JP4645448B2 - Vacuum film forming apparatus, vacuum film forming method, and solar cell material - Google Patents

Description

【Technical field】
[0001]
The present invention relates to a vacuum film forming apparatus, a vacuum film forming method, and a solar cell material.
[Background]
[0002]
The vacuum film forming apparatus for forming a thin film on the surface of the substrate by heating the substrate includes a low pressure CVD apparatus and a plasma CVD apparatus using a method classified as a chemical vapor deposition (CVD) method, and a physical atmosphere. A vapor deposition apparatus, a sputtering apparatus, an ionization vapor deposition apparatus, and the like using a method classified as a phase growth (PVD) method are known.
[0003]
Among these, in the apparatus using the CVD method, after heating the substrate to a predetermined temperature, the substrate is held in a film formation chamber in which a vacuum is maintained, and a source gas containing an element constituting the thin film material is placed on the substrate. By supplying, a desired thin film is formed on the substrate by chemical vapor deposition by chemical reaction on the vapor phase and the substrate surface. In this CVD method, the temperature of the substrate on which the film is formed is more closely related to the film characteristics than the PVD method, and a reaction at a higher temperature is often required. Therefore, particularly in the CVD method, it is important to raise the substrate temperature uniformly and quickly.
[0004]
Of the CVD methods, the plasma CVD method has recently become increasingly important as an industrial application field for forming a film on a large area substrate. In particular, film formation on a glass substrate has occupied an important position as an application field. A glass substrate easily breaks if the in-plane distribution of the substrate temperature is non-uniform, but it is a difficult technique to raise the temperature of a large-area substrate having such characteristics at a low cost at a high speed.
[0005]
For this reason, the conventional vacuum film-forming apparatus is usually inefficient because it can process only one or two substrates. On the other hand, when it is intended to process three or more substrates simultaneously, There is a problem of enlarging the size.
[0006]
As this type of vacuum film forming apparatus that has been conventionally proposed, for example, as shown in Patent Document 1, a heating chamber for heating a substrate to a temperature higher than the film forming temperature, a load lock chamber, and a predetermined thin film on the surface of the substrate. The film formation chamber to be created is hermetically connected in this order with a gate valve interposed therebetween. In the heating chamber, the substrate is heated by forced convection, and the gas passing through the heat source is circulated and supplied by a blower to generate high-temperature gas. Is supplied to the substrate to heat the substrate.
[0007]
Moreover, as shown in Patent Document 2, as an in-line plasma CVD apparatus, an atmospheric heating furnace that preheats the substrate, a load chamber that heats the substrate conveyed from the atmospheric heating furnace to a predetermined temperature in a vacuum, There is a chamber in which a reaction chamber for forming a film on a substrate surface and an unload chamber for cooling the substrate are continuously arranged.
[Prior art documents]
[Patent Literature]
[008]
[Patent Document 1]
JP 2001-187332 A
[Patent Document 2]
Japanese Patent No. 3211356
Summary of the Invention
[Problems to be solved by the invention]
[0009]
According to Patent Document 1, a plurality of large-area substrates can be processed at the same time without increasing the size of the apparatus, so that the productivity of forming a thin film on the substrate can be greatly improved.
[0010]
However, in Patent Document 1, it is difficult to heat the entire surface of the substrate at a uniform temperature in a short time. That is, in Patent Document 1, a heated high-temperature gas flows between substrates and the substrate is heated by forced convection, and the high-temperature gas flows in a laminar flow parallel to the surface of the substrate. Even when the heating of the substrate temperature is completed by such laminar heating, a substantially uniform temperature can be obtained in the surface direction, but a large temperature non-uniformity often occurs in the temperature rising process. In the temperature rising process of laminar heating, on the upstream side of the flow, the heat of the gas flowing in the immediate vicinity of the heated body is transmitted to the heated body, and the heated body is heated, and at the same time, the gas is cooled. This cooled gas flows in a laminar flow along the heated body downstream, but the heat of the high-temperature gas flowing away from the heated body is removed during this movement (heat is replenished) again. Heated. The gas heated again in this way raises the temperature of the heated object on the downstream side. For these reasons, the temperature of the gas immediately adjacent to the object to be heated gradually decreases as it goes downstream. For this reason, in the heating by the laminar flow, the temperature increase rate on the downstream side is always slower than that on the upstream side. Therefore, when the object to be heated is made of a material that is brittle with respect to the temperature gradient such as glass, there is a possibility that the material is damaged due to thermal distortion during the temperature increase.
