JPH07107191B2 - Film forming equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a deposited film on a substrate, particularly a functional film, particularly a semiconductor device, a photosensitive device for electrophotography, a licensor for image input, and an imaging device. The present invention relates to improvement of a film forming apparatus for forming a semiconductor film or the like used for a photovoltaic element.

[Prior art]

Conventionally, the following is known as a film forming apparatus capable of efficiently producing one of the film forming apparatuses, for example, an electrophotographic photosensitive drum.

That is, as shown in FIG. 1, 20 is a shield box, and a holding electrode 22 having a bottomed cylindrical structure is provided inside thereof via insulators 21A and 21B. The shield box 20 is grounded, and the holding electrode 22 is insulated from the shield box 20. Moreover, the shield box 20 prevents the high frequency supplied to the holding electrode 22 from leaking to the outside as described later.

Reference numeral 23 denotes a rod, which penetrates the bottom wall of the shield box 20 and the bottom wall of the holding electrode 22 so as to be located on the axis of the holding electrode 22. The rod 23 is arranged on the bottom of the shield box 20, and the holding electrode 22 is provided by an annular insulator 24 provided so as to penetrate the bottom of the holding electrode 22.
Insulated from. Reference numeral 25 denotes a sealing mechanism, which is arranged outside the bottom wall of the shield box 20 and thereby hermetically seals between the rod 23 and the shield box 20.

Reference numeral 26 denotes a gate valve, which is arranged at the upper end of the shield box 20 and airtightly opens and closes the upper end opening of the shield box 20. Reference numeral 27 is an annular insulator provided between the gate valve 26 and the insulator 21A so as to hermetically seal between the gate valve 26 and the holding electrode 22. Thus, the holding electrode 22 (shield box 20) forms a closed structure.

28 is a heater, which is provided on the inner peripheral wall of the shield box 20. Reference numeral 29 denotes a conductive member that penetrates the shield box 20 via an insulator 31, one end of which is connected to the holding electrode 22 and the other end of which is connected to the RF power source 30. High frequency power from the RF power source 30 is supplied to the holding electrode 22 via the conductive member 29.

Tapered surfaces 22A and 22B are formed on the inner peripheral wall of the upper end portion and the inner peripheral wall of the lower end portion of the holding electrode 22, respectively.

Exhaust ports 22C and 22D for exhausting gas are provided through the tapered surfaces 22A and 22B.

32A and 32B are gas exhaust pipes and shield boxes
One end is fixed to the upper end portion and the lower end portion of 20, respectively, and furthermore, they communicate with annular grooves 41B and 42B formed in the upper end portion and the lower end portion of the cassette 40 via insulators 21A and 21B, respectively. The other ends of these gas exhaust pipes 32A and 32B are connected to the intake means.

The peripheral wall of the holding electrode 22 has a double wall structure, that is, the outer peripheral wall.
22E and inner peripheral wall 22F. An annular space 33 serving as a gas chamber is formed between the outer peripheral wall 22E and the inner peripheral wall 22F, and a row of a plurality of gas discharge holes 34 formed in the axial direction is circumferentially formed in the inner peripheral wall 22F. By forming a plurality of rows at equal intervals, the reaction gas discharge distribution can be made uniform.

37 is a gas supply pipe, one end of which is a shield box
It is connected to the annular space 33 via a connecting pipe 36 fixed to the outer peripheral wall 22E of the holding electrode 22 and an insulator 35. The other end of the gas supply pipe 37 is connected to a gas supply source (not shown), so that the reaction gas from the gas supply source is annular space 33 through the gas supply pipe 37, the insulator 35, and the connecting pipe 36. Supplied within.

The rod 23 is coupled to a motor 39 via a speed reduction mechanism 38, and is rotated by driving the motor 39. The motor 39 is fixed to an elevating means (not shown), and the elevating means moves the rod 23 up and down on the axis of the holding electrode 22.

The cassette 40 has a bottomed cylindrical structure made of a conductive material such as aluminum or stainless steel, and has gas exhaust portions 41 and 42 at its upper and lower ends, respectively. The exhaust portions 41 and 42 are formed into a taper having a size such that they are in close contact with each other on the inner peripheral surfaces of the upper end portion and the lower end portion of the holding electrode 22, and penetrate at a plurality of positions in the circumferential direction at equal intervals. The holes 41A and 42A are formed, respectively.

In the portion of the cassette 40 excluding the exhaust portions 41 and 42, a plurality of rows of gas ejection holes 43 formed in the axial direction are formed at equal intervals in the circumferential direction. Further, the cassette 40 has an outer diameter substantially the same as the inner diameter of the holding electrode 22, and the gas ejection holes 43
As will be described later, when the cassette 40 is tightly accommodated in the holding electrode 22, the cassette 40 is formed so as to be positioned so as to match the position of the gas release hole 34 formed in the inner peripheral wall 22F of the holding electrode 22. ing. The cassette 40 is made of a conductive material such as aluminum.

