JPS61238964A - Film forming device - Google Patents

Abstract

PURPOSE:To provide a device which is simple in construction and improves electric discharge stability and the uniformity of film quality with respect to a device which forms the film by making use of electric discharge by using conductive and electrically insulating members to constitute a cassette in which the discharge is induced by the electrical connection with a holding electrode. CONSTITUTION:The cassette 50 is constituted primarily of the conductive member and the insulating member and is supported by a lower insulating ring 54 which is brought into tight contact with a holder 52 for supporting a cylindrical base body 51 to be formed with the film from the inside. A cathode electrode 55 of the cassette 50 is supported by contacting tightly with the upper part of a ring 64 and is insulated from the holder 52. conductive gaskets 32A, 32B held to the top and bottom ends of the inside circumferential wall of the holding electrode 32 provided with insulating rings 31A, 31B contact respectively tightly with the top and bottom ends of the outside circumferential wall of the electrode 55. An upper insulating ring 56 for the cassette is further supported by contacting tightly with the top end of the electrode 55. The electrode 55 part is thereby electrically separated from the cylindrical electrode and the peripheral structural members thereof, by which the generation of the abnormal discharge at the end of the electrode 55, etc., is reduced and the stable generation of the discharge is made possible.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention is applicable to films deposited on a substrate, particularly functional films, particularly semiconductor devices, photosensitive devices for electrophotography, line sensors for image input, and imaging devices. This invention relates to improvements in film forming apparatuses used to form semiconductor films and the like.

[Prior art]

2. Description of the Related Art Conventionally, the following is known as a film forming apparatus, for example, a film forming apparatus that can efficiently produce electrophotographic photoreceptor drums.

That is, as shown in FIG. 1, 1 is a shield box, and insulators IA and IB
A holding electrode 2 having a bottomed cylindrical structure is provided inside the holding electrode 2 via the holding electrode 2 . The shield box 1 is grounded, and the holding electrode 2 is insulated from the shield box 1. Moreover, this shield box 1 prevents the high frequency waves supplied to the holding electrode 2 from leaking to the outside, as will be described later.

A rond 3 penetrates through the bottom wall of the shield box 1 and the bottom wall of the holding electrode 2 so as to be located on the axis of the holding electrode 2 . The rond 3 is placed on the bottom of the shield box 1 and is connected to the holding electrode 2 by an annular insulator 4 provided so as to penetrate through the bottom of the holding electrode 2.
insulated from A sealing mechanism 5 is disposed outside the bottom wall of the shield box 1, thereby airtightly sealing the space between the rod 3 and the shield box 1.

Reference numeral 6 denotes a gate valve, which is arranged at the upper end of the shield box 1 and opens and closes the upper end opening of the shield box 1 in an airtight manner. Reference numeral 7 denotes an annular insulator provided between the gate valve 6 and the insulator LA so as to airtightly seal the gap between the gate valve 6 and the holding electrode 2. Thus, the holding electrode 2 (shield box l) forms a sealed structure.

A heater 8 is provided on the inner peripheral wall of the shield box 1. Reference numeral 9 denotes a conductive member that penetrates the shield box 1 via an insulator 16, and one end of which is connected to the holding electrode 2.
The other end is connected to the RF power source 10. High frequency power from an RF power source 0 is supplied to the holding electrode 2 through the conductive member 9 .

Tapered surfaces 2A and 2B are formed on the inner circumferential wall of the upper end and the inner circumferential wall of the lower end of the holding electrode 2, respectively. These tapered surfaces 2A and 2B have exhaust ports 2C for exhausting gas.
and 2D are provided penetrating therethrough. IIA and I
IB is a gas exhaust pipe, one end of which is fixed to the upper and lower ends of the shield box 1, and annular pipes 2 formed at the upper and lower ends of the cassette 20.
1B and 22B via insulators IA and IB, respectively. The other ends of these gas exhaust pipes 11A and IIB are connected to intake means.

