JP6759167B2 - Plasma processing equipment - Google Patents

Description

The present invention relates to a plasma processing apparatus that performs plasma processing such as plasma etching.

In recent years, semiconductor devices have been miniaturized, and the processing dimensions have reached the region of 10 nm or less. The structure of the semiconductor device has also changed from a planar type structure to a three-dimensional structure. In response to these changes, control at the atomic level is required in the shape processing of semiconductor devices in recent years. For example, in the process of vertically etching a substrate or a material formed on a substrate, the aspect ratio, which is the ratio of the etching depth to the opening width, is large while suppressing under-etching due to the etching proceeding in the horizontal direction. The walls formed by the etching are required to be vertical and smooth on an atomic level scale.

In order to realize such microfabrication, multiple combinations (steps) of processing conditions such as gas type (gas type), flow rate, processing chamber pressure, and processing time to be used are prepared, and steps having different characteristics are periodically performed. In some cases, a method called cycle etching is used in which the formation of a protective film on the side wall to be etched and the progress of etching are independently controlled by the treatment. In cycle etching, periodic irregularities (scalloping) may be seen on the vertical wall formed by etching, but if the time for each step can be shortened, the scalloping amplitude can generally be reduced.

On the other hand, immediately after the step is switched, the desired type of gas is not introduced into the processing chamber, and there may be a transition time in which conditions such as pressure are temporarily unstable, so that the precision at the atomic level is high. When each step time is shortened in order to obtain a good shape processability, the effect may be particularly remarkable because the ratio of this transition time to the entire plasma processing is large. The issues due to this transition time will be described below.

During this transition time, the processing conditions are unstable and can be a factor that reduces the reproducibility of etching. It is also possible to use a method in which the plasma discharge is interrupted once when a certain step is completed, the gas of the next step is introduced into the treatment chamber in that state, and the plasma is discharged again after the conditions such as the pressure in the treatment chamber are set. It is possible. However, if the plasma discharge is interrupted each time the step is switched, in addition to the decrease in throughput due to the etching not being performed while the discharge is interrupted, the particles trapped in the sheath during the discharge fall onto the wafer. There is a problem that processing defects occur because the lower part of the particles is not etched.

In order to avoid such a problem, a method of switching steps while maintaining the plasma may be used. However, as described above, the transition state associated with the step switching causes a decrease in throughput due to not being etched at a desired rate, in addition to a decrease in etching reproducibility.

The problem of transition time as described above appears particularly prominently when the step time is shortened in order to obtain precise shape processability at the atomic level, because the ratio of the transition time to the entire plasma processing is large. Therefore, it is required to suppress the influence of this transition time by shortening the time until the conditions in the processing chamber are set after the step switching.

As a method for shortening the transition time associated with step switching, there is, for example, Patent Document 1 (Japanese Unexamined Patent Publication No. 2008-91651). Patent Document 1 describes a method for eliminating a delay in a mass flow controller used for introducing a gas into a processing chamber. In the introduction of gas into the processing chamber, the gas flow rate is widely controlled by the mass flow controller, but from the time when the mass flow controller is instructed to flow the gas of the desired flow rate until the actual flow rate reaches that value. Has a time lag. Due to this rise time difference, the gas flow rate introduced into the treatment chamber becomes unstable temporarily, leading to instability of the conditions in the treatment chamber. Therefore, the mass flow controller used for the next step is started up in advance to let the gas of the next step flow to the exhaust line, and at the moment when the step is switched, the gas flowing to the exhaust line is switched to flow to the processing chamber. Eliminates the rise delay of.

Japanese Unexamined Patent Publication No. 2008-91651

As described above, when performing plasma processing while switching between multiple steps, shortening the unstable transition time immediately after switching steps is a highly accurate process, especially in technologies that require atomic layer level etching. It is important for shape control.

One of the reasons why this step switching takes time is the distance of the piping from the mass flow controller to the processing chamber. If the piping is long, it takes time for the gas controlled by the mass flow controller to reach the processing chamber, so that the transition time due to step switching becomes long.

