KR980010306A - DUAL VERTICAL THERMAL PROCESSING FURNACE - Google Patents

Abstract

The present invention relates to a vertical semiconductor wafer comprising a single housing (16) each having a first (12) and a second (14) vertical furnace having a heating chamber (46) for heat treating the semiconductor wafer (W). The processing furnace 10 is related. The first and second vertical furnaces are arranged asymmetrically with respect to each other to reduce the overall footprint of the treatment furnace. 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 placing a selected number of semiconductor wafers W. Support assembly 54. The transfer device selectively moves one of the support structures along the vertical axis to the inside and outside of the processing tube, and the wafer transfer device 36 selectively moves the semiconductor wafer to or from one of the support devices. The furnace also includes a heating sleeve 100 or envelope that is suitable for controlling the ambient flow environment surrounding the support structure and that can be moved independently of the support structure. The heating sleeve is suitable for sealingly connecting with the portion 54B of the support device to create a flow seal forming the loadlock processing assembly 108. The assembly is connected to a vertical transfer assembly that selectively and vertically moves the processing assembly into a vertical heating chamber 46. Additionally, the heating sleeve 100 can be moved vertically with respect to the support structure 40 to connect and disconnect the heating sleeve repeatedly, easily and automatically with respect to the support structure.

Description

DUAL VERTICAL THERMAL PROCESSING FURNACE

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

Heat treatment furnaces, known as diffusion furnaces, are widely known and have long been used to perform various semiconductor fabrication processes including annealing, diffusion, oxidation and chemical vapor deposition. Thus, these processes have been particularly well understood for the effect of process variables on the quality and uniformity of the final product. The heat treatment furnace is typically a vertical or horizontal furnace. For some applications, a vertical furnace is preferred, which produces less particles during use, reducing the incidence of contamination and wafer waste, and can be easily automated, and also because of the relatively small footprint This is because it requires a floor area.

These two types of diffusion furnaces facilitate the diffusion of dopants to a desired depth while maintaining a line width of less than 1 micron, or as known, other than the deposition of a chemical deposition layer on a wafer or the formation of an oxide layer on a wafer. It is designed to heat the semiconductor wafer to the desired temperature in order to carry out the process technology. Since the need to heat the wafer during the process is well known and well understood, they are monitored in detail.

Conventional vertical heat treatment furnaces are designed to support the process tubes in a vertical position in the furnace. The heat treatment furnace also typically uses a waferboat assembly that is installed in a suitable transfer mechanism for moving the wafer into and out of the process tube. Wafer steer assemblies are typically disposed adjacent and parallel to the wafer boat assembly to transfer the semiconductor wafer from the wafer cassette, which typically houses 100 wafers, to the wafer boat assembly. The wafer steer assembly is typically located in a loadlock chamber separate from the chamber housing the process tube, the environment of which is controlled in detail by appropriate monitoring structures. The load lock on which the wafer steer assembly is mounted can be separated from the wafer cassette by installing the wafer cassette in one or more load locks in selective communication with the wafer steer assembly load lock. Thus, the series connection of the loadlocks allows the tight environmental control needed during the process to reduce or eliminate the generation of contamination formed on the wafer during heating. The load locks are separated from each other by gate valves that are selectively opened and closed to allow transfer of wafers from the wafer cassette to the wafer boat or from the wafer boat to the wafer cassette.

In fact, after a vacuum is formed in the load lock chamber in which the wafer boat is installed, an injection gas such as nitrogen is introduced to fill the load lock chamber and air is removed from the load lock chamber. Removing air from the load lock chamber prevents formation of a native oxide film on the surface of the semiconductor wafer. As described above, since the load lock chamber is connected to the semiconductor wafer cassette and another series load lock on which the wafer steering assembly is placed, it is therefore possible to load and unload the wafer in a nitrogen atmosphere. The wafer is then loaded from the wafer cassette through the wafer steer assembly into the wafer boat to form a wafer batch. The wafer batch is then placed in a furnace where a user select process occurs at elevated temperatures. Typical vertical furnaces of these types are shown and described in US Pat. No. 5,217,501 to Fuses and US Pat. No. 5,387,265 to Kakizaki.