Reference numeral 12 denotes a gas supply pipe, one end of which passes through the shield box 1, and an insulator 1 fixed to the holding electrode 2.
3, it communicates with an annular space 14 which becomes a gas chamber. The other end of this gas supply pipe 12 is connected to a gas supply source (not shown), so that the reaction gas from the gas supply source is transferred to the holding electrode 2 and the cassette 20 via the gas supply pipe '12 and the insulator 13. It is supplied into the annular space 14 between.

The rod 3 is coupled to a motor 3B via a speed reduction mechanism 3A, and is rotated by the drive of this motor 3B. Further, the motor 3B is fixed to an elevating means (not shown), and the rod 3 is moved up and down on the axis of the holding electrode 2 by this elevating means.

FIG. 2 is a cross-sectional view of a cassette 20 housed in a holding electrode 2 of a conventional film forming apparatus.

The cassette 20 has a cylindrical structure with a bottom, and has gas exhaust portions 21 and 22 at its upper and lower ends, respectively. These exhaust portions 21 and 22 form a taper with a size that makes close contact with the inner peripheral surfaces of the upper and lower ends of the holding electrode 2 over the entire circumference, and are connected to the exhaust ports 2C and 2D of the holding electrode 2. Through holes are formed at the positions where they communicate with each other.

In the gas exhaust portions 21 and 22, exhaust ports 21A and 22A for exhausting the inside of the cassette 20 are formed through the gas exhaust portions 21 and 22 at a plurality of locations in the circumferential direction at equal intervals.

The reaction gas exhausted from the exhaust ports 21A and 22A passes through the annular pipes 21B and 22B formed by the cassette 20 and the exhaust portions 21 and 22 at its upper and lower ends, and passes through the exhaust port 2C of the holding electrode 2. and?
Exhaust from D.

In a portion of the cassette 20 excluding the exhaust portions 21 and 22, a plurality of rows of gas ejection holes 23 are formed in the axial direction at equal intervals in the circumferential direction. The bookmark set 20 is made of a conductive material, such as aluminum.

The cylindrical support 25 is removably fitted with a cylindrical support 27 for forming an electrophotographic photosensitive drum on the outside of the main body 25A.The cylindrical support 27 is attached to the lower end of the main body 25A. Its lower end abuts against the stepped portion of the section, and its upper end abuts against an annular presser foot 28 that is fitted and fixed on the outside of the upper end portion of the main body 25A. By removing it from the main body 25A, the cylinder 27 can be removed from the main body 25A.

Further, the upper exhaust portion 21 closes the upper end opening of the cassette 20, and a projection 21G having a cylindrical structure is formed at the center thereof. Also, the lower exhaust part 22 of the cassette 20
A similar protrusion 22C is also formed at the center of the bottom wall. The projections 21C and 22C consist of a tapered portion and a straight pipe portion continuous to the tapered portion. Exhaust parts 21 and 2
2 are connected to the upper and lower ends of the cassette 20 by a well-known can manufacturing method.

The cassette 20 in which the cylindrical substrate 25 is housed as described above is housed in the holding electrode 2 in the following manner.

By storing the cassette 2.0 in the holding electrode 2 as shown in FIG. Conductive gas shells (15A and 15) fixed in the grooves at the upper and lower ends of electrode 2
A ring-shaped space 14 is formed which becomes a gas chamber for making the release distribution of the reaction gas uniform.

The rod 3 is then raised to lift the cylindrical substrate 25 from the bottom of the cassette 20 and support it within the cassette 20 insulated therefrom.

In this way, the cassette 20 constitutes a cathode electrode in electrical contact with the holding electrode 2, while the cassette 20
A cylindrical base body 25, which is insulated and supported therein, is grounded via the rod 3.

In the manner described above, the cylindrical base body 25 is housed within the holding electrode 2. Then, the cylindrical base body 25 is rotated by the rod 3, and a reaction gas is supplied into the cassette 20 maintained in a vacuum via the gas supply pipe 12, the insulator 13, the annular space 14, and the gas jet hole 23, By heating the inside of the cassette 20 with the heater 8 and supplying high-frequency power to the holding electrode 2 and the cassette 20, a discharge is generated and the reaction gas is decomposed, so that, for example, amorphous・Deposit a silicon film. .

The cylindrical substrate 25 on which the film has been formed is carried out of the holding electrode z together with the cassette 20, and taken out from the cassette 20 outside the reactor.

