JP2961167B2 - Boat and heat treatment apparatus and method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a basket-type boat for mounting an object to be processed such as a semiconductor wafer.

(Prior Art) For example, a boat used for carrying a semiconductor wafer into a heat treatment furnace for heat treatment is a quartz having a plurality of support rods fixed to a side plate and a groove for supporting a wafer formed in each support rod. Boats are common.

In this type of boat, especially LTO (Low Temperature Oxi
dation), there is a problem that the film thickness formed on the wafer is not uniform.

Therefore, as a boat used for this kind of LTO, a cage type boat aimed at suppressing the flow of gas has come to be used.

As shown in FIG. 12, a conventional cage type boat has a groove (not shown) capable of supporting a wafer (not shown) at a predetermined pitch.
Is divided into a lower boat 1 and an upper boat 2 which can be opened and closed with respect to the lower boat 1.
Is composed. A slit 4 for introducing a process gas is formed in the lower boat 1 and the upper boat 2.

(Problems to be Solved by the Invention) According to the split-type basket-type boat 3 having the above-described structure, gas is introduced between the wafers as compared with a boat in which the wafers are arranged and supported by the grooves formed in the support rods. The slit 4
Can be set as desired, and the gas flow can be suppressed by reducing the aperture ratio, so that uniformity of the film thickness can be ensured even when used for LTO.

However, the upper boat 2 needs to be opened and closed each time a wafer is taken out of the cassette and set or placed on the cassette because of the divided structure. Since it was difficult to automate the opening and closing operation, it was not suitable for automation.

In addition, when the split-type basket-shaped boat 3 is used in a horizontal furnace, the opening of the upper boat 2 is regulated by its own weight, but when used in a vertical furnace, there is no such guarantee.
Even if it was attempted to prevent this by fitting, several washings, especially washing with hydrofluoric acid, etc., consumed quartz itself, causing fitting problems, and it was virtually impossible to respond to vertical furnaces .

Therefore, the present invention solves the above-mentioned conventional problems, and can regulate the flow of the process gas to the object to be processed, and even when using an active gas such as LTO, the film thickness can be made uniform. It is an object of the present invention to provide a basket-type boat that can deal with automation of transfer of an object to be processed and is suitable for use in a vertical furnace.

[Structure of the Invention] (Means for Solving the Problems and Their Functions) The boat according to the invention according to claim 1, wherein a plurality of objects to be processed are supported by a plurality of ring-shaped partition members, respectively. A boat that surrounds and supports an object to be processed by a plurality of ring-shaped partition members, and allows each of the plurality of objects to be carried in and out of the boat, and processes the object. A plurality of slits formed between the plurality of ring-shaped partition members to allow introduction of a process gas, and at least a plurality of the slits are arranged along a direction in which the plurality of processing objects are arranged at least on a loading / unloading side of the processing object. A ring-shaped partition member is cut out, communicates with the plurality of slits, and has a narrow notch portion for preventing interference with the loading / unloading jig for the plurality of objects to be processed. .

According to the first aspect of the present invention, the following operation and effect can be obtained.

(A) The object to be processed is inserted into the boat through the slit, the object to be processed is transferred to the boat by the loading / unloading jig using the space of the notch, and the object is processed by the ring-shaped partition member of the boat. The processing object is supported. Here, the notch has both a function as an escape portion for preventing interference with a loading / unloading jig when the object to be processed is transferred to the boat, and a function for introducing a process gas into the boat. Having. The slit also has both a function of inserting the object to be processed and a function of introducing a process gas. The introduction of the process gas is performed through the slit and the notch, and the opening ratio thereof is relatively small, so that the supply amount of the active gas can be limited.

Therefore, both the slit for inserting the object to be processed and the notch for preventing interference also serve as a gas inlet having a small opening ratio, and the opening ratio is narrowed without using a conventional split type or ring type. Boat can be formed. For this reason, while achieving uniform processing such as the film thickness formed on the object to be processed, the notch and the slit prevent interference between the jig and the boat, and a favorable object transfer processing can be performed. It can easily cope with automation of transfer of the object.