The prior art creates an isothermal region extending between about 20 inches and 30 inches in a process tube in which a wafer batch with about 150 to 200 wafers is placed.

Because of the relatively large heat capacity associated with this wafer arrangement, the ramp-up ratio is relatively small, for example from about 5 ° C./min to about 10 ° C./min and the ramp down ratio is also from about 2.5 ° C./min to about 5 It is relatively small at about ℃ / min. This results in a relatively long thermal cycle per batch, thus a relatively large thermal capacity per wafer.

Another disadvantage of these conventional vertical heat treatment furnaces is that relatively low throughput is achieved because the cycle time per batch is increased. Thus, these conventional systems are not suitable to meet the increasing demands on today's semiconductor wafers.

Another disadvantage of these furnaces is the use of a prestaging loadlock assembly that creates an air free environment for the transfer of wafers to or from the waferboat. The time taken to evacuate and remove air from the loadlock to achieve these airless conditions increases the overall processing time per batch, thus 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 clean room, resulting in inefficient use of the expensive clean room.

Because of 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.

Another object of the present invention is to provide a furnace with improved ramp up and ramp down ratios.

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

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

The present invention provides a vertical semiconductor wafer processing furnace comprising a single housing each having a first and a second vertical path having heating chambers for heat treatment semiconductor wafers. Each vertical furnace includes a semiconductor support assembly that includes support structures such as wafer boats, boat lifters, motors, and guide rods for axially placing a selected number of semiconductor wafers.

According to one aspect of the invention, the transfer element selectively moves one of the support elements in and out of the processing tube along the vertical axis, and the wafer transfer element selectively transfers the semiconductor wafer from or to the support element. According to one preferred embodiment there is a conveying element associated with each wafer support assembly to selectively move the support element into the heating chamber along each longitudinal axis.

According to another feature of the invention, the furnace is in response to a control signal, eg a user-generated control signal for generating a position signal, and adjusts the movement of one of the support structures along the axis in response to the position signal, e. And a control element for transmitting the position signal to the conveying element for the purpose. 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 for operating the support structure in cooperation 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 ramp up ratio and the selected temperature ramp down ratio.

According to another feature of the invention, the conveying element is capable of generating a movement signal indicative of the movement speed of at least one of the first and second support elements, and the control signal in response to the movement signal along the longitudinal axis. Control the movement speed of either.

In accordance with another feature of the invention, each vertical furnace, such as the first and second vertical furnaces, comprises a heat generating element for transferring heat to each corresponding processing chamber. The control element can independently or simultaneously control the temperatures of the first and second processing chambers by adjusting the thermal energy output of each heat generating element. In one embodiment, the control element may adjust the heat generating element to obtain a substantially uniform temperature along at least a portion of the chamber to create a substantially isothermal environment.

According to another feature of the invention, the furnace comprises a heating sleeve or envelope suitable for controlling the atmospheric flow environment surrounding the support structure, for example a wafer boat. The heating sleeve includes a flanged bottom adapted to be hermetically coupled to a portion of the support element to create a flow seal that forms a loadlock processing assembly. The assembly is connected to a vertical transfer assembly that selectively moves the processing assembly vertically into the heating chamber of the vertical furnace. According to a preferred embodiment, the heating sleeve is associated with each vertical furnace. In addition, the heating sleeve may be moved perpendicular to the support structure in order to engage and disengage the heating sleeve repeatedly and easily and automatically with respect to the support structure.

When the heating sleeve is installed on the support structure and sealingly connected with the lower portion of the support structure, the assembly forms a loadlock processing chamber in which the selected treatment technique can be performed. The chamber may be coupled to a suitable flow branch to introduce one or more selected gases into the chamber and also to discharge one or more gases.