The cylindrical support base 45 has a support plate 46 at the inner upper end portion of its body 45A, and a cylindrical support 47 for forming an electrophotographic photosensitive drum is detachably fitted on the outside of the body 45A. It is fixed. The cylindrical support 47 has its lower end abutted on the stepped portion of the lower end portion of the main body 45A, and its upper end abutted on an annular presser 48 fitted and fixed to the outside of the upper end of the main body 45A, and thus on the outside of the main body 45A. Fitted and fixed. By removing the presser foot 48 from the main body 45A, the cylindrical support 47 is
Can be removed from 5A.

The lid 44 covers the exhaust portion 41 to close the upper end opening of the cassette 40. A protrusion 44A having a cylindrical structure is formed in the central portion of the lid 44. A similar projection 49 is also formed on the central portion of the bottom wall of the lower end of the cassette body 40. The protrusions 44A and 49 are composed of a tapered portion and a straight pipe portion continuous with the tapered portion. The lid 44 is connected to the upper end of the cassette 40 by a well-known can making method.

The cassette 40 having the cylindrical substrate 45 housed therein as described above is housed in the holding electrode 22 as follows.

The cassette 40 is stored in a transfer chamber (not shown) that can be evacuated and transferred.

Then, the transfer chamber accommodating the cassette 40 in this manner is positioned immediately above the shield box 20 in which the inside thereof has been evacuated and evacuated, and on the gate valve 26 at the upper end of the shield box 20 and at the lower end of the transfer chamber. The mounted gate valve (not shown) is placed so that the central axis of the transfer chamber coincides with the central axis of the shield box 20.

Then, a space between the two gate valves is evacuated by a suitable exhaust means (not shown) to make a vacuum, and then the two gate valves are opened.

Then, a suspension rod (not shown) attached to the transfer chamber is lowered to insert the cassette 40 into the holding electrode 22. At this time, the rod 23 is lowered to an appropriate position inside the holding electrode 22.

Then, the cassette 40 is lowered until the bottom surface of the cassette 40 contacts the bottom surface of the holding electrode 22. In this state,
The cassette 40 is in intimate contact with the inside of the holding electrode 22. That is, the taper of the upper and lower ends of the cassette 40 is
The upper and lower end portions of the holding electrode 22 are in close contact with the tapered surfaces 22A and 22B over the entire circumference, and the portion excluding the upper and lower end portions of the cassette 40 is closely attached to the inner peripheral wall excluding the upper and lower end portions of the holding electrode 22. The gas ejection holes 43 formed in the cassette 40 communicate with the gas emission holes 34 formed in the holding electrode 22. Therefore, the reaction gas is
It is supplied into the annular space 33 through the 37, the insulator 35, and the communication pipe 36, and further, from there, is supplied into the cassette 40 through the gas discharge hole 34 and the gas ejection hole 43. Further, the gas in the cassette 40 is discharged into the exhaust ports 22C and 22D at the upper and lower ends of the holding electrode 22 via the exhaust portions 41A and 42A at the upper and lower ends thereof and the annular grooves 41B and 42B, and from there, The gas is taken into the intake means via the gas exhaust pipes 32A and 32B.

Next, the chuck (not shown) at the tip of the suspension rod is removed from the hole 46A of the support plate 46 of the cylindrical substrate 45, and the suspension rod is raised to be housed in the transfer chamber, while the rod 23 is raised. , The head 23A at its tip is brought into contact with the support plate 46 of the cylindrical substrate 45, and the rod 23 is further raised to lift the cylindrical substrate 45 from the bottom of the cassette 40 and insulate it from the inside of the cassette 40. To support.

Next, the gate valve 26 at the upper end of the shield box 20 is closed, and the transfer chamber (not shown) is transferred from above the shield box 20 to another predetermined location. In this way, the cassette 40 makes electrical contact with the holding electrode 22 to form the cathode electrode, while the cylindrical substrate 45, which is insulated and supported in the cassette 40, is grounded via the rod 23.

As described above, the cylindrical substrate 45 is housed in the holding electrode 22. Then, the cylindrical substrate 45 is rotated by the rod 23 as needed, and the cassette is held in vacuum.
In 40, the gas supply pipe 37, the insulating portion 35, the communication pipe 36, the annular space 33,
A reaction gas is supplied through the gas discharge holes 34 and the gas ejection holes 43, the inside of the cassette 40 is kept warm by the heater 28, and high-frequency power is supplied to the holding electrode 22 and the cassette 40, whereby the outer peripheral surface of the cylindrical substrate 45. A film of, for example, amorphous silicon is deposited on top.

