KR100350612B1 - Dual Vertical Heat Treatment Furnace - Google Patents

Abstract

The present invention includes a vertical type including a single housing 16 having a first vertical furnace 12 and a second vertical furnace 14 each having a heating chamber 46 for heat treating the semiconductor wafer W. FIG. The semiconductor wafer processing furnace 10 is related. The first and second vertical paths are arranged asymmetrically with respect to each other to reduce the overall footprint of the process. Each vertical path includes a wafer including support structures such as wafer boat 40, boat lift 58, motor 64 and guide rod 60 for axially mounting a selected number of semiconductor wafers W. Support assembly 54. The transfer element selectively moves one of the support elements into and out of the process tube along the vertical axis, and the wafer transfer element 36 selectively transfers the semiconductor wafer to or from one of the support elements. The furnace also includes a heating sleeve 100 or envelope suitable for controlling the surrounding fluid environment surrounding the support structure and capable of being moved independently of the support structure. The heating sleeve is adapted to be hermetically coupled with a portion 54B of the support element to form a fluid tight seal that forms the loadlock processing assembly 108. The assembly is connected to a vertical transfer assembly that selectively moves the processing assembly vertically into the heating chamber 46 of the furnace. In addition, the heating sleeve 100 can move vertically with respect to the support structure 40 to engage and disengage the heating sleeve repeatedly, easily and automatically with respect to the support structure.

Description

Double Vertical Heat Treatment Furnace

The present invention relates to a heat treatment furnace for processing a semiconductor wafer, and more particularly, to a vertical heat treatment furnace.

Heat treatment furnaces, known as diffusion furnaces, are widely known and perform various semiconductor fabrication processes, including annealing, diffusion, oxidation, and chemical vapor deposition. Has been used for years. As a result, these processes are particularly well known for the effect of process variables on the quality and uniformity of the final product. The heat treatment furnace usually employs a vertical or horizontal furnace. For some examples, a vertical furnace is preferred, which produces less particles during use and thus reduces the incidence of contamination and damage to the wafer, and can be easily automated, and also allows for a relatively small footprint ( The footprint requires less floor space.

Both conventional diffusion furnaces, as known, promote diffusion of dopants to a desired depth while maintaining a line width of less than 1 micron, or a chemical vapor deposition layer on the wafer or an oxide layer on the wafer. It is designed to heat semiconductor wafers to a desired temperature in order to perform applications and other conventional processing techniques. Since the heating requirements for the wafer during the process are known and well known, they are strictly checked.

Conventional vertical heat treatment furnaces are designed to support the treatment tubes in a vertical position in the furnace. The heat treatment furnace also typically uses a wafer boat assembly that is mounted to a suitable transfer mechanism for moving the wafer into and out of the process tube. In order to transfer semiconductor wafers from a wafer cassette, which typically holds up to 100 wafers, to a wafer boat assembly, a wafer-handling assembly is placed adjacent to and parallel to the wafer boat assembly. The wafer handling assembly is typically located in a loadlock chamber separate from the chamber containing the process tube, and the environment of this separate loadlock chamber is tightly controlled by an appropriate monitoring structure. The loadlock mounting the wafer handling assembly is isolated from these wafer cassettes by, for example, installing the wafer cassette in one or more loadlocks in selective fluid communication with the wafer handling assembly loadlock. May be Thus, the serial chain of loadlocks enables precise environmental control during processing to reduce or eliminate the formation of contaminants on the wafer during heating. These load locks are separated from each other by gate valves that are selectively opened and closed to enable transfer of wafers from the wafer cassette to the wafer boat or from the wafer boat to the wafer cassette.

In practice, after forming a vacuum in the load lock chamber in which the wafer boat is installed, an inert gas such as nitrogen is introduced to fill the load lock chamber while removing air therefrom. This removal of air from the loadlock chamber prevents the formation of natural oxide films on the semiconductor wafer surface. As described above, the loadlock chamber is connected to another serial loadlock that houses the semiconductor wafer cassette and wafer handling assembly, so that loading and unloading of the wafer boat in a nitrogen atmosphere is Will be done. The wafer is then loaded from the wafer cassette into the wafer boat through the wafer handling assembly to form a wafer batch. Next, the wafer batch is placed in a furnace where it is subjected to a user selected process under elevated temperature. Conventional verticals of these types are illustrated and described in US Pat. No. 5,217,501 to Fuse et al. And US Pat. No. 5,387,265 to Kakizaki et al.