Further, when a plurality of gas types are mixed, the distance to the vacuum processing chamber may differ depending on the mixing method. In this case, the time of arrival of the gas to the vacuum processing chamber differs depending on the gas type, which is a problem that causes instability in setting the conditions in the processing chamber.

An object of the present invention is to provide a technique capable of shortening the time from step switching to stabilization of conditions in the processing chamber in plasma processing and improving the shape controllability of the material to be processed in plasma processing. ..

The aforementioned object and novel features of the present invention will become apparent from the description and accompanying drawings herein.

A brief overview of typical embodiments disclosed in the present application is as follows.

The plasma processing apparatus according to the embodiment has a processing chamber in which plasma processing is performed, a gas reservoir provided in the processing chamber and partitioned by a shower plate, and a flow rate of a plurality of processing gases introduced into the processing chamber. Each has a plurality of adjustable gas control units and a gas supply mechanism for supplying each of the plurality of processed gases from the plurality of gas control units to the processing chamber via a gas introduction path. Further, the gas introduction path includes a first pipe for gas mixing, one end of which is connected to a gas introduction port communicating with the treatment chamber, and the other of the first pipe, which is connected to the other end of the first pipe. It has a plurality of second pipes arranged radially from the connection point with the end. Further, the plurality of second pipes are provided in the same number as the plurality of gas control units, and each of the plurality of second pipes communicates with the plurality of gas control units, and the length of the first pipe is set. The first time required for the mixed gas composed of the plurality of processing gases to pass through the first pipe, and the second time required for the mixed gas to diffuse to a distance corresponding to the radius of the first pipe. Are the lengths that are equal.

Among the inventions disclosed in the present application, the effects obtained by typical ones will be briefly described as follows.

The time required from step switching to stabilization of the conditions in the processing chamber can be shortened. As a result, it is possible to suppress a decrease in throughput due to a shortened cycle etch, and it is possible to improve shape controllability in plasma processing.

It is the schematic which shows an example of the typical structure of the plasma processing apparatus which concerns on embodiment of this invention. FIG. 5 is a plan view showing an example of a structure in which the plasma processing apparatus shown in FIG. 1 is viewed from above in a gas reservoir. It is a perspective view which shows an example of the arrangement of the parts inside the gas supply unit (gas supply mechanism) in the plasma processing apparatus shown in FIG. It is a graph which shows an example of the relationship between the diameter of a gas pipe in the plasma processing apparatus shown in FIG. 1 and a gas introduction time. It is a partial side view which shows an example of the arrangement structure of a plurality of gas pipes and a valve in the plasma processing apparatus shown in FIG. It is a top view which shows the pressure distribution of the gas in the gas reservoir in the case where the installation place of the gas introduction port is one place examined by this inventor.

Hereinafter, the present embodiment will be described with reference to FIG. FIG. 1 is a schematic view showing an example of a schematic structure of a plasma processing apparatus according to an embodiment of the present invention. The plasma processing apparatus 100 shown in FIG. 1 is an example thereof, a microwave ECR (Electron Cyclotron Resonance) plasma etching apparatus. Here, electrodes installed inside the vacuum processing chamber 102, an electric field installed outside the vacuum processing chamber 102, a magnetic field supply device, a power supply, and the like are schematically shown.

Explaining the outline of the plasma processing apparatus 100 of the present embodiment shown in FIG. 1, the plasma processing apparatus 100 performs plasma etching processing on a silicon wafer (hereinafter, also simply referred to as wafer 101) which is a material to be processed. Moreover, the vacuum processing chamber (processing chamber) 102 whose upper part is open is provided. A disk-shaped shower plate 106 and a dielectric window 105 in which a plurality of pores 132 for introducing an etching gas are formed are installed in the open upper portion of the vacuum processing chamber 102. That is, the processing gas for performing plasma etching is introduced through the plurality of pores 132 provided in the shower plate 106.