[0011]
As described above, in laminar heating, heat transfer from a gas at a position away from the heated object to a gas in the immediate vicinity of the heated object plays a major role. However, since the heat transfer in the direction perpendicular to the air flow in the laminar flow is governed by diffusion, the heat conduction speed is slow. As a result, the temperature increase rate on the downstream side of the heated object tends to be further slowed down.
[0012]
In addition, when a wide (slit-shaped) high-temperature gas is flowed and heated along the substrate, a deviation in the gas flow rate in the width direction is likely to occur. There is a problem that the time required to raise the temperature to the desired temperature is extended, and there is a problem that the object to be heated is damaged due to thermal distortion when the temperature gradient in the temperature raising process is significant.
[0013]
On the other hand, in Patent Document 2, in order to heat a substrate to a predetermined temperature in a vacuum, a lamp heater is provided and radiant heating is performed. However, there is a problem that heating efficiency is low and heating takes a long time. is there. Furthermore, since the substrate is moved by the stainless steel chain conveyor, it is difficult to heat a plurality of substrates at the same time. Basically, only one sheet can be heated at a time, and thus the productivity is very low. There is a problem.
[0014]
Moreover, in the said patent document 1, since it heats by atmospheric pressure, it is possible to use city gas, kerosene, etc. with a low cost per unit heat generation amount and a small carbon dioxide generation amount per unit heat generation amount as a heat source. However, since the patent No. 311356 is heating in a vacuum, electric energy must be used, and it can be said that the heating method has a large environmental load.
[0015]
Moreover, in the heating by the lamp heater shown by patent document 2, the near infrared ray of the high energy density emitted from a high temperature heat source is used. When a heat source with a high energy density is used in this way, if the heat capacity of the object to be heated varies greatly depending on the location, there is a possibility that a large non-uniform temperature in the surface direction will occur when the temperature rise is completed. For example, when the heat capacity of the cage that supports the object to be heated is small and the heat capacity of the object to be heated is large, when the object to be heated is raised to a desired temperature, the temperature of the cage may rise abnormally. In general, it is known that the emissivity and reflectance for near-infrared rays vary greatly depending on the type of substance and the surface condition. Therefore, if there is a difference or change in the surface property with respect to infrared rays in the surface of the heated body itself or between the heated body and the cage, uniform and reproducible heating cannot be expected.
[0016]
In view of the above situation, the present invention heats the substrate as a pretreatment when performing vacuum film formation on the substrate with high efficiency in a short time, and at the same surface temperature during and after the temperature rise. In addition, an object is to increase the productivity of solar cell materials and the like by simultaneously heating a plurality of substrates.
[Means for Solving the Problems]
[0017]
The present invention is a vacuum film forming apparatus for forming a film by introducing a substrate heated by a substrate heating apparatus into the film forming chamber, wherein the substrate heating apparatus includes: a heating chamber; A carriage that supports the surface of the substrate in a vertical direction and carries it into the heating chamber; Placed in the heating chamber with the required distance from the surface of the substrate carried into the heating chamber. The bag-shaped face plates on both sides face the substrate. A flat plate nozzle, A gas inlet for introducing a heated gas between the face plates of the plate nozzle; A heating gas introduction device for introducing a heating gas to the gas introduction port is provided, and a plurality of gas injection ports for heating the substrate by a collision jet of heating gas are provided on a face plate facing the substrate in the plate nozzle.
[0018]
Therefore, according to the present invention, the heating gas is led out by the gas jet port formed in the plate nozzle and the substrate is heated by the collision jet, so that the heating efficiency can be improved and the heating time of the substrate can be shortened.
[0019]
In general, when there is no collision object, the state of the jet flow can be classified into a potential core region, a transition region, and a development region in order from the vicinity of the gas outlet. Although the heat transfer coefficient varies depending on the region where the substrate to be heated is placed, a large heat transfer coefficient can be obtained by placing the substrate in a development region close to the transition region. On the contrary, if the substrate is arranged at a distance away from the gas ejection port, a large heat transfer coefficient cannot be obtained. The state of the jet flow is also related to the size of the gas outlet of the plate nozzle. The gas ejection port here is an opening for ejecting heated gas toward the substrate.
