JPH02112255A - Wafer loading mechanism - Google Patents

Abstract

PURPOSE:To mount each wafer so that it comes closely into contact with a wafer mounting stand and uniformize film thicknesses of waters by installing an elevating mechanism at an arm for moving pins for pushing up the wafer which moves in parallel to a moving path of a wafer handling arm along the lower face of the wafer mounting stand in such a way that its mechanism makes the pins for pushing up the wafer go up and down at a prescribed position through respective through holes. CONSTITUTION:A water 1 which is mounted on a handling arm 7 moves horizontally together with an arm 8 for moving pushing-up pins and stops at a specific position. Positions of the pins 5 for pushing up the wafer correspond with through holes 6 at the above specific position. Then an elevating mechanism 9 of the pushing up wafer operates to make the pins 5 go up. The pins 5 abut upon the wafer 1 to support it. In a state that the wafer is supported, the handling arm 7 moves to return to its original position. Then operation of the elevating mechanism 9 makes the pins 5 for pushing up the wafer go down and then, the wafer 1 is mounted to come closely into contact with the mounting face of a wafer mounting plate 3. After that, the arm 8 for moving the pushing up pins moves so as to return to its original position. Then a wafer loading is brought to an end. If the procedures for loading is reversed, the wafer 1 is recovered from the mounting face of the wafer mounting plate 3.

Description

[Detailed Description of the Invention] [Summary] It relates to a vertical CVD thin film forming apparatus, in particular a wafer row that places wafers on a wafer mounting table that is stacked in the form of a shelf of a wafer boulder that can be carried into and taken out of a reaction furnace. Regarding the dengue mechanism, the purpose is to provide a wafer loading mechanism that can obtain uniform wafer thickness in a vertical CVD thin film forming apparatus. A wafer loading mechanism for automatically loading/retrieving wafers on a wafer holder consisting of a plurality of held wafer mounting plates, wherein each of the wafer mounting plates is penetrated by a plurality of wafer push-up pins. a wafer handling arm capable of horizontally transporting the wafer along the mounting surface of each of the wafer mounting plates, stopping at a predetermined position, or returning to the initial position;
a push-up pin moving arm that moves parallel to the movement path of the wafer handling arm along the lower surface of each of the wafer placement plates and has a wafer push-up pin; It consists of a push pin lifting mechanism that raises and lowers the pin.

[Industrial application field]

The present invention relates to a vertical CVD thin film forming apparatus, and more particularly to a wafer loading mechanism that places wafers on a wafer mounting table that is stacked in the form of a shelf of a wafer holder that can be carried in and out of a reaction furnace.

One of the methods widely used in the semiconductor industry to form thin films is chemical vapor deposition (CVD).
: Chemical Vapor Deposit
tion). CVD refers to turning a gaseous substance into a solid substance through a chemical reaction, and depositing the solid substance in the form of a thin film on a substrate such as a wafer. The characteristics of CVD are that various thin films can be obtained at a deposition temperature considerably lower than the melting point of the thin film to be grown, the purity of the grown thin film is high, and the electrical characteristics are stable even when grown on a thermal oxide film. Therefore, it is widely used as a protective film on the surface of semiconductors, but as the diameter of wafers has increased in recent years, it has become difficult to obtain uniformity in film quality and thickness within the wafer in low-pressure CVD. In order to achieve uniform distribution within the wafer, it is effective to place the wafer on a mounting plate with a larger diameter than the wafer, and this is applied to flat CVD thin film forming equipment, etc., but there are limitations due to the loading mechanism. Therefore, it is difficult to apply it to a vertical CVD thin film forming apparatus, and its realization is desired.

[Conventional technology]

In order to mass-produce wafers as workpieces, CVD thin film forming apparatuses are generally classified into flat types, vertical types, and horizontal types based on the shape of the reactor.

FIG. 2 is a block diagram of a wafer loading device applied to a conventional horizontal plasma CVD thin film forming device, and FIG. 3 is a perspective view of a wafer placed on the electrode in FIG. This method was disclosed in the Public Utility Model Publication (1986-073232) in which the devices are arranged vertically and horizontally, and detailed explanation of the operating procedure will be omitted.

In plasma CVD, a high frequency voltage is applied between electrodes as a means for generating active gas in the CVD method.

As shown in FIG. 3, the plurality of electrodes 11 are connected to the power supply bar 2
The wafers 11 are stacked vertically in a horizontal row at regular intervals so as to be alternately connected by the wafers 11 on both sides of each electrode 11.
is housed in a reaction chamber of a plasma CVD 1l film forming apparatus (not shown) in a state where it is supported.