Further, the inside of the vacuum processing chamber 102 is airtightly sealed by a dielectric window 105 provided above the vacuum processing chamber 102. Further, in the vacuum processing chamber 102, a lower electrode 103, which is a sample table, is installed facing the shower plate 106. Then, the wafer 101 to be plasma-etched is transferred onto the lower electrode 103 by a transfer device (not shown) such as a robot arm.

Next, the plasma processing apparatus 100 will be described in detail. The microwave oscillated from the power source for the plasma source, for example, the microwave source 119, is introduced into the vacuum processing chamber 102 via the square waveguide 121, the square circular waveguide converter 129, and the circular waveguide 130. Then, the reflected wave can be automatically suppressed by the automatic matching device 120. As the microwave source 119, for example, a magnetron having an oscillation frequency of 2.45 GHz was used.

The circular waveguide 130 is connected to the cavity resonance portion 111. The cavity resonance portion 111 has a function of adjusting the microwave electromagnetic field distribution to a distribution suitable for plasma processing.

A vacuum processing chamber 102 is provided below the cavity resonance portion 111 via a dielectric window 105 and a shower plate 106, which are microwave introduction windows. That is, a shower plate 106 is provided between the cavity resonance portion 111 and the vacuum processing chamber 102, and a gas reservoir 107 partitioned by the shower plate 106 is further provided. Then, the plasma of the reactive gas in the vacuum processing chamber 102 is generated by the microwave introduced into the vacuum processing chamber 102 and the electron cyclotron resonance (hereinafter, also referred to as ECR) by the magnetic field formed by the solenoid coils 122, 123, 124. Is formed.

The ECR is a place where electrons move while rotating along the magnetic field lines of the magnetic fields generated by the solenoid coils 122, 123, 124, and microwaves having a frequency corresponding to the rotation cycle are incident on the plasma to cause electrons. It is an effective heating method of plasma. Further, as another advantage of using the static magnetic field, the position where the ECR is generated can be controlled by changing the distribution of the static magnetic field, and the plasma generation region can be controlled. The distribution of the static magnetic field can be controlled by changing the currents flowing through the three solenoid coils. Further, it is known that the diffusion of plasma is suppressed in the direction perpendicular to the magnetic field line, and the diffusion of plasma can be controlled and the loss of plasma can be reduced. Due to these effects, the distribution of plasma can be controlled, and therefore the uniformity of plasma processing can be improved.

Further, outside the vacuum processing chamber 102, a plurality of gas control devices (gas control units) 113 capable of adjusting the flow rates of the plurality of processing gases introduced into the vacuum processing chamber 102 are provided. Specifically, the flow rate of the reactive gas (processed gas) supplied from the plurality of gas sources 114 is controlled in the gas control device 113, and the pipe (first pipe) 135 and the pipe communicate with the vacuum processing chamber 102. It is introduced into the vacuum processing chamber 102 via the (second pipe) 112 and further via the shower plate 106 installed on the surface facing the lower electrode 103 which is the sample table. Further, the gas in the vacuum processing chamber 102 is exhausted from the turbo molecular pump (hereinafter, TMP) 108, which is an exhaust device. Further, the exhaust conductance adjusting valve 109 provided in the upstream portion of the TMP 108 is feedback-controlled so that the measured value of the pressure gauge 128 becomes a desired value, and the opening degree thereof is adjusted.

Further, the plasma processing device 100 is provided with a gas supply unit (gas supply mechanism) 104 that supplies each of the plurality of processed gases from the plurality of gas control devices 113 to the vacuum processing chamber 102 via the gas introduction path. ..

The wafer 101, which is the material to be treated, can be adsorbed and held on the lower electrode 103 by electrostatic adsorption. Then, a high frequency lower than the frequency of the plasma source power supply, for example, a frequency of 400 kHz, is applied to the lower electrode 103 via the matching unit to improve the control of the processing performance and the processing speed. be able to.

Further, the vacuum processing chamber 102, the lower electrode 103, and the TMP 108 are each substantially cylindrical, and the axes of the cylinders are the same. The lower electrode 103 is supported by a beam in the vacuum processing chamber 102.

