JP2005329353A - Plasma treatment method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure of an electrode having a high plasma generation efficiency and a means (manner) for voltage application to the electrode. <P>SOLUTION: A plurality of objects to be treated are arranged at intervals in a magazine and installed in a chamber; paired electrodes to which high-frequency electric power in different frequency bands is applied are arranged on the opposite to each other in both side faces of the magazine in the chamber; further gas supply ports for supplying a gas toward the electrodes are formed in at least two parts outside of both electrodes in the chamber; gas discharge adjustment ports are formed in at least two parts in two approximately center directions of the chamber; the gas gotten in plasma state by the electrodes is supplied to the objects to be treated from both side faces; and gas currents are generated toward the both side face directions from the gas supply direction to carry out plasma treatment under uniform gas flow in both of the front and the rear faces of the objects to be treated. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to semiconductor lead frame substrates, substrate substrates such as BGA or CSP, various electronic parts, fuel cell objects to be processed, surface modification, adhesion improvement, oxide film removal, etc. The present invention relates to a plasma processing method and apparatus used to process various objects to be processed. More specifically, an object to be processed (hereinafter simply referred to as an object to be processed) such as the above-described semiconductor lead frame substrate is placed in an airtight chamber, a process gas is supplied into the chamber in a reduced pressure atmosphere, and a high frequency is applied to the plasma electrode. The present invention relates to a plasma processing method and apparatus for converting a process gas into plasma by applying electric power and performing processing such as cleaning and surface modification using the plasma.

  The present invention is also applied to plasma processing performed as pre-processing such as chip mounting, wire bonding, and molding performed as a post-process of the semiconductor manufacturing process.

  In the plasma treatment, in a state where the process gas is supplied to the depressurized chamber, high-frequency power is applied to the electrodes to perform discharge to generate reactive species such as electrons, ions, radicals, etc., and etching, It is a technique for performing various processes such as filming and cleaning, and is carried out in a semiconductor device manufacturing process.

A reference example to be compared with the apparatus according to the present invention will be described with reference to FIG.
The chamber basically has a sealed structure, and an object to be processed is placed and unloaded by opening and closing a door (not shown). The electrodes A and B have a pair structure and are disposed at opposing positions sandwiching the workpiece to be plasma-treated, and the workpiece to be plasma-treated is above the substrate to which the third electrode C is connected. Are mounted one by one. When the arrangement of the objects to be processed is completed and the door is closed, a vacuum pump (not shown) is operated to discharge the gas in the chamber, and then the process gas is supplied to the electrodes A, B, and C. When the high frequency power is applied, the plasma treatment is performed by the process gas that has been turned into plasma by the discharge from the electrode coming into contact with the surface of the workpiece.

  The characteristic features of the above-mentioned apparatus are that the process gas is supplied and discharged in a simple direction from IN to OUT, electrodes A and B are formed of a plate material, and power supplies in different frequency bands are used. However, only a specific high frequency power such as 40 KHz is applied to the electrode A, and only another specific high frequency power such as 13.56 MHz is applied to the electrode B.

  On the other hand, in the plasma processing apparatus, various configurations are known in which two or more electric powers having different frequencies are applied to a plurality of discharge electrodes as described below.

  In Patent Document 1, a primary coil connected to a power source and an insulating coil connected to the upper and lower electrodes are connected between the upper and lower electrodes disposed opposite to each other in the vacuum vessel and the RF power source. A configuration is disclosed in which a transformer having a secondary coil is provided so that power is supplied to each electrode with the same voltage and with a phase shifted by 180 °.

  Patent Document 2 discloses a configuration in which a tap is provided on a secondary coil so that different voltages are supplied to opposing electrodes while being 180 degrees out of phase.

  In Patent Document 3, the primary side coil connected to the first power source and the secondary side coils connected at both ends to the first and second electrodes respectively have a phase difference of 180 ° from each other. A transformer that feeds power to the first and second electrodes and power that has a frequency different from that of the power fed from the first power supply are superposed on and fed to at least one of the first electrode and the second electrode. A configuration having a second power supply is shown, and it is disclosed that power having a frequency of about 40.6 MHz is supplied to the first electrode and power having a frequency of about 13.56 MHz is supplied to the second electrode. Has been.

