JP3595433B2 - Plasma dry cleaner - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a plasma dry cleaner for cleaning the surface of each part on a substrate on which a semiconductor or the like is mounted by using plasma.
[0002]
[Prior art]
Conventionally, the surfaces of semiconductors and lenses have been cleaned with a liquid such as Freon. However, since CFCs cause environmental destruction, their production and use have been discontinued, and various organic solvents that have been used instead are also flammable and toxic to evaporative gases. There is a problem that handling is difficult. Therefore, a dry cleaning apparatus that cleans the surface with plasma has attracted attention in recent years.
[0003]
In a conventional plasma dry etching apparatus, a reaction chamber is cylindrical, and a pair of semi-cylindrical electrodes are arranged outside the reaction chamber along an outer wall of the reaction chamber, and an object to be cleaned is placed inside the reaction chamber. The tray was to be loaded. A reaction gas (cleaning gas) is introduced into the reaction chamber, and high-frequency power is applied between the two external electrodes to generate plasma. The particles were chemically removed by collision and reaction.
[0004]
[Problems to be solved by the invention]
Such a conventional apparatus has a drawback that the space efficiency in the reaction chamber is poor, and only a small amount of the object to be cleaned can be cleaned in spite of the large size of the entire apparatus. In addition, since both electrodes are outside, the ions in the plasma cannot be positively used, and a cleaning effect on inorganic contamination cannot be expected.
[0005]
The present invention has been made in order to solve such a problem, and an object of the present invention is to be able to wash a large amount of objects to be washed at a time with good space efficiency and to reduce organic and inorganic substances. Regardless, it is an object of the present invention to provide a plasma dry cleaner that can efficiently clean all kinds of stains and can easily set an object to be cleaned in a short time.
[0006]
[Means for Solving the Problems]
The plasma dry cleaner according to the present invention made to solve the above-mentioned problem,
a) a reaction chamber having a rectangular parallelepiped shape, which can be hermetically closed;
b) a slide rail provided on the inner wall surface of the reaction chamber for loading a plurality of trays into the reaction chamber;
c) It is composed of a tray side terminal provided on the tray and a reaction chamber side terminal provided in the reaction chamber, and when the tray is inserted into the reaction chamber, they come into contact with each other to electrically connect the reaction chamber and the tray. Electrical connection means;
It is characterized by having.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
In the present plasma dry cleaner, an electrode is buried in a tray inserted into the reaction chamber, or the tray itself becomes an electrode. The tray is inserted into the reaction chamber by being pushed along a slide rail provided on the inner wall surface of the reaction chamber, and the terminal on the tray side contacts the terminal on the reaction chamber side in the loaded state, so that the reaction chamber and the tray are contacted. Are electrically connected. This contact may be made to automatically contact by loading a tray as shown in an embodiment to be described later, or after loading the tray, for example, a hook provided on the near side of the tray A simple operation may be performed such that a contact is formed by an operation of rotating the to fix the tray.
[0008]
As described above, an electrode is embedded in the tray, or the tray itself becomes an electrode. Therefore, after the reaction gas is introduced into the reaction chamber, a high-frequency voltage is applied between (1) the tray and the inner wall of the reaction chamber, or (2) between the tray and the adjacent tray, so that the reaction gas is applied between the two. Is generated, and the object to be cleaned placed on the tray is cleaned. By using trays having various structures as described later, it is possible to perform cleaning by various methods.
[0009]
When used in the mode (2), it is necessary to prepare two types of trays, a ground side tray and a high frequency side tray. At this time, it is desirable that the electrical connection means of the ground side tray and the electrical connection means of the high frequency side tray are provided at different places so as not to contact with different types of electrical connection means. This eliminates the need for a troublesome operation of confirming the type of the tray before or at the time of loading and performing correct electrical connection, thereby reducing the burden on the user and preventing an electrical accident.
[0010]
【Example】
A plasma dry cleaner according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, a plasma dry cleaner 10 according to the present embodiment includes a reaction chamber 11 having a rectangular parallelepiped shape, and a control unit 12 provided in the same housing as the reaction chamber. On both sides of the inner wall of the reaction chamber 11, there are provided a plurality of rails 13 for inserting a tray 20 to be described later, and four rows of bus bars 14 and 15 are provided on the rear surface of the inner wall. The four rows of busbars 14 and 15 have the high frequency side 14 in the center two rows and the grounding side 15 in the outer two rows, and each of the busbars 14 and 15 has a tray side at a position corresponding to the height of the rail 13. Insertion ports 141 and 151 (FIG. 2) for inserting terminals are provided. An elastic holding means is provided in each of the insertion openings 141 and 151 to ensure contact when a later-described tray-side terminal is inserted.
