JPH01102842A - End station for ion implanting device - Google Patents

Abstract

PURPOSE:To enhance the efficiency of a process by furnishing a specially devoted cassette to accommodate wafers and carry into a vacuum system, transferring wafers into this cassette from a transport cassette, and carrying into a load lock chamber, or carrying out of it. CONSTITUTION:Wafers are accommodated in a specially devoted cassette 5a (5b) besides transport cassettes 2a, 2b,... and carried in and out to/from a vacuum system. To reduce contamination with dust when wafers are introduced into the vacuum system, it is necessary to prevent dust from being brought into the vacuum system, to open inside it, and sink frequency of vacuum drafts. This is made practicable by accommodating a plurality of wafers in the specially devotes cassette 5a (5b) and introducing them into the vacuum system together with the cassette 5a (5b) wherein no transport cassettes 2a, 2b,... shall be inserted into the vacuum system.

Description

Detailed Description of the Invention <Industrial Field of Application> The present invention relates to a so-called end device which is placed adjacent to a vacuum chamber of an ion implanter in a semiconductor manufacturing process and is used to introduce and extract a semiconductor wafer into and out of the vacuum chamber. Regarding Stacylan.

<Prior Art> Conventionally, the following three methods have been used to insert a semiconductor wafer, which is housed in a transport cassette and is transported, into a vacuum chamber of an ion implanter placed in a clean room.
There are two ways.

■A load lock chamber (preliminary vacuum chamber) is provided, which is separated from the vacuum chamber by a first door that can be opened and closed, and from the atmosphere by a second door that can also be opened and closed. Insert the wafers one by one into this load lock chamber through the second door, evacuate the load lock chamber each time,
The first door is opened and the wafer in the load lock chamber is introduced into the vacuum chamber.

■Similarly, a load lock chamber is provided, the second door is opened, the transport cassette is inserted into the load lock chamber, the load lock chamber is evacuated, and the first door is opened to introduce the wafer into the vacuum chamber. .

■ Break the vacuum in the vacuum chamber and introduce the wafer in the transport cassette directly into the vacuum chamber.

<Problems to be solved by the invention> Of the conventional methods, (2) inevitably requires a high degree of opening/closing of the lock chamber, which not only increases the time required for evacuation during the process. (This has the disadvantage that the probability of bringing dust into the vacuum system increases, and the dust is more likely to fly up due to vacuuming.As is well known, the cleanliness inside the vacuum system decreases due to dust being brought in. This is a major factor in deteriorating the yield in the ion implantation process.Furthermore, since the load rotor chamber is frequently opened and closed, there is also the problem that the load on the vacuum pump increases.

Regarding ■, the frequency of opening and closing of the load lock chamber is significantly reduced compared to ■, improving process efficiency and reducing the burden on vacuum pumps. There is quite a bit of dust attached, and some of the dust is brought into the vacuum system.
This has the disadvantage of lowering the cleanliness.

Regarding (2), a vacuum chamber usually houses a disk up to 1 meter in diameter for mounting a wafer, and a large-volume chamber housing such a disk is repeatedly brought from atmospheric pressure to high vacuum. It is necessary to evacuate up to 300 degrees, which increases the process time and increases the burden on the vacuum pump.Furthermore, the aperture large enough for the disk to go in and out is exposed to the atmosphere, making it easy for dust to be brought in, and with a large capacity. Due to the rapid exhausting of the wafer, there is a strong phenomenon of dust being lifted up, and the drawback is that dust tends to adhere to the wafer.

The present invention has been made in view of the above, and an object of the present invention is to provide an end station for an ion implanter that is less likely to introduce dust into a vacuum system and that requires less time for evacuation.

<Means for Solving the Problems> A configuration for achieving the above object will be described with reference to FIG. 1 corresponding to the embodiment. The transport cassette 2a is installed in a clean room.