[0020]
The shape of the opening of the gas outlet can be selected according to design requirements, such as square or circular, but when the representative dimension of the outlet is B, , The substrate and the face plate of the plate nozzle It is desirable to have a relationship of H / B <20 with the interval (distance) H. The representative dimension B indicates, for example, the length of one side of a square when a square opening is selected, and the diameter of the circle when a circular opening is selected. More generally, the dimensions employed when determining the Reynolds number that governs the flow at the gas outlet are typical dimensions.
[0021]
An industrially large heating rate can be obtained by setting the ratio H / B to 20 or less.
[0022]
In the heating by the impinging jet, local heating is performed around the stagnation point in front of the gas jet outlet. The local heat input is relaxed by the heat transfer in the lateral direction of the substrate, the temperature of the entire substrate rises, and the temperature of the substrate is equalized. For a material such as glass that breaks when the local temperature rises severely, it is necessary to sufficiently consider this point in heating by the impinging jet. If the glass is sufficiently thick, heat conduction in the glass surface increases, so that the glass surface temperature non-uniformity decreases, and the non-uniformity decreases even if the number density of gas outlets is increased.
[0023]
In order to prevent breakage of the glass, when the substrate is glass having a thickness t, it is desirable that r / t <20 when the distance between the gas ejection ports is r.
[0024]
Further, the gas nozzles may be provided on the face plates on both sides of the plate nozzle, and the substrate may be disposed so as to face the face plates on both sides of the plate nozzle. Further, the plate nozzle arranged so as to sandwich the substrate may be provided with a gas introduction port at a position where the nonuniformity of the gas ejection amount generated by the pressure gradient generated in each plate nozzle cancels each other. Further, the plate nozzle may be a comb-tooth nozzle provided in a plurality of comb-teeth so that the substrate is disposed between them. The substrate may be supported by a carriage and conveyed, and the heated gas ejected from the plate nozzle may be guided to the heated gas introduction device through the carriage.
[0025]
Since the plate nozzle arranged so as to sandwich the substrate is provided with a gas inlet at a position where the non-uniformity of the gas ejection amount caused by the pressure gradient generated in each plate nozzle cancels each other, the substrate has a more uniform surface temperature. Can be heated.
[0026]
Since the heated gas after heating the substrate is circulated through the carriage to the heated gas introducing device, the flow of the heated gas is stabilized and the heating of the substrate is stabilized.
[0027]
Another aspect of the present invention is a vacuum film forming method, in which a substrate heating apparatus is connected to a film forming chamber, arranged, a substrate is carried into the substrate heating apparatus, and a plate nozzle having a required distance from the surface of the substrate A heating gas is ejected from a gas outlet provided in the face plate, the substrate is heated by jet heating, the substrate is heated to a uniform temperature, and then the substrate is carried into a deposition chamber for film formation. It is.
[0028]
The film forming method may be a plasma CVD method.
[0029]
Another aspect of the present invention is a solar cell material manufactured as described above.
[0030]
Therefore, according to the present invention, since the heating gas is introduced by the gas jet port formed in the plate nozzle and the substrate is heated by the collision jet, the heating efficiency can be increased and the heating time of the substrate can be shortened.
[0031]
Therefore, the solar cell material can be manufactured with high efficiency.
[Brief description of the drawings]
[0032]
FIG. 1 is a schematic plan view showing the overall arrangement of the vacuum film forming apparatus of the present invention, FIG. 2 is a cut front view showing an example of a substrate heating apparatus in the vacuum film forming apparatus of the present invention, and FIG. 4 is a perspective view of a part of the carriage and the rail, FIG. 5 is an enlarged sectional view of a part of the plate nozzle in FIG. 2, and FIG. 6 is a gas formed on the face plate of the plate nozzle. FIG. 7 is a partial cross-sectional view showing another embodiment in which the substrate is heated by the plate nozzle, and FIG. 8 is a portion showing still another embodiment in which the substrate is heated by the plate nozzle. FIG. 9 is a cross-sectional view, FIG. 9 is a sectional plan view when the gas inlets of the plate nozzles arranged so as to sandwich the substrate are formed at opposite ends, and FIG. 10 is a diagram showing the heating of the substrate by the collision jet of the present invention. And when the substrate is heated by conventional laminar flow By comparing the relationship between the change of the course and the temperature of the substrate definitive time is a diagram showing.
BEST MODE FOR CARRYING OUT THE INVENTION
[0033]
Embodiments of the present invention will be described below with reference to the drawings.
