JP3149701U - Shower head for semiconductor processing equipment - Google Patents

Abstract

A shower head capable of improving uniformity of film thickness within a substrate surface is provided. A shower head for a semiconductor processing apparatus is provided. The shower head includes an internal space defined by a top plate, a side wall, and a bottom plate, a gas introduction port coupled to the internal space, a shower plate having a plurality of pores provided in the bottom plate, and a shower in the internal space. A block plate having a plurality of holes installed in parallel with the plate, and a throttle mechanism in the internal space and installed in parallel with the block plate and the shower plate To do. [Selection] Figure 2

Description

  The present invention relates to a structure of a shower head for a semiconductor processing apparatus.

  Conventionally, a plasma CVD method is often used for depositing a thin film on the surface of a semiconductor substrate. In the plasma CVD method, high-frequency power is applied to the reaction space inside the reactor to turn the process gas into plasma, and the plasma active species generated thereby causes a chemical reaction near the surface of the semiconductor substrate, and a thin film is formed on the semiconductor substrate. It is to be deposited.

  In general, a plasma CVD apparatus includes a reactor, a susceptor for placing a semiconductor substrate installed inside the reactor, a shower head arranged inside and parallel to the susceptor, and a high-frequency power (RF). ) It has an oscillator and an exhaust device for evacuating the reactor.

  The susceptor is grounded to form a lower electrode for plasma discharge, and the shower head is connected to a high frequency power oscillator to form an upper electrode for plasma discharge. The bottom surface of the shower head is provided with a plurality of pores for injecting process gas uniformly onto the semiconductor substrate.

  When the conventional plasma CVD apparatus is used, the in-plane uniformity of the film thickness deposited on the semiconductor substrate is ± 2% or more, which meets the demand for the trend toward larger and finer semiconductor substrates. I can't.

  Accordingly, a structure has been devised in which a gas dispersion plate is inserted into the shower head to disperse the process gas flow once and then flow into the shower plate (see, for example, Patent Document 1).

  However, even with this structure, sufficient film thickness uniformity cannot be achieved.

  In addition, as a method of controlling the film thickness uniformity, there is a method of adjusting the electric field in the reaction space, the temperature distribution of the semiconductor substrate, the pressure, etc., but the work is complicated and it is difficult to achieve the desired film thickness uniformity. is there.

  Furthermore, since the film thickness uniformity changes each time the film formation process is repeated, it is extremely difficult to control the film thickness uniformity between wafers within a desired range.

  Furthermore, the shower plate is generally replaced depending on the semiconductor manufacturing recipe and process application. Along with this replacement work, there is also a problem that throughput decreases.

Japanese Patent Laid-Open No. 9-232298

  In view of the above problems, an object of the present invention is to provide a shower head capable of improving the in-plane uniformity of film thickness.

  Another object of the present invention is to provide a shower head that is simple to work and can achieve the desired film thickness in-plane uniformity.

  Another object of the present invention is to provide a shower head capable of minimizing the difference in film thickness uniformity between wafers.

  Another object of the present invention is to provide a shower head that can improve the throughput without having to replace the shower plate in accordance with a semiconductor manufacturing recipe or application.

In one aspect of the present invention, a shower head for a semiconductor processing apparatus is provided, the shower head comprising:
An internal space defined by the top plate, side walls and bottom plate;
A gas inlet coupled to the internal space;
A shower plate having a plurality of pores provided in the bottom plate;
A block plate having a plurality of holes installed in the internal space facing the shower plate in parallel;
A throttle mechanism located in the inner space and installed in parallel to the block plate and the shower plate,
It is provided with.

The diaphragm mechanism has at least two diaphragm blades, and the gas distribution in the semiconductor substrate surface of the process gas is controlled by moving the diaphragm blades.
It is characterized by that.

  In one aspect, the throttle mechanism is installed between the block plate and the shower plate.

  In another aspect, the block plate is installed between the throttle mechanism and the shower plate.