The dual heating envelope and furnace use in a single heat treatment furnace allows the furnace to use two independent treatment technologies independently, increasing the flexibility of the furnace use. The furnace also achieves improved ramp up and ramp down rates, reducing the total time needed to process the waypub batches, thus increasing the overall output of the furnace. This is accomplished by employing waferboats with increased wafer pitch and also processing smaller batch sizes and by packaging double furnaces in a single housing having a smaller diameter.

Other general objects of the present invention will become 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, and like reference numerals refer to like parts throughout. The figures illustrate the principles of the present invention and show relative sizes rather than actual sizes.

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

2 is a partial cross-sectional perspective view showing the interior of the heat treatment furnace of FIG.

3 shows a top view of a wafer transfer assembly housed in the heat treatment furnace of FIG. 1 and an asymmetric furnace arrangement in accordance with the techniques of the present invention.

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

The heat treatment furnace 10 described includes a main outer housing 16 that seals a pair of vertical furnaces 12, 14. The housing 16 includes a plurality of side surfaces 16A and a front surface 16B including a wafer storage compartment. A pair of vertically spaced carousels (rotary round conveyors) 28 and 26 supporting eight wafer cassettes in which a selected number of wafers are placed is installed in the compartment 20. These wafers may be unprocessed or processed wafers. The door panel 22 seals and covers the compartment 20. As shown, a monitor 30 is installed on the front face 16B of the housing 16 to allow the operator to monitor selected process control variables such as temperature, process time, type of gas and other selected process control variables. do.

Referring to FIG. 3, the wafer cassette 24 is installed in the carousel 28. As shown in FIG. The three-axis wafer transfer assembly 36 having the mechanical transfer arm 36A transfers the wafer W from one of the selected cassettes 24 to one of the wafer boats 40 installed in each of the vertical paths 12 and 14. The carousel 28 may optionally be rotated to position the selected wafer cassette at a location where the mechanical transfer arm 36 may remove the wafer from a particular cassette or place the wafer in a particular cassette. In this manner, the described heat treatment furnace 10 is capable of continuous processing of the wafer and the selected control during the furnace operation. The transfer assembly 36 can move vertically to allow the transfer arm 36 to access the wafer cassette 24 to the upper carousel 28 or the lower carousel 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.

1 to 3, in particular FIG. 2, illustrate the components of the heat treatment furnace 10 of the present invention. The vertical furnace 14 has a cylindrical processing tube 44 having a closed multi-part 44A and an open opposite end 44B. The cylindrical tube 44 defines a heating chamber 46. Process tube 44 may be made of any high temperature material such as alumina, silicon carbide, and other ceramic materials, and is preferably made of quartz. The treatment tube is wrapped in a resistive heating element or RF heated black body cavity susceptor as the primary heating source. This type of heating source is simple to use and is specified and widely accepted as a reliable technique for stable and uniform control of furnace temperatures. According to one embodiment, the heating source 48 forms part of the heater module, which is a three-sided heating unit in the vertical direction. The heating element may be made of a bulky high temperature metallic wire. The insulator surrounding the heating source may be made of Celmic fiber having a high insulation value and a low thermal size. All are designed to react quickly to temperature changes. The module also includes an air cooling system to help cool the heating chamber 46. The size perpendicular to the diameter of the processing tube 44 can be easily reduced to accommodate wafers of varying sizes.

The heating source 48 is adapted to heat the inside of the tube in the case of chemical vapor deposition to a prescribed temperature, such as 400 ° C. to 1200 ° C., or to 800 ° C. to 1200 ° C. in the case of oxidation or diffusion. It is provided for each treatment tube 44. The control unit 66 may be used to adjust the temperature of the treatment tube 44 in accordance with the urgency of the treatment technique. For example, according to one embodiment, a temperature sensor, such as an optical pyrometer, may be used to sense the chamber temperature and may be connected to the control unit 66. The heating unit forms an isothermal heating zone in the heating chamber as is known in the art.