A wafer loading apparatus shown in FIG. 2 is a mechanism for automatically feeding the wafer 1 in close contact with such an electrode position.

In FIG. 2, an arm mechanism 16 including a support 14 for fixing a comb-shaped arm 13 is slid in the horizontal direction by the drive of an air cylinder 15 with respect to a pedestal 12 that holds the entire electrode 11 with a clamp 22. is configured to do so. The arm mechanism 16 includes the arm 13 and the arm 1.
3, a frame 18 fixed to one end of the column 14, and a slide section 19 that fixes the frame 18. to move in the direction of slide axis B.

The comb-like arm 13 on which the wafer 1 is placed is inserted into the gap between the electrodes 11 arranged like a shelf by this sliding movement. The rotating arm 20 fixed to the sliding part 19 rotates in the direction shown by arrow A via the drive belt 21 by the rotation of the motor 17, and rotates the pedestal 12 and the arm mechanism 16 into the 9
The wafer 1 on the arm 13 is rotated by 0 degrees and moved to the electrode 11 in a vertical holding position. During this movement, the wafer 1 is stopped by a protrusion 24 provided on the mounting surface of the electrode 11.

Also, when the motor 17 rotates in the opposite direction, the electrode 11
The wafer 1 held by the wafer 1 is moved onto the arm 13, and the wafer 1 is automatically attached to and detachable from the electrode 11.

Further, after the wafer 1 is moved to the electrodes 11, the arm mechanism 16 is pulled out from the gap between each electrode 11 by driving the air cylinder 15 while the wafer 1 is further rotated 90 degrees in the same direction, and the wafer 1 is returned to the initial state. In the same way, the cassette carrier (not shown) is placed on the comb-like arm 13,
The wafers L can be attached to both sides of the electrodes 11 by inserting them into the gaps between the electrodes 11 arranged in a shelf-like manner by sliding them in the same manner as in the above-mentioned procedure, and by rotating the motor 17 in the opposite direction to return the wafers 11 by 90 degrees. can. Further, by performing this procedure in reverse, the wafer 1 attached to both sides of the electrode 11 can be removed.

The wafer 1, which has been attached to both sides of the electrode 11 by the above-described procedure, is tightened in this state (remove the J bracket 22 and maintain the state shown in Fig. 3, plasma CV I) into the reaction chamber of the thin film forming apparatus. It is meant to accommodate.

The function of attaching and detaching only one side of the electrode 11 of this wafer loading device can be applied to the wafer loading device of the vertical CVD thin film forming device described above.
Thereby, the wafer corresponding to the electrode 11 can be automatically placed in close contact with the wafer.

FIG. 4 is a partial cross-sectional view of a conventional flat CVD thin film forming apparatus.
FIG. 5 shows a sectional view of essential parts of the wafer loading mechanism shown in FIG. 4. The functions of FIG. 4 will be explained below with reference to FIG.

In both figures, a plurality of disc-shaped wafer mounting tables 32 that can be rotated or rotated around the same time are installed inside a reactor 31, and wafers l, which are workpieces, are supplied onto the wafer mounting tables 32. However, a wafer transport means 33 is provided for transporting the wafer 1 that has undergone the film formation process.

Although not shown, a heating means is provided at the bottom of the wafer mounting table 32, and is configured to be able to heat the wafer 1 on the table via the wafer mounting table 32 to the temperature required for the film-forming reaction. has been done.

Further, a gate portion 34 is provided protruding from the reactor 31 for supplying the wafer 1 into the reactor 31 or for carrying out the wafer 1 from the reactor 31. Reference numeral 35 denotes a fork-type wafer handling arm, on which the wafer 1 is placed so as to be passed over the two forked strips. Then, this wafer handling arm 35 is advanced into the reactor 31 from the gate part 34, and
Send it to the top.

When the wafer 1 reaches almost directly above the wafer mounting table 32, the forward movement of the wafer handling arm 35 is stopped. Thereafter, the wafer push-up pin 36, which is disposed so as to be freely protrusive and retractable through a hole provided in the wafer mounting table 32, is moved to the pin elevating mechanism 37.
The wafer 1 is driven to rise above the 1 surface of the wafer mounting table 32, and the wafer 1 is picked up from the wafer handling arm 35.

The wafer handling arm 35 then retreats and exits the reactor 31.