  Patent Document 4 has a primary side coil connected to an RF power source and a secondary side coil connected to an upper electrode and a lower electrode. Power is supplied to both electrodes through the RF power source, and power of a frequency of about 350 to 450 kHz is supplied to each electrode from the RF power source. As power supplied from the RF power source, power having different frequencies is supplied from the high frequency power source to the upper electrode. The high frequency power supply supplies power with a frequency of about 40.6 MHz to the upper electrode, and power with a frequency of about 13.56 MHz to the lower electrode. A configuration is disclosed.

  In Patent Document 5, a processing container that can be evacuated, a wafer mounting table that is disposed in the processing container and has a mounting surface for mounting a wafer to be processed, and a mounting surface that faces the above-described mounting surface, A plurality of gas flow paths forming a multiple spiral structure along a plane substantially parallel to the writing surface, and a gas flow path for each gas flow path on the surface of the gas flow channel facing the mounting surface. A gas-phase processing apparatus including a plurality of gas ejection holes formed along the same is disclosed. The plurality of gas flow paths are formed of a conductive material, and further, high-frequency power is supplied to the plurality of gas flow paths. A configuration in which at least one high-frequency power source is provided, the plurality of gas flow paths are electrically insulated from each other, and the high-frequency power supply is provided for each of the plurality of gas flow paths. High frequency of at least two frequencies from at least one A configuration for supplying the folded high-frequency power at a desired power ratio, a configuration in which a surface facing the mounting surface of the plurality of gas flow paths is a flat surface parallel to the mounting surface, the first and first In one of the two gas phase processing steps, or in both the first and second gas phase processing steps, high frequency power is supplied to the plurality of gas flow paths to generate high frequency plasma in the processing vessel. And a configuration for supplying high-frequency power on which at least two types of frequencies are superimposed in one of the first and second vapor-phase processing steps is disclosed. .

  In Patent Document 6, a high frequency power component (RF power having a relatively high frequency) having a frequency of fHIGH and a low frequency power component having a frequency of fLOW (RF power having a relatively low frequency) are applied to an electrode in a vacuum chamber. ) Is applied in a plasma, and the processing gas is converted to plasma, and the object to be processed placed on the electrode is subjected to predetermined processing by the plasma. A configuration is disclosed in which the frequency is controlled so as not to follow a change in the electric field therein.

  In the configuration of Patent Document 6, (1) the frequency fLOW of the low-frequency power component is a frequency that is relatively higher than the ion plasma frequency of ions that are ions in the plasma and that are the main component of the ion-assisted plasma treatment, preferably Ions generated by following a change in electric field even in high-density plasma if the frequency fLOW is set to 3 MHz to 10 MHz, more preferably, the frequency fLOW is set to 3 MHz. (2) If a power of the above frequency is used, a high self-bias voltage can be generated on the electrode, so that ions can be accelerated to a desired state. (3) Since the period during which ions are accelerated becomes longer, for example When the processing member is subjected to an etching treatment, without etching rate decreases, it is stated that it is possible to perform uniform processing reliably. (4) If the frequency fHIGH of the high-frequency power component is set to 10 MHz or more, the processing gas introduced into the chamber can be reliably dissociated, so that high-density plasma can be generated, It is stated that microfabrication can be performed rapidly and uniformly on the processing body, and the maximum frequency fHIGH is 200 MHz, preferably 100 MHz.