After removing the cylindrical base, 20' is disassembled,
It is cleaned, reassembled, and used for film deposition.

However, in such conventional film deposition equipment,
There was a theme as follows:

That is, when high-frequency power is introduced into the cassette 20 from the holding electrode 2 and used as a cathode electrode, the cylindrical base 25 is used as an anode electrode, so the cylindrical base 2
5, it is essential to electrically separate it from the cassette 20, and therefore, a mechanism for this purpose, for example, when raising the rod to electrically separate it from the cassette 20, a drive mechanism is required, and the device The mechanism and film forming process become complicated. It's a bird. Also 1. Since the cassette 20 has an integral structure, its entirety serves as a cathode electrode, and the exhaust portion 2 not only exists between the cassette 20 and the cylindrical base 25 but also at its upper or lower end.
15 and 22 and the upper and lower edges of the cylindrical base 25,
Discharge also occurs in unnecessary places such as between the inner wall surface of the cylindrical base 25, and abnormal discharge is likely to occur due to the unevenness of such places, which makes the discharge unstable. This method has the drawback of adversely affecting the properties of the deposited film formed.

In addition, exhaust parts 21 and 22 are provided at the upper and lower ends of the cassette 20 in order to uniformly adjust the exhaust pressure in the circumferential direction inside the cassette 20. When a film is formed, silicon powder that is generated during film formation and does not contribute to film formation accumulates on the inner wall surface of this pipe, narrowing the pipe diameter and resulting in a change in exhaust pressure distribution even during film formation. changes, and the cylindrical base 2
There was a drawback that the film thickness distribution in the circumferential direction of No. 5 was poor.

[Purpose of the invention]

The purpose of the present invention is to solve the above-mentioned problems, simplify the structure of the device, and improve the discharge stability during film formation, thereby increasing the uniformity of film quality and stably
It is an object of the present invention to provide a film forming apparatus capable of forming a film on a substrate with good yield.

[Summary of disclosure]

The film forming apparatus of the present invention is a film forming apparatus that performs film forming using electric discharge, and includes a holding electrode and a substrate for film forming therein, and is electrically connected to the holding electrode. It is characterized in that it has a cassette in which a discharge can be generated, and the cassette is composed of an electrically conductive member and an electrically insulating member.

〔Example〕

FIG. 3 shows a cross section of a film forming apparatus in an embodiment of the film forming apparatus according to the present invention.

In FIG. 3, 30 is a shield box, and a holding electrode 32 having a cylindrical structure is provided inside the shield box via insulating rings 31A and 31B. The shield box 30 is grounded, and the holding electrode 32 is insulated from the shield box 30. Moreover, this shield box 30 prevents the high frequency waves supplied to the holding electrode 32 from leaking to the outside, as will be described later.

Reference numeral 33 denotes a conductive member that penetrates the shield box 30 via an insulator 34, and has one end connected to the holding electrode 32 and the other end connected to the RF power source 35. High frequency power from an RF power source 35 is supplied to the holding electrode 32 via this conductive member 33 .

Tapered surfaces 36A and 37A are formed on the inner peripheral wall of the upper and lower ends of the holding electrode 32, respectively, and exhaust ports 36B and 37B for exhausting the reaction gas are provided.
Exhaust portions 36 and 37 each formed in a tapered surface are arranged. Upper exhaust section 36 and lower exhaust section 3
7, exhaust pipes 36C and 37C connected to intake means (not shown) are connected to the exhaust ports 36B and 37B.
It is likely to be penetrated and provided so as to communicate with the.

38 is a gas supply pipe, one end of which passes through the shield box 30 and communicates with the inside of the holding electrode 32 via an insulator 39 fixed to the holding electrode 32. The other end of this gas supply pipe 38 is connected to a gas supply source (not shown), so that the reaction gas from the gas supply source is supplied into the holding electrode 32 via the gas supply pipe 38 and the insulator 39. .

32A and 32B are conductive gaskets fixed to grooves in the inner circumferential wall of the upper end of the holding electrode 32 and grooves in the inner circumferential wall of the lower insulating ring 31B at the interface with the lower end of the holding electrode 3z; electrically connected.

