JP4569042B2 - Heat treatment equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a single wafer heat treatment apparatus for performing a predetermined heat treatment on a semiconductor wafer or the like.
[0002]
[Prior art]
Generally, in order to manufacture a semiconductor integrated circuit, various heat treatments such as film formation, etching, oxidative diffusion, and annealing are repeatedly performed on a semiconductor wafer. Here, an example of a conventional single wafer heat treatment apparatus for performing this kind of heat treatment will be described with reference to FIG.
In the cylindrical processing container 2 that can be evacuated, a mounting table 6 having a built-in heater 4 is provided, and a semiconductor wafer W is mounted on the upper surface of the mounting table 6. Yes. In addition, a shower head unit 8 is provided on the ceiling of the processing container 2, and when a necessary processing gas, for example, a thin film is deposited, a film forming gas is introduced into the processing container, and CVD (Chemical Vapor Deposition) is performed. Deposit a thin film.
[0003]
[Problems to be solved by the invention]
By the way, most of the processing gas introduced into the processing container 2 from the shower head unit 8 diffuses and spreads from the central part to the peripheral part in the processing space, and exhausts downward substantially uniformly from the peripheral part of the mounting table 6. It will be done. However, a part of the processing gas G1 tends to stay in a portion of the ceiling space 10 formed on the outer peripheral side of the shower head unit 8, and as a result, the flow of the processing gas at the peripheral edge of the wafer is disturbed. For example, the gas flow rate is slightly increased.
Further, since the ceiling space 10 on the outer peripheral side of the shower head portion 8 as described above is present in the form of a ceiling surface of the case which looked top from the surface of the wafer W has become uneven, the As a result, a large temperature difference occurred in the wafer surface, and the in-plane uniformity of the wafer temperature was lowered.
[0004]
For this reason, the in-plane uniformity of the film thickness of the deposited film formed on the wafer surface is deteriorated, and the film thickness at the wafer peripheral part is larger than the wafer central part, for example, as shown in FIG. There was a problem.
In such a case, conventionally, as shown in FIG. 7, the temperature of the central portion of the wafer is such that the heater 4 is concentrically divided into zones and the temperature can be individually controlled for each zone. In this way, the temperature at the periphery of the wafer is controlled to be intentionally lower, which slightly suppresses the film formation rate at the periphery of the wafer, resulting in in-plane uniformity of the film thickness on the wafer surface. Techniques to improve the quality have also been proposed.
[0005]
However, in this case, for example, when the film forming process temperature is about 480 ° C., for example, the temperature difference Δt between the wafer center and the wafer periphery reaches about 20 to 30 ° C. As described above, when the design rule of the semiconductor manufacturing technology is not so strict, it did not become a big problem. However, in recent years when the design rule becomes more strict due to further miniaturization and thinning, as described above. When a temperature difference of 20 to 30 ° C. occurs, the film quality is affected, and desired electrical characteristics cannot be obtained.
The present invention has been devised to pay attention to the above problems and to effectively solve them. An object of the present invention is to provide a heat treatment apparatus that can improve the uniformity of the in-plane temperature of an object to be processed and can eliminate the retention of a processing gas.
[0006]
[Means for Solving the Problems]
According to the first aspect of the present invention, a predetermined amount is applied to an object to be processed that is installed on a mounting table while supplying a processing gas from a shower head provided on a ceiling lid that is provided so as to be deployable on a ceiling of the processing container. In the heat treatment apparatus for performing heat treatment, on the outer peripheral side of the shower head unit, the lower surface is set at the same horizontal level as the lower surface of the shower head unit in order to improve the shape of the unevenness of the ceiling surface with respect to the mounting table. The shape improving member that maintains the space on the outer peripheral side of the shower head portion as a space is provided between the side wall of the shower head portion and the side wall of the processing vessel except for a gap necessary for the deployment of the ceiling lid. it is obtained by configuration so that provided over the entire region.
As described above, by providing the shape improving member on the outer peripheral side of the shower head unit, the shape of the unevenness of the ceiling surface with respect to the mounting table in the processing container is made uniform , and it is unnecessary to cause turbulence of the processing gas. As a result, the in-plane uniformity of the temperature distribution of the object to be processed can be greatly improved. As a result, the in-plane uniformity of the heat treatment, for example, the in-plane uniformity of the film thickness in the case of a film forming process can be improved. It becomes possible to greatly improve.
[0007]
In this case, for example, as prescribed in claim 2, wherein the form improvements member is formed of a material substantially the same material constituting the shower head.