The housing 16 surrounds a wafer support assembly 54 that includes a waferboat 40 supported by an adiabatic stanza. The lower portion 54A of the wafer support assembly 54 has a flange plate 54B which is integrally formed and extends outward in the radial direction. The wafer support assembly 54 described is coupled to a boat lift 58 that slides with the guide rod 60. Thus, the wafer support assembly may be selectively moved along the vertical axis of the guide rod 60 for selectively moving 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 selects the wafer from one of the waferboats 40 of each furnace 12 or 14 by placing a selected cassette 24 placed in one of the carousels 26, 28. Move to. The waferboat optionally has a plurality of wafers to be processed, such as 50 to 100 wafers, preferably about 75 wafers. Thus, waferboats have about half the number of wafers that conventional waferboats have. This reduction in batch size reduces the heat size of the overall batch, thus raising the temperature ramp ratio of the furnace. Because of the elevated ramp rate, the overall time the wafer is exposed to high temperatures is reduced.

The wafers are arranged on the waferboat at defined vertical intervals known as wafer pitch and are preferably separated from 5 mm to about 20 mm and most preferably from about 10 mm to 20 mm. This selected wafer pitch provides a relatively large gap between vertically adjacent wafers, which results in good wafer and wafer-to-wafer temperature uniformity. In contrast, some prior designs use wafer pitches of about 3 mm to 5 mm for standard furnace processing.

An important advantage of this large wafer pitch is that it allows for relatively rapid temperature ramping of the wafer without degrading wafer uniformity. This large spacing also reduces the mechanical tolerances of the mechanical transfer arm 36A during the loading and unloading of the waferboat, since the arms have large space for operation. The smaller the wafer arrangement size of the waferboat, the smaller the amount of semiconductor to be heated during the heat treatment. Thus, since the temperature of the semiconductor wafer is easily ramped up and down, the overall throughput of the system is increased.

Referring again to FIG. 2, the servomotor 64 controls the movement of the boat lift 58 along the guide rod 60. The servo motor 64 is controlled by the control unit 66 including the operation controller 68 by the selection signal transmitted along the electric conductor 70. The operational controller 68 described is in electrical communication with the host computer 74 as shown by the data flow path 76. Similarly, computer 74 communicates bidirectionally with the data acquisition stage, which accumulates selected processing data related to the heat treatment operation of the furnace described. Data may be transferred between the host computer 74 and the data acquisition end via the data flow path 78.

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

Thus, the computer 74, the operation controller 68, the data acquisition stage 72 and the 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. A closed loop feedback control stage is formed. One of ordinary skill in the art would realize that one or more of the operation controller, data acquisition stage, and robot controller can be realized in hardware and / or software so that they form part of the computer 74 rather than being provided as an independent stage. You can see that.

The furnace 10 described includes a heating sleeve 100 of a size to be placed within the processing tube 44. The heating sleeve 100, which is similar in structure to the process tube, is also made of a high temperature material, such as quartz, having a closed first end 100A and an open opposite end 100B. The sleeve open end 100B also includes an outwardly extending flange portion 100C. The heating tube 100 is connected to a sleeve elevator 104 slidably coupled to the guide rod 60 or other suitable guide structure. The heating sleeve 100 may be moved independently of the wafer support assembly 54.

The relative vertical position of the heating sleeve 100 can be feedback controlled by the operation controller stage 68 of the control unit 66.

For example, the operation controller 68 may be used to selectively operate the servomotor 64 to raise or lower the heating sleeve 100, the wafer support assembly 54, or to simultaneously raise or lower both.

The flange 100C of the heating sleeve is adapted to slidably engage with the flange portion 54B of the wafer support assembly 54 to form flow and vacuum sealing. Thus, when the heating sleeve 100 is disposed on the wafer boat and the stance 50 and slidably 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 cooperates with the wafer support assembly to form an atmosphere control mechanism for controlling the atmosphere environment of the wafer loaded on the wafer boat 40 except for the environment of the heating chamber 46 of the processing tube 44. . Thus, when flange 100C is hermetically connected to flange 54B, the sleeve operates in one selected position as a vertically movable loadlock chamber that can optionally be used in heating chamber 46. The heating sleeve 100 can be raised or lowered together with the wafer support assembly 54 into the heating chamber 46 so that the wafers are in a tightly controlled atmosphere during a temperature ramp up (heat) or ramp down (cool) state. do.