Then, the wafer push-up pin 36 is driven by the pin lifting mechanism 37 and lowers, and the wafer 1 is placed on the wafer mounting table 32 in close contact with it.

FIG. 6 shows an explanatory diagram of a wafer loading method applied to a conventional vertical CVD thin film forming apparatus. In the figure, reference numeral 2 denotes a wafer boulder, which is composed of three pillars 2b fixed to a frame 2a and a plurality of wafer mounting plates 3 held horizontally in the corners of the pillars 2b at fixed intervals in the form of shelves. A quartz disk or a carbon disk is used for the wafer mounting plate 3.

The reactor 4 is placed with the wafer 1 placed on each wafer placement plate 3.
It is housed inside in the direction of arrow C.

FIG. 7 is a diagram showing the wafer mounting method of FIG. 6. As shown in the figure, the wafer 1 is placed on a wafer placement plate 3 via a spacer 3a. If you try to use the flat wafer loading mechanism shown in FIGS. 4 and 5 without using the spacer 3a, the pin lifting mechanism 37
This is not possible because the presence of the wafer mounting plate 3 requires a large space between the wafer mounting plates 3. Therefore, the pin lifting mechanism 37 is omitted, and a gap is provided between the mounting surface of the wafer mounting plate 3 and the wafer 1 by the spacer 3a, so that the wafer handling arm 35 can be inserted.

[Problem to be solved by the invention]

When the horizontal wafer loading mechanism explained in FIGS. 2 and 3 is used as a vertical wafer loading mechanism, a plurality of protrusions 24 always come into contact with the periphery of one wafer 1. The presence of the protrusions 24 has the disadvantage that the uniformity of the film thickness is impaired.

Furthermore, when using the flat type wafer loading mechanism explained in FIGS. It is necessary to use the spacer 3a shown in the figure, and in this case as well, the uniformity of the film thickness of the wafer 1 in the portion that is in contact with the spacer 3a is impaired, especially (High Temperature).
In the case of high temperature oxide (HTO), the periphery of the wafer 1 inevitably becomes thicker.

The present invention has been made in view of the above-mentioned conventional drawbacks, and an object of the present invention is to provide a wafer loading mechanism that can obtain uniformity in the film thickness of a wafer in a vertical CVD thin film forming apparatus.

[Means to solve the problem]

FIG. 1 is an explanatory diagram of the structure and operation of the wafer loading mechanism of the present invention. Vertical CV I) A wafer 1 is automatically placed on a wafer holder 2 consisting of a plurality of wafer placement plates 3 held horizontally in the form of a shelf for loading/unloading into the reactor of a fit film forming apparatus. A wafer loading mechanism 10 for placing/recovering wafers includes a plurality of through holes 6 formed in each of the wafer placement plates 3 to allow a plurality of wafer push-up pins 5 to pass therethrough, and a plurality of through holes 6 in each of the wafer placement plates 3. A wafer handling arm 7 that can horizontally transport the wafer 1 along a mounting surface, stop it at a predetermined position, or return to an initial position; a push-up pin moving arm 8 that moves in parallel with the movement path of 7 and has a wafer push-up pin 5;
It consists of a push-up pin elevating mechanism 9 that raises and lowers the.

[Effect]

FIG. 1 fat to ff1 show the wafer loading procedure, and the reverse shows the recovery procedure. (a) In the figure, the wafer 1 placed on the wafer handling arm 7 moves horizontally together with the push-up pin moving arm 8, and
b1 Stop at the position shown in the diagram. This position is the wafer push-up pin 5
The position corresponds to the through hole 6. (In Figure 81, the push-up pin lifting mechanism 9 operates to raise the wafer push-up pin 5, and it contacts and supports the wafer 1. In this supported state, (d) the wafer handling arm is moved as shown in the figure. 7 returns to its original position. (In Fig. 81, the pin lifting mechanism 9 operates to lower the wafer push-up pin 5 and place the wafer 1 closely on the mounting surface of the wafer mounting plate 3. (f) In the figure, the push-up pin moving arm 8 moves back to its original position and wafer loading is completed.The wafer 1 can be recovered from the mounting surface of the wafer mounting plate 3 by this reverse procedure. .

〔Example〕

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

In order to make the explanation of the structure and operation easier to understand, the same parts throughout the country will be given the same reference numerals and repeated explanation will be omitted.