  In Patent Document 7, a CVD (chemical vapor deposition) apparatus, in particular, a function of forming a film on a wafer or the like using microwave plasma and radio frequency (RF) plasma is generated on the inner wall surface of the reaction chamber at the time of film formation. As a high-density plasma CVD apparatus having a cleaning function for removing deposited deposits, a reaction chamber having an upper chamber, a middle chamber, and a lower chamber that are electrically insulated from each other, and a reaction chamber disposed in the reaction chamber, A substrate electrode on which an object is disposed, a microwave introduction part for introducing microwaves into the reaction chamber, and a film forming gas is introduced into the reaction chamber during film formation on the object to be processed, and the reaction chamber is disposed during cleaning of the deposited film A gas introduction part for introducing an etching gas into the gas, a discharge part for discharging the gas from the reaction chamber, and a first high-frequency power source connected to the substrate electrode And a deposited film cleaning method for a plasma CVD apparatus configured to include a second high-frequency power source connected to the middle chamber, wherein the reaction chamber of the plasma CVD apparatus is electrically insulated from each other, an upper chamber, a middle chamber, Divided into lower chambers, the upper and lower chambers are grounded, an etching gas is introduced into the reaction chamber by a gas introduction unit, and a high frequency voltage is applied from the high frequency power source to the middle chamber and deposited in the reaction chamber. A configuration for cleaning a deposited film of a thin film material is disclosed.

Patent Document 8 uses plasma such as RIE (Reactive Ion Etching) having means for solving the problem that radical species generated by plasma and reactive products generated by etching adhere to the inner wall of the vacuum reaction chamber. As a plasma processing apparatus, a processing container that performs plasma processing and a substrate to be processed that is provided in the processing container and on which plasma processing is performed are placed, and high-frequency power having two or more frequencies is applied. For monitoring whether the inside of the processing container is in a predetermined state, the gas introduction means for introducing a gas to be plasma into the processing container, the power generating means for generating electric power having two or more frequencies Means for monitoring the impedance, voltage, current and system related to the system in the processing vessel including the plasma and electrodes generated in the processing vessel. Configuration at least one physical quantity of a phase and a monitor means including measuring means for measuring simultaneously for the two or more frequencies is disclosed.
Japanese Patent Laid-Open No. 2-177459 Japanese Patent Laid-Open No. 4-48727 Japanese Unexamined Patent Publication No. 7-74159 JP-A-8-31596 JP-A-8-55802 JP 2000-156370 A JP 2002-235173 A JP 2002-299322 A

An object of the present invention is to solve the following problems.
In the apparatus of the reference example shown in FIG. 14, a substrate (base) on which an object to be processed is placed is placed on one electrode C, and an electrode A placed at a predetermined interval from this electrode C. The plasma is generated by the discharge between the electrode B and the electrode B. In the apparatus having such an electrode structure, since the generation efficiency of plasma is low, not only processing time is long, but also dissatisfaction is left in processing performance. For this reason, an electrode structure with high plasma generation efficiency and a power coining means (system) for the electrode are desired.

  In addition, it can be said in common with the above-mentioned Patent Documents 1 to 8. Since the objects to be processed are arranged one by one on the substrate, the unprocessed objects that have undergone the plasma processing are unloaded and the objects to be processed next time. In addition to taking time and labor, the amount of plasma treatment at one time is limited. For this reason, the structure which increases the quantity of the to-be-processed object which can be processed at once, and the structure which can perform the arrangement | positioning work of the to-be-processed object to a chamber simply and rapidly are desired.

  Furthermore, as can be said in common with the Patent Documents 1 to 8, since the objects to be processed are various and have different sizes and shapes, the size and shape of the objects to be processed, and the amount of the objects to be processed, etc. It is desired to improve the structure of the chamber that can be arbitrarily adapted, in particular, the supply means of the object to be processed, the size change of the processing space, and the corresponding structure of the electrodes associated therewith.

  Next, the processing gas supplied into the chamber in a reduced pressure atmosphere is turned into plasma by the discharge between the electrodes. However, when the flow of the plasma gas in the chamber is poor, the plasma gas is unevenly distributed. As a result, a difference occurs in the amount of plasma gas in contact with the surface of the object to be processed, so that uniform processing cannot be performed, and generally only a low processing capacity is obtained. For example, even if a configuration in which the plasma gas is forced to flow in the chamber by a fan or the like is adopted, the conventional electrode structure is plate-like, and this becomes a barrier, so that the surface of the non-processed object is A homogeneous flow of plasma gas toward it will not be obtained. From this point of view, an electrode structure capable of improving the plasma flow is desired.

  Therefore, a first problem of the present invention is to provide an electrode structