JP4655395B2 - Heat treatment apparatus and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat treatment apparatus and method for performing heat treatment on a substrate such as a semiconductor wafer.
[0002]
[Prior art]
As one of the semiconductor device manufacturing processes, a semiconductor wafer (hereinafter referred to as a wafer) is subjected to a film forming process by, for example, chemical vapor deposition (CVD), and an annealing process is performed to improve the film quality of the thin film formed by the film forming process. May do. As an example of such a process, there is a process of forming a tantalum oxide (Ta2O5) film and supplying oxygen radicals to the film to improve the film quality.
[0003]
The apparatus of FIG. 7 will be described. In FIG. 7, reference numeral 11 denotes a processing container. Inside the processing container 11 is a mounting table 12 on which a wafer W as a substrate to be processed is mounted, and a film is formed from above the mounting table 12. A shower head 13 for supplying gas is provided, and a lower opening of the mounting table 12 is airtightly closed by a transmission window 14 made of, for example, quartz. A heating lamp 15 for heating the wafer W from the back side is provided below the processing container 11. Active species generating means 16 is provided in the vicinity of the processing vessel 11. In the annealing process, for example, the wafer W is heated by the heating lamp 15 and the source gas is activated by the active species generating means 16 to generate oxygen. This is performed by generating radicals and supplying an activated gas containing oxygen radicals from the side to the surface of the wafer W through a gas supply port 17 opening in the side wall of the processing vessel 11. In such a process, oxygen radicals enter the thin film on the surface of the wafer W to become oxygen ions, and tantalum and oxygen ions form a chemically stable structure in the film. As a result, the film quality is improved.
[0004]
[Problems to be solved by the invention]
However, when an activated gas containing oxygen radicals is supplied from the side wall of the processing vessel 11 toward the surface of the wafer W, the gas advances forward while diffusing left and right as it moves away from the supply port 17, as shown in FIG. When the gas supply port 17 is blown out, the central portion has a higher flow velocity. Therefore, when the gas flow is modeled and considered, it spreads as shown by an arc-shaped dotted line in FIG. The arc-shaped dotted line shown in FIG. 8 shows that the gas blown out at a certain point of time is diffused, and the concentration of active species is higher on the near side when viewed from the gas supply port 17 and becomes lower as the distance from this is increased. Therefore, when looking directly from a certain point on the center line, the concentration in the left and right regions is lower than the concentration of the active species at that point, so that the in-plane uniformity of the reforming process becomes lower corresponding to this concentration distribution. There's a problem.
[0005]
If the wafer W is rotated here, the uniformity of the concentration distribution of the active species can be improved. However, since the heating lamp 14 is disposed on the lower side of the processing vessel 11, a complicated rotation mechanism is provided. There is a need.
[0006]
On the other hand, it is conceivable to supply active species from the shower head 13, but the shower head is formed inside a plurality of diffusion plates for uniformly diffusing the film forming gas. The flow path has a long distance, and if the active species are flowed, the service life is exhausted in the middle of the flow path, and the concentration of the active species supplied into the processing container 11 is likely to be lower than a predetermined value, which is not practical.
[0007]
The present invention has been made based on such circumstances, and the purpose thereof is to perform highly uniform processing when processing the substrate by introducing the active species generated outside the processing container into the processing container. It is to provide technology that can be used.
[0008]
[Means for Solving the Problems]
A heat treatment apparatus according to the present invention includes a processing container provided with a substrate mounting table, and a heating unit for heating the substrate mounted on the mounting table, and the substrates are placed one by one in the processing container. In a heat treatment apparatus that carries in and processes the substrate with active species while heating the substrate,
An active species generating means provided in the vicinity of the processing vessel for activating a source gas to generate active species;
A gas supply port for supplying the active species from the side toward the surface of the substrate;
Wind direction adjusting means for swinging the direction in which the active species flows from the gas supply port to the left and right when viewing the substrate from the gas supply port,
A film forming gas supply unit that is provided so as to face the surface of the substrate placed on the mounting table and includes a large number of holes, and supplies a film forming gas to the substrate through these holes,
A control unit that controls the apparatus to supply a deposition gas to the substrate from the deposition gas supply unit to form a thin film, and then supply active species to the substrate from the gas supply port to perform processing on the thin film. And .