[0034]
FIG. 1 is a schematic plan view showing the overall arrangement of a plasma CVD apparatus which is an embodiment of the vacuum film forming apparatus of the present invention. This plasma CVD apparatus is a substrate provided with a substrate mounting portion 1 and a plate nozzle 33. A load lock chamber 6 having a heating device 3, a soaking device 4 and a decompression device 5; a film formation chamber 11 having an inductively coupled electrode 7, a decompression device 8, a source gas supply device 9 and a temperature control device 10; And an unload lock chamber 13 provided with the outside air inlet 2 and the decompression device 12, and a substrate take-out portion 14. Reference numerals 15a, 15b, 15c, 15d, and 15e are openable and closable gate valves, and 16 is a carriage that supports a plurality of substrates 17 in a vertically movable manner.
[0035]
The operation of forming a film on the substrate 17 supported by the carriage 16 is performed as follows. The substrate 17 is vertically supported on the carriage 16 in the substrate mounting portion 1. In the example of FIG. 1, six substrates 17 are supported on a carriage 16.
[0036]
The carriage 16 that supports the substrate 17 opens the gate valve 15 a and enters the substrate heating device 3, and then closes the gate valve 15 a and then uniformly heats the substrate 17 to a predetermined temperature by the action of the plate nozzle 33. .
[0037]
Next, the gate valve 15b is opened, the carriage 16 is moved to the load lock chamber 6, and then the gate valve 15b is closed. Then, the pressure inside the load lock chamber 6 is reduced to the same negative pressure as the film forming chamber 11 by the pressure reducing device 5. Then, the temperature of the substrate 17 is maintained at the predetermined temperature by the soaking device 4.
[0038]
Thereafter, the gate valve 15c is opened and the substrate 17 is carried into the film forming chamber 11. Subsequently, after the gate valve 15c is closed, the substrate is controlled by the temperature adjusting device 10 while maintaining a predetermined negative pressure by the pressure reducing device 8. A raw material gas is supplied from the raw material gas supply device 9 while maintaining the temperature 17 at the predetermined temperature, and a silicon film is formed on the substrate 17 by the action of the inductively coupled electrode 7.
[0039]
When the film formation of the substrate 17 is completed, the gate valve 15 d is opened and the substrate 17 is carried out to the unload lock chamber 13. At this time, the inside of the unload lock chamber 13 is previously depressurized to the same negative pressure as the film forming chamber 11 by the decompression device 12, and the gate valve 15d is closed when the substrate 17 is carried out to the unload lock chamber 13.
[0040]
Thereafter, the outside air introduction port 2 is opened, the unload lock chamber 13 is increased to atmospheric pressure, the gate valve 15e is opened, and the carriage 16 is led out. Then, the carriage 16 is moved to the substrate take-out portion 14 and the film-formed substrate 17 supported by the carriage 16 is removed.
[0041]
According to the vacuum film forming apparatus shown in FIG. 1, the heating of the substrate 17 and the formation of the silicon film on the heated substrate 17 can be performed substantially continuously. Since the substrate 17 can be supported and heated and a silicon film can be formed at the same time, the efficiency can be further improved.
[0042]
Details of the substrate heating apparatus 3 for heating the substrate 17 to a predetermined temperature and a uniform surface temperature in a short time in the plasma CVD apparatus of FIG. 1 will be described below.
[0043]
First, the carriage 16 will be described prior to the description of the substrate heating apparatus 3. 2 to 4, the carriage 16 includes a rectangular-shaped support base 20 that can run on wheels 18 on rails 18 a and 18 b provided in an inner fixed portion of the heating chamber 23 that constitutes the substrate heating device 3. In addition, on the front and back sides of the support base 20 in the traveling direction, five support columns 21 and 21 'are fixed vertically so as to face each other at a required interval in the left-right direction. And the board | substrate 17 is supported via the support tool 22, respectively on the right side of the front and back support | pillars 21 and 21 'in the leftmost side of FIG. 4, and the left side of the 2nd front and back support | pillars 21 and 21' from the left side, respectively. The two substrates 17 are arranged so as to face each other. Further, the third and fourth support columns 21 and 21 'and the fifth and sixth support columns 21 and 21' are supported so that the two substrates 17 face each other in the same manner as described above. Has been. Thus, three pairs and six substrates 17 facing each other are vertically arranged on the carriage 16.