The cylindrical substrate 45 on which film formation has been completed is carried out together with the cassette 40 in the reverse process of the carrying-in operation described above, and the cassette 40 is placed outside the reaction furnace.
Taken from.

After taking out the cylindrical substrate 45, the cassette 40 is disassembled, washed, and reassembled to be used for film formation.

However, in such a conventional film forming apparatus,
There are the following problems.

That is, the peripheral wall of the holding electrode 22 has a double structure so as to form a gas chamber, the structure is complicated, and it is very difficult to clean the annular space 33 serving as the gas chamber.

Further, when the cassette 40 is inserted into the holding electrode 22, a gas ejection hole 43 for uniformly discharging the source gas into the cassette 40.
Is formed on the inner peripheral wall 22F of the holding electrode 22.
The cassette 40 must be positioned so as to accurately match the position corresponding to, and high-precision work is required. If this position is deviated, the gas emission distribution will collapse and the amorphous-silicon film formed will have a non-uniform film thickness distribution, making it impossible to obtain a good electrophotographic photoreceptor.

Further, the reaction gas ejected from the gas ejection hole 43 is sealed,
The taper 22 at the upper and lower ends of the holding electrode 22 provided for discharging the reaction gas into the cassette 40 from the gas discharge hole 34
A and 22B fulfill the function by closely contacting the taper of the upper and lower ends of the cassette 40 over the entire circumference.

However, heating causes the holding electrode 22 and the cassette 40 to
When each of them expands in the direction of the central axis, even if the lower taper is in contact, the upper taper cannot be in contact, the reaction gas is not discharged into the cassette 40, and the taper 22A from the upper end to the exhaust hole 22C. Will leak out and be exhausted, and the reaction gas necessary for the reaction will not be supplied.

Further, high frequency power for causing a reaction is also supplied to the cassette 40 by the electrical contact of the taper portion, but the transmission path changes depending on the presence or absence of the contact of the upper taper 22A, and the electrical resistance of the material of the cassette 40. The discharge intensity distribution changes due to the potential drop due to
There is also a problem that the supply state of the reaction gas and the high-frequency power changes each time the cassette is replaced, and the reproducibility of the formed film characteristics deteriorates.

[Object of the Invention]

Therefore, the object of the present invention is to solve the above problems,
It is an object of the present invention to provide a film forming apparatus having a simple structure and capable of reliably supplying a reaction gas and high-frequency power into a cassette and stably forming a film on a substrate with a high yield.

[Outline of disclosure]

The film forming apparatus of the present invention includes a substrate mounting portion, a cathode electrode having a large number of gas ejection ports provided around the substrate mounting portion with a first space opened, and an exhaust gas for exhausting the space. And an area for accommodating a cassette for accommodating a substrate for film formation on a substrate mounting portion provided therein and accommodating the substrate, and forming at least a part of the area. A holding electrode connected to a power source formed around the cassette to be housed; and a second space formed between the cathode electrode and the holding electrode from the plurality of gas ejection ports A gas supply pipe for introducing a raw material gas to be supplied into the first space; a gas exhaust pipe for exhausting the first space through the exhaust port; and a gas exhaust pipe arranged to be in contact with the cathode electrode. Has a conductive gasket that can be electrically connected to the holding electrode It is characterized in.

〔Example〕

FIG. 2 shows a cross section of a reaction gas seal and a high frequency power supply unit in an embodiment of the film forming apparatus according to the present invention.

In FIG. 2, 50A is an upper conductive gasket, which is held in a groove formed in the upper inner peripheral wall of the holding electrode 22.

50B is a lower conductive gasket, which is also the holding electrode 60
Is held in a groove formed in the lower inner peripheral wall of the.

40A is a flange provided on the upper outer peripheral wall of the cassette 40,
When the cassette 40 is inserted into the holding electrode 60, it is partially tapered in order to facilitate tightening of the cassette 40 with the upper conductive gasket 50A. Further, the lower conductive gasket 50B is attached to the cassette 4 by the lower taper of the cassette 40.
The lower outer peripheral wall of 0 can be easily tightened. The upper flange 40A of the cassette 40 is formed so that the length of the seal portion region is long in consideration of expansion and contraction of the cassette 40 and the holding electrode 60 due to thermal expansion.

60 is a holding electrode, but unlike the conventional example, the inner peripheral wall 22F
If the cassette 40 is not inserted, the first
The annular space 33 serving as the gas chamber as shown in the drawing is not formed, and the annular space 51 serving as the gas chamber can be simultaneously formed by inserting the cassette 40. Therefore, the device of the present invention has a structure that allows maintenance such as cleaning to be extremely easily performed without impairing the function of releasing gas in a uniform distribution state without the cassette 40 being inserted. ing.