A gas manifold may be coupled to the wafer transfer assembly 54 and the heating sleeve 100 to control the flow environment of the loadlock processing chamber 108 associated with the furnace 14 of FIG. For example, according to one embodiment, a small crystal conduit is connected to the flange plate of the gas box 112 and the wafer transfer assembly 54 to transfer the selected process gas contained in the gas box to the top of the process chamber 108. The process gas passes through the wafer boat, for example, through a suitable discharge port located below the process chamber, and is discharged through the duct line into the gas box discharge port. The gas box can be coupled to an associated gas panel, such as 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 can be replaced by a single gas box.

The gas introduction pipe allows the selected process gas to be introduced into the process chamber 108. Various processing gases may be introduced into the processing chamber to form a selected film on the semiconductor wafer. For example, oxygen may be introduced to make an oxide film, SiH ₄ may be introduced to make a polysilicon film, and NH ₄ and SiH ₂ Cl ₂ may be introduced to make a silicon nitride film. In addition, purge gas, such as nitrogen, may optionally be introduced into the process chamber to remove air from the process chamber 108. As is known, a considerably thick and poor oxide film is formed 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 located at the top or bottom of the heating sleeve 100 or may be similarly installed in the wafer transfer assembly 54. A discharge pipe 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 in the heating sleeve can be discharged through the discharge pipe, thereby setting the inside of the heating sleeve to a prescribed vacuum or removing the gas previously introduced 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 gases form a film having a selected thickness on the wafer by a preselected amount into the processing chamber.

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 the wafer arrangement 40 containing the selected number of wafers to be processed into the waferboat 40. As discussed above, the size of a batch is generally about half the size of a typical wafer batch. The transfer arm 36A loads the wafer boat 40 by removing the wafer from the selected wafer cassette 24. If the wafer boat 40 is loaded, the operation controller end 68 of the control unit 66 has a flange plate of the wafer transfer assembly 54 with the flange 100C positioned at the open end 100B of the sleeve 100. The selected signal is output to the servomotor 64 in order to lower the heating sleeve 100 along the guide rod 60 until it is slidably coupled with the 54B. Optionally, the servomotor raises the flange plate of the wafer assembly to allow the flange plate to engage 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 a heating source having a selected processing temperature with a significantly promoted temperature ramp up ratio. The processing gas is supplied to form a film on the wafer.

After the user's selection of the back of the furnace 14 in the heating zone, the sleeve and the transfer arm 54 are lowered and removed from the heating chamber 46. The wafers remain in the loadlock processing chamber 108, where the wafers are cooled to a fairly rapid temperature ramp down rate. The wafer temperature is reduced by thermal radiation cooling (even if direct cooling techniques can be used) until the temperature of the wafer is at a desired value, such as 50 ° C. or lower. 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 block or separate the sealing bond formed between the support assembly and the heating sleeve. Let's do it. The processed wafers stored in waferboat 40 are then sequentially removed by the wafer transfer assembly and transferred to the wafer cassette.

Not only is the wafer pitch increased but the batch size of the wafer boat becomes smaller, so the temperature ramp up and ramp down ratios are significantly improved. For example, an increase in the temperature ramp up rate can be achieved, approaching or exceeding 100 ° C. per minute. Likewise, the temperature rampdown rate can be improved to approach or exceed 50 ° C. per minute. In practical applications, however, a ramp up between about 30 ° C. and 75 ° C. per minute, a ramp down rate of about 15 ° C. per minute and a ramp down ratio of about 40 ° C. per minute are sufficient. These increased ramp up and ramp down temperature rates significantly reduce the overall batch processing time, thereby significantly increasing the overall throughput of the heat treatment furnace 10. The temperature rampdown rate can be influenced by introducing a cooling jet stream that flows across the surface of the wafer to remove heat from the wafer. For example, a non-oxidizing injection gas, such as nitrogen, may be introduced into the chamber 108, or may further shorten wafer cooling time when the sleeve 100 is separated from the wafer transfer assembly 54 applied directly across the wafer. Can be. Thus, Figure 2 illustrates a wafer support assembly 54 and a heating sleeve 1000, which may optionally be disposed within the furnace's heating chamber 46. Although not shown, a similar heating and processing structure is present in the vertical furnace 12 For example, vertical furnace 12 includes a processing tube wrapped by a selected heating source, optionally a vertically movable heating sleeve 100 and wafer transfer assembly 54 in combination with the processing tube. May optionally be located within.