(B) Conventionally disclosed in, for example, JP-A-58-108735 and JP-A-58-108735.
No. 197823, Microfilm of Japanese Utility Model Application No. 59-10840, Microfilm of Japanese Utility Model Application No. 62-75534, Japanese Utility Model Application No. 62-61823
In the microfilm and the like, a support plate is formed in a ring shape so as to cover the entire circumference of the object to be processed. For this reason, when mounting an object to be processed on a support plate using a jig, it is difficult to insert the jig into the slit, and the jig and the support plate collide with each other. There was a risk that the workpiece was damaged due to the application of force. In addition, if an attempt is made to increase the slit width (distance between support plates) in order to allow the jig to move to some extent, the overall aperture ratio is increased, so that the process gas cannot be regulated.

On the other hand, in the present application, even when the slit width is relatively small, the notch portion prevents interference between the loading / unloading jig of a plurality of objects to be processed and the boat, so that good transfer processing can be performed. . In addition, since the slit width is small, a large number of objects can be mounted on a boat with a certain height and batch processing can be performed. The thickness can be made uniform.

(C) For example, conventional Japanese Utility Model Application No. 61-15694 (Japanese Utility Model Application Laid-open No. 62-128)
No. 63), the support plate (ring) is formed only in a semicircular arc shape, the exposed portion of the object to be processed to the boat is large, and the gas introduction amount cannot be regulated. In addition, since it has a semi-circular shape, it may be detached from the boat due to vibration, impact, or the like during loading, and cannot be stably supported.

On the other hand, in the present application, the cutout portion is formed with a width narrow enough to prevent the above-described interference, so that the amount of gas introduced into the boat can be appropriately regulated and the film thickness can be made uniform. . Further, since the plurality of ring-shaped partition members are formed so as to surround the plurality of workpieces, the workpieces can be stably supported even during loading.

(D) The gas introduction amount can be changed only by changing the aperture ratio of the slit and the notch at the manufacturing stage, so that the manufacturing cost can be reduced and the manufacturing process can be simplified. A boat that can be formed to have a uniform thickness can be provided.

In the boat according to the second aspect of the present invention, in the first aspect, the aperture ratio of the slit and the notch is set such that the film thickness formed on the surface of the processing target is substantially uniform. It is characterized by the following.

According to the second aspect of the present invention, by adjusting the aperture ratio of one or both of the slit and the notch, the aperture ratio is adjusted such that the film thickness formed on the surface of the processing target becomes uniform. Can be set.

In this case, when adjusting the aperture ratio of the notch, the aperture ratio can be set such that the film thickness formed on the surface of the object to be processed is uniform regardless of the aperture ratio of the slit. Thus, in order to configure a large number of workpieces to be mounted, the aperture ratio of the slit is naturally reduced, but the optimal aperture ratio can be adjusted to the size of the cutout portion regardless of the number of mounted components.
The aperture ratio is optimally set while forming a large number of objects to be processed, and the film thickness of the object can be made uniform. In addition, when the aperture ratio of the slit is adjusted, the entire aperture ratio can be set optimally without forming a large notch, and the film thickness of the object to be processed can be made uniform.

A boat according to a third aspect of the present invention is the boat according to the first or second aspect, wherein the plurality of ring-shaped partition members are formed of quartz, and support a semiconductor wafer as the object to be processed.

According to the third aspect of the present invention, quartz is excellent as a boat material for semiconductor wafers because it has excellent heat resistance and emits little contamination at high temperatures.

According to a fourth aspect of the present invention, there is provided the boat according to any one of the first to third aspects, wherein the slits are formed at an equal pitch.

According to the fourth aspect of the present invention, the distance between the surfaces of the plurality of objects to be processed becomes equal, and the uniformity of the processing among the objects to be processed is ensured.

The heat treatment apparatus according to the invention described in claim 5 is a heat treatment apparatus according to claim 1.
The boat according to any one of claims 1 to 4, a transfer machine for inserting and removing an object to and from the boat, a vertical furnace for processing a plurality of the objects to be mounted mounted on the boat, and A loader section for loading / unloading the vertical furnace from below the vertical furnace with the boat supported vertically.