[0011]
The control unit 12 includes a high-frequency unit for supplying high-frequency power for plasma generation (generally 13.56 MHz) to the high-frequency side terminal and a control circuit for controlling the operation of the entire cleaner.
[0012]
The tray 20 accommodated in the reaction chamber 11 is provided with a plurality of types having different structures and functions. First, there are two types, a high frequency side tray 21 and a ground side tray 22, depending on the polarity of the electrodes used. As shown in FIGS. 2 (a) and 2 (b), both have the same overall size, and both can be inserted into the rails 13 of any stage of the reaction chamber 11 without distinction. The projected positions of the provided terminals 24 and 25 are different. That is, the terminal 24 of the high frequency side tray 21 is provided near the center so as to fit the insertion port 141 of the high frequency side bus bar 14, and the terminal 25 of the ground side tray 22 fits the insertion port 151 of the ground side bus bar 15. As shown in FIG. Therefore, when the high frequency side tray 21 is pushed along the rail 13 of the reaction chamber 11, the terminal 24 of the tray 21 always enters the insertion port 141 of the high frequency side bus bar 14 and never enters the insertion port 151 of the ground side bus bar 15. There is no. Conversely, when the ground side tray 22 is inserted, the terminal 25 always enters the insertion port 151 of the ground side bus bar 15 and never enters the insertion port 141 of the high frequency side bus bar 14.
[0013]
Since the housing of the reaction chamber 11 is grounded, the high frequency side tray 21 is separated from the frame 211 contacting the rail 13 and the object-to-be-cleaned mounting plate 213 fixed inside the frame 211 via the insulating member 212. (FIG. 2A). The object-to-be-washed plate 213 serves as a high-frequency electrode for generating plasma, and the tray terminal 24 inserted into the high-frequency bus bar 14 protrudes rearward from the object-to-be-washed plate 213. The ground side tray 22 does not need to be electrically floated, and can be made of an electrically integrated metal body (FIG. 2B).
[0014]
Trays are divided into simple flat trays, grid-shaped trays, and open trays having an opening at the center in terms of shape.
[0015]
By appropriately combining these various trays, various types of articles can be washed in various modes as follows.
[0016]
(PE mode)
As shown in the upper two tiers of FIG. 3, the high-frequency side tray 31 is placed above and the ground side tray 32 is placed below, and the object 33 to be cleaned is placed on the lower ground side tray 32. In this state, the reaction chamber 11 is sealed, and after sufficiently exhausting air, a reaction gas is put into the reaction chamber 11 and high-frequency power (RF) is applied to the high-frequency side tray 31. Discharge occurs, and plasma (positive ions and electrons) of the reaction gas and radicals are generated. Here, the high-frequency side electrode (high-frequency side tray 31) is relatively negatively charged (self-bias) due to the difference in mobility between ions and electrons. For this reason, most of the positively charged ions are attracted toward the high frequency side tray 31, and the object 33 to be cleaned placed on the ground side tray 32 is mainly irradiated with radicals. The plasma etching (PE) mode is suitable for cleaning in which a strong etching action by ions is harmful, for example, for cleaning a semiconductor substrate or the like in which a vapor-deposited thin film still exists on the surface.
[0017]
The pressure of the reaction gas in the reaction chamber depends on the purpose of cleaning and the object to be cleaned, but is set to about several Torr to about 10-2 Torr.
[0018]
(Remote mode)
When the object to be cleaned further dislikes ion irradiation, as shown in the lower three rows of FIG. 3, between the upper high-frequency tray 34 and the ground-side tray 36 on which the lower object 33 is placed. The grid-side tray 35 on the ground side is inserted. As a result, ions traveling toward the lower ground-side tray 36 are captured by the ground-side grid-shaped tray 35, and the object 33 to be cleaned is irradiated with only radicals. This mode is suitable for cleaning when accumulation of charges is harmful, for example, when cleaning the insulating layer of a MOS semiconductor.
[0019]
(RIE mode)
As shown in the center of FIG. 3, when the ground side tray 32 is placed above and the high frequency side tray 34 is placed below and the object 33 to be cleaned is placed on the lower side high frequency side tray 34, reactive ion etching is performed. (RIE) mode. In this arrangement, as described above, the high-frequency side tray 34 is negatively charged by the self-bias, so that the ions of the reactive gas are strongly irradiated onto the cleaning target 33 on the high-frequency side tray 34. At this time, radicals in the plasma also carry out a chemical reaction. Therefore, the RIE mode is suitable for the purpose of cleaning, in which dust and rust are removed by physical impact of ion irradiation.