In a prior art furnace, a batch of wafers having between about 150 and 200 wafers is placed, setting up one isothermal region in the processing tube extending between about 20 inches and 30 inches. Due to the relatively large thermal mass associated with this wafer batch, for example, the temperature ramp-up rates are relatively small between about 5 ° C./min and about 10 ° C./min, and the temperature drop rate ( temperature ramp-down rates) are also relatively small, between about 2.5 ° C / min and about 5 ° C / min. This results in a relatively long thermal cycle per batch, resulting in a relatively high thermal budget per wafer. Another disadvantage of these and other conventional vertical heat treatment furnaces is the relatively low throughput since the cycle time per batch is increased. Thus, these conventional systems are not suitable for meeting the demand for semiconductor wafers today.

Another disadvantage of these furnaces is that they include a prestaging loadlock assembly that forms an air-free environment for transferring wafers to or from the wafer boat. To achieve this, the time involved in venting and removing air from the loadlock increases the overall processing time per batch, further reducing the throughput of the furnace system.

Another disadvantage of these furnace systems is that these furnaces have a relatively large footprint and occupy a relatively large floor area in the cleanroom, resulting in inefficient use of expensive cleanrooms.

Due to the above and other disadvantages of the prior art vertical heat treatment furnaces, it is an object of the present invention to provide a vertical furnace which provides a relatively high throughput.

It is another object of the present invention to provide a furnace which achieves an improved rate of temperature rise and temperature drop.

Another object of the present invention is to provide a heat treatment furnace which can be easily automated and occupies a relatively small floor space.

Other general and other specific objects of the present invention will be in part apparent from the following detailed description and the accompanying drawings.

The present invention provides a vertical semiconductor wafer processing furnace comprising a single housing for receiving first and second vertical furnaces each having a heating chamber for semiconductor wafer heat treatment. Each vertical furnace includes a wafer support assembly that includes support structures such as waferboats, boat lifts, motors, and guide rods for axially mounting a selected number of semiconductor wafers.

According to one aspect of the invention, the transfer element selectively moves one of the support elements into and out of the process tube along a vertical axis, wherein the wafer transfer element is a semiconductor from one of the support elements or as one of the support elements. The wafer is selectively transferred. According to one preferred embodiment, there is a transfer element along each axis in the longitudinal direction and associated with each wafer support assembly for selectively moving the support elements into the heating chamber.

According to another form, the furnace generates a position signal and a control signal for transmitting the position signal to the conveying element for adjusting, eg starting, modifying or stopping the movement of one of the support structures along the axis in response to the position signal. For example, a control element responsive to a control signal generated by the user. Thus, the control elements respectively control the speed of movement of the support structure independently or simultaneously. According to one embodiment, the control element comprises an operation controller and a support structure for working with a host computer generating a position signal. The control signal applied to the control element may indicate at least one of the selected temperature rise rate condition and the selected temperature fall rate condition.

According to yet another aspect, the conveying element may generate a movement signal indicative of a movement speed of at least one of the first and second support elements, wherein the control element is one of the support elements along the longitudinal axis in response to the movement signal. To control the speed of one movement,

According to yet another aspect of the present invention, each vertical furnace, such as the first and second vertical furnaces, includes a heat generating element for transferring heat to the corresponding respective processing chambers. The control element can independently or simultaneously control the temperatures of the first and second processing chambers by adjusting the heat energy output of each heat generating element. According to one embodiment, the control element may adjust the heat generating element to achieve a substantially uniform temperature along at least a portion of the chamber to form a substantially isothermal environment.

According to another aspect of the present invention, the furnace comprises a heating sleeve or envelope adapted to control the surrounding fluid environment surrounding the support structure, such as, for example, a wafer boat. The heating sleeve includes a flanged bottom adapted to be hermetically coupled with a portion of the support element to create a fluid-tight seal that forms a loadlock processing assembly. The loadlock treatment assembly is connected to a vertical transfer assembly that selectively and vertically moves the treatment assembly into a heating chamber of a vertical furnace. According to a preferred embodiment, the heating sleeve is associated with each vertical furnace. In addition, the heating sleeve can be moved vertically with respect to the support structure so that it can be combined and detached repeatedly, easily and automatically with respect to the support structure.