All of the above configurations are connected to a control computer, and the timing and amount of operation are controlled so that they operate in an appropriate sequence. The detailed parameters of the operation sequence are called recipes, and the operations are performed based on the preset recipes.

A recipe usually consists of multiple steps. Processing conditions such as gas type and gas flow rate are set for each step, and each step is executed in order for a preset time. Further, when switching steps, there are a method of interrupting plasma formation and a method of maintaining plasma.

Next, the gas supply system of the plasma processing apparatus 100 of the present embodiment will be described.

In the present embodiment, an example of an optimum apparatus configuration capable of replacing the processing gas in the vacuum processing chamber 102 at high speed, particularly when switching the processing gas while maintaining the plasma between steps, is shown in FIGS. 2 and FIG. 3 will be described. The description of the configuration with the same reference numerals as those shown in FIG. 1 and the parts having the same functions as described above will be omitted. FIG. 2 is a plan view showing an example of a structure in which the plasma processing apparatus shown in FIG. 1 is viewed from above in a gas reservoir, and FIG. 3 shows an example of arrangement of internal components of the gas supply unit in the plasma processing apparatus shown in FIG. It is a perspective view.

As shown in FIG. 2, two gas supply units (gas supply mechanisms) 104 having the same configuration are in close contact with the outer peripheral side of the substantially cylindrical coil case 127, and with respect to the central axis of the vacuum processing chamber 102. They are arranged so as to be substantially symmetrical.

In each gas supply unit 104, the gas control device 113 and the pipe 112 connected to the gas control device 113 for each gas type are located at the end (hereinafter referred to as an inlet) of the pipe 135 on the upstream side (hereinafter referred to as an inlet) with respect to the gas flow. (S part) in FIG. 3) is arranged substantially radially as shown in FIG. Further, the vacuum processing chamber 102 and the gas control device 113 shown in FIG. 1 are arranged in substantially the same plane as the gas reservoir 107 composed of the dielectric window 105 and the shower plate 106, and the gas introduction port 110 shown in FIG. And the pipe 135, the pipe 112, and the valve (first valve) 115 for controlling the start / stop of the gas supply are communicated with each other.

Further, as shown in FIG. 2, each gas introduction port 110 communicating with each gas supply unit 104 is arranged so as to face each other in the gas reservoir 107. Further, as shown in FIG. 1, the pipe 135 passes between the solenoid coil 123 and the solenoid coil 124, is arranged along the periphery of the vacuum processing chamber 102, and communicates with the gas introduction port 110 shown in FIG. .. Then, as shown in FIG. 1, the coil case 127 can be vertically separated between the solenoid coil 123 and the solenoid coil 124.

Further, the gas introduction path for introducing the processing gas into the vacuum processing chamber 102 is the gas mixing pipe (first pipe) 135, one end of which is connected to the gas introduction port 110 communicating with the vacuum processing chamber 102, and the pipe 135. It has a plurality of pipes (second pipes) 112 that are connected to the other end and are arranged radially from the connection point S (see FIG. 3) of the pipe 135 with the other end. As shown in FIG. 3, the plurality of pipes 112 are provided in the same number as the plurality of gas control devices 113, and each of the plurality of pipes 112 communicates with the gas control device 113.

Here, the optimum length L ₁ of the pipe 135 shown in FIG. 2 is that the flow rate of the gas used in the etching process is Q, the mean pressure in the pipe 135, the mean free path, and the velocity of the gas molecules, respectively, as described later. When expressed by p, λ, v, it is expressed by L ₁ = 3Q / (πpλv). When there are a plurality of processing conditions used for the etching process, the value calculated using the processing conditions in which L ₁ is the largest is the optimum length of the pipe 135.