The heat treatment method according to the invention according to claim 6 is the method according to claim 1.
A step of inserting the object to be processed through the slit into the boat according to any one of (1) to (4), and supporting the object with the ring-shaped partition member; And from the lower region of the vertical furnace with a heating unit, loaded into the process tube,
Setting a process position, introducing a process gas into the process tube, and setting a predetermined process temperature by the heating unit, guiding the process gas into the boat through the slit, And a step of processing the object to be processed.

According to the fifth and sixth aspects, the boat does not need to be opened and closed each time the object to be processed is put in and out, so that the boat can be used in a vertical furnace. The object to be processed inserted into the boat through the slit is supported by the ring-shaped partition member, and is loaded into the process tube from below the vertical furnace. The process gas introduced into the process tube is guided into the boat through the slit, and the processing of the object is performed.

(Embodiment) An embodiment in which the present invention is applied to a vertical cage type boat used for LTO will be specifically described with reference to the drawings.

This basket-shaped boat 10 has side plates 12, 1
4, a substantially annular partition member 20 disposed between the side plates 12, 14 at a predetermined pitch, for example, at a 3/16 inch pitch, and for arranging and supporting the side plates 12, 14 at a predetermined pitch. For example, it has four support plates 16.

When the boat is carried into the process tube, the side plate 12 is turned to the upper side, and has a cylindrical locking projection 12a protruding from its surface in the longitudinal axis direction of the boat. On the other hand, the side plate 14 is turned to the lower side when the boat is carried in, has a cylindrical locking projection 14a, and also has the locking projection 14a.
Has a flange-like protrusion 14b protruding outward from the peripheral surface of the cylindrical member. Each of these projections is for chucking a boat as a vertical boat.

As shown in FIG. 3, the partition member 20 is formed in a substantially annular shape, and a part thereof (a part on the upper side when the boat 10 is placed horizontally) is a cutout portion 21 which is cut out. I have. The notch 21 is an escape for tweezers when the wafer 18 is manually inserted, and is not always necessary.

As shown in FIGS. 2 to 5, the partition member 20 includes an annular gas regulating ring 22 formed substantially along the entire circumference of the wafer 18 and, for example, 180
And an inner ring 23 for forming a step 24 for supporting the wafer 18.

A plurality of the partition members 20 are provided and supported by the support plate 16 at a predetermined pitch a, for example, 3/16 inch (4.7625 mm). Note that the slit width b between the partition members 20, 20 is 2 mm, and the gas regulating ring 2
2 has a thickness c of 2.7625 mm, and the inner ring 23 has a thickness d of 2 mm. Therefore, the depth e of the step portion 24 is 0.7625 mm.

The thickness of the wafer 18 set on the step portion 24 is
It is about 650 μm.

Further, the wafer 18 used in this embodiment is a 6-inch wafer, and therefore, the outer diameter f of the gas regulating ring 22 is 16 inches.
0 mm, the inside diameter (ie, the outside diameter of the step portion 24) g is 152 mm, and the inside diameter h of the inner ring member 23 is 144 mm.

Each of the above-mentioned constituent members is made of a member having excellent heat resistance and emitting less contamination at a high temperature, generally quartz.

Next, a vertical furnace and a loader apparatus for carrying out the heat treatment of the wafers 18 by loading the basket-type boat 10 will be described with reference to FIGS.

The vertical furnace 30 includes at least a process tube 31 and a heater 32 around the process tube 31, and is arranged along a vertical direction. Although not shown,
In order to introduce the process gas into the process tube 31, for example, an injector formed so as to extend from the lower end toward the upper end is arranged in the process tube 31, and the process gas is supplied from a position opposed between the wafer surfaces of the injector. It gushes out.

And, when the basket-type boat 10 is loaded into the vertical furnace 30, and, when placed in the vertical furnace 30, a soaking temperature range in the furnace core is secured, and the vertical furnace 30 A heat retaining cylinder 40 for preventing gas from escaping from the lower end opening is provided.

The heat retaining cylinder 40 is provided at the lower end projection 14a of the basket type boat 10.
And a hole 41 through which the lower end protrusion 14 is inserted.
The cage-shaped boat 10 is vertically supported by its own weight on the heat retaining cylinder 40 by inserting the a and inserting the flange-shaped protrusion 14b.