When a heating sleeve is installed over the support structure and coupled in hermetically with the bottom of the support structure, the assembly forms the loadlock processing chamber in which the selected processing technique can be performed therein. The chamber can be coupled to a suitable fluid manifolding to introduce one or more selected gases into the chamber and to discharge one or more gases therefrom.

The use of double heating envelopes and double furnaces in a single heat treatment furnace allows the furnace to perform two independent treatment techniques separately and independently, thereby increasing furnace flexibility. In addition, the furnace improves the rate of ascent and descent, thereby reducing the overall time required to process the wafer batch, thus increasing the overall throughput of the furnace. These are all achieved by mounting the duplex in a single housing with small dimensions and employing a wafer boat that handles batches of small size while increasing wafer pitch.

Other general and more specific objects of the present invention will be apparent in part from the following detailed description and the accompanying drawings.

The above and other objects, features and advantages of the present invention will become apparent from the accompanying drawings and the following detailed description, wherein like reference numerals refer to like parts throughout the different views. The drawings illustrate the principles of the present invention and illustrate the relative size, although not in scale.

1 is a plan view of a heat treatment furnace according to the present invention.

Figure 2 is a partial cross-sectional perspective view showing the interior of the heat treatment furnace of Figure 1;

3 is a front view of the wafer transfer assembly accommodated in the heat treatment furnace of FIG. 1 showing an asymmetrical arrangement of the furnace in accordance with the techniques of the present invention.

* Explanation of symbols for main parts of the drawings

10: vertical semiconductor wafer processing furnace 12: first vertical heating means

14: second vertical heating means 16: housing

36: wafer transfer means 40: wafer boat

46: heating chamber 64: transfer means

66: control means 100: heating sleeve

1 is a perspective view of a vertical heat treatment furnace 10 of the present invention, partially showing a double vertical furnace 12, 14 according to one aspect of the present invention. The heat treatment furnace 10 is designed to have a compact and relatively small footprint. For example, according to one embodiment of the invention, the furnace may have a width of about 40 inches, a depth of about 65 inches and a height of about 96.5 inches. Furnaces are commonly used to perform a variety of semiconductor manufacturing processes including annealing, diffusion, oxidation and low pressure and high pressure chemical vapor deposition.

The illustrated heat treatment furnace 10 includes a main outer housing 16 that encloses a pair of vertical furnaces 12, 14. The housing 16 includes a plurality of wafer storage compartments 20. Side 16A and front side 16B. A pair of carousals (rotary circular conveyors) 28 and 26 are mounted in the compartment 20 to support eight wafer cassettes holding a selected number of wafers, and vertically spaced apart. These wafers may be unprocessed or processed wafers. The door panel 22 surrounds the compartment 20. As shown, a monitor 30 is installed within the front face 16B of the housing 16 such that the operator monitors selected process control variables such as temperature, process time, type of gas, and other selected process control parameters. To do it.

Referring to FIG. 3, the wafer cassette 24 is mounted on the curation section 28. The three-axis wafer transfer assembly 36 with the mechanical transfer arm 36A is one of the wafer boats 40 located in each vertical path 12, 14 from the selected cassette 24. ). The curable section 28 may be selectively rotated to position the selected wafer cassette at a position such that the mechanical transfer arm 36 may remove the wafer from the particular cassette or position the wafer over the particular cassette. In this way, the illustrated heat treatment furnace 10 may be capable of continuous processing with selected control of the wafer during operation of the furnace. The transfer assembly 36 is preferably movable vertically in order to allow the transfer arm 36 to access the wafer cassette 24 on the upper or lower curvatures 26. Those skilled in the art will readily understand and appreciate the various types of transfer assemblies that may be used in the heat treatment furnace, as well as the operation of the wafer transfer assembly 36 in connection with wafer handling and processing.