[0044]
A rack 24 extending in the front-rear direction is provided on the lower surface of the support base 20, and a shaft 26 having a pinion 25 that meshes with the rack 24 passes through the heating chamber 23 and is connected to an external drive device 27. . Therefore, the carriage 16 can travel along the rails 18a and 18b via the rack 24 by driving the driving device 27 and rotating the pinion 25. At this time, the rails 18a and 18b are cut for the installation of the gate valves 15a, 15b, 15c, 15d and 15e in FIG. 1, so that the driving device 27 and the pinion 25 are connected to the load lock chamber 6 and the film formation chamber. 11, the unload lock chamber 13 is provided correspondingly, and the carriage 16 includes a plurality of wheels 19 so that the carriage 16 can travel over the cut portions of the rails 18a, 18b.
[0045]
Inside the heating chamber 23, as shown in FIG. 2, an upper partition plate 28 for partitioning the upper portion of the carriage 16 and a side partition plate 29 for partitioning one side (right side) of the carriage 16 in the traveling direction are provided. The upper end of the side partition plate 29 is fixed to the upper partition plate 28, and the lower end extends to the vicinity of the support base 20. Further, as shown in FIG. 4, the right rail 18b has a shape in which a ladder is placed sideways, and an opening 30 for gas circulation is formed. Furthermore, a gas passage 36 is formed in the support base 20 that supports the substrate 17 of the carriage 16 so that the heated gas flowing between the substrates 17 can flow downward. As a result, gas circulation between the substrates 17 on the carriage 16, the lower part of the carriage 16, the lower right side of the side partition plate 29, and the upper right side of the upper partition plate 28 is communicated with the heating chamber 23. A flow path 31 is formed and constitutes a part of the heated gas introduction device 32.
[0046]
At the lower portion of the upper partition plate 28, the upper end of a plate nozzle 33 having a rectangular flat shape that is parallel to the substrate 17 and has a larger area than the substrate 17 at a position corresponding to the middle of the substrate 17 that is opposed and supported by the carriage 16. A gas inlet 34 is formed at the upper end of the plate nozzle 33 to communicate the gas circulation channel 31 on the upper side of the upper partition plate 28 with the inside of the plate nozzle 33. Accordingly, the plate nozzle 33 has a flat bag shape with a gas inlet 34 formed in the upper part. In FIG. 2, three plate nozzles 33 are provided in a comb-like shape with respect to the upper partition plate 28 so as to correspond to the three sets of opposed substrates 17.
[0047]
As shown in FIGS. 2, 5, and 6, the flat plate-like plate nozzle 33 has a face plate 33 a that faces the substrate 17, and as shown in FIGS. The gas ejection part A is configured by forming a plurality of gas ejection ports 35 to be formed. The arrangement of the gas ejection ports 35 of the gas ejection part A is not particularly limited as long as the temperature distribution of the substrate 17 is practically uniform, and therefore may be regular, such as a grid or staggered pattern. Alternatively, it may be irregularly arranged so as to have a constant surface density.
[0048]
The heating gas introduction device 32 is provided with a partition wall 37 at an upper and lower intermediate position of the gas circulation channel 31, and a circulation fan 39 that is rotated by a drive device 38 is provided at an opening formed in the partition wall 37. Further, a gas heater 40 for heating gas is provided between the partition wall 37 in the gas circulation passage 31 and the rail 18b having the opening 30. The gas heater 40 shown in FIG. 2 arranges a heat transfer pipe 41 in the gas circulation passage 31 below the circulation fan 39, supplies a high-temperature fluid to the heat transfer pipe 41 via a control valve 42, and performs heat exchange. The gas is heated. In addition to the method of heating the gas by the heat transfer tube 41, for example, a combustion cylinder may be installed in the gas circulation passage 31 and the gas may be heated by burning the fuel in the combustion cylinder. In this case, the fuel flow rate is adjusted by the control valve 42. A high temperature filter 43 is provided at a position above the upper partition plate 28.
[0049]
Further, a temperature detector 44 for detecting a gas temperature in the heating chamber 23, preferably a gas temperature just above the upper partition plate 28, is provided. A temperature regulator 45 is provided which regulates the heating of the gas by the gas heater 40 by adjusting the regulating valve 42 so as to be maintained at a predetermined constant value.