[0008]
Further, for example, as prescribed in請Motomeko 3, before Symbol form improvements member is formed of a circular-ring of rings whose inside was made hollow.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a heat treatment apparatus according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view showing a heat treatment apparatus according to the present invention, FIG. 2 is a bottom view showing a ceiling surface in a processing container, and FIG. 3 is a schematic diagram showing a flow of processing gas in the processing container. Here, a case where CVD film formation is performed as a heat treatment apparatus will be described as an example. As shown in the figure, the heat treatment apparatus 20 has a processing container 22 formed into a cylindrical shape with aluminum, for example.
Further, an exhaust port 24 connected to a vacuum pump (not shown) is provided at the bottom of the processing container 22 so that the processing container 22 can be evacuated as necessary. And in this processing container 22, in order to mount the semiconductor wafer W as a to-be-processed object, the mounting base 28 raised from the bottom part via the support | pillar 26 is provided. The mounting table 28 is entirely made of a dielectric, for example, ceramics such as AlN, and a heater 30 made of a resistor such as molybdenum wire is arranged and embedded in a predetermined pattern. A heater power source 32 is connected to the heater 30 via a wiring 34, and power is supplied to the heater 30 as necessary. Note that a heating lamp may be used in place of the heater 30.
[0010]
The mounting table 28 is formed with a plurality of pin holes 40 penetrating in the vertical direction, and each pin hole 40 has a lower end commonly connected to the connection ring 42, for example, a quartz push-up. The pin 44 is accommodated in a loosely fitted state. The connecting ring 42 is connected to the upper end of a retracting rod 46 that is provided so as to be vertically movable through the bottom of the container. The lower end of the retracting rod 46 is connected to an air cylinder 48. As a result, the push-up pins 44 are projected and retracted upward from the upper ends of the pin holes 40 when the wafer W is transferred. In addition, a bellows 50 that can be expanded and contracted is interposed in a penetrating portion of the retractable rod 46 with respect to the container bottom so that the retractable rod 46 can be moved up and down while maintaining the airtightness in the processing container 22. It has become.
[0011]
A loading / unloading port 52 for loading / unloading a wafer is formed on the side wall of the processing container 22, and a gate valve 54 is provided on the loading / unloading port 52 so as to be opened and closed. The gate valve 54 is connected to a load lock chamber, a transfer chamber, etc. (not shown).
A ceiling lid 58, which is partly supported by a hinge 56 and can be opened and closed, is airtightly provided through a sealing member 60 such as an O-ring at the upper end opening of the processing container 22. The ceiling lid 58 is provided with a shower head portion 64 having a large number of gas ejection holes 62 on the lower surface, thereby introducing, for example, a film forming gas as a processing gas into the processing space S in the processing vessel 22. It can be done. Note that a diffusion plate may be provided in the shower head portion 64.
[0012]
The shower head portion 64 is formed in a hollow disk shape as shown in the drawing, and the whole is formed of, for example, aluminum. A plate thickness ΔL of a partition wall that partitions the shower head portion 64 is set to about 3 to 4 mm, for example.
A form improving member 66 is provided on the outer peripheral side of the shower head portion 64 to improve the unevenness of the ceiling surface with respect to the mounting table 28 described above. Specifically, the shape condition improvement member 66, in order to improve the unevenness in the form of a ceiling surface, for example a material substantially the same material constituting the shower head portion 64, for example, here made of aluminum, The inside is hollow, and is constituted by a ring-shaped circular ring body 68 having a rectangular cross section .
[0013]
Furthermore , in order to improve the shape of the unevenness of the ceiling surface, the lower surface of the shower head portion 64 and the lower surface of the bottom wall 68C of the circular ring body 68 of the shape improving member 66 are set at substantially the same horizontal level. cage, concave convex is not to occur to the ceiling surface to the surface side of the mounting table 6.
Such forms improvements member 66, the unevenness in the form of a ceiling surface of the ring-shaped space formed between the upper side wall 22A of the side wall 64A and the processing vessel 22 of the shower head portion 64 in order to improve It is provided in almost the entire area. In the illustrated example, the side wall 64 </ b> A of the shower head portion 64 and the inner peripheral wall 68 </ b> A of the circular ring body 68 of the shape improving member 66 are provided in a joined state, and the outer peripheral wall 68 </ b> B of the circular ring body 68 is between the side walls 22A of the treatment Barber unit 22, a short distance [Delta] L2, for example, only about 1mm are spaced is gap formed, ceiling lid 58 the shower head 6 4 and form an improved member 68 is attached and when to open and close by deploying the hinge 56 as a fulcrum, deployment trajectory of the distal end side of this form improvements member 6 6 farthest from the hinge 56 is prevented from colliding with the side wall 22A of the processing container 22 .