In FIGS. 1-3, in particular FIG. 2 shows the components of the heat treatment furnace 10 of the invention. The vertical furnace 14 includes a cylindrical processing tube 44 having a closed end 44A and an open end 44B opposite. The cylindrical processing tube 44 forms the heating chamber 46. Process tube 44 may be formed of any high temperature material, such as alumina, silicon carbide, and other ceramic materials, but is preferably made of quartz. The treatment tube is surrounded by a resistive heating element or an RF heated black body cavity susceptor as the primary heating source. This particular type of heating source is widely accepted because it is simple to implement and has the characteristics of a reliable technique for controlling the temperature of the furnace stably and uniformly. According to one embodiment, the heating element 48 forms part of a heater module which is a resistive heating unit of three regions facing vertically. The heating element may consist of metal wires of low mass and high temperature. The insulator surrounding the heating element may be composed of ceramic fibers of high thermal insulation value and low thermal mass. They are all designed to react quickly to temperature changes. The module also includes an air cooling system to help cool the heating chamber 46. The diameter of the process tube 44 and thus the size of the vertical can be easily added or subtracted to accommodate wafers of varying sizes.

The heating element 48 is adapted for each treatment tube 44 to heat the inside of the tube to a predetermined temperature, for example 400 ° C. to 1200 ° C. in the case of chemical vapor deposition, or to 800 ° C. to 1200 ° C. in the case of oxidation or diffusion. ) Is placed around. The control unit 66 may be used to adjust the temperature of the treatment tube 44 according to the requirements required for the treatment technique. For example, according to one embodiment, a temperature sensor, such as an optical pyrometer, can be used to sense the temperature of the chamber and can be connected to the control unit 66. The heating unit preferably forms an isothermal heating zone in the heating chamber as is known in the art.

The housing 16 encloses a wafer support assembly 54 that includes a waferboat 40 supported by an adiabatic stanza. Lower portion 54A of wafer support assembly 54 has a flange plate 54B that is integrally formed and extends radially outward. The illustrated wafer support assembly 54 is connected to a boat lift 58 that is slidably coupled with the guide rod 60. Thus, the wafer support assembly can be selectively moved in the vertical direction along the vertical axis of the guide rod 60 to selectively move the wafer support assembly into and out of the heating chamber 46 of the furnace.

The vertical furnace 12 is similarly constructed.

The mechanical transfer arm 36A of the mechanical transfer assembly 36 carries wafers from each of the wafer boats 40 of each furnace 12 or 14 from a selected cassette 24 mounted in one of the sections 26 and 28. Selectively move to one. The wafer boat selectively holds a plurality of wafers to be processed, such as between about 50 and about 100 wafers, preferably about 75 wafers. Thus, the wafer boat maintains about half of the number of wafers of conventional wafer boats. This reduction in batch size reduces the total amount of the batch, thereby increasing the rate of temperature rise in the furnace. As the rate of increase is increased, the overall time the wafer is exposed to high temperatures is reduced.

The wafers are arranged on the wafer boat at predetermined vertical intervals, known as wafer pitch, preferably separated between 5 mm and about 20 mm, most preferably between about 10 mm and 20 mm. The wafer pitch thus selected forms a relatively large gap between vertically adjacent wafers, thereby improving the temperature uniformity of the wafer and the wafer-to-wafer in the wafer. In contrast, some prior designs typically use wafer pitches between about 3 mm and 5 mm for standard furnace treatments.

An important advantage of this relatively large wafer pitch is that it allows for a relatively fast temperature rise of the wafer without degrading wafer uniformity. This relatively large spacing also reduces the mechanical tolerances of the mechanical transfer arm 36A during loading and unloading of the wafer boat, since the arms have a relatively large working space. The smaller the size of the wafer batch of the wafer boat, the smaller the mass of semiconductor that must be heated during the heat treatment. Thus, the temperature of the semiconductor wafer can be raised and lowered more easily, thereby increasing the overall throughput of the system.

Referring again to FIG. 2, the servomotor 64 controls the movement of the boat elevator 58 along the guide rod 60. The servomotor 64 is preferably controlled by a control unit 66, which may include an operation controller 68, via a selection signal transmitted along the electrical conductor 70. In addition, the illustrated motion controller 68 is in electrical communication with the host computer 74 as shown by the dataflow path 76. Similarly, computer 74 also communicates bidirectionally with a data acquisition stage, which accumulates selected process data related to the heat treatment operation of the illustrated furnace. Data may be transferred between the host computer 74 and the data acquisition stage along the data flow path 78.