[0009]
According to such a configuration, a heat treatment with high in-plane uniformity can be performed, and further, active species can be supplied uniformly toward the substrate surface. For this reason, there is an effect that unevenness of the processing hardly occurs in the annealing process.
[0010]
Since a highly uniform process can be performed without rotating the substrate, it is effective when the apparatus is shared by the film forming process and the above-described annealing process performed after the film forming .
[0011]
The thin film formed in such a configuration is, for example, a metal oxide film such as tantalum oxide. For example, by using oxygen radicals as active species, oxygen radicals enter and stabilize the thin film, and as a result, the film quality is improved. .
[0012]
Further, a heat treatment apparatus according to another invention is a heat treatment apparatus for heating a substrate disposed in a processing vessel and processing the substrate with a processing gas.
A gas supply port for supplying a processing gas from the side toward the surface of the substrate;
A first gas passage is provided on the left side of the gas supply port, and blows the carrier gas toward the front right side of the gas supply port to bring the direction of the flow of the processing gas flowing into the processing container from the gas supply port to the right side. Gas injection means,
A second gas passage is provided on the right side of the gas supply port, and blows the carrier gas toward the front left side of the gas supply port to move the flow direction of the processing gas flowing into the processing container from the gas supply port toward the left side. Gas injection means,
And an adjusting unit for adjusting the gas injection flow rates of the first gas injection unit and the second gas injection unit to change the flow direction of the processing gas to the left and right.
[0013]
According to such a configuration, by using the first and second gas injection means, the direction of the processing gas supplied from the side with respect to the substrate is set in the left-right direction as viewed from the processing gas supply side. Since it can be shaken, processing unevenness hardly occurs for each portion of the substrate surface, and heat treatment with high in-plane uniformity can be performed .
[0014]
Moreover, the heat treatment method according to the present invention includes a step of carrying a substrate into a processing container,
Next, a process of forming a thin film by supplying a deposition gas to the substrate from a number of gas supply holes provided to face the surface of the substrate;
Thereafter, the active species are supplied toward the surface of the substrate while changing the inflow direction from the side to the left and right, and the thin film is processed.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a heat treatment apparatus according to the present invention will be described below with reference to FIGS. Reference numeral 21 denotes a processing vessel made of, for example, aluminum, and a carbon wafer mounting table 22 made of, for example, SiC coated in a slightly larger disk shape than the wafer W that is a substrate to be processed is provided in the processing vessel 21. ing. Further, a gate valve 23 for carrying the wafer W into the processing container 21 is provided on one side wall of the processing container 21, and an opening 24 that is a gas supply port is formed on the other side. A gas supply path 31 that communicates with the active species generating means 3 is connected in an airtight manner.
[0016]
The active species generating means 3 generates active species such as oxygen radicals supplied toward the surface of the wafer W in order to improve the film quality of a thin film formed on the surface of the wafer W in a film forming process to be described later. A high frequency voltage is applied to the source gas to activate the gas. The active species generating means 3 is provided at a position close to the side of the processing vessel 21 in consideration of the short life of the active species, and the opening 24 is close to the surface of the wafer W and faces the wafer W, for example, It is formed on the side wall of the processing vessel 21 at substantially the same level as the surface of the wafer W. On the other hand, a raw material gas for generating oxygen radicals, for example, a mixed gas of nitrogen and oxygen in the active species generating means 3 is configured to be supplied from a raw material gas supply source 33 through a supply path 32 and a valve V0.
[0017]
A pair of gas injection means 4a, which are wind direction adjusting means, are provided on the side wall of the processing container 21 to swing the direction in which the active species flows into the processing container 21 through the gas supply path 31 and the opening 24 from side to side. 4b (not shown in FIG. 1).