Further, the optimum diameter d ₁ of the pipe 135 is (3d ₁ ² / λv + p) when the diameter, length, and internal gas pressure of the pipe 112 are d ₂ , L ₂ , and p ₂ , respectively, as described later. ₂ π d ₂ ² L ₂ / 4Q) is the minimum d ₁ . When there are a plurality of processing conditions used for the etching process, the value calculated using the processing conditions in which d ₁ is the smallest is the optimum diameter of the pipe 135.

On the other hand, the optimum length L ₂ of the pipe 112 shown in FIG. 5, which will be described later, differs depending on the gas type. Using the dimension w shown in FIG. 5 and the number N of gas species in the valve 115 shown in FIG. 5, it is expressed as L ₂ = w / 2tan (360 ° / 2N).

Then, in the plasma processing apparatus 100, as shown in FIG. 2, the length of each of the plurality of pipes 112 is shorter than the length of the pipe 135 (L ₂ <L ₁ ).

With the above configuration, each gas control device 113 is arranged in the immediate vicinity of the vacuum processing chamber 102, and has the same volume and a certain volume of a portion (pipe 135 and pipe 112) connecting each gas control device 113 and the gas reservoir 107. It is possible to minimize the pipe length under the condition that the conductance with respect to the gas flow rate is equalized and the gas is mixed.

Further, as shown in FIG. 1, each of the pipes 112 has a gas pipe 117 communicating with the roughing pump (exhaust device) 118 and a valve (second valve) 116 for selecting a gas route. It is possible to operate the gas control device 113 so that the response delay associated with the start of operation does not affect the responsiveness of the gas replacement. The operation procedure will be described later.

That is, as shown in FIGS. 1 and 2, each of the plurality of gas control devices 113 is connected to the second path 138 which branches from the first path 137 communicating with the gas reservoir 107 and communicates with the roughing pump 118. A valve (first valve) 115 is located between the branch point T of the first path 137 and the second path 138 and the other end (connection point S) that is not connected to the gas inlet 110 of the pipe 135. Is placed. Further, a valve (second valve) 116 is arranged between the branch point T and the roughing pump 118, that is, in the second path 138. The second path 138 that communicates with the roughing pump 118 also communicates with the TMP (exhaust device) 108 via the valve 125.

Next, the length and diameter of the pipe 135 and the length of the pipe 112 will be described. Generally, the time T required for gas to pass through a gas pipe having a circular cross section is T = pπd ² L, where Q is the flow rate, L is the pipe length, d is the diameter of the pipe, and p is the pressure inside the pipe. It is expressed as / 4Q. Here, when typical values such as Q = 100 ccm, p = 3 kPa, and d = 4.35 mm are used, the introduction of gas is delayed by 0.26 s per 1 m of the pipe. From this, it can be seen from the gas control device 113 that the gas introduction time can be shortened by shortening the gas pipe of the path leading to the gas reservoir 107 via the valve 115, the pipe 112 and the pipe 135, and the gas introduction port 110.

On the other hand, in order to make the processed shape uniform in the same wafer, it is required that each gas type is uniformly mixed inside the gas reservoir 107 at the time of gas introduction. For that purpose, it is necessary to arrange a pipe having a certain length upstream of the gas reservoir 107 and mix the gas in the pipe. Since the pressure inside the gas pipe is as low as several thousand Pa, the Reynolds number is as small as about 50 to 200, that is, the gas flow is laminar. Therefore, the mixing depends mainly on the diffusion accompanying the thermal motion of the gas. Then, assuming that the mean free path is λ and the average velocity of gas molecules is v, the diffusion constant D representing the velocity in diffusion is represented by D = λv / 3, and the gas diffuses to a place separated by the length x. The time required for this is expressed as TD = x ² / D. When a gas pipe for gas mixing is provided, when the time for the gas to pass through the inside and the time for the gas to diffuse sufficiently in the diameter direction of the pipe are equal, the gas pipe length becomes the shortest, and the gas is mixed. The gas introduction time can be shortened. In other words, the length of the pipe 135 is required for the first time required for the mixed gas composed of a plurality of processing gases to pass through the pipe 135 and for the mixed gas to diffuse to a distance corresponding to the radius of the pipe 135. The length is equal to that of the second time.