The robot controller 82 also communicates bidirectionally with the computer 74 via the signal path 80 and also transmits the selected control signal along the electrical conductor 86 to the wafer transfer assembly 36. Thus, the robot controller controls the selected position and relative motion of the transfer arm 36A to load or remove the wafer onto the selected cassette 24 mounted on one of the corout clauses 26 and 28.

Thus, the computer 74, motion controller 68, data acquisition stage 72 and robot controller 82 not only control the relative movement of the mechanical transfer arm 36A but also selectively raise and lower the wafer support assembly. The closed loop feedback control stage is formed. One of ordinary skill in the art would be able to execute one or more of the motion controller, data acquisition stage, and robot controller in hardware and / or software, thus eliminating a portion of compute 74 rather than providing a separate stage. It will be appreciated that it can be formed.

The illustrated furnace 10 further includes a heating sleeve 100 of a size that is acceptable within the processing tube 44. Since the structure is similar to the process tube, the heating sleeve 100 also has an open end 100B opposite the first closed end 100A and is formed of a high temperature material such as quartz, for example. The open end 100B of the sleeve further comprises an outwardly extending flange portion 100C. The heating tube 100 is connected to a sleeve lifter 104 that slides with the guide rod 60 or other suitable guide structure. The heating sleeve 100 can move independently of the wafer support assembly 54.

The relative vertical position of the heating sleeve 100 can be feedback controlled by the motion controller stage 68 of the control unit 66. For example, motion controller 68 may be used to selectively operate servomotor 64 to simultaneously raise or lower heating sleeve 100, wafer support assembly 54, or both, flanges of heating sleeve. 100C is slidably engaged with the flange portion 54B of the wafer support assembly 54 to form a fluid-tight and vacuum-tight seal. Thus, when the heating sleeve 100 is disposed on the wafer boat and the stance 50 and is sealingly engaged with the flange portion 54B of the wafer support assembly 54, the sleeve 100 is loaded with the load lock processing chamber 108. To form. The heating sleeve 100 works with the wafer support assembly to form an ambient control mechanism for controlling the ambient environment of the wafer mounted on the wafer boat 40 except for the environment of the heating chamber 46 of the process tube 44. do. Thus, the sleeve operates in one position selected as a vertically movable loadlock chamber that can be selectively positioned within the heating chamber 46, for example when the flange 100C is hermetically connected to the flange 54B. The heating sleeve 100 may be raised or lowered together with the wafer support assembly 54 into the heating chamber 46 such that the wafers are subjected to a tightly controlled ambient environment during two states of temperature rising (heating) or falling (cooling). Will be.

A gas manifolding structure may be connected to the wafer transfer assembly 54 and the heating sleeve 100 to control the fluid environment of the loadlock processing chamber 108 associated with the furnace 14 of FIG. 2. For example, according to one embodiment, a small quartz conduit may be applied to the gas box 112 and wafer transfer assembly 54 to transfer the selected process gas contained within the gas box to the top of the process chamber 108. It is connected to the flange plate. The process gas is passed through the wafer boat through, for example, an appropriate exhaust port located below the process chamber, and is discharged into the discharge port of the gas box through an exhaust duct operation. The gas box can be connected to an associated gas panel, for example gas panel 112A, and also to the control unit 66. The other gas box 116 and associated gas panel 116A correspond to the other vertical furnace 12. Those skilled in the art will appreciate that two gas boxes may be replaced by one gas box.

By the gas introduction pipe, the selected processing gas can be introduced into the processing chamber 108. Various processing gases may be introduced into the processing chamber to form the selected film on the semiconductor wafer. For example, oxygen may be introduced into the chamber to form an oxide film, SiH ₄ may be introduced to form a polycrystalline silicon film, and NH ₄ and SiH ₂ Cl ₂ to form a silicon nitride film. Can be introduced. In addition, a purge gas, such as nitrogen, may optionally be introduced into the processing chamber 108 to remove air from the processing chamber 108. As is known, the presence of air in the processing chamber during high temperature processing and annealing of the semiconductor wafer results in the formation of a relatively thick and poor quality oxide film on the semiconductor wafer. In addition, a cleaning gas for removing the native oxide film from the wafer may be introduced into the processing chamber 108. For example, the cleaning gas may be a plasma etching gas such as NF ₃ and HCl, a reducing gas such as hydrogen, or other suitable gases. The gas introduction pipe may be formed above or below the heating sleeve 100, or may be similarly installed in the wafer transfer assembly 54. A discharge tube is similarly formed in the heating sleeve or wafer transfer assembly to selectively remove the gas introduced into the processing chamber 108. Therefore, the gas located in the heating sleeve can be discharged through the discharge pipe, thereby setting the inside of the heating sleeve to a predetermined vacuum degree or removing the gas introduced in advance through the gas introduction pipe.