[0050]
In FIG. 2 and FIG. 5, the surface plate 33 a on both sides of the plate nozzle 33 is provided with the gas ejection part A by the gas ejection port 35, and the substrate 17 is disposed so as to face the gas ejection part A. Although the case where only one surface is heated is shown, as shown in FIG. 7, only one surface of the substrate 17 is heated by providing the gas ejection part A only on the face plate 33a on one side of the plate nozzle 33. Also good. On the other hand, as shown in FIG. 8, the gas ejection part A may be provided on the face plates 33 a on both sides of the plate nozzle 33, and both surfaces of the substrate 17 may be heated simultaneously by the ejection of the heating gas from the gas ejection port 35.
[0051]
Further, as shown in the cut plan view of FIG. 9, in the plate nozzles 33 arranged so as to sandwich the substrate 17 and provided with the gas ejection part A on the surface facing the substrate 17, it is generated in each plate nozzle 33. It is preferable to provide the gas inlet 34 so that the nonuniformity of the gas ejection amount caused by the pressure gradient is offset. In other words, the gas inlets 34 provided in the plate nozzles 33 sandwiching the substrate 17 may be formed so as to be located at the ends of the opposite sides (upper and lower sides or left and right sides). In FIG. 9, one (left) plate nozzle 33 is provided with a gas inlet 34 at the top of the paper surface, and the other (right) plate nozzle 33 is provided with a gas inlet 34 below the paper surface. Accordingly, the heated gas introduced from one gas inlet 34 to one plate nozzle 33 and the gas introduced from the other gas inlet 34 to the other plate nozzle 33 flow in opposite directions to each other. The gas is ejected from each gas ejection port 35.
[0052]
The operation of the above embodiment will be described below.
[0053]
In the configuration of FIG. 2, the circulation fan 39 is driven by the driving device 38 so that the gas in the gas circulation channel 31 flows from the bottom to the top, and the high-temperature fluid is supplied to the heat transfer tube 41 of the gas heater 40. To heat the gas. The high-temperature gas heated by the gas heater 40 is sent from the circulation fan 39 to the high-temperature filter 43 to be cleaned, and is then introduced into each plate nozzle 33 from the gas inlet 34, and the face plate 33 a of the plate nozzle 33. Are blown so as to vertically collide with the surface of the substrate 17 from the plurality of gas jets 35 of the gas jetting part A formed in the above. As a result, the substrate 17 is heated.
[0054]
The heated gas that has been sprayed onto the substrate 17 to heat the substrate 17 flows down between the opposing substrates 17, flows downward through the gas passage 36 of the support 20, and passes through the opening 30 of the rail 18 b. Then, it is led to the gas heater 40 again.
[0055]
At this time, the temperature controller 45 that inputs the detected gas temperature of the temperature detector 44 provided on the upper part of the upper partition plate 28 is introduced into the plate nozzle 33 by adjusting the flow rate of the high-temperature fluid by the control valve 42. The temperature of the heated gas is controlled to always be kept at a predetermined constant value. This ensures that the substrate 17 is always heated to the desired predetermined temperature. In addition to the method of adjusting the flow rate of the high-temperature fluid supplied to the gas heater 40, the heating temperature of the substrate 17 may be adjusted by adjusting the circulation amount of the heating gas by the circulation fan 39.
[0056]
As shown in FIGS. 5, 7, and 8, the plate nozzle 33 sprays the heated gas so as to collide vertically with the surface of the substrate 17 by the gas ejection ports 35 of the gas ejection part A. The substrate 17 is heated with high efficiency by the collision jet generated by gas collision.
[0057]
FIG. 10 shows the case where the substrate is heated by a collision jet flow so that the heated gas collides against the surface of the substrate 17 as shown in FIGS. The relationship between the passage of time and the change in temperature of the substrate 17 when the substrate is heated by a heating gas in a creeping flow (laminar flow) parallel to the substrate (broken line) as in the conventional example shown in JP-A-187332 It is shown in comparison. FIG. 10 qualitatively shows the temperature change of the substrate 17 when heating to the target temperature range using the same heating gas flow rate.
[0058]
As apparent from FIG. 10, the heating by the laminar flow (broken line) requires a longer time to reach the target temperature range than the heating by the impinging jet (solid line) in the present invention. Therefore, when it is attempted to shorten the heating time in the laminar heating, it is necessary to greatly increase the supply of the heating gas, thus increasing the operation cost. In addition, when a large amount of heated gas is caused to flow along the substrate 17 in this way, it becomes more difficult to adjust the flow rate in the width direction of the substrate 17 to be uniform. There is a problem that non-uniformity is more likely to occur.