Accordingly, the present invention provides a wafer transfer with a single host computer (or multiple integrated control stages, FIG. 2) to selectively load a pair of waferboats that can be moved in and out of the corresponding vertical paths 12 and 14. Use assembly. Thus, 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. Vertical furnaces 12, 14 may also be selectively installed relative to one another in an asymmetrical shape as shown in FIGS. 1 and 3 to minimize the overall size of furnace 10 to provide a relatively small footprint. .

The heat treatment furnace of the present invention can improve the temperature ramp up and ramp down ratios without sacrificing throughput in a relatively small housing having a relatively small footprint. Since the furnace of the present invention improves the heating and cooling of the wafer, the thermal cost required for each batch is reduced. This is a significant cost savings and increases throughput.

Another advantage of the present invention involves the use of dual vertical furnaces, which can perform two independent semiconductor processing techniques on separate wafer batches independently of each other in each furnace if necessary. For example, a polycrystalline silicon film may be deposited in another batch in another furnace while an oxide film is formed over one wafer arrangement in one of the furnaces.

Installed in a single housing, this multi-treatment multiplexer provides a highly flexible heat treatment furnace with significant advantages over heat treatment furnaces known to date. In addition, the use of duplication in a single housing device reduces the overall wafer processing time, thereby increasing the throughput of the system. For example, one wafer batch may be processed while another wafer batch placed in another furnace may be cooled, and one wafer batch may be unloaded while another wafer batch is loaded. Thus, this duplex device can additionally reduce operator contact requirements, 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, allows the dual furnace to share a single wafer machine transfer assembly. This results in more efficient use of the transfer assembly, since in conventional systems the transfer assembly is used less than 25% of the total processing time.

3 also shows a non-contrast arrangement of the furnaces 12, 14 of the present invention. If the double vertical paths 12, 14 are located symmetrically in the housing 16, the vertical paths are symmetrical about the boundary line 47 and are colinear along the axis 49. This arrangement will provide a large housing footprint. By moving one of the furnaces from the axis 49 in the housing to place the furnaces asymmetrically, the furnaces are no longer symmetrical with respect to the boundary line 47 and the overlap A of the two furnaces 12, 14 The housing footprint is reduced by the corresponding amount. This small footprint offers significant advantages, since furnaces are typically installed in clean rooms where the cost per cubic foot is quite high. Therefore, reducing the size of the heat treatment apparatus means that it takes up less space in the clean room, which allows more heat treatment furnaces to be installed in the clean room. This in turn reduces costs while improving the efficiency and throughput of the plant.

According to one embodiment, the upright has a width of about 40 inches. If the furnaces were disposed along the axis 49, the furnace would occupy at least 80 inches along the width of the housing 16. As shown, if the furnaces 12, 14 are installed asymmetrically, the overlap A may be about 8 inches, thereby providing 10% or other arrangement of space occupied by the furnace over the width of the housing. The furnace reduces even more. Those skilled in the art will appreciate that there may be other asymmetrical arrangements in the furnace and this will form part of the present invention.

The asymmetrical arrangement of furnaces 12 and 14 allows the use of a single wafer transfer assembly 36 by installing the wafer transfer assembly in a convenient location so that a single wafer assembly can serve both vertically. Optimize.

Accordingly, the present invention can efficiently achieve the objects described above among those made apparent in the foregoing description. Since any modification can be made in the above structure without departing from the scope of the present invention, the objects and advantages shown in the accompanying drawings or included in the above description should be understood in an illustrative rather than a restrictive sense.