The gas introduced into the processing chamber during heating is preferably decomposed by the high temperature environment and deposited on the exposed surface of the semiconductor wafer. Thus, the gas is introduced into the processing chamber by a preselected amount to form a film having a selected thickness on the wafer.

In operation, the mechanical transfer arm 36A of the mechanical transfer assembly 36 is feedback controlled by the robot controller 82 to selectively place or remove the wafer from the wafer cassette 24 or the wafer boat 40. According to one embodiment, while the vertical position of the wafer support assembly is changed, the mechanical transfer arm 36A loads a wafer batch containing the selected number of wafers to be processed into the waferboat 40. As noted above, the size of the batch is generally about half the size of a conventional wafer batch. The transfer arm 36A causes the wafer boat 40 to be loaded by removing the wafer from the selected wafer cassette 24. Once the wafer boat 40 has been loaded, the motion controller stage 68 of the control unit 66 has a flange 100C located at the open end 100B of the sleeve 100 and a flange of the wafer transfer assembly 54. The signal selected to lower the heating sleeve 100 along the guide rod 60 is output to the servomotor 64 until it is sealed in contact with the plate 54B. Optionally, the flange plate of the wafer assembly is raised by the servomotor to enable the flange plate to be hermetically coupled to the heating sleeve flange 100C. If desired, a selected gas is introduced into the loadlock processing chamber 108 formed by the heating sleeve 100 and the wafer support assembly. The heating sleeve 100 and / or wafer support assembly 54 are then selectively raised to be introduced into the heating chamber 46 of the processing tube 44. Depending on the specific processing technique to be performed, the wafer batch is heated by the heating element to a selected processing temperature at a relatively rapid rate of temperature rise. The process gas is supplied to form a film on the wafer.

After a user-selected period of time in the isothermal heating zone of the furnace 14, the sleeve and transfer assembly 54 are lowered and exit from the heating chamber 46. The wafers remain in the loadlock processing chamber 108 where the wafers are cooled at a relatively fast rate of temperature drop. The temperature of the wafer is lowered by radiative cooling until the temperature of the wafer is at a desired value, such as 50 ° C. or lower (although direct cooling techniques can be used). After the wafer has cooled, the computer 74 operates the servomotor 64 to raise the heating sleeve 100 relative to the wafer support assembly 54 to separate or disengage the sealing bond formed therebetween. The processed wafers stored in wafer boat 40 are then sequentially removed by the wafer transfer assembly and transferred to the wafer cassette.

As the wafer pitch is increased as well as the batch size of the wafer boat becomes relatively small, the rate of temperature rise and fall is significantly improved. For example, the rate of temperature rise can be increased significantly, approaching or exceeding 100 ° C. per minute. Likewise, the rate of temperature drop can also be improved to approach or exceed 50 ° C. per minute. In a practical example, however, a rise rate between about 30 ° C. and about 75 ° C. per minute and a fall rate of about 15 ° C. per minute and about 40 ° C. per minute are sufficient. By increasing the temperature rise rate and fall rate, the overall processing time of the batch is considerably reduced, thereby significantly increasing the work output of the heat treatment furnace 10. The rate of temperature drop can be further affected by introducing cooling jet streams that flow across the surface of the wafer to remove heat from the wafer. For example, non-oxidizing inert gas, such as nitrogen, may be introduced into the chamber 108, or wafer cooling time may be further increased in situations where the sleeve 100 is separated from the wafer transfer assembly 54 applied directly across the wafer. Can be shortened. Thus, FIG. 2 illustrates a wafer support assembly 54 and heating sleeve 100 that can be selectively positioned within the heating chamber 46 of the furnace. Although not shown, similar heating and processing structures exist and are associated with the vertical furnace 12. For example, vertical furnace 12 includes a process tube surrounded by a selected heating element. In addition, the heating sleeve 100 and the wafer transfer assembly 54, which may be selectively moved vertically, may be coupled and selectively positioned in the processing tube.