Considering the above, when x in the above TD equation is the radius of the gas pipe, the shortest length L ₁ min of the pipe 135 is L ₁ min = 3Q / (πpλv) as described above. .. For example, when an argon molecule at room temperature is used, λ = 0.007 / p [m] and v = 432 m / s, so if the unit of Q is ccm, then L ₁ min = 0.053 Q [cm]. For example, in a process of 500 ccm of argon, which has a relatively large flow rate, L ₁ min becomes about 30 cm. That is, the length of the pipe 135 is preferably 30 cm or less.

However, since the plasma processing apparatus generally uses a plurality of processing conditions, the length of L ₁ min differs depending on these processing conditions. Therefore, for the optimum length L ₁ of the pipe 135, the _one having the longest L ₁ min is selected from the processing conditions to be used, and the value of L ₁ min at that time is set to L ₁ .

On the other hand, considering the diameter of the pipe 135, the smaller the diameter, the shorter the time required for the gas to diffuse, so that the time spent for the gas to pass through the pipe 135 can be shortened. However, if the diameter of the pipe 135 is reduced, the conductance is reduced and the pressure at the pipe inlet is increased. As the pressure at the inlet of the pipe 135 increases, the pressure inside the pipe 112 connected to the pipe 135 also increases, but as described above, the time T required to pass through the gas pipe is proportional to the pressure. The time required for the gas to pass through the 112 is rather long.

The time for introducing gas into the pipe 135 and the pipe 112 can be calculated by the sum of TD and T described above (3d ₁ ² / λv + p ₂ πd ₂ ² L ₂ / 4Q), and is shown in FIG. 4, for example. Such a graph of the diameter of the pipe 135 and the gas introduction time can be plotted. From this, it is possible to obtain the optimum value of the diameter of the pipe 135 that minimizes the time required for gas introduction. As can be seen from FIG. 4, when the diameter of the gas pipe becomes smaller than the optimum diameter, the gas introduction time sharply increases, but when the diameter increases, the gas introduction time does not change so much. Therefore, when a plurality of etching treatment conditions are used, the treatment condition in which the optimum value of the diameter of the pipe 135 is the smallest may be found, and the optimum value calculated under the treatment condition may be set as the diameter.

In order to shorten the gas introduction time, it is required to minimize the pipe length also for the path from the inlet of the pipe 135 to the gas control device 113. In order to shorten the length of the pipes for all gas types in the same manner, the pipes from the inlet of the pipe 135 to the valve 115 of each gas type may be arranged radially. At this time, in order to prevent the valves 115 of each gas type from interfering with each other and to minimize the length of the pipe 112, circumscribe the valve 115 with the length of the pipe 112 as the radius as shown in FIG. The valve 115 may be arranged at. Here, FIG. 5 is a partial side view showing an example of an arrangement structure of a plurality of gas pipes and valves in the plasma processing apparatus shown in FIG. As shown in FIG. 3, a plurality of valves (first valves) 115 are arranged according to the number of installed gas control devices 113. Each of the plurality of valves 115 circumscribes the virtual circle 136 shown in FIG. 5 formed around the other end (connection point S) that is not connected to the gas introduction port 110 of the pipe 135 shown in FIG. The diameter of the virtual circle 136 is the minimum diameter at which the plurality of valves 115 circumscribing the virtual circle 136 are arranged so as not to overlap each other.

Further, as shown in FIG. 5, assuming that the length of the side circumscribing each of the virtual circles 136 of the plurality of valves 115 is w and the number of gas types is N, the valve 115 has a positive side length of w. Since it forms an N-side, the length L ₂ of the pipe 112 is represented by L ₂ = w / 2tan (360 ° / 2N). The lengths of the plurality of pipes 112 installed radially are equal to each other.