Reference numeral 40 denotes a heater for heating and keeping the substrate warm during film formation, and is fixed to the inner bottom of the lower exhaust part 37 along the central axis of the holding electrode 32.

Reference numeral 41 denotes a gate valve, which is attached to the opening of the upper exhaust section 36, and is opened and closed when carrying the cassette 50 (Fig. 5) into and out of the holding electrode 32, and is closed during film formation to ensure vacuum sealing. Hold.

Vacuum gas seals are provided at all interfaces where the holding electrode 32, upper insulating ring 31A, lower end insulating ring 31B, upper exhaust section 36, lower exhaust section 37, gate valve 41, gas supply pipe 38, and insulator 39 join. The structure is such that the film-forming equipment is kept in a vacuum.

Further, the upper exhaust section 36, the lower exhaust section 37, the shield box 30, the gate valve 41, the gas supply pipe 38, and the heater 40 are each connected to ground, and are all at the same potential.

FIG. 4 is a sectional view showing the component configuration of the cassette 50.

The cassette 50 is roughly divided into a conductive member and an insulating member. As the material of the conductive member, aluminum, stainless steel, etc. are preferably used, and as the material of the insulating member, ceramic, glass, Teflon, etc. are suitably used.

51 is a cylindrical base for film formation, and 52 is a holder for supporting this from the inside. Holder 52
At the bottom of the cassette 50, there is attached a feed φ hole part 52A which is a space for making the internal exhaust pressure uniform when the cassette 50 is assembled, and its outer peripheral wall is connected to the film forming apparatus main body. A tapered surface 52B is formed in close contact with the tapered surface 37A of the lower exhaust portion 37. Also,
An exhaust port 52C is opened in the tapered surface 52B at a position that matches the exhaust port 37B. Furthermore,
The upper part of this feed through portion 52A is opened in a cylindrical shape. Note that 52D is a chucking protrusion used when transporting the cassette 50.

A dummy base 53 is attached to the top of the cylindrical base 5, and is supported by a holder 52.

54 is a lower insulating ring for the cassette, and the holder 52
The cassette 50 is closely supported on the upper part of the feed sle part 52A, and a plurality of exhaust ports 54A are formed in the circumferential direction on the bottom plate of the cassette 50 to uniformly adjust the exhaust pressure in the circumferential direction inside the cassette 50. .

Reference numeral 55 denotes a cathode electrode of the cassette 50, which is closely supported on the upper part of the lower insulating ring 54 for the cassette and is electrically insulated from the holder 52. Further, holding electrodes 3 are provided at the upper and lower ends of the outer peripheral wall.
so that the conductive gas kerats 32A and 32B held at the upper and lower ends of the inner peripheral wall of 2 are in close contact with each other, respectively.
Flange portions 55A and 55B having tapered surfaces are formed. Further, on the wall surface, a plurality of rows of gas ejection holes 55G formed in the axial direction are formed in a plurality of rows at equal intervals in the circumferential direction.

Reference numeral 56 denotes an upper insulating ring for the cassette, which is closely supported at the upper end of the cathode electrode 55. Similar to the lower insulating ring 56 for the cassette, a plurality of exhaust ports 56A are formed in the circumferential direction on the top plate.

57 is the upper exhaust ring of cassette 1-50, and holder 5
Similar to the one attached to the lower part of No. 2, a feed through hole portion 57A is formed to make the exhaust pressure uniform. Further, a tapered surface 57B is formed on the outer peripheral wall so as to come into close contact with the tapered surface 36A of the upper exhaust portion 36 of the main body of the film forming apparatus. Furthermore, an exhaust port 57C is opened in the tapered surface 57B at a position that matches the exhaust port 36B. The lower part of the upper exhaust ring 57 is opened in a circumferential shape, and by placing it on the upper part of the upper insulating ring 56 for three-force setting, a part of the feed through with only the exhaust port 56A open is formed. .