[0018]
Here, assuming that the center line of the gas supply path 31 that connects the center of the active species generating means 3 and the center of the wafer W with a straight line is L1, the gas injection means 4a and 4b have openings as shown in the plan view of FIG. 24 are provided on the left and right sides so as to be symmetrical with respect to the center line L1. The direction in which the discharge holes 41 at the tips of the gas injection means 4a and 4b face is the front of the direction facing the wafer W from the opening 24, and the gas injection port 4a provided in the right hand is the gas injection provided in the left front. Each of the ports 4b is positioned so as to face right front, and a propulsive force by a carrier gas, which will be described later, can be given to the active species from an obliquely rear side.
[0019]
On the other hand, the base end side of the gas injection means 4a is supplied through a valve V1, and the base end side of the gas injection means 4b is supplied through a valve V2 to supply a carrier gas made of an inert gas such as nitrogen gas, respectively. Are connected to a carrier gas supply source 42. The valves V1 and V2 are provided to adjust the discharge flow rate of the carrier gas, and the controller 43 is configured to adjust the opening degrees of the valves V1 and V2. Since the opening degree adjustment in the control unit 43 can be performed separately for the valve V1 and the valve V2, the direction in which the active species flows from the opening 24 can be viewed from the opening 24 by changing the balance. You can swing left and right.
[0020]
Further, around the wafer mounting table 22, as shown in the figure, for example, exhaust ports 101 and 102 are provided in front of the opening 24, and exhaust ports 103 and 104 are provided on the back side. Connected with pump. These exhaust ports 101 to 104 are configured so that, for example, the control unit 43 controls an opening / closing means (not shown) so that the location where the exhaust is performed can be switched. By switching the open / close locations in the modification process (annealing process), a gas flow suitable for each process can be formed in the process vessel 21.
[0021]
Here, returning to FIG. 1 again, the description will be continued. A shower head 51, which is a film forming gas supply unit, is provided on the ceiling of the processing vessel 21 so as to face the wafer mounting table 22. A number of holes 52 facing downward are formed on the bottom surface 51 so that the film forming gas can be supplied to the entire surface of the wafer W. Inside the shower head 51, a plurality of diffusion plates 54 having a large number of holes 53 are provided. Although a plurality of diffusion plates 54 are actually provided as described above, only one diffusion plate 54 is shown here for convenience of drawing. A film forming gas supply source 56 is connected to the upper end of the shower head 51 via a gas supply pipe 55 and a valve V3. For example, a liquid source of Ta (OC 2 H 5) 5 is stored as a film forming component of a tantalum oxide (Ta 2 O 5) film in the film forming gas supply source 56, and this liquid source is vaporized using a carrier gas during the film forming process. The steam is configured to be sent to the shower head 51 as a film forming gas together with a carrier gas supplied from a carrier gas supply source (not shown).
[0022]
A wafer lift 25 is provided around the wafer mounting table 22, and the wafer lift 25 is configured to be movable up and down so that the wafer W can be transferred to and from a transfer arm (not shown) that loads and unloads the wafer W. Yes. Further, a gas rectifying plate 26 having a hole so that an inert gas can flow therethrough is provided on the lower side of the wafer mounting table 22, and further on the lower side thereof, a permeation for closing the lower opening of the processing vessel 21. A window 27 is provided in an airtight manner.