Accordingly, the present invention provides a single host computer (or multiple integrated controls) for selectively loading a pair of wafer boats that can be moved into and out of corresponding vertical lanes 12, 14 individually and independently. Stage, FIG. 2) and a wafer transfer assembly are used. Accordingly, the heat treatment furnace 10 of the present invention accommodates a pair of process tubes, a pair of heating sleeves, and a pair of wafer support assemblies 54. In addition, the vertical furnaces 12 and 14 are optional in asymmetrical shapes with respect to each other, as shown in FIGS. 1 and 3, to further provide a relatively small footprint by minimizing the overall dimensions of the furnace 10. Is located.

The heat treatment furnace of the present invention can achieve an improvement in the rate of temperature rise and rate of fall without sacrificing throughput in a relatively small housing having a relatively small footprint. As the furnace of the present invention achieves improved heating and cooling of the wafer, the amount of heat supply required for each batch is significantly reduced. This significantly reduces costs and increases throughput.

Another advantage of the present invention includes the use of dual vertical furnaces, which can perform two separate semiconductor processing techniques on individual wafer batches that are independent of each other in each furnace, if necessary. For example, a polycrystalline silicon film may be deposited on another batch in another furnace while an oxide film is formed on one wafer batch in one of the furnaces. Installed in a single housing, this multi-treatment multiplexer provides a relatively flexible heat treatment furnace with significant advantages over heat treatment furnaces known to date. In addition, the use of dual in a single housing device reduces the overall processing time of the wafer, thereby increasing the throughput of the system. For example, one wafer batch may be processed while another wafer batch located in another furnace is cooled, and one wafer batch may be unloaded while another wafer batch is loaded. As a result, this dual device concomitantly reduces the need for operator contact, while reducing the overall processing time of the wafer batch by 25% or more.

The dual vertical furnace device, integrated in one package, minimizes floor space, allowing the double furnace to share a single wafer mechanical transfer assembly. This results in a more efficient use of the transfer assembly, since in conventional systems the transfer assembly is typically used less than about 25% of the total processing time.

3 also illustrates the asymmetrical arrangement of the furnaces 12, 14 of the present invention. If the double vertical paths 12, 14 are located symmetrically within the housing 16, these vertical paths are symmetrical about the boundary line 47 and are collinear along the axis 49. This arrangement makes the housing footprint relatively wider. By moving one of the furnaces away from the axis 49 in the housing and asymmetrically placing the furnaces, the furnaces are no longer symmetrical with respect to the boundary line 47 and the overlap of the two furnaces 12, 14 The footprint of the housing is reduced by an amount corresponding to (A). These relatively small prints offer significant advantages because the furnaces are typically installed in clean rooms where the cost per square foot is quite expensive. Therefore, reducing the size of the heat treatment apparatus means that it takes up less space in the clean room, whereby more heat treatment furnaces can be installed in the clean room. As a result, the cost is reduced, while the efficiency and throughput of the facility are increased.

According to one embodiment, the vertical line has a width of about 40 inches. If the furnaces were arranged along the axis 49, the furnace would occupy at least 80 inches along the width of the housing 16. If the furnaces 12, 14 are arranged asymmetrically as shown, the overlap A can be about 8 inches, thereby allowing the furnace to occupy about 10% of the space along the width of the housing, or other device. Is reduced even more. Those skilled in the art will appreciate that other asymmetrical furnace arrangements may exist, but they are considered to form part of the present invention.

In addition, the use of a single wafer transfer assembly 36 by placing the wafer transfer assembly at a convenient location such that the asymmetrical arrangement of furnaces 12 and 14 allows the single wafer transfer assembly to service both vertically. This is optimized.

Accordingly, it will be appreciated that the present invention can efficiently achieve the objects described above among those apparent from the foregoing description. Since any modifications may be made in the above structure without departing from the scope of the present invention, all problems shown in the accompanying drawings or included in the above description should be understood in a descriptive sense rather than a restrictive sense.