The wafer before ion implantation, which is transported while being housed in the vacuum chamber 1 and the outside, is transported in a load lock chamber 3 (4 ) is a station S for introducing the ion-implanted wafer into the load rotor chamber 3 (4) and leading the wafer out of the load rotor chamber 3 (4), and includes at least one dedicated cassette 5a (
5b) and the wafers in the transport cassettes 2a, 2b- or the dedicated cassette 5a (5b) are transferred to the dedicated cassette 5.
a (5b) or transfer cassettes 2c, 2d... Lock room (4
) It is characterized by having a dedicated cassette transport mechanism 7 for transporting the cassette to the outside.

Function> The wafer is taken in and out of the vacuum system while being accommodated in a dedicated cassette 5a (5b) separate from the transport cassettes 2a, 2b, . . . .

In order to reduce dust contamination when introducing a wafer into a vacuum system, (a) do not introduce dust into the vacuum system, and (b) reduce the frequency of opening and evacuation of the vacuum system. It is.

By storing a plurality of wafers in a dedicated cassette 5a (5b) and introducing the dedicated cassette 5a (5b) into the vacuum system without inserting the transport cassettes 2a, 2b, etc. into the vacuum system, Both (a) and (b) can be achieved.

<Example> Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a plan view showing the configuration of an embodiment of the present invention.

The end station S is disposed adjacent to the vacuum chamber 1 of the ion implantation apparatus, and includes a wafer handling mechanism 6 and a dedicated cassette transport mechanism 7 provided on a table T. A duct (not shown) protruding from the ion implantation device is disposed above the table T, and the upper surface of the table T is always sprayed with laminar flow from above.

The wafer handling mechanism 6 is disposed approximately at the center of the top surface of the table T, and is rotatable around a vertical axis and has an extendable arm, so that it can carry wafers one by one. .

On the table T around the wafer handling mechanism 6, there are transport cassettes 2a, 2b, 2c, 2.
d is placed, and an orientation flat alignment unit 8 is also provided. The transport cassettes 2a to 2d are cassettes for storing a plurality of wafers and transporting them within a clean room, and can be commercially available normal ones called wafer carriers or the like. The orientation flat alignment unit 8 is a unit for aligning the orientation flat of the wafer in a predetermined direction, and is a known unit equipped with a rotatable table and the like.

Two load rotor chambers 3 and 4 are provided adjacent to both the vacuum chamber 1 and the table T, respectively.

Each of the load lock chambers 3 and 4 is separated from the vacuum chamber 1 by m3a or 4a and from the top surface of the table T by a door 3b or 4b, respectively, and is kept at a predetermined degree of vacuum lower than that of the vacuum chamber 1. can be exhausted up to.

The dedicated cassette transport mechanism 7 described above includes at least two dedicated cassettes 5a prepared for insertion into the vacuum chamber 1 and the load lock chamber 3.4.

5b, and includes seven belt conveyors 7a to 7g arranged on table T, four belt conveyors 7h to 7 in load lock chamber 3, and and four belt conveyors 7m to 7q in the load lock chamber 4, forming a loop-shaped conveyance path that communicates with the inside and outside of the vacuum system as a whole. In addition, among each conveyor, for conveyor pairs that intersect, one side (7a
, 7g, 7, and 7m) are constructed using two thin belts to open the center of the conveyance path and to allow the whole to be displaced in the vertical direction.

The other side is disposed inside the open portion, and one side is lowered when driving the other side to avoid mutual interference.

In addition, as for the belt conveyor disposed across at least the door 3a, 3b, 4a or 4b, as shown in the enlarged front view of the main part in FIG. By making the top surface almost coincide with the top surface of the belt lid and also serving as a cassette transport guide, smooth transport is possible.

The belt conveyor 7d on the table T is open at the center of its conveyance path, similar to the above-mentioned conveyors 7a, 7g, etc., and the cassette attitude changing mechanism 9 is disposed in the open section. As shown in an enlarged front view of FIG. 3, this cassette attitude changing mechanism 9 can move up and down around the conveyance surface of the conveyor 7d, and can also rotate around a vertical axis while being displaced upward. The direction of the cassette on the conveyor 7d can be changed.