In the gas reservoir 107 shown in FIG. 2, not only all gas types are required to be uniformly mixed, but also the pressure distribution of the mixed gas is required to be uniform. This is because if the pressure distribution inside the gas reservoir 107 is not uniform, the flow rate of the gas flowing out from the pores 132 of the shower plate 106 differs depending on the location, which affects the uniformity of the processed shape of the wafer 101 shown in FIG. Is. If only one gas introduction port 110 shown in FIG. 2 is installed in the gas reservoir 107, the gas pressure becomes smaller as the distance from the gas introduction port 110 increases as shown in FIG. Here, FIG. 6 is a plan view showing the pressure distribution of gas in the gas reservoir when the installation location of the gas introduction port examined by the present inventor is one. Therefore, in the plasma processing apparatus 100 of the present embodiment, the gas inlets 110 are installed at two locations in the gas reservoir 107. That is, in the gas reservoir 107 in a plan view, the gas introduction ports 110 are arranged at positions facing each other. By doing so, it becomes possible to make the pressure distribution of the gas in the gas reservoir 107 uniform.

Further, the gas control device 113, the valve 115 and the valve 116 shown in FIG. 1 operate according to the procedure shown below. Explaining the operation procedure, before the processing, the flow rate of all the gas control devices 113 is set to 0, and the valves 115 and 116 are both closed.

Then, when processing is initiated and a gas type is needed in the next step, the control computer sends a request to the gas controller 113 corresponding to that gas to flow the gas at the flow rate set in the next step. .. At the same time, the valve 116 corresponding to the gas is opened, and the other valve 115 is closed to communicate the gas control device 113 and the exhaust pump TMP108 (the valve 125 is also opened). Then, when switching to the next step, the gas is supplied to the vacuum processing chamber 102 by closing the valve 116 and opening the other valve 115.

Originally, the gas control device 113 takes a long time from requesting the gas to flow at a certain flow rate until it actually flows at that flow rate. As a result, there is a time lag between the step switching and the actual introduction of the desired gas into the vacuum processing chamber 102 at the desired flow rate. However, in the plasma processing device 100 of the present embodiment, the gas control device 113 can be prepared in advance for the next step by the operation of the valve 115 and the valve 116 as described above, whereby the processing step is switched. Therefore, it becomes possible to introduce a desired gas into the vacuum processing chamber 102 at a desired flow rate in a short time.

With the above configuration, the time from switching the steps until the gas is introduced can be shortened, and the shape controllability of the material to be processed of the plasma processing apparatus 100 can be improved. That is, by shortening the gas pipe consisting of the pipe 135 and the pipe 112 and unifying the pipe length for each gas type, the time required from the step switching to the stabilization of the processing conditions in the vacuum processing chamber 102 can be shortened. Can be done. As a result, it is possible to suppress the decrease in throughput due to the shortening of the cycle etch, and it is possible to improve the shape controllability of the material to be treated in the plasma treatment.

Although the invention made by the present inventor has been specifically described above based on the embodiment, the present invention is not limited to the above-described embodiment and includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations.

It is also possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. .. Further, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration. It should be noted that each member and the relative size described in the drawings have been simplified and idealized in order to explain the present invention in an easy-to-understand manner, and have a more complicated shape in terms of mounting.

The structure and method described in the above embodiment are not limited to those in the above embodiment, and include various application examples. For example, in the above embodiment, the electron cyclotron resonance plasma etching apparatus (ECR) has been described as an example of the plasma processing apparatus, but inductively coupled plasma (ICP: Inductively Coupled Plasma) and capacitively coupled plasma (CCP: Capacitively Coupled) have been described. The same effect can be obtained in a plasma processing apparatus such as Plasma).