FIG. 5 is an assembled sectional view of the cassette components. The cassette 50 is first fitted with a lower cassette insulating ring 54 from above the cylinder of the holder 52, and then fitted and fixed onto the upper part of the feed through portion 52A of the holder 52. As a result, the lower feed through portion 52A is formed by inserting the zero-order cylindrical base 51, which is formed as a space having an exhaust port 54A above, along the central axis from above the cylinder of the holder 52, and then inserting the dummy body 52 in the same manner. Next, the cathode electrode 5 is inserted and fixed to the upper end of the cylindrical base 51.
5, and the flange 55B thereof is fitted and fixed in close contact with the stepped portion of the lower insulating ring 54 for the cassette. Further, an upper insulating ring 56 for the cassette is placed on top of the cassette, and finally an upper exhaust ring 57 is placed on it to complete the cassette 50.

Note that the above assembly process is preferably performed in a cleaning atmosphere such as a clean room.

The completed cassette) 50 is suspended and transported by the chucking mechanism as in the conventional example using the chucking protrusion at the upper end of the holder 52, and is stored in a vacuum transportable pot (not shown). The gate valve 41 attached to the top of the film forming apparatus is opened, and the film is inserted into the film forming apparatus which is already kept in a vacuum.

FIG. 6 shows a cross section of a film forming apparatus in which a cassette 50 is installed.

At the position where the insertion of the cassette 50 is completed, the conductive gaskets 32A and 32B fixed to the upper and lower ends of the inner circumferential wall of the holding electrode 32 are attached to the upper and lower ends of the outer circumferential wall of the cassette 50. Flange portion 55 formed
A and 55B are in close contact with each other around the entire circumference to enable sealing of reaction gas and introduction of high frequency power, and between the holding electrode 32 and the cathode electrode 55 is a gas chamber for discharging gas in a uniform distribution state. An annular space 60 is formed.

Further, the lower tapered surface 52B of the holder 52 and the tapered surface 37A of the lower exhaust portion 37 are in close contact with each other, and the exhaust port 52C and the exhaust pipe 37C communicate with each other, allowing the inside of the cassette 50 to be exhausted from the lower part.

Further, the tapered surface 57B of the upper exhaust ring 57 and the tapered surface 36A of the upper exhaust portion 36 are in close contact with each other, and the exhaust port 57C and the exhaust pipe 36C are in communication with each other, so that the inside of the cassette 50 can be exhausted from the upper part.

Film formation on the cylindrical substrate 51 inside the housed cassette 50 is performed as follows.

The cylindrical substrate 541 is heated to the optimum temperature for film formation using the heater 40.
heated and maintained by Then, a reaction gas is supplied into the cassette 50 maintained in a vacuum via the gas supply pipe 38, the insulator 39, the annular space 60, and the gas ejection hole 55C. Next, the RF power supply 35 supplies the conductive member 33, the holding electrode 32, and the conductive gas at the upper and lower ends thereof.
By supplying high frequency power to the cathode electrode 55 through 32A and 32B, a discharge is generated between the cylindrical base 51 which is grounded, and the reaction gas is decomposed. For example, a film of amorphous silicon is deposited on the outer peripheral surface of the substrate.

In this device, during the discharge, the cathode electrode 5
The conductive members of the cassettes 50 (other than cassettes 5) are grounded similarly to the cylindrical electrode 51, and the distance from the cathode electrode 55 is also the same as the distance from the cylindrical base 51 due to upper and lower cassette insulating rings 54 and 56. Since the same or higher level is ensured, abnormal discharge will not occur, and unnecessary areas during film formation, that is, the cathode electrode 5.
High frequency power is not applied to parts other than 5.

The pressure distribution inside the cassette 50 during film formation is determined by the position and shape of the exhaust port and the exhaust speed. Exhaust port 54A
and 56A equalize the pressure distribution in the circumferential direction of the cylindrical base body 51, and feed through portions 52A and 57A
This makes the exhaust speed of each exhaust port uniform.

