JPH09219376A - Ion implantation apparatus and substrate cooling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent the increase in temperature of a substrate by providing an ion implanter with a low-temperature air blow means which blows low- temperature air against the substrate before ion implantation. SOLUTION: A chamber 4c is provided with a pipe 4d connected to a vacuum pump and a pipe 4e through which dry nitrogen (low-temperature air) is carried in. In the chamber 4c, a substrate support table 4f to support a glass substrate A is installed and a filter 4g for eliminating impurities included in dry nitrogen is installed above the substrate support table 4f. The glass substrate A is mounted on the substrate support table 4f and then an entrance gate is closed. After that, the inside of the chamber 4c is made into a vacuum atmosphere by the vacuum pump and at the same time, dry nitrogen is carried into the chamber through the pipe 4e and then is blown agains the glass substrate A. After the blowing is finished, the pipe 4e is closed and the inside of the chamber 4c becomes a. vacuum By this method, the increase in temperature of the substrate can surely be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion implantation apparatus and a substrate cooling method, and more particularly to a technique for preventing heating of a substrate due to ion implantation.

[0002]

2. Description of the Related Art As an apparatus for forming a semiconductor element on a substrate such as a glass substrate used for a liquid crystal display panel or a semiconductor wafer, there is an ion implantation apparatus for accelerating a substance to be doped into an ion state and implanting it into the substrate. When performing ion implantation using this ion implantation device, it is necessary to cool the substrate in order to suppress heat generated by the implantation. Conventionally, this cooling has been performed by placing a substrate inserted in a vacuum chamber on a cooling panel provided with a cooling pipe.

[0003]

However, in the above cooling method, the substrate is simply placed on the cooling panel, and when viewed microscopically, the substrate and the cooling panel are only in point contact, and the contact area is small. The cooling effect cannot be expected because it can not take enough. Further, since the substrate is warped during the ion implantation, the adhesion between the substrate and the cooling panel may be further impaired, and the allowable temperature may be exceeded depending on the implantation energy and the implantation dose amount.

The present invention has been made in view of the above-mentioned problems, and when the ion implantation is performed, the temperature rise of the substrate is surely performed without being affected by the contact area between the substrate and the cooling panel and the warp of the substrate. An object of the present invention is to provide an ion implantation apparatus and a substrate cooling method capable of preventing the above.

[0005]

To achieve the above object, as a first means, in an ion implantation apparatus for implanting ions into a substrate, a low-temperature gas spraying means for spraying a low-temperature gas onto the substrate before the ion implantation. Is adopted. As a second means, in the above first means, a means in which the low temperature gas spraying means includes a filter for removing impurities contained in the low temperature gas is adopted. As a third means, in a cooling method for implanting ions into a substrate, a means of precooling the substrate with a low temperature gas prior to ion implantation is adopted. As a fourth means, a means of using dry nitrogen as the low temperature gas is adopted in the third means.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2,
An embodiment of the ion implantation apparatus and the substrate cooling method according to the present invention will be described.

FIG. 1 is a plan view showing the overall structure of the ion implantation apparatus of this embodiment. In this figure, reference numeral 1a
Numeral 1c is a substrate mounting table, for example, a large number of glass substrates A for forming a liquid crystal display plate as substrates are housed and mounted in the glass cassette 2. This glass cassette 2
Are mounted on the substrate mounting table 1a by, for example, an automatic guided vehicle.

Reference numerals 3a to 3d are robots, which hold the glass cassette 2 and move it along the arrow. Reference numeral 4 denotes a load lock chamber (low temperature gas spraying means), which has an entrance gate 4a and an exit gate 4b. A vacuum pump is connected to the load lock chamber 4, and the load lock chamber 4 is a chamber for switching the atmosphere of the glass substrate A from an atmospheric state to a vacuum state. At the time of this switching, precooling is performed and the glass is cooled. The impurities adhering to the substrate A are removed. The details of the load lock chamber 4 will be described later.

Reference numeral 5a is a robot chamber connected to the load lock chamber 4, and the robot 3 is provided inside.
The working space of c is a vacuum atmosphere. Reference numeral 6 is a process chamber having an entrance gate 6a and an exit gate 6b, and the robot chamber 5 is provided via the entrance gate 6a.
It is connected to a. The process chamber 6 is for implanting ions supplied from the ion generator 7 into the glass substrate A. The ion generator 7 generates and accelerates the ions.

Reference numeral 5b is a robot chamber connected to the process chamber 6, and the working space of the robot 3d provided inside is a vacuum atmosphere. Reference numeral 8 denotes a load lock chamber having an entrance gate 8a and an exit gate 8b, which is provided to shut off and switch between the vacuum atmosphere inside the robot chamber 5b and the atmosphere outside the chambers, and the inside is vacuumed by a vacuum pump. It is considered as an atmosphere.

Reference numeral 9 is a control device, which operates the robots 3a to 3d to automatically transfer the glass substrate and controls and monitors the injection device and the vacuum device. Reference numeral 10 is a monitor panel for inputting implantation conditions using a touch panel display, automatically executing a series of ion implantation processes, and for allowing a worker to confirm control and monitoring states by the control device 9 Is.