100 Plasma etching processing equipment (plasma processing equipment)
101 Wafer 102 Vacuum processing chamber (processing chamber)
103 Lower electrode 104 Gas supply unit (gas supply unit)
105 Dielectric window 106 Shower plate 107 Gas reservoir 108 TMP (exhaust device)
109 Exhaust conductance adjusting valve 110 Gas inlet 111 Cavity resonance part 112 Piping (second piping)
113 Gas control device (gas control unit)
114 Gas source 115 valve (1st valve)
116 valve (second valve)
117 Piping 118 Roughing pump (exhaust device)
119 Microwave source 120 Automatic matching device 121 Square waveguide 122, 123, 124 Solenoid coil 125 Valve 126 High frequency power supply 127 Coil case 128 Pressure gauge 129 Square waveguide converter 130 Circular waveguide 132 Pore 135 Piping (No. 1 piping)
136 Virtual circle 137 1st route 138 2nd route

Claims (10)

The processing room where plasma processing is performed and
A dielectric window located above the processing chamber and transmitting high frequencies,
A gas supply plate arranged below the dielectric window and supplying gas to the processing chamber,
A gas reservoir composed of the dielectric window and the gas supply plate,
A plurality of gas control units that control the flow rates of a plurality of gases supplied to the processing chamber via the gas supply path, and a plurality of gas control units.
With
The gas supply path was arranged radially from a first pipe having one end connected to a gas supply port communicating with the processing chamber and a portion connected to the other end of the first pipe and connected to the other end . Equipped with multiple second pipes ,
The number of the second pipes is the same as the number of the plurality of gas control units.
Each of the second pipes communicates with each of the gas control units,
The length of the first pipe is approximately equal to the time required for the gas to pass through the first pipe and the time required for the gas to diffuse to a distance corresponding to the radius of the first pipe. A plasma processing device characterized by its length. In the plasma processing apparatus according to claim 1,
A plasma processing apparatus characterized in that the length of the first pipe is 30 cm or less. In the plasma processing apparatus according to claim 1,
The flow rate of the gas is Q, the mean pressure of the gas in the first pipe is p, the mean free path of the gas in the first pipe is λ, and the velocity of the gas in the first pipe is λ. A plasma processing apparatus characterized in that the length of the first pipe is obtained by a mathematical formula of 3 Q / (πpλv) , where v is used. In the plasma processing apparatus according to claim 3,
A plasma processing apparatus characterized in that when there are a plurality of processing conditions for the plasma processing , the value when the value of the mathematical formula becomes the largest is set as the length of the first pipe. In the plasma processing apparatus according to claim 1 or 2 .
The flow rate of the gas is Q, the average free stroke of the gas in the first pipe is λ, the velocity of the gas in the first pipe is v, the diameter of the first pipe is d ₁ , and the second When the diameter of the pipe is d ₂ , the length of the second pipe is L ₂ , and the gas pressure inside the second pipe is p ₂ , the type and flow rate of the gas under the processing conditions of the plasma treatment are (1). ^{_{3d 1 2 / λv + p 2}} πd 2 2 L 2 / 4Q) plasma processing apparatus the value of the formula is characterized in that it is set to be the minimum. In the plasma processing apparatus according to claim 5.
Wherein when the processing conditions of the plasma treatment are a plurality of plasma processing apparatus characterized by values of the formulas and wherein d ₁ of the first pipe diameter when minimized. In the plasma processing apparatus according to claim 1,
Before each outs scan control unit is connected to the second path which communicates with the exhaust system branched from the first passage communicating with said reservoir gas,
The first valve is disposed between the first path and the branch point and the previous SL other end branches into the second path,
The plasma processing apparatus, wherein a second valve is disposed between the branch point and the previous SL exhaust system. In the plasma processing apparatus according to claim 7.
The first valve is disposed along a virtual circle around the plurality disposed Rutotomoni the other end,
The diameter of an imaginary circle, a plasma processing apparatus which is a diameter when the previous SL first valve is arranged so as not to overlap each other. In the plasma processing apparatus according to claim 1,
A pair of the gas supply port in plan view, a plasma processing apparatus characterized by one and the other is placed at a position facing each other. In the plasma processing apparatus according to claim 8,
Wherein the length of the second pipe L _2, W the width of said first valve in a side view, when the number of types of the gas is N, the length of the second pipe, L ₂ = W / 2tan ( A plasma processing apparatus characterized in that it is obtained by a mathematical formula of 360 ° / 2N).

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