Further, the inner diameter of the upper conductive gasket 50A is larger than that of the lower conductive gasket 50B.
The insertion of the zero electrode into the holding electrode 60 is facilitated.

FIG. 2 shows a state in which the cassette 40 is already housed in the holding electrode 60, but the carrying-in method is not shown in the same manner as the conventional example described in FIG. 1 but the cassette 40 assembled outside the reaction furnace. The cassette 40 is stored in the transfer chamber and vacuum-transferred, the gate valve 26 attached to the upper part of the holding electrode 60 is opened, and the cassette 40 is inserted into the holding electrode 60 that has already been evacuated.

When the cassette 40 is inserted, the upper flange 40A
50A taper and lower taper are conductive gaskets
And 50B and further lowering the cassette 40 to compress the gaskets 50A and 50B, and the desired clamping required to seal the reaction gas at the position where the bottom of the cassette 40 reaches the bottom of the holding electrode 60. A force can be obtained.

However, this tightening force does not need to have a sealing property enough to maintain a vacuum, and the reaction gas in the vacuum will not exhaust the exhaust holes 22C and 2C.
It is enough if it does not leak from 2D.

When the cassette 40 reaches the above position, the upper and lower conductive gas packets 50A and 50B, the holding electrode 60, and the cassette 40 form an annular space 51 serving as a gas chamber.

After accommodating the cassette 40 in the holding electrode 60 in this manner, the suspension rod 23 is raised as in the conventional example, and the cylindrical electrode 45
Is electrically separated from the cassette 40.

Then, the gate valve 26 is closed, and the reaction gas is supplied into the annular space 51 from the gas supply system (not shown) through the gas supply pipe 37, the insulator 35, and the communication pipe 36 as in the conventional example, and further,
From there, the reaction gas is supplied into the cassette 40 through the gas ejection port 43. Further, the gas in the cassette 40 is discharged into the annular grooves 22C and 22D at the upper and lower ends of the holding electrode 60 via the exhaust portions 41A and 42A at the upper and lower ends thereof, and from there,
The gas is taken into the intake means via the gas exhaust pipes 32A and 32B.

Next, high-frequency power is supplied from the high-frequency power source 30 to the cassette 40 via the holding electrode 60 and the upper and lower conductive gas seals 50A and 50B to cause discharge and film formation.

The cassette after the film formation is carried out of the reaction furnace by the same procedure as the conventional example.

In the present invention, as the conductive gasket, one having excellent electric conductivity and elastic recovery force, for example, "helico.
Metal O-rings such as "Flex" (trade name, manufactured by CEFILAC (France)) are used. In addition, the surface of conductive rubber O-rings and electrically insulating O-rings such as silicon rubber is coated with Al. It is also possible to use those coated with a conductive material such as Ag, Au, or the like.

〔The invention's effect〕

As described in detail above, according to the film forming apparatus of the present invention, the structure of the holding electrode 22 can be simplified and the maintenance of the apparatus itself can be facilitated. Furthermore, since the gas seal and the instability of the high frequency power supply due to the dimensional deformation of the cassette due to the positional deviation at the time of carrying in the cassette and the heating during the film formation can be eliminated, if the cassette having the same shape is used, It is possible to always create the same film formation situation, and it is possible to mass-produce a deposited film having good characteristics with good reproducibility and high efficiency.

[Brief description of drawings]

 FIG. 1 is a sectional view of a conventional film forming apparatus. FIG. 2 is a sectional view of the film forming apparatus according to the present invention. 20 …… Shield box 30 …… High frequency power supply 40 …… Cassette 40A …… Flange 45 …… Cylindrical support 50A, 50B …… Conductive gas packet 51 …… Annular space 60 …… Holding electrode

Claims (2)

[Claims] 1. A substrate mounting portion, a cathode electrode having a large number of gas ejection openings provided around the substrate mounting portion with a first space provided, and an exhaust port for exhausting the space. And has a region for accommodating a cassette capable of accommodating a substrate for film formation on the substrate mounting portion provided therein, and accommodating at least a part of the region. A holding electrode connected to a power source formed around the cassette, the first space through a second space formed between the cathode electrode and the holding electrode from the plurality of gas ejection ports. A gas supply pipe for introducing a source gas to be supplied therein, a gas exhaust pipe for exhausting the inside of the first space through the exhaust port, the holding electrode arranged so as to be in contact with the cathode electrode, and Having a conductive gasket that enables electrical connection Film forming apparatus for the butterflies. 2. The film forming apparatus according to claim 1, wherein the conductive gasket is arranged so as to be in contact with the cathode electrode of the cassette.