[0023]
On the other hand, a heating unit 6 is provided below the transmission window 27, and the heating unit 6 includes a reflector 61 having a plurality of mortar-shaped recesses 60 and, for example, concentric circles so as to fit in the recesses 60. A plurality of heating lamps 62 made of, for example, halogen lamps or arc lamps, and a rotary table 63 for rotating the reflecting plate 61 around the vertical axis from the back surface side in order to raise the temperature of the wafer W evenly over the entire surface. It consists of
[0024]
Next, the operation in the above embodiment will be described. First, when the gate valve 23 is opened, a transfer arm (not shown) enters the processing container 21 and the wafer W is transferred from the transfer arm to the wafer lift 25. Thereafter, the wafer lift 25 is lowered to place the wafer W on the center of the wafer mounting table 22, and the surface temperature of the wafer W is raised to a predetermined process temperature, for example, 480 ° C. by the heating lamp 62. Then, the valve V3 is opened, and when the film forming gas is supplied from the shower head 51 toward the surface of the wafer W, the inside of the processing vessel 21 is maintained at a predetermined degree of vacuum by a vacuum pump (not shown) through the exhaust ports 101 to 104. As a result, the film forming gas is decomposed by receiving thermal energy on the wafer W, and a thin film of, for example, tantalum oxide (Ta2O5) is formed on the entire surface of the wafer W by chemical vapor reaction. Then, the supply of the film forming gas is stopped, and the heating by the heating unit 6 is stopped to lower the temperature of the wafer W to the annealing process temperature of the next step.
[0025]
Next, an annealing process for improving the film quality of the tantalum oxide film formed on the surface of the wafer W will be described. First, an inert gas is supplied from the shower head 51 to make the inside of the processing vessel 21 an inert gas atmosphere, and the two exhaust ports 101 and 102 are closed and evacuated through the remaining two exhaust ports 103 and 104. Maintain a predetermined degree of vacuum. On the other hand, the wafer W is maintained at a predetermined process temperature, for example, 580 ° C. by the heating lamp 62, and in this state, for example, a raw material gas mixed with nitrogen and oxygen is supplied to the active species generating means 3 to generate oxygen radicals as active species. The activated gas (plasma) containing is supplied into the processing container 21 through the opening 24. This gas goes to the surface of the wafer W, and oxygen radicals enter the thin film on the surface of the wafer W to become oxygen ions, and tantalum and oxygen ions form a chemically stable structure in the film. In the processing vessel 21, gas control of the gas injection means 4a and 4b is performed by the control unit 43, whereby the gas flow is supplied by changing its direction from left to right. Here, the relationship between the direction of the gas flow and the action of the gas injection means 4a and 4b will be described with reference to FIG. The object here is to distribute the gas flow straight from the active species generating means 3 along the gas supply path 31 in the left-right direction when facing the wafer W from the opening 24, and oxygen radicals are transferred to the wafer W. It is to be evenly distributed over the entire surface. In the present embodiment, the horizontal distribution is realized by changing the balance of the carrier gas discharge flow rates of the gas injection means 4a and the gas injection means 4b.
[0026]
That is, first, the control unit 43 closes the valve V1 related to the gas injection unit 4a and fully opens the valve V2 related to the gas injection unit 4b. As a result, when the gas flow advances forward from the front end of the gas injection means 4b, it receives the carrier gas injection pressure from the diagonally left rear, and the course of the gas flows in the right direction as shown by the solid line in FIG. Will change.
[0027]
The valve V1 is gradually opened to increase the discharge flow rate of the gas injection means 4a, and the valve V2 is closed to decrease the discharge flow rate of the gas injection means 4b. The direction of the gas flow is as shown in FIG. The wafer W is gradually shaken from the right side to the left side of the wafer W indicated by the dotted line. An arrow indicated by a solid line in FIG. 3B indicates a traveling direction of the gas flow when the discharge flow rate of the gas injection unit 4a is slightly higher than the discharge flow rate of the gas injection unit 4b, for example. FIG. 3C shows a state in which the valve V2 related to the gas injection means 4b is closed and the valve V1 related to the gas injection means 4 (a) is fully opened. Thus, the direction of the gas flow is the wafer. When reaching the left end of W, the direction of the gas flow is reversed from FIG. 3 (c) to FIG. 3 (b) and FIG. 3 (a) in order, and a series of operations are repeated.