Next, the loader unit 50 that moves the heat retaining cylinder 40 in the vertical direction and swings the heat retaining cylinder 40 in parallel with the horizontal plane will be described.

The loader unit 50 includes a ball screw 51 formed along the vertical direction, a first motor 52 that rotates the ball screw 51, and a movable unit that moves in the direction A in FIG. 53 and a support member fixed to the movable portion 53 and capable of swinging in the direction of arrow B with respect to the movable portion 53.
54 and has.

Next, a handler 60 for chucking the basket-type boat 10
Will be described.

The handler 60 includes a ball screw 61 formed along the direction of arrow A, a second motor 62 for driving the ball screw 61, and a second motor 62 that moves along the ball screw 61 and can swing in the direction of arrow C. One swing drive unit 63,
It comprises a second swing drive section 64 capable of swinging in the direction of arrow D with respect to the first swing drive section 63, and a handler section 65 fixed to the second swing drive section 64.

As shown in FIG. 8, the handler section 65 has an attachment section 66 attached to the second swing drive section 64 and movable in the direction E in the drawing. The table 67 has a boat clamp arm at the upper end
68 are provided.

The boat mounting table 67 has a projection 67a that is in contact with the lower side plate 14 of the basket-shaped boat 10 made of quartz.

In addition, the boat clamp arm 68 is indicated by an arrow F in FIG.
Clamp portion 68a that can be freely opened and closed in the direction and that clamps the protrusion 12a protruding from the upper side plate 12.
Are also made of quartz.

Next, the operation of the basket type boat 10 is characterized in that the slit for inserting the wafers 18 and the slit for introducing the process gas after the arrangement of the wafers 18 are both used. That is, the insertion of the wafer 18 is performed through the slit 25 between the partition members 20, and each wafer 18 of the step portion 24 is locked. Such a wafer 18
Are stored in a cassette (not shown) in advance, and wafers 18 are transferred collectively from the cassette to the basket-shaped boat 10 by, for example, 25 wafers at a time by a wafer transfer device (not shown).

After the transfer of the wafers 18 is completed, the basket boat 10 is transported by the boat transport device (not shown), and the basket boat 10 is delivered to the handler 60.

That is, the flange-like projection 14b at the lower end of the basket-shaped boat 10
Is placed on the boat mounting table 67, and the projection 12a at the upper end thereof is clamped by the boat clamp arm 68, so that the basket 60 can be held by the handler 60.

Thereafter, the basket-shaped boat 10 is positioned vertically below the vertical furnace 30 in a state where the basket-shaped boat 10 is erected vertically by various driving units of the handler 60,
By moving the handler 60 upward by driving the second motor 62, the upper end of the basket-shaped boat 10 is moved to the process tube.
Place in 31.

Next, the movable part 53 is rotated with the heat insulating cylinder 40 placed on the support member 54, the heat insulating cylinder 40 is arranged below the basket-shaped boat 10, the handler 60 is lowered, and the hole of the heat insulating cylinder 40 is lowered. The lower end projection 14a of the basket-shaped boat 10 is inserted into the portion 41, and the flange-shaped projection 14b is brought into contact with the upper surface of the heat retaining cylinder 40. As a result,
The cage boat 10 can be supported vertically on the heat retaining tube 40, and the support by the handler 60 is released here.

Next, by driving the first motor 52 and moving the movable part 53 upward, the basket-shaped boat 10 can be set at the furnace core position of the process tube 31 as shown in FIG.

Thereafter, the inside of the furnace process tube 31 is purged with an inert gas to exhaust unnecessary gas, and the process gas is introduced when the process temperature (for example, about 400 ° C. in the case of LTO) is reached by controlling the heater 33. The heat treatment will be started.