  The hole of the block plate is larger in diameter than the pore of the shower plate.

  According to the present invention, a shower head capable of improving the in-plane uniformity of film thickness can be provided.

  In addition, according to the present invention, a shower head that is simple in operation and capable of achieving desired film thickness in-plane uniformity can be provided.

  Furthermore, according to this invention, the shower head which can suppress the difference in the in-plane uniformity of film thickness between wafers can be provided.

  Furthermore, according to the present invention, there is no need to replace the shower plate according to the semiconductor manufacturing recipe or application, and a shower head capable of improving the throughput can be provided.

FIG. 1 schematically shows a cross section of a semiconductor processing apparatus using a shower head according to the present invention. FIG. 2 schematically shows a sectional view of the shower head according to the first embodiment of the present invention. FIG. 3 is a plan view schematically showing a first embodiment of the aperture mechanism used in the shower head according to the present invention. FIG. 4 is a plan view schematically showing a second embodiment of the diaphragm mechanism used in the shower head according to the present invention, and shows a start state of the diaphragm. FIG. 5 is a plan view schematically showing a second embodiment of the diaphragm mechanism used in the shower head according to the present invention, and shows a state where the diaphragm is finished. FIG. 6 schematically shows a cross-sectional view of a shower head according to a second embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First embodiment of the invention]
FIG. 1 schematically shows a semiconductor processing apparatus using a shower head according to the present invention. The semiconductor processing apparatus 1 includes a reactor 2, a susceptor 4 installed inside the reactor 2 for supporting the semiconductor substrate 3, and a shower disposed inside the reactor 2, facing the susceptor 4 and arranged in parallel therewith. And a head 5.

  The susceptor 4 has a resistance heater 6 embedded therein, for example, and can heat and hold the semiconductor substrate 3 at a desired temperature. Further, the susceptor 4 is coupled to the lifting mechanism 7 and can move up and down in the vertical direction. Further, when the semiconductor processing apparatus 1 is a plasma CVD apparatus, the susceptor 4 is electrically grounded 8 and defines one electrode for plasma discharge.

  A transfer chamber (not shown) is coupled to the reactor 2 via a gate valve 9. Further, an exhaust port 10 is provided at the bottom of the side surface of the reactor 2, and the exhaust port 10 is coupled to a vacuum exhaust pump (not shown) via a conductance adjustment valve 11 so that the interior of the reactor 2 is desired. Controlled by pressure.

  As will be described in detail below, the shower head 5 has a hollow structure composed of an internal space 20 defined by a top plate, side walls, and a bottom plate. The internal space 20 includes a block plate 26 and a throttle mechanism 28. Is provided (see FIG. 2). The bottom plate of the shower head 5 is provided with a plurality of pores to define a shower plate 25 (see FIG. 2). A gas inlet 12 for process gas is provided on the top plate of the shower head 5, and the gas inlet 12 is connected to a process gas supply device (not shown) through a gas inlet pipe 13.

  When the semiconductor processing apparatus 1 is a plasma CVD apparatus, the shower head 5 is electrically connected to a high-frequency oscillator 14 (for example, 13.56 MHz) via an output cable 15, and the other electrode for plasma discharge. Is defined. When using a mixture of high-frequency power and low-frequency power (for example, 400 kHz), a matching circuit 16 is provided between the high-frequency oscillator and the shower head 5.

  A shower head according to a first embodiment of the present invention is shown in FIG. Here, the same components as those in FIG.

  The shower head 5 according to the first embodiment of the present invention has a hollow structure including an inner space 23 defined by a top plate 20, a side wall 21, and a bottom plate 22. A gas inlet 12 is provided at a substantially central portion of the top plate 20. The bottom plate 22 is provided with hundreds to thousands of pores 24 having a diameter of 0.1 mm to several mm in order to penetrate the bottom plate 22 to constitute a shower plate 25. The pitch and range of the pores 24 can be arbitrarily designed.