[0028]
By the way, since the gas flow is diffused as shown in FIG. 8 described above, the oxygen radical concentration is further away from the line connecting the center of the wafer W and the opening 24 when the gas flow is directed toward the center of the wafer W. However, when the gas flow direction is swung to the right, the oxygen radical concentration in the right region of the wafer W is large, the oxygen radical concentration in the central region of the wafer W is small, and the gas flow direction is swung to the left. Sometimes, the oxygen radical concentration in the left region of the wafer W is large and the oxygen radical concentration in the central region of the wafer W is small, so that the oxygen radical concentration is eventually leveled and the wafer W is reformed with high in-plane uniformity. It can be performed.
[0029]
Thus, according to the present embodiment, in-plane uniformity is improved in the annealing process for improving the film quality performed on the wafer after film formation. Since the pair of gas injection means 4a and 4b is used to distribute the active species to each part of the wafer W, the film forming process and the annealing process for modifying the thin film are performed by a common apparatus. In addition, the above-described effect can be improved without using the rotation mechanism of the wafer W, and there is no possibility that the lifetime of the active species will be exhausted during the movement in the annealing process. Further, since the traveling direction of the active species is changed by the gas jet power, there is an advantage that the movable parts in the processing container can be reduced.
[0030]
The gas injection means 4a, 4b in the above-described embodiment is configured to be able to rotate in the left-right direction, and by changing the direction of gas injection in addition to the ratio of the gas discharge flow rates in both gas injection means 4a, 4b, The traveling direction of the gas flow may be finely adjusted.
[0031]
Further, the wind direction adjusting means in the present embodiment is not limited to the gas injection means, and other means that achieve the same effect can be used. For example, in the embodiment shown in FIG. 4, a wind direction adjusting plate 71 is provided in the vicinity of the tip of the gas supply path 31 instead of the gas injection means 4 a and 4 b described above as the wind direction adjusting means. As shown in FIG. 5, for example, the wind direction adjusting means includes a wind direction adjusting plate 71 having a streamlined cross section, a shaft portion 72 that airtightly penetrates the gas supply passage 31 in the vertical direction, and supports the wind direction adjusting plate 71. For example, an operating portion 73 provided outside the gas supply path 31 at the upper end of the shaft portion 72 is provided. The operated portion 73 is rotated around the vertical axis by a magnetic force from an operating portion (not shown), for example. To do. When supplying the active species to the wafer W, the direction of the tip of the wind direction adjusting plate 71 is gradually changed as shown in FIG. The oxygen radicals are spread throughout the wafer W with high uniformity. The position of the wind direction adjusting plate 71 can be set to an arbitrary position as long as the direction of the gas flow can be swung left and right.
[0032]
Furthermore, the embodiment shown in FIG. 6 can achieve the same effects as those of the above-described two embodiments. In the present embodiment, the shape of the tip 81 of the gas supply path 31 is a trumpet shape that extends from the active species generating means 3 side to the processing container 21 side, and the rear end and the active species generating means 3 can be bent freely. In addition, the active species generating means 3 is provided with a moving means 83 including a drive unit and a rail, and the active species generating means 3 itself slides in the left-right direction of the wafer W. It is comprised as follows.
[0033]
That is, in the present embodiment, the active species generating means 3 itself is moved to determine the advancing direction of the active species, and the bellows 82 is moved along with the movement of the active species generating means 3 in the gas supply path 31. Since the tip 81 is bent and stretched and the tip 81 has a shape in which the tip spreads in accordance with the moving angle of the active species generating means 3, the gas flow may strike the left and right ends of the opening 24 and change its direction. There are few, and it goes straight toward the left-right direction of the wafer W surface according to the position of the active species generating means 3. Therefore, also in the present embodiment, the gas flow can be distributed to the right and left as in the above-described embodiment, and a reforming process with high in-plane uniformity can be performed. .