[0059]
As described above, the heated gas is sprayed so as to vertically collide with the surface of the substrate 17 by the gas ejection port 35 of the gas ejection part A provided in the face plate 33a of the plate nozzle 33, and the substrate 17 is heated by the collision jet. As a result, the substrate 17 can be heated with high efficiency in a short time.
[0060]
Furthermore, since the gas outlets 35 of the gas ejection part A provided on the face plate 33a are formed so as to be able to uniformly heat the substrate 17 in the surface direction, the surface temperature of the substrate 17 can be uniformly heated with high accuracy.
[0061]
In the embodiment of the present invention, the gas outlet 35 is circular. Further, as a central condition of the experiment, the diameter B was set to 3 mm, and the distance H between the face plate 33a and the substrate 17 was set to 30 mm. The temperature increase rate of the substrate 17 was measured by changing the interval H in the range of 15 mm to 150 mm while keeping the diameter B constant. As a result, the rate of temperature increase was almost unchanged from 15 mm to 20 mm, but the rate of temperature increase increased once from 15 mm to 30 mm to take the maximum value, and then the rate of temperature increase decreased at intervals of 30 mm or more. did. When the interval was 60 mm, the temperature increased to a temperature increase rate of about 60% of the maximum value. A similar experiment was conducted with the diameter of the gas outlet 35 being 2 mm. However, when the interval was 40 mm or more, the temperature increase rate was drastically reduced.
[0062]
In general, it is said that the heat transfer coefficient cannot be described uniformly in the heating by the impinging jet because the heat transfer coefficient changes in a complicated manner depending on the interval H, the diameter B, the flow velocity, and the like. However, from this experiment, it was found that the substrate 17 can be heated at a high speed if the ratio H / B is kept at 20 or less when conditions such as industrially applicable flow rates are taken into account.
[0063]
Further, in this example, the experiment was performed by using a gas grid 35 having a pitch r of 35 mm and arranging the gas jets 35 in a square lattice pattern and using glass 4 mm in thickness as the substrate 17. The temperature difference between the stagnation point in front of the gas injection port 35 and the position farthest from the gas injection port 35 was measured. When heating was performed under the central conditions of the experiment, the maximum temperature difference at each point in the temperature rising process was 30 ° C. It is empirically known that the in-plane temperature difference of the glass substrate exceeds 50 ° C., so that the probability of breakage increases. In this example, it was found that there was almost no fear of breakage. However, for example, it has been found that when the bitch of the gas injection port 35 is enlarged to 60 mm or more, the glass substrate is damaged due to a temperature difference in the glass surface. Moreover, when the thickness of the glass substrate was reduced to about 2 mm or less, the heat transfer in the surface of the glass substrate was slowed, so that it could be estimated that the glass substrate was damaged.
[0064]
On the other hand, the heated gas introduced into the plate nozzle 33 from the gas inlet 34 at the upper end of the bag-shaped plate nozzle 33 changes from the upper and lower gas outlets 35 by changing the pressure between the upper and lower parts. The amount of heated gas ejected from the lower gas ejection port 35 is reduced with respect to the amount of heated gas ejected. For this reason, there is a possibility that the heating temperature of the substrate 17 may be deviated vertically. However, it has been found that in practice it is possible to cause almost no temperature deviation. That is, in order to make the gas ejection amount at the upper gas ejection port 35 and the gas ejection amount at the lower gas ejection port 35 almost the same, the pressure difference between the upstream side and the downstream side of the plate nozzle 33 should be made as small as possible. For this reason, by designing the space capacity of the plate nozzle 33 to be large, the upstream gas ejection amount and the downstream gas ejection amount can be made substantially equal, and the temperature deviation can be almost eliminated.
[0065]
On the other hand, as shown in FIG. 9, if the gas inlets 34 of the plate nozzles 33 arranged so as to sandwich the substrate 17 are formed at opposite ends, the pressure in the plate nozzles 33 will be described. Are offset in opposite directions, so that the sum of the ejection amounts of the heated gas ejected from the left and right plate nozzles 33 sandwiching the substrate 17 is even in the longitudinal direction (vertical direction in FIG. 9). Thus, the substrate can be heated at a uniform temperature.