FIG. 1 shows an explanatory diagram of the structure and operation of the wafer loading mechanism of the present invention. In the figure, 5 is a wafer push-up pin, which corresponds to the wafer push-up pin 36 in FIG. 6 is a through hole for passing the wafer push-up pin 5 through, and 7 is a 4th wafer handling arm for mounting and transporting the wafer 1.
This corresponds to the wafer handling arm 35 in the figure. Alternatively, it may be a plurality of strip-shaped plates, from the loading mechanism 10 to the wafer mounting plate 3! ! It is provided so as to be horizontally movable along two mounting surfaces. 8 is a pin moving arm having a push-up pin elevating mechanism 9;
The wafer mounting plate 3 is provided so as to be horizontally movable along the lower surface of the mounting surface of the wafer mounting plate 3 from the loading mechanism 10 in parallel to the moving direction of the wafer mounting plate 3 .

Figure fa1 shows the state at the start of loading, and the wafer handling arm 7 directly takes out the wafer 1 from a wafer cassette (not shown). Or, after the wafer 1 is placed on the wafer handling arm 7 by another handling arm or other moving means (not shown), the wafer hunting arm 7 and the push-up pin moving arm 9 are interlocked in FIG. Both stop at a position where the position of the wafer push-up pin 5 and the position of the through hole 6 match. (In Figure C1, the push-up pin lifting mechanism 9 operates to push up the wafer push-up pin 5, and it comes into contact with the bottom surface of the wafer 1 and is lifted and supported from the surface of the wafer mounting plate 3. In this state, (Figure dJ) The wafer handling arm 7 is restored to its original position as shown.

Next, the push-up pin elevating mechanism 1] in FIG. 1(e) operates to lower the wafer push-up pins 5 and place the wafer 1 in close contact with the mounting surface of the wafer mounting plate 3. Wafer loading is completed by restoring the push-up pin moving arm 8 to its original position as shown in Figure ff1.

When recovering the wafer l placed closely on the mounting surface of the wafer mounting plate 3, it can be performed in accordance with the procedure shown in (Fig. f1 -> Fig. (a)).

In the above embodiment, the wafer placement plate 3 is flat, and the wafer 1 is placed closely on the wafer placement plate 3. However, if consideration is given to the generation of dust due to close contact, or the influence of the heat capacity of the wafer placement plate 3. If this is a problem, a plurality of very low protrusions may be provided on the surface of the wafer mounting plate 3.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the vertical C
In the VD thin film forming apparatus, the wafer can be placed in close contact with the wafer mounting plate, which has the effect of improving film quality and film thickness distribution within the wafer plane.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the structure and operation of the wafer loading mechanism of the present invention, FIG. 2 is a diagram of the configuration of a wafer loading device applied to a conventional horizontal plasma CVD thin film forming device, and FIG. 3 is an electrode diagram of the wafer loading mechanism of the present invention. 4 is a partial cross-sectional view of a conventional flat type CVD thin film forming apparatus, FIG. 5 is an explanatory diagram of the operation of the wafer loading mechanism shown in FIG. 4, and FIG. FIG. 7 is a perspective view of essential parts of the type CVD thin film forming apparatus. FIG. 7 is a diagram showing the wafer mounting method of FIG. 6. In Fig. 1, ■ is a wafer, 2 is a wafer boulder, 3 is a wafer mounting plate, 5 is a wafer push-up pin, 6 is a through hole, 7 is a wafer handling arm, 8 is an arm for moving the push-up pin, and 9 is the push-up pin lifting/lowering The mechanism and 10 indicate a wafer loading mechanism, respectively.

Claims (1)

[Claims] Automatically attaches to a wafer holder (2) consisting of a plurality of wafer mounting plates (3) held horizontally in the form of a shelf for carrying in/out of a reactor of a vertical CVD thin film forming apparatus. wafer (1
A wafer loading mechanism (10) for loading/recovering wafers ( ), the wafer loading mechanism (10) having a plurality of wafer push-up pins (
A plurality of through holes (6) are formed to penetrate the wafers (5) along the mounting surface of each of the wafer mounting plates (3).
1) A wafer handling arm (7) that can horizontally transport wafers, stop them at a predetermined position, or return them to their initial positions.
and a push-up pin moving arm (8) that moves parallel to the movement path of the wafer handling arm (7) along the lower surface of each of the wafer placement plates (3) and has a wafer push-up pin (5). A wafer loading mechanism comprising: a push-up pin elevating mechanism (9) that raises/lowers the wafer push-up pin (5) at the predetermined position via the through hole (6).