  A block plate 26 is provided in the internal space 23 in parallel with the shower plate 25. The block plate 26 is provided with several tens to several hundreds of holes 27 having a diameter of several mm to several tens of mm. The diameter of the hole 27 is generally larger than the diameter of the pore 24. The pitch and range of the holes 27 can be arbitrarily designed.

  The shower plate 25 and the block plate 26 are made of, for example, aluminum or an aluminum alloy by polishing or grinding, but may be made of other metals, ceramics, or the like.

  In the first embodiment, a diaphragm mechanism 28 is provided between the shower plate 25 and the block plate 26 in the internal space 23 in parallel with them. As will be described in detail below, the diaphragm mechanism 28 has a central opening 29 and at least two diaphragm blades, and flows radially from the center of the wafer toward the wafer outer periphery by moving the diaphragm blades. The flow of process gas is automatically controlled.

  FIG. 3 shows one embodiment of the aperture mechanism 28. The diaphragm mechanism 28 has a substrate 30 and an opening 31 through which gas flows in the central portion of the substrate, and diaphragm blades 32 and 33 that are punched on the left and right thereof are arranged in the left and right direction. By simultaneously moving the diaphragm blades 32 and 33 in the opposite directions at the same time, the opening diameter of the opening 31 can be varied to adjust the flow rate of the process gas. The aperture blade 33 has a guide hole 34 and a guide pin 35 that is mechanically coupled to a drive motor (not shown), and the aperture blade 32 is provided with a hole 37 for attachment to the substrate 30. A pin 36 for controlling the operating position of the diaphragm blades 32 and 33 is attached to the substrate 30. The shape of the aperture blade is not limited to that shown in FIG. 3, and various shapes can be implemented.

  4 and 5 show another embodiment of the aperture mechanism. FIG. 4 shows a state in which the aperture mechanism 28 'is in the start position, and FIG. 5 shows that the aperture mechanism 28' is in an operation end state.

  In this embodiment, the diaphragm mechanism 28 ′ has a substrate 40, and an opening 41 through which gas flows in the center of the substrate 40, and a diaphragm ring 42 and seven diaphragm blades 43 are arranged around the circumference of the opening 41. Is arranged. Seven apertures 42 are formed in the aperture ring 42 at substantially equal angular intervals, and teeth 45 are formed in a predetermined angular range on the outer periphery of the aperture ring 42. A light shielding portion 49 is provided at a predetermined position on the outer periphery of the aperture ring 42. The light shielding unit 49 is configured to enter and exit between the light emitting unit and the light receiving unit of the photosensor 49a. Here, all the diaphragm blades 43 have the same shape, and have a shaft pin 43a and an engagement pin 46 on the substrate 40 side, and the shaft pin 43a is rotatably fitted in a hole formed in the substrate 40. The engaging pin 46 is inserted into the aperture ring 42.

  The actuator for driving the aperture mechanism is a known step motor. The rotor 47 includes an output gear 47a integrally formed with the shaft portion, and is rotatably attached to the substrate 40. A two-stage gear including a reduction gear 48 and including a parent gear and a child gear is rotatably attached to the substrate 40. Here, the master gear meshes with the output gear 47 a of the rotor 47, and the slave gear meshes with the tooth portion 45 of the aperture ring 42.

  In FIG. 4, when the power of the aperture mechanism is turned on, the step motor is started, the output gear 47a of the rotor 47 rotates the aperture ring 42 via the reduction gear 48, and the light shielding portion 49 of the aperture ring is a photosensor. The optical path 49a is blocked, the photo sensor 49a emits an L level signal, the rotor 47 stops, and the initial position of the diaphragm blade 43 as shown in FIG. 4 is obtained.

  In FIG. 5, when a pulse signal is issued to the coils 50 and 51, the rotation of the clockwise direction is continued without stopping the rotor 47. As a result, the cam groove 44 of the aperture ring 42 starts to push the engagement pin 46 of the aperture blade 43, and simultaneously rotates the 7 aperture blades 43 counterclockwise to enter the opening 41. By applying the pulse signal to the step motor, the rotation of the rotor 47 is stopped, and the seven diaphragm blades 43 are stopped at a predetermined diaphragm opening control position as shown in FIG.