Next, FIG. 2 is a side sectional view showing the internal structure of the load lock chamber 4. In this figure, reference numeral 4c
Is a chamber forming the load lock chamber 4, and a pipe 4d communicating with a vacuum pump and a pipe 4e into which dry nitrogen (low temperature gas) is fed are connected to the chamber 4c. A substrate support base 4f for supporting the glass substrate A is provided in the chamber 4c, and a filter 4g for removing impurities contained in dry nitrogen is provided above the substrate support base 4f.

Next, a method of cooling the glass substrate A in the ion implanter thus constructed will be described.
First, the glass substrate A in the cassette placed on the substrate platform 1a by an automated guided vehicle or the like is moved to the substrate platform 1b by the robot 3a, and the position is adjusted.
Then, when the entrance gate 4a of the load lock chamber 4 is opened, the glass substrate A on the substrate mounting table 1b is transferred to the robot 3b.
Is inserted into the load lock chamber 4.

The glass substrate A is placed on the substrate support 4f, the entrance gate 4a is closed, and the air in the load lock chamber 4 is exhausted by the vacuum pump to create a vacuum atmosphere. Dry nitrogen is sent into the load lock chamber 4 from the
The impurities are removed by g, and the glass substrate A is sprayed for a predetermined time. When this spraying ends, the pipe 4e
A valve (not shown) located upstream of the load lock chamber 4 is closed to create a vacuum atmosphere in the load lock chamber 4.

Here, the spraying time of dry nitrogen is determined in advance by the implantation conditions in the ion implantation in the next step. Since the temperature rise of the glass substrate A during ion implantation depends on the ion implantation density and time, the spraying time is set according to the ion implantation density and time, for example, to cool the glass substrate A to around 0 ° C. It When the substrate is a wafer, the spraying time is set according to the implantation conditions for the wafer.

In this way, the glass substrate A is cooled to a predetermined temperature and the inside of the load lock chamber 4 is changed to the robot chamber 5a.
When the degree of vacuum inside is approached, the exit gate 4b is opened and the entrance gate 6a of the process chamber 6 is opened, and the glass substrate A is transferred into the process chamber 6 by the robot 3c. Then, when the inlet gate 6a is closed, the ions generated by the ion generator 7 and accelerated to a constant speed are injected into the glass substrate A to form a semiconductor element on the surface.

When the ion implantation is completed, the exit gate 6b
When the gate is opened, the entrance gate 8a of the load lock chamber 8
And the robot 3d opens the process chamber 6
The glass substrate A therein is transferred into the load lock chamber 8.
When the entrance gate 8a is closed, the inside of the load lock chamber 8 is returned to the atmospheric state, and then the exit gate 8b is opened, and the glass substrate A is placed on the substrate mounting table 1 by the robot 3a.
The glass substrate A on the substrate mounting table 1b is further moved onto the substrate mounting table 1c by the robot 3a. When the above-described series of processing is completed for all the glass substrates A inserted in the cassette on the substrate platform 1a, the cassette including the glass substrate A on the substrate platform 1c is carried out by the automated guided vehicle. It

[0018]

As described above, the ion implantation apparatus and the substrate cooling method according to the present invention have the following effects. (1) Since the substrate is pre-cooled in advance, it is possible to reliably suppress the temperature rise of the substrate regardless of whether the substrate is warped during ion implantation. (2) It is possible to control the temperature at the 1 ° C level by controlling the temperature of the cooling gas sprayed onto the substrate and the spraying time. (3) Since precooling is performed by blowing a cooling gas, for example, dry nitrogen, precooling can be performed very easily. (4) Since the cooling gas is blown in the vacuum atmosphere, the impurity particles attached to the substrate surface can be removed simultaneously with cooling.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of an ion implantation apparatus and a substrate cooling method according to the present invention.

FIG. 2 is a side sectional view showing an embodiment of the configuration of a load lock chamber in the ion implantation apparatus and the substrate cooling method according to the present invention.

[Explanation of symbols]

 1a to 1c Substrate mounting table 2 Glass cassettes 3a to 3d Robot 4 Load lock chamber (low temperature gas spraying means) 4a Entrance gate 4b Exit gate 4c Chambers 4d, 4e Piping 4f Substrate support 4g Filters 5a, 5b Robot chamber 6 Process chamber 7 Ion generator 8 Load lock chamber 9 Control equipment 10 Monitor panel A Glass substrate (substrate)

Claims (4)

[Claims] 1. An ion implantation apparatus for implanting ions into a substrate, comprising: a low temperature gas spraying unit for spraying a low temperature gas onto the substrate before the ion implantation. 2. The ion implanter according to claim 2, wherein the low temperature gas spraying means comprises a filter for removing impurities contained in the low temperature gas. 3. A cooling method for implanting ions into a substrate, wherein the substrate is pre-cooled with a low temperature gas prior to ion implantation. 4. The method for cooling a substrate according to claim 3, wherein the low temperature gas is dry nitrogen.