Here, the periphery of the wafer 18 mounted on the basket-shaped boat 10 is
Since the generally annular partition member 20 is covered by the gas regulating ring 22 in particular, the slit 25 for introducing the gas onto the wafer is formed by the wafer 18 disposed on the step portion 24 as shown in FIG. And a narrow slit formed between the gas control ring 22 and the adjacent gas regulating ring 22. Since the aperture ratio is small, the gas supply amount / time to the wafer 18 is reduced, and an active gas such as LTO is used. Even in this case, it is possible to solve the problem that the reaction is promoted only at the edge of the wafer and the film thickness at the center is reduced.

Further, according to the configuration of the basket-type boat 10, since it is not divided as in the conventional basket-type boat, it can be used without any problem even when used in a vertical furnace. It can be applied to a vertical furnace.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention.

As a modification of the present invention, a basket type boat compatible with a horizontal furnace will be described with reference to FIG.

The difference between the basket type boat 70 for a horizontal furnace and the basket type boat 10 is that first, projections 12a, 14a,
14b is unnecessary in the mechanism, and instead, the side plates 12, 1
4 is provided with legs 12c and 14c.

In the case of horizontal placement, the wafer is set upright. However, it is preferable that the wafer be supported obliquely in accordance with the demand for stability during transfer, and the partition member 20 is vertically set. It is fixed obliquely to the direction.

Even in such a horizontal furnace basket-type boat 70, wafers can be arranged and supported through slits between the partition members 20, similarly to the basket-type boat 10, and the aperture ratio is small by using the slits. Gas inlet can be configured, LTO
Even when such an active gas is used, a uniform film can be formed. In the case of horizontal furnace, as shown in FIG. 11, for example, a bottom side of the process tube, the injector 72 for the SiH ₄ gas under the boat 70, and injectors 74 for O ₂ gas Have been placed.

Next, referring to a modification of the vertical furnace basket-type boat 10 and the horizontal furnace basket-type boat 70, first, the wafer
Regarding the supporting method of 18, the groove may be formed in addition to the method of mounting the wafer on the step portion 24 as described above, and the locking portion of the wafer may be formed as in the above-described embodiment.
It is not limited to the one formed continuously over 0 °, but may be configured as a plurality of locking portions that are arranged at least apart from each other and stably cut the wafer by locking. In the case of a vertical furnace, since the wafer is supported horizontally, it is preferable that the wafer locking portions are separated and arranged in an area of 180 ° or more.

Further, in the above embodiment, the partition member 20 is arranged to be inclined only for the horizontal furnace basket-type boat 70, but the vertical furnace basket-type boat 10 can be similarly formed. An advantage of this case is that the boat can be rotationally driven in the vertical furnace, so that in the case of the inclined support, stable wafer support against the rotation can be ensured, and a more uniform film Thickness formation can be ensured.

Further, in the above embodiment, the partition member 20 is not formed in a complete annular shape, and the cutout portion 21 is formed in a part thereof.
This is convenient for manual insertion, and a perfect annular shape is superior in reducing the aperture ratio. However, the partition member does not necessarily need to be a partition member that covers the entire circumference of the wafer, and it is sufficient that the partition member 20 is formed in a range where the aperture ratio is small and a sufficient aperture ratio can be obtained to ensure uniform film thickness.

Further, the slits 25 of the above embodiment are used for inserting the wafer 18 and also serving as a gas introduction port, but the number of such slits 25 is the same as the number of wafers to be mounted on the wafer insertion side. Although it is necessary, such a requirement is not always required on the opposite side (in the embodiment of FIG. 1, a region of 180 ° having no notch 21), and at least the aperture ratio for gas introduction is reduced. Any slit may be used as long as the shape, position and number of slits are arbitrary.

[Effect of the Invention] According to the invention of claim 1, both the slit for inserting the object to be processed and the notch for preventing interference with the jig also serve as a gas inlet having a small aperture ratio. By the slits and cutouts, it is possible to form a boat having a narrower aperture ratio without using a split type, a ring type, etc. Workpiece transfer processing can be performed.

In addition, since the slit width can be small, a large number of workpieces can be mounted and batch processing can be performed, and mass production processing of the workpieces can be performed.

Further, unlike the case where the support plate is formed only in a semicircular shape, the plurality of partition members are formed so as to surround the plurality of objects to be processed. The amount of gas to be introduced can be appropriately regulated, thereby reducing the manufacturing cost and simplifying the manufacturing process.