  The diaphragm mechanism usable in the present invention is not limited to these. Needless to say, the number of aperture blades is arbitrary, and adjustment of the aperture opening can be automatically controlled by a computer or the like.

  By providing the above-described throttle mechanism inside the shower head, it becomes possible to adjust the gas distribution of the process gas sprayed onto the semiconductor substrate via the shower plate. As a result, the film thickness uniformity within the wafer surface is improved.

  In addition, the gas distribution can be adjusted without changing the electric field or the temperature distribution simply by controlling the throttle mechanism. As a result, the film thickness control operation is simplified.

Furthermore, the diaphragm mechanism can be controlled for each process step. As a result, the difference in film thickness uniformity for each semiconductor substrate can be reduced.
Furthermore, the control of the diaphragm mechanism can be optimized according to the semiconductor manufacturing recipe. As a result, the process margin is widened, the shower plate can be shared between applications, and the productivity can be prevented from being lowered due to component replacement. Thereby, the throughput is improved.

  Thus, according to the shower head according to the first embodiment of the present invention, the gas distribution on the semiconductor substrate is adjusted, and the film thickness uniformity is improved.

[Second Embodiment of the Invention]
Next, a second embodiment of the present invention will be described. FIG. 6 schematically shows a cross section of a shower head 5 ′ according to a second embodiment of the present invention. The same components as those in the first embodiment are denoted by the same reference numerals.

  The shower head 5 ′ according to the second embodiment is different from the first embodiment in that the arrangement of the throttle mechanism 28 and the block plate 26 is reversed. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

  Also in the second embodiment of the present invention, the gas distribution on the semiconductor substrate is adjusted, and the film thickness uniformity is improved.

[Others]
Although specific embodiments of the present invention have been described above, the structure of the apparatus disclosed herein is merely an example, and various configurations can be made without departing from the spirit of the present invention described in the claims of the utility model registration. Those skilled in the art know that modifications and changes are possible.

  For example, although embodiments of the present invention have been described with reference to plasma CVD apparatus, thermal CVD apparatus, atomic layer deposition apparatus (ALD), plasma enhanced atomic layer deposition apparatus (PE-ALD), physical vapor deposition The same applies to the apparatus (PVD).

DESCRIPTION OF SYMBOLS 1 ... Semiconductor manufacturing apparatus, 2 ... Reactor, 3 ... Semiconductor substrate, 4 ... Susceptor, 5 ... Shower head, 6 ... Sheath heater, 7 ... Lifting device, 8 ... Grounding 9 ... Gate valve 10 ... Exhaust port 11 ... Conductance adjusting valve 12 ... Gas inlet port 13 ... Piping 14 ... High frequency oscillator 15 ... Output cable, 16 ... matching circuit, 20 ... top plate, 21 ... side wall, 22 ... bottom plate, 23 ... internal space, 24 ... pore, 25 ... shower plate, 26... Block plate, 27... Hole, 28.

Claims (5)

A shower head for a semiconductor processing apparatus,
An internal space defined by the top plate, side walls and bottom plate;
A gas inlet coupled to the internal space;
A shower plate having a plurality of pores provided in the bottom plate;
A block plate having a plurality of holes installed in the internal space facing the shower plate in parallel;
A throttle mechanism located in the inner space and installed in parallel to the block plate and the shower plate,
A shower head characterized by comprising: The diaphragm mechanism has at least two diaphragm blades, and the gas distribution in the semiconductor substrate surface of the process gas is controlled by moving the diaphragm blades.
The shower head according to claim 1. The aperture mechanism is installed between the block plate and the shower plate.
The shower head according to claim 1. The block plate is installed between the throttle mechanism and the shower plate,
The shower head according to claim 1. The hole of the block plate has a larger diameter than the pore of the shower plate,
The shower head according to claim 1.

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