Here, an example of the dimensions of each part will be described. In an example of an apparatus for processing a wafer having a diameter of 30 cm, the inner diameter D1 of the circular ring body 68 is about 294 to 349 mm, depending on the size of the shower head part 64. The outer diameter D2 is about 429 mm, and the height H1 is about 39 to 44 mm.
[0014]
Next, the operation of the present embodiment configured as described above will be described.
First, the gate valve 54 provided on the side wall of the processing container 22 is opened, and an unprocessed semiconductor wafer W is loaded into the processing container 22 from a load lock chamber or the like (not shown) through the loading / unloading port 52 and pushed up. The wafer W is placed on the mounting table 28 by being transferred to the pins 44 and lowered.
Next, the inside of the processing vessel 22 is hermetically sealed, and the electric power supplied to the heater 30 is increased to raise the temperature of the mounting table 28 that has been preheated to the process temperature and maintain it. At the same time, a film forming gas whose flow rate is controlled as a processing gas is supplied from the shower head unit 64 to the processing space S in the processing container 22, and at the same time, the processing container 22 is evacuated from the exhaust port 24 to evacuate the processing container 22. The inside is maintained at a predetermined process pressure, and a film forming process is performed. As the film forming gas, for example, when depositing a thin film of Ta ₂ O ₅ film, for example, PET (pentaethoxy tantalum) and oxygen (O ₂ ) are used.
[0015]
The film forming gas discharged from the gas ejection holes 62 of the shower head portion 64 into the processing space S diffuses from the center side of the mounting table 28 toward the peripheral side while flowing down the processing space S, and Then, the outer peripheral side of the mounting table 28 flows down at a substantially uniform flow rate and is discharged from the exhaust port 24 to the outside of the container.
Here, in the conventional apparatus, since the dead space-like ceiling space 10 exists on the side portion of the shower head portion (see FIG. 5), the form of the ceiling surface when viewed from above the wafer surface is the ceiling space. However, in this embodiment, since the shape improving member 66 is provided on the outer peripheral side of the shower head portion 64, the surface of the wafer is not uniform. Since the shape of the ceiling surface when viewed from above is almost free of irregularities , the uniformity can be greatly improved. As a result, the thermal condition related to the radiant heat on the container ceiling side on the wafer surface becomes substantially uniform in the wafer surface, and the in-plane uniformity of the wafer temperature can be improved.
[0016]
Further, as a result of providing the shape improving member 66 as described above, the dead space existing in the case of the conventional apparatus is eliminated on the outer peripheral side of the shower head portion 64 in the case of the present embodiment. In this case, the film formation gas does not stay due to vortex or the like, and flows down while being smoothly diffused from the center toward the periphery in the film formation gas processing space S. As a result, the gas flow rate in the processing space S is substantially uniform in the plane of the wafer. As a result, the wafer does not have a temperature distribution as shown in FIG. The in-plane uniformity of this heat treatment (film formation process) can be improved while being held, and in the case of this embodiment, the in-plane uniformity of the film thickness can be greatly improved.
Particularly, in the case of the embodiment, since the setting and the lower surface of the lower surface and form an improved member 66 of the shower head 64 to be substantially the same horizontal level, the ceiling surface against the wafer surface than this point The shape of the unevenness can be made uniform .
[0017]
Furthermore, since the constituent materials of the shower head portion 64 and the shape improving member 66 are set to be the same so that the thermal conditions such as radiation are the same, the ceiling surface relative to the wafer surface is more than this point. it can be further equalized in the form of concave convex.
Still further, such as by forming the inner portion forms an improved member 66 hollow, since the structure similar to the shower head portion 64 having a diffusion chamber therein, the thermal conditions of the container ceiling to the wafer surface Thus, the wafer surface becomes substantially uniform, and the in-plane uniformity of the wafer temperature can be further improved.
In addition, as described above, as a result of the provision of the shape improving member 66 , the capacity of the processing space S can be reduced accordingly. For example, when an ALD (Atomic Layer Deposition) method of depositing a metal film one atomic layer at a time is performed. Since gas replacement can be performed quickly, the throughput can be improved accordingly.
[0018]
When the temperature distribution on the wafer surface of the conventional apparatus and the apparatus of the present invention is actually compared, the maximum temperature is 441.6 ° C. and the minimum temperature is 439.2 ° C., and the difference is 2.4. In the case of the apparatus of the present invention, the maximum temperature is 440.2 ° C., the minimum temperature is 438.7 ° C., and the difference is 1.5 ° C. In the case of the apparatus of the present invention, the wafer temperature is in the plane. It has been found that the uniformity can be greatly improved. At this time, the wafer set temperature is 485 ° C. and the process pressure is 40 Pa (0.3 Torr).