The dedicated cassettes 1-5a and 5b are cassettes used exclusively in the vacuum system consisting of the vacuum chamber 1 and load-lock chambers 3 and 4, and on the table T under the laminar row, and their structure is similar to that of the transport cassette 2a. The same is fine.

A wafer handling mechanism 10 similar to the wafer handling mechanism 6 described above is disposed inside the vacuum chamber 1, and a dedicated cassette 5b carried into the vacuum chamber 1 is placed inside the vacuum chamber 1.
The wafers can be carried and positioned one by one between the disks 11 and 11.

Next, the operation will be explained. FIG. 4 is a flowchart showing the operating procedure. In FIG. 1, a transport cassette 2a or 2b is a cassette that accommodates a wafer before ion implantation, and a cassette 2c or 2d is a cassette that accommodates a wafer after ion implantation.

In addition, in the following explanation, the transport cassette 1-2a means
The transport cassette 2c represents 2C or 2d, and the dedicated cassette 5 represents 5a or 5b.

First, the transport cassette 2a containing the wafers to be implanted with ions is inserted into the wafer handling mechanism 6.
Place it on the table T facing toward (STI).

Note that, prior to starting the process, one of the dedicated cassettes 5 is placed on standby on the conveyor 7d with its opening facing the wafer handling mechanism 6 side.

The wafers in the transport cassette 2a are sequentially taken out by the wafer handling mechanism 6, aligned with the orientation flat on the orientation flat alignment unit 8 as necessary, and then transferred into the dedicated cassette 5 on the conveyor 7d (Sr1). −
0 Then, the cassette attitude changing device 9 is driven so that the opening surface of the dedicated cassette 5 faces upward in FIG. 1 (Sr3).
The cassette is transported into the left load lock chamber 3 by the dedicated cassette transport mechanism 7 (Sr4).

Next, the door 3b is closed (Sr1), and after the inside of the load lock chamber 3 is brought to a low vacuum (Sr1), the door 3a is opened and the dedicated cassette 5 inside is carried into the vacuum chamber 1 (S77. 8). During this time, another empty dedicated cassette 5 is placed on the conveyor 7d with its opening facing the wafer handling mechanism 6. be placed.

Next, the door 3a is closed (Sr9), and the wafers in the dedicated cassette 5 carried into the vacuum chamber 1 are loaded onto the disks 11 one by one by the wafer handling mechanism 10 (STIO).

After all wafers are attached, ion implantation is performed
(STII).

The wafer after ion implantation is transferred to the wafer handling mechanism 10.
Then, it is stored again in the special cassette 5 waiting in the vacuum chamber 1 (ST12), and after the door 4a is opened, it is carried into the load lock chamber 4 (ST 13.14).
. Next, the door 4a is closed (ST15), and the vacuum in the load lock chamber 4 is removed by Nt gas (ST16).
Then, by opening the door 4b, the dedicated cassette 5 inside is carried out onto the table and positioned on the conveyor 7d, and the Jjt 4b is closed to start vacuuming the load lock chamber 4 (ST 17.18).

The dedicated cassette 5 on the conveyor 7d is then rotated by the cassette attitude changing mechanism 9 so that the opening face faces the wafer handling mechanism 6 (ST19), and then the ion-implanted wafer inside is transported by the wafer handling mechanism 6. are sequentially carried into the storage cassette 2C (ST20).

In the above routine, after Sr9 ends, 5TIO
- In parallel with 3T17, break the vacuum inside the load lock chamber 3 and open the door 3b 5T50) STI-3T6
By executing the same routine as (ST51)
, at the end of Sr10, the next dedicated cassette 5 is waiting in the evacuated load lock chamber 3, and it is possible to immediately proceed to ST7 and subsequent steps.

