 1 at the time of carrying out is completely neutralized. Therefore, no electrostatic attraction is generated between the transfer arm 6 and the insulating substrate 1, and extremely smooth handling can be performed. Therefore, there is no transportation trouble or damage to the insulating substrate 1.

FIG. 2 is a schematic diagram showing a reference example. FIG.
Corresponding reference numerals are assigned to portions corresponding to and facilitate understanding. In this reference example, the operation of the electron gun 4 is completely stopped after the ion implantation process is performed on the insulating substrate 1 held and fixed on the disk 5 at the vertical position.
Therefore, unlike the present invention, a considerable amount of charge remains on the insulating substrate 1. This remaining charge is held as it is even when the disk 5 returns to the horizontal position. In this state, the transfer arm 6 operates to suck the insulating substrate 1 and carry it out of the chamber 2. The unloaded insulating substrate 1 is transferred to the cassette 7 by the transfer arm 6 and stored individually.

FIG. 3 shows a state of the insulating substrate 1 attracted to the transfer arm 6 via the non-slip pad 8.
The insulating substrate 1 is polarized by residual charges. For example, a positive charge appears on the front surface, and a negative charge appears on the back surface.

FIG. 4 shows the transfer arm 6 in the cassette 7.
3 shows a state in which the insulating substrate 1 is separated from the substrate. When the insulating substrate 1 and the transfer arm 6 separate from each other, the transfer arm 6
A positive charge opposite to that of the back surface of the insulating substrate 1 appears on the front surface, and the insulating substrate 1 and the transfer arm 6 attract each other again because they attract each other. As a result, transport trouble frequently occurs.

FIG. 5 is a block diagram showing a specific example of the configuration of the ion implantation apparatus shown in FIG. In this example, the ion gun 3 includes an ionization chamber 31, a mass separation chamber 32, and an acceleration tube 33. The ions generated in the ionization chamber 31 pass through the mass separation chamber 32, and only the desired ion species is selected. The selected ion species is accelerated by the acceleration tube 33 and the disk 5
Irradiation is performed on the insulating substrate held and fixed to the substrate. The disk 5 is mounted on the chamber 2. As shown, the disk 5 is movable between a horizontal position and a vertical position. When performing the ion implantation process, the disk 5 moves to the vertical position. An electron gun 4 is provided in the vicinity of the acceleration tube 33, and emits secondary electrons for charge neutralization. Chamber 2
And three cassettes 7 are spaced apart from each other. The transfer arm 6 is interposed between the cassette 7 and the chamber 2. When the disk 5 is in the horizontal position, the arm 6 carries in and out the insulating substrate 1 between the chamber 2 and the cassette 7.

[0014]

As described above, according to the present invention, after the impurities are ionized and injected into the insulating substrate, an electron shower is applied until the insulating substrate is carried out of the chamber. Is neutralized. As a result, there is obtained an effect that it is possible to eliminate the attraction between the unloaded insulating substrate and the transfer arm, thereby preventing a transfer trouble.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing an ion implantation apparatus according to the present invention.

FIG. 2 is a schematic view showing a reference example of an ion implantation method.

FIG. 3 is a detailed explanatory diagram of a reference example.

FIG. 4 is a detailed explanatory view of the reference example.

FIG. 5 is a block diagram illustrating a specific configuration example of the ion implantation apparatus illustrated in FIG. 1;

FIG. 6 is a schematic view showing a conventional ion implantation method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating substrate 2 Chamber 3 Ion gun 4 Electron gun 5 Disk 6 Transfer arm 7 Cassette

Claims (1)

(57) [Claims] After a preceding step including a process of forming a semiconductor thin film using an insulating substrate, the insulating substrate is carried into a predetermined chamber to perform ion implantation, and then the insulating substrate is carried out of the chamber. In the method of manufacturing a thin-film element that performs post-processing including feed wiring in the next step, a procedure for reducing the electrification of the insulating substrate by applying an electron shower during the ion implantation processing, and adding the procedure prior to the removal from the chamber after the ion implantation processing is completed. A process of neutralizing the charge remaining on the insulating substrate by applying an electron shower as described above.