Further, as a result of simulating the flow of the processing gas of the conventional apparatus and the apparatus of the present invention, as shown in FIG. 3A, in the case of the conventional apparatus, the ceiling space 10 on the outer peripheral side of the shower head 8 is spirally formed. In the case of the apparatus of the present invention, since the stagnant processing gas was seen, since the shape improving member 66 was provided on the outer peripheral side of the shower head portion 64 as shown in FIG. 3B, the dead space was eliminated. It has been found that the gas flows smoothly without staying in the ceiling space 10 .
[0019]
In the above embodiment, the shape improving member 66 is a circular ring body 68 having a hollow inside. However, the present invention is not limited to this, and as shown in FIG. 4, for example, a circular ring plate 70 is used as the shape improving member 66. The circular ring plate 70 may be integrally connected and fixed to the outer peripheral surface of the side wall 64A of the shower head portion 64, and the lower surface of the circular ring plate 70 may be set to be substantially the same horizontal level as the lower surface of the shower head portion 64. . According to this, even if there is a ceiling space 10 that is a dead space on the outer peripheral side of the shower head portion 64, the ceiling space 10 is substantially separated from the processing space S side, so that the processing gas flows into this space portion. Intrusion hardly occurs, and the shape of the unevenness of the ceiling surface with respect to the wafer surface can be improved.
[0020]
In the above embodiment, the shape improving member 66 is made of aluminum. However, the present invention is not limited to this, and any material may be used as long as it is a material with little metal contamination. For example, stainless steel or ceramic can be used.
In the above embodiment, the CVD processing apparatus is described as an example of the heat treatment apparatus. However, the present invention is not limited to this, and the present invention can of course be applied to a plasma processing apparatus, an etching apparatus, an oxidation diffusion apparatus, a reforming apparatus, and the like. It is.
In this embodiment, the semiconductor wafer is described as an example of the object to be processed. However, the present invention is not limited to this, and the present invention can be applied to the case of processing an LCD substrate, a glass substrate, or the like.
[0021]
【The invention's effect】
As described above, according to the heat treatment apparatus of the present invention, the following excellent effects can be achieved.
According to the present invention, by providing the shape improving member on the outer peripheral side of the shower head part, the shape of the unevenness of the ceiling surface with respect to the mounting table in the processing container is made uniform, and the process gas is disturbed. Unnecessary space is eliminated, and as a result, the in-plane uniformity of the temperature distribution of the object to be processed can be greatly improved. In-plane uniformity of heat treatment, for example, in-plane uniformity of film thickness in the case of film formation Can greatly improve the performance.
[Brief description of the drawings]
FIG. 1 is a cross-sectional configuration diagram showing a heat treatment apparatus according to the present invention.
FIG. 2 is a bottom view showing a ceiling surface in a processing container.
FIG. 3 is a schematic diagram showing a flow of a processing gas in a processing container.
FIG. 4 is a view showing a modification of the heat treatment apparatus of the present invention.
FIG. 5 is a configuration diagram showing an example of a conventional single-wafer type heat treatment apparatus that performs heat treatment.
FIG. 6 is a diagram showing an in-plane distribution of the film thickness of a deposited film.
FIG. 7 is a diagram illustrating an example of an in-plane temperature distribution of a semiconductor wafer.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 20 Heat processing apparatus 22 Processing container 22A Side wall 28 Mounting stand 58 Ceiling cover 64 Shower head part 64A Side wall 66 Shape improvement member 68 Circular ring body 70 Circular ring board W Semiconductor wafer (to-be-processed object)

Claims (3)

In the heat treatment apparatus for performing a predetermined heat treatment on object to be treated placed the process gas from the setting digit shower head on a mounting table while supplying the ceiling lid arranged to be deployed in a ceiling portion of the processing chamber,
In order to improve the unevenness of the ceiling surface with respect to the mounting table on the outer peripheral side of the shower head unit, the lower surface is set at the same horizontal level as the lower surface of the shower head unit, and the outer periphery of the shower head unit so that provided the form improvements member to maintain the area of the side as a space, over the entire region between the side wall and the sidewall of the processing chamber of the shower head with the exception of the clearance required for deployment of the ceiling cover The heat processing apparatus characterized by comprising. The form improvements member, a heat treatment apparatus according to claim 1, characterized in that it is formed of a material substantially the same material constituting the sheet Yawaheddo unit. The heat treatment apparatus according to claim 1 or 2 , wherein the shape improving member is formed of a ring-shaped circular ring body having a hollow inside.

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