In addition, the following claims are to be understood as including all descriptions of the scope of the invention that may fall within the scope and features of the invention as a matter of all the general and specific features and language of the invention described herein.

Having described the invention, it is claimed that it is novel and is as claimed by the patent as follows.

Claims (13)

First vertical heating means 12 extending along a first longitudinal axis and including means for forming a first heating chamber 46 for heat treating the semiconductor wafer W; Extending along a second longitudinal axis and including means for forming a second heating chamber 46 for thermally processing the semiconductor wafer W, the said housing in a single housing to reduce the overall footprint of the housing; Second vertical heating means 14 asymmetrically positioned relative to the first vertical heating means, A first wafer support assembly 54 comprising first support means for axially mounting a selected number of semiconductor wafers; A second wafer support assembly 54 comprising second support means for axially mounting a selected number of semiconductor wafers; Transfer means 64 for selectively moving at least one of the first and second support means along the corresponding longitudinal axis, and A single housing 16 associated with the first and second support means and having wafer transfer means 36 for selectively transferring semiconductor wafers from or to at least one of the first and second support means. Into a vertical semiconductor wafer process. The method of claim 1, And control means 66 for generating a position signal 70 and responding to a control signal for transmitting the position signal to the transfer means 64, wherein the transfer means is further configured in response to the position signal. A vertical semiconductor wafer process furnace for moving at least one of the first and second support means along a corresponding longitudinal axis. The method of claim 1, The transfer means 64, First transfer means 64 associated with the first wafer support structure 54 and for moving the first support means along the first longitudinal axis in response to a first position signal 70, and Vertically associated with the second wafer support structure 54 and including second transfer means 64 for moving the second support means along the second longitudinal axis in response to a second position signal 70. With mold semiconductor wafer processing. The method of claim 1, And a control means (66) for independently controlling the temperatures of each of said first and second heating chambers. The method of claim 1, Each of the first and second wafer support assemblies 54 includes a wafer boat 40 connected to a boat lift 58 and means 64 for moving the boat lift in a vertical direction along the corresponding axis. To vertical semiconductor wafer processing. The method of claim 1, The first vertical heating means comprises peripheral control means 100 for selectively controlling the surrounding gas surrounding the first support means 54, the peripheral control means being in the first heating chamber 46. With vertical semiconductor wafer processing, which can be selectively positioned. The method of claim 6, The ambient control means selectively heats the heating sleeve 100 associated with the first heating means 12 and into the first heating chamber 46 along the first axis and from the first heating chamber. Means for moving, said heating sleeve selectively positioned over said first support means and sealingly connected to said first support means. The method of claim 7, wherein The heating sleeve (100) is a vertical semiconductor wafer processing furnace which can move along the first axis together with or independently of the first support means. First vertical heating means extending along a first longitudinal axis and including means for forming a first heating chamber for heat treating the semiconductor wafer; Extending along a second longitudinal axis and including means for forming a second heating chamber for thermally processing the semiconductor wafer, the first vertical in a single housing to reduce the overall footprint of the housing; Second vertical heating means asymmetrically positioned with respect to the heating means, A first wafer support assembly comprising first support means for axially mounting a selected number of semiconductor wafers; A second wafer support assembly comprising second support means for axially mounting a selected number of semiconductor wafers; Transfer means for selectively moving at least one of the first and second support means along the corresponding longitudinal axis; Wafer transfer means associated with said first and second support means for selectively transferring semiconductor wafers from or to at least one of said first and second support means; Sleeve means for forming a heating sleeve associated with said first heating means; And said single housing having means for selectively moving said heating sleeve into and out of said first heating chamber along said first axis, said heating sleeve selectively over said first supporting means. With vertical semiconductor wafer processing that can be located. The method of claim 9, And control means coupled to said means for selectively moving said heating sleeve to selectively control movement of said heating sleeve. The method of claim 9, Wherein said heating sleeve is hermetically coupled to said first wafer support assembly to form a processing chamber. The method of claim 9, And means for selectively moving the heating sleeve, wherein the means for selectively moving the heating sleeve comprises moving the heating sleeve in response to the position signal. The method of claim 9, Wherein said first vertical heating means comprises a processing tube and a heating element at least partially surrounding said processing tube.

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