[0020]
(Both sides cleaning mode)
As shown in FIG. 4B, ground-side trays 41 and 43 are arranged vertically, and an opening tray 42 on the high-frequency side is inserted between the trays, and a metal-based cleaning object 422 is placed in the opening 421. Place. Then, the object to be cleaned 422 is irradiated with plasma ions from both sides, and both sides are cleaned at once. For example, a seek head for a hard disk drive has a structure in which an electrode layer is formed on both surfaces of a thin stainless steel sheet via a polyimide film. Such an article can be cleaned on both sides at once by using the plasma dry cleaner according to the present invention.
[0021]
The upper and lower trays may be on the high frequency side (RF), and the opening tray interposed therebetween may be on the ground side (GD). Alternatively, a grid-like tray may be inserted between the upper and lower trays and the opening tray, and the remote mode and the double-sided cleaning mode may be combined.
[0022]
(Magazine use mode)
When a series of processes such as vapor deposition and cleaning are performed on a small component such as a lead frame, it is very inefficient if the processes are performed one by one. Therefore, a container called a magazine 52 for accommodating a large number of small parts 51 in a shelf shape is used, and various processes are collectively performed for the large number of small parts 51 while being stored in the magazine 52. . In the plasma dry cleaner according to the present invention, such a magazine 52 is placed on a tray 54, and a tray 53 of the opposite polarity is disposed above the magazine 52 (or the ceiling itself of the reaction chamber may be used as a ground electrode). ), Cleaning can be performed in the PE mode or the RIE mode.
[0023]
The above-described various modes have been conventionally performed independently, but in the plasma dry cleaner according to the present invention, these can be performed simultaneously by appropriately arranging the trays. That is, it is possible to perform cleaning of various kinds of objects to be cleaned in a short time.
[0024]
【The invention's effect】
In the plasma dry cleaner according to the present invention, since a plurality of electrodes serving also as trays for placing the objects to be cleaned can be loaded into the reaction chamber, a large number of objects to be cleaned can be simultaneously cleaned, The number of processes per unit time is greatly increased as compared with the conventional cleaning apparatus. Further, since the reaction chamber is a rectangular parallelepiped, a uniform plasma distribution can be obtained in a relatively wide range by using a flat tray, so that many objects to be cleaned can be uniformly cleaned.
[0025]
Next, the electrical connection means of the ground side tray and the electrical connection means of the high frequency side tray are provided at different places so that they do not come in contact with different types of electrical connection means, so that it is troublesome when loading the tray. No electrode confirmation and connection operation is required, the burden on the user is reduced, and electrical accidents can be prevented.
[0026]
Further, by variously changing the polarity connection of the trays in the reaction chamber, it is possible to perform cleaning by various methods depending on purposes, such as a method of cleaning mainly with ions and a method of cleaning mainly with radicals. In addition, by preparing trays of various structures in addition to the above, cleaning can be performed by various methods such as cleaning from both sides of a planar conductive cleaning object and batch cleaning of small parts. .
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional perspective view of a plasma dry cleaner according to one embodiment of the present invention.
FIG. 2 is a perspective view showing a relationship between a high-frequency side tray (a) and a ground side tray (b) and a bus bar.
FIG. 3 is an explanatory diagram showing the relationship between the arrangement of various trays and a cleaning mode.
4A is a perspective view of an opening tray, and FIG. 4B is a cross-sectional view of a reaction chamber in use.
FIG. 5 is a sectional view of a reaction chamber in a magazine use mode.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Plasma dry cleaner 11 ... Reaction chamber 12 ... Control part 13 ... Slide rail 14 ... High frequency side bus bar 141 ... Terminal insertion port 15 ... Ground side bus bar 151 ... Terminal insertion port 20, 31, 32, 34, 36, 41, 53 54, tray 21 high frequency side tray 211 frame 212 insulating member 213 cleaning object mounting plate 22 ground side tray 24, 25 terminal 35 grid grid 42 opening tray 421 opening 422 Cleaning object 51: Small parts 52: Magazine

Claims (4)

a) a reaction chamber having a rectangular parallelepiped shape, which can be hermetically closed;
b) a slide rail provided on the inner wall surface of the reaction chamber for loading a plurality of trays into the reaction chamber;
c) It is composed of a tray side terminal provided on the tray and a reaction chamber side terminal provided in the reaction chamber, and when the tray is inserted into the reaction chamber, they come into contact with each other to electrically connect the reaction chamber and the tray. Electrical connection means;
A plasma dry cleaner comprising: Two types of trays, a ground side tray and a high frequency side tray, are provided, and the electrical connection means of the ground side tray and the electrical connection means of the high frequency side tray are provided at different places, and are related to the other type of electrical connection means. The plasma dry cleaner according to claim 1, wherein the plasma dry cleaner does not match. A grid-like tray used in the plasma dry cleaner according to claim 1. A tray having an opening for use in the plasma dry cleaner according to claim 1.

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