[0034]
The three embodiments described so far may be used in combination. For example, in the embodiment shown in FIG. 4, the tip of the gas supply path 31 is like the tip 81 shown in FIG. If the position of the plate-like body 7 is arranged behind the opening 24, for example, the amount of active species that hit the inner wall of the processing vessel 21 near the opening 24 can be reduced. The accuracy of directing the active species to the intended site can be increased.
[0035]
In addition, each wind direction adjusting means used in the above-described embodiment is not used only in the annealing process using oxygen radicals, but may be used, for example, when supplying a processing gas for CVD or etching.
[0036]
【The invention's effect】
As described above, according to the heat treatment apparatus and method according to the present invention, heat treatment with high in-plane uniformity can be performed on the substrate. In particular, the reforming process for the thin film after the film forming process is effective in preventing the occurrence of process unevenness.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of a heat treatment apparatus according to the present invention.
FIG. 2 is a plan view showing an embodiment of a heat treatment apparatus according to the present invention.
FIG. 3 is an operation explanatory diagram for explaining the operation of the present embodiment;
FIG. 4 is a schematic plan view showing another embodiment of the heat treatment apparatus according to the present invention.
FIG. 5 is a schematic perspective view for explaining a main part in the other embodiment.
FIG. 6 is a schematic perspective view showing still another embodiment of the heat treatment apparatus according to the present invention.
FIG. 7 is a schematic plan view showing a heat treatment apparatus according to a conventional invention.
FIG. 8 is an explanatory diagram for explaining a problem to be solved by the invention.
[Explanation of symbols]
W Wafer 21 Processing Container 22 Wafer Placement Base 24 Opening 3 Active Species Generation Unit 31 Gas Supply Paths 4a and 4b Gas Injection Unit 41 Discharge Hole 42 Carrier Gas Supply Source 43 Control Unit 51 Shower Head 56 Film Formation Gas Supply Source 6 Heating Unit

Claims (4)

A processing container provided with a substrate mounting table, and a heating unit for heating the substrate mounted on the mounting table, and carrying the substrates one by one into the processing container while heating the substrate In a heat treatment apparatus for processing the substrate with active species,
An active species generating means provided in the vicinity of the processing vessel for activating a source gas to generate active species;
A gas supply port for supplying the active species from the side toward the surface of the substrate;
Wind direction adjusting means for swinging the direction in which the active species flows from the gas supply port to the left and right when viewing the substrate from the gas supply port;
A film forming gas supply unit that is provided so as to face the surface of the substrate placed on the mounting table and includes a large number of holes, and supplies a film forming gas to the substrate through these holes,
A control unit that controls the apparatus to supply a film forming gas to the substrate from the film forming gas supply unit to form a thin film, and then to supply active species to the substrate from the gas supply port to perform processing on the thin film And a heat treatment apparatus comprising: 2. The heat treatment apparatus according to claim 1 , wherein the thin film is a metal oxide film, the active species is oxygen radicals, and the treatment for the thin film is a modification process of the metal oxide film. In a heat treatment apparatus for heating a substrate disposed in a processing container and processing the substrate with a processing gas,
A gas supply port for supplying a processing gas from the side toward the surface of the substrate;
A first gas passage is provided on the left side of the gas supply port, and blows the carrier gas toward the front right side of the gas supply port so that the flow direction of the processing gas flowing into the processing container from the gas supply port is shifted to the right side. Gas injection means,
A second gas gas is provided on the right side of the gas supply port, and blows the carrier gas toward the front left side of the gas supply port to move the flow direction of the processing gas flowing into the processing container from the gas supply port to the left side. Gas injection means,
A heat treatment apparatus , comprising: an adjustment unit configured to adjust a gas injection flow rate of the first gas injection unit and the second gas injection unit to change the flow direction of the processing gas to the left and right . Carrying a substrate into a processing container;
Next, a process of forming a thin film by supplying a deposition gas to the substrate from a number of gas supply holes provided to face the surface of the substrate;
Then, the active species is supplied toward the surface of the substrate while changing the inflow direction from the side to the left and right, and the thin film is processed.

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