[0066]
The substrate 17 heated to a predetermined surface temperature and a uniform surface temperature by the substrate heating device 3 as described above is carried into the load lock chamber 6 of FIG. The substrate 17 is carried into the film forming chamber 11 and a silicon film is formed. At this time, the substrate 17 is maintained at the predetermined temperature by the temperature adjusting device 10 provided in the film forming chamber 11. Accordingly, since the silicon film is formed on the substrate 17 while maintaining a uniform surface temperature, a silicon film of good quality is formed on the substrate 17.
[0067]
Therefore, according to said vacuum film-forming apparatus, a high quality solar cell material can be produced efficiently.
[0068]
The present invention is not limited only to the above-described embodiments, but can also be applied to a vacuum film forming apparatus that requires heating of a substrate, such as a sputtering apparatus other than a plasma CVD apparatus, a vapor deposition apparatus, and an ionization vapor deposition apparatus. Of course, various changes can be made without departing from the scope of the present invention, such as the shape of the nozzle can be variously changed, and the heated gas introduction device can also adopt a configuration other than the above-described embodiment. is there.
[Industrial applicability]
[0069]
Substrate heating can be performed efficiently as a pretreatment for vacuum film formation on the substrate, and a uniform surface temperature can be obtained in the middle of heating and after completion of heating. Heating can be performed at the same time, so that products such as high quality solar cell materials can be produced with high efficiency.

Claims (12)

A vacuum film forming apparatus for forming a film by introducing a substrate heated by a substrate heating apparatus into the film forming chamber, wherein the substrate heating apparatus supports the heating chamber and the surface of the substrate in a vertical direction and performs the heating. a carriage for carrying the chamber, the plate nozzles flat shape plane as required intervals disposed in the heating chamber has a been bag-shaped sides of the face plate of the substrate opposed to the substrate to be carried into the heating chamber, said A gas introduction port for introducing a heating gas between the face plates of the plate nozzle and a heating gas introduction device for introducing the heating gas to the gas introduction port. The substrate is placed on the face plate facing the substrate in the plate nozzle by a collision jet of the heating gas. A vacuum film-forming apparatus comprising a plurality of gas jets for heating.   2. The first aspect of claim 1, wherein when a representative dimension of the gas outlet is set to B, a relationship of H / B <20 is established between B and the required interval H. Vacuum deposition equipment.   2. The vacuum forming method according to claim 1, wherein the substrate is made of glass having a thickness t, and a relationship r / t <20 is established, where r is a distance between the gas ejection ports. Membrane device.   When a representative dimension of the gas outlet is set as B, a relationship of H / B <20 is established between B and the required interval H, and the substrate is glass having a thickness t. 2. The vacuum film forming apparatus according to claim 1, wherein a relationship r / t <20 is established, where r is a distance between the gas ejection ports.   2. The vacuum film forming apparatus according to claim 1, wherein a gas jet is provided in the face plates on both sides of the plate nozzle, and the substrate is disposed so as to face the face plates on both sides of the plate nozzle.   The plate nozzle arranged so as to sandwich the substrate includes a gas introduction port at a position where non-uniformity in gas ejection amount caused by a pressure gradient generated in each plate nozzle cancels each other. 2. A vacuum film forming apparatus according to item 1.   2. The vacuum film forming apparatus according to claim 1, wherein the plate nozzles are comb-tooth nozzles provided in a plurality of comb-teeth shapes so that the substrates are disposed therebetween.   2. The vacuum film formation according to claim 1, wherein the substrate is supported by a carriage and conveyed, and the heated gas ejected from the plate nozzle is guided to the heated gas introduction device through the carriage. apparatus. The substrate heating apparatus according to claim 1 is arranged in connection with the film forming chamber, and the substrate supported in the vertical direction on the carriage is carried into the substrate heating apparatus, and is attached to the face plate of the plate nozzle having the required distance from the substrate surface. A vacuum forming process is characterized in that a heating gas is ejected from a gas outlet provided, the substrate is heated by a collision jet, the substrate is heated to a uniform temperature, and then the substrate is carried into a deposition chamber for film formation. Membrane method.   10. The vacuum film forming method according to claim 9, wherein the film forming method is a plasma CVD method.   A solar cell material produced by the vacuum film-forming method according to claim 9.   The solar cell material manufactured by the vacuum film-forming method of Claim 10.

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