According to the second aspect of the invention, by adjusting the aperture ratio of one or both of the slit and the notch, it is possible to set the aperture ratio such that the film thickness formed on the surface of the processing target becomes uniform. .

According to the third aspect of the present invention, the heat resistance is improved, and the release of contamination at a high temperature can be reduced.

According to the invention of claim 4, the distance between the surfaces of the objects to be processed becomes equal, and the uniformity of the processing between the objects to be processed is ensured.

According to claims 5 and 6, the boat does not involve opening and closing operations each time the object to be processed is put in and out, so that the boat can be used in a vertical furnace.
The object to be processed can be processed by loading it into the process tube from below the vertical furnace.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view for explaining an embodiment in which the present invention is applied to a vertical furnace basket type boat, FIG. 2 is a schematic front view of the basket type boat shown in FIG. The figure is a schematic explanatory view as viewed from the line AA 'in FIG. 2, FIG. 4 is an enlarged sectional view along the line BB' in FIG. 3, and FIG. 5 is an enlarged view of a portion C in FIG. Fig. 6, Fig. 6 is a schematic explanatory view showing an example of a vertical furnace and a loader device, Fig. 7 is a schematic perspective view of a vertical furnace, a basket-shaped boat and a heat retaining cylinder, and Fig. 8 is a schematic of a handler section. FIG. 9 is a schematic front view of a basket type boat for a horizontal furnace which is a modified example of the present invention, FIG. 10 is a schematic plan view of the boat of FIG. 9, and FIG. FIG. 12 is a schematic side view of a boat, and FIG. 12 is a schematic explanatory view of a conventional split-type basket-type boat. 10,70… Category boat, 12,14… Side plate, 12a, 14a, 14b… Protrusions to be locked, 12c, 14c… Leg, 16… Support plate, 18… 20 ... partition member, 22 ... gas regulating ring, 25 ... slit, 30 ... vertical furnace, 60 ... handler, 72,74 ... injector.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-102225 (JP, A) JP-A-62-229932 (JP, A) JP-A-58-108735 (JP, A) JP-A-58-108 197823 (JP, A) Actually open 1987-128633 (JP, U) Actually open 60-124031 (JP, U) Actually open 1988-163223 (JP, U) Actually open 1988-170466 (JP, U)

Claims (6)

(57) [Claims] 1. A boat in which a plurality of workpieces are respectively supported by a plurality of ring-shaped partition members, and the plurality of workpieces are arranged and supported by being surrounded by a plurality of ring-shaped partition members. A plurality of slits formed between the plurality of ring-shaped partition members, allowing each of the processing objects to be carried in and out of the boat, and allowing the introduction of a process gas for processing the processing object, At least on the loading / unloading side of the object to be processed, the plurality of ring-shaped partition members are cut out along the arrangement direction of the plurality of objects to communicate with the plurality of slits, and the plurality of objects to be processed are A boat having a narrow notch for preventing interference with a loading / unloading jig. 2. The boat according to claim 1, wherein the aperture ratio of the slit and the notch is set such that the film thickness formed on the surface of the object to be processed is substantially uniform. 3. The boat according to claim 1, wherein the plurality of ring-shaped partition members are formed of quartz, and support a semiconductor wafer as the object to be processed. 4. The boat according to claim 1, wherein the slits are formed at an equal pitch. 5. The boat according to any one of claims 1 to 4, a transfer machine for inserting and removing an object to and from the boat, and a plurality of the objects mounted on the boat. A heat treatment apparatus comprising: a vertical furnace to be processed; and a loader unit that loads / unloads the boat into the vertical furnace from below the vertical furnace while vertically supporting the boat. 6. A step of inserting the object to be processed into the boat according to any one of claims 1 to 4 through the slit and supporting the object with the ring-shaped partition member, and mounting the object to be processed. Loading the boat into the process tube from the lower region of the vertical furnace equipped with a process tube and a heating unit, setting the processing position, and introducing a process gas into the process tube, And a step of setting the process temperature to a predetermined temperature by the heating unit, guiding the process gas into the boat through the slit, and treating the object to be processed.