Here, since the dedicated cassettes 5a and 5b are used only in the vacuum system and under laminar flow on the table T, the number of dust attached thereto is extremely small compared to the transport cassettes 2a to 2d.

In addition, in the above example, two dedicated cassettes 5 were prepared, but
The number is arbitrary. However, by preparing two or more cassettes and arranging them at appropriate locations on the dedicated cassette transport mechanism 7, it is possible to execute each operation in parallel, and it is preferable to reduce the dead time of the process.

FIG. 5 is a plan view showing the configuration of another embodiment of the present invention. In this figure, the same members as those in the previous embodiment are given the same numbers as in FIG. 1, and the explanation thereof will be omitted.

This embodiment is different from the embodiment shown in FIG. 10, the wafer is transported and mounted on the disk 11, or vice versa.

Accordingly, the conveyance path of the dedicated cassette conveyance mechanism is not loop-shaped, and the conveyors 7r and 7st are arranged in series through the door 3b of the loadlock chamber 3.
Conveyors 7t and 7u are arranged in series through the door 4b.
It is composed of two mutually independent and parallel conveyance paths.

The dedicated cassette 5a is alternately transported back and forth exclusively within the load-lock chamber 3 and on the table T, and the dedicated cassette 5b is exclusively transported within the load-lock chamber 4 and above the table T, respectively, to load and unload wafers.

This example has the advantage that the dedicated cassette transport mechanism is simplified, and that the opening surfaces of the dedicated cassettes 5a and 5b are always directed in a fixed direction, eliminating the need for a cassette attitude changing mechanism.

In each of the above embodiments, it goes without saying that the wafer handling mechanism and dedicated cassette transport mechanism may be of any type and structure as long as they have the functions described in their respective descriptions.

<Effects of the Invention> As explained above, according to the present invention, in addition to the cassette used for transporting wafers in a clean room, a dedicated cassette for storing a plurality of wafers and transporting them into a vacuum system is provided. The wafers are transferred from the transport cassette into this dedicated cassette and carried into the load-lock chamber or carried out from the load-lock chamber, so the frequency of opening and closing of the load-lock chamber is reduced in the same way as in the conventional method (2) above. The time required for evacuation is low and the time required for vacuuming is short, which improves process efficiency, significantly reduces the amount of dust carried into the vacuum system, improves the cleanliness of the vacuum system, and improves process efficiency. Yield is improved.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the configuration of an embodiment of the present invention, FIG. 2 is an enlarged front view of the main parts of the dedicated cassette transport mechanism 7, FIG. 3 is an enlarged front view of the cassette attitude changing mechanism 9, and FIG. 1 is a flowchart showing the operation of the embodiment shown in FIG. 1, and FIG. 5 is a plan view showing the configuration of another embodiment of the present invention. 1... Vacuum chambers 2a to 2d... Transport cassette 3.4... Load lock chambers 3a, 3b, 4a, 4b... Doors 5a, 5b... Dedicated cassette 6.10... Wafer Handling mechanisms 7a to 7u...
・Belt conveyor 8...Orientation flat alignment unit 9...Cassette attitude change mechanism 11...Disc, patent applicant Shimadzu Corporation Agent
Patent Attorney Nishi 1) New Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] installed adjacent to the vacuum chamber of the ion implanter;
The wafer before ion implantation, which is transported in a transport cassette in the clean room, is introduced into a load lock chamber that is separated from the vacuum chamber and the outside by a door that can be opened and closed. at least one station capable of accommodating a plurality of wafers for leading the wafers out of the load lock chamber;
a dedicated cassette, a wafer handling mechanism for transferring the wafers in the transport cassette or the dedicated cassette to the dedicated cassette or the transport cassette, and a wafer handling mechanism for transferring the dedicated cassette containing wafers to the outside of the load lock room. An end station for an ion implanter, characterized in that it is equipped with a dedicated cassette transport mechanism for transporting the cassette or transporting it outside the load lock chamber.