It is also to be understood that the following claims cover all comprehensive features of the invention described herein and all statements within the scope of the invention that may be included in the invention.

Claims (14)

Means for forming a first heating chamber 46 for heat treating the semiconductor wafer W, the first vertical heating means 12 extending along the first longitudinal axis, and a material for heat treating the semiconductor wafer W; A second asymmetrical installation with respect to said first vertical heating means in a single housing, comprising means for forming a second heating chamber 46 and extending along the second longitudinal axis and also reducing the overall footprint of the housing. A first semiconductor wafer support assembly 54 comprising vertical heating means, first supporting means for axially placing a selected number of semiconductor wafers, first supporting means for axially placing a selected number of semiconductor wafers A second peninsula wafer support assembly 54 comprising: a conveying means 64 for selectively moving at least one of the first and second support means along the corresponding longitudinal axis; and the first and second supports And a single housing (16) having wafer transfer means (36) associated with said first and second support means for selectively transferring semiconductor wafers from at least one or at least one of the stages. 2. The apparatus according to claim 1, further comprising control means (66) responsive to a control signal to generate a position signal (70) and to transmit the position signal to the transfer means (64), wherein the transfer means includes the position signal. In response to moving at least one of the first and second support means along the corresponding longitudinal axis. The method of claim 1, wherein the transfer means 64 is coupled to the first wafer support structure 54 for moving the first support means along the first longitudinal axis in response to a first position signal (70). A second transfer means 64 coupled with the second wafer support structure 54 to move the second support means along the second longitudinal axis in response to the first transfer means 64 and the second position signal 70. Furnace characterized by including). The furnace according to claim 1, further comprising control means (66) for independently controlling the temperature of each of said first and second heating chambers. 2. The device of claim 1, wherein each of the first and second wafer support assemblies 54 comprises a wafer boat 40 connected to a boat lift 58 and means for moving the boat lift longitudinally along the corresponding axis 64. Furnace characterized by including). The method of claim 1, wherein the first vertical heating means comprises an atmosphere control means 100 for selectively controlling the atmosphere gas surrounding the first support means 54, wherein the atmosphere control means is the first heating chamber ( 46. Furnace characterized in that it can be optionally arranged within. The method of claim 6, wherein the atmosphere control means to selectively move the heating sleeve along the first axis to the inside and outside of the heating sleeve 100 and the first heating chamber 46 coupled to the first heating means (12). And means for making said heating sleeve selectively arranged in said first support unit and sealingly connected to said support means. 8. The furnace of claim 7, wherein the heating sleeve (100) is movable along the first axis together with or independently of the first support means. Vertical heating means 12 extending along the longitudinal axis, comprising means for forming a heating chamber 46 for heating the semiconductor wafer W, wafer supporting means for axially placing a selected number of semiconductor wafers ( 54) a heating sleeve 100 defining a processing chamber 108 and optionally disposed above the wafer supporting means 54, and at least one of the heating sleeve and the wafer supporting means along the longitudinal axis into the heating chamber. Vertical semiconductor wafer processing furnace 10, characterized in that it comprises a conveying means (64) for selectively moving the. 10. The method of claim 9, further comprising a control means 66 connected to the transfer means 64 for selectively and independently controlling the movement of one of the heating sleeve 100 and the wafer support means 54. Characteristic furnace. 10. The furnace according to claim 9, wherein the heating sleeve (100) is suitable for sealingly coupling with the wafer support means (54) to form the processing chamber (108). 10. The apparatus according to claim 9, further comprising control means (66) for generating a position signal, wherein the transfer means (64) is in response to the position signal, one of the wafer support means (54) and the heating sleeve (100). Characterized by moving the furnace. 10. The furnace according to claim 9, wherein the vertical heating means (12) comprises a processing tube (44) and a heating source (48) at least partially surrounding the processing tube. 10. The furnace of claim 9 wherein said vertical heating means comprises first and second furnaces extending vertically. ※ Note: This is to be disclosed based on the first application.