Further, the introduced reaction gas is exhausted by an intake means (not shown) through the exhaust ports 54A and 56A, the feed passage portions 52A and 57A, the exhaust ports 52C and 57C, and the exhaust pipes 37C and 36C. At that time, for example, when forming an amorphous silicon film,
Part of the reactant gas passing through the piping generates and deposits polysilane powder on the inner wall of the piping, but in this device, part of the feed through has a large inner wall area, and the exhaust flow is directed to the wall. By arranging the position of the exhaust port in such a way that it collides with the feed, a large amount of polysilane powder can be collected in a part of the feed stream, and the subsequent accumulation of polysilane powder on the piping can be avoided. The amount can be reduced. This reduces the overall amount of polysilane powder deposited within the device.

The cylindrical substrate 51 on which the film has been formed is carried out of the film forming apparatus together with the cassette 50 by the reverse operation of the carrying-in process, and
The cassette 50 is taken out.

The cassette 50 from which the cylindrical substrate 51 has been taken out is disassembled, washed, reassembled, and used for film formation as in the conventional example.

In the above embodiments, the structure of the film deposition apparatus and cassette was mainly explained using an upward/downward transport mode using a hanging rod as a transport means. The present invention can also be applied to.

However, in this case, it is more preferable that the cylindrical substrate heating heater 40 be housed inside the holder 52 and transported together with the cassette 50, rather than being fixed to the film forming apparatus side.

Further, in the embodiment described above, the evacuation method is in the vertical direction of the cassette 50, but depending on the length of the cylindrical base 51, etc., it is also possible to select only one of the evacuation systems.

〔Effect of the invention〕

As described above in detail, according to the film forming apparatus of the present invention, since the cassette is composed of a conductive member and an electrically insulating member, the cathode electrode portion is separated from the cylindrical electrode and its surrounding structural members. It can be electrically isolated, reducing the occurrence of abnormal discharge at the end of the cathode electrode, etc., and making it possible to generate stable discharge.

Furthermore, with this structure, there is no need to provide a mechanism (for example, a rod) to separate the electrodes during film formation, and film formation can be achieved simply by inserting the cassette into the holding electrode. It is possible to have a very simple device configuration, and the work process can also be simplified.

Furthermore, since the substrate is fitted into the cassette within the cassette, the substrate position will not shift due to vibration etc. during cassette transport, and the distance from the cathode electrode will not change, making it possible to form a film. At this time, a uniform and stable discharge can be generated in the circumferential direction.

In addition, if a feed-through section is provided inside the cassette, the exhaust pressure can be adjusted at a portion of the feed-through, and the thickness distribution and characteristic distribution of the film deposited on the substrate can be adjusted. can.

Furthermore, it is possible to efficiently collect the polysilane powder that reacts and forms in a part of this feed thru and adheres to and accumulates on the reactor, piping, etc., and removes the polysilane powder that accumulates on the piping other than the cassette. Since the amount can be reduced, fluctuations in internal pressure due to clogging of piping can be prevented, and stable film formation can be performed.

In other words, according to the film-forming apparatus of the present invention, the cassette for film-forming and the reactor main body, which is an auxiliary device for creating the conditions, can be mass-produced with high efficiency.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional film-forming apparatus, FIG. 2 is a cross-sectional view of a cassette inserted into the conventional film-forming apparatus, FIG. 3 is a cross-sectional view of only the reactor of the film-forming apparatus according to the present invention, and FIG. FIG. 5 is a cross-sectional view of the cassette, FIG. 5 is an assembled cross-sectional view thereof, and FIG. 6 is a cross-sectional view showing an embodiment of the entire film forming apparatus according to the present invention. 31A, 31B --- one insulating ring 32 --- one holding electrode 32A,
32B---- Conductive gasket 50------
---------One cassette 51-----
-One cylindrical base 52---------Holder 54, 56------Insulating ring 55 for cassette---------------------- One cathode electrode No. 6
figure

Claims (3)

[Claims] (1) In a film forming apparatus that forms a film using electric discharge,
It has a holding electrode and a cassette which houses a film-forming substrate therein and is electrically connected to the holding electrode to generate an electric discharge therein, and the cassette has a conductive member and an electrically insulating member. A film forming apparatus comprising: (2) The film forming apparatus according to claim 1, wherein at least a part of the conductive member constituting the cassette is electrically connected to the holding electrode. (3) The film forming apparatus according to claim 1, wherein the cassette has a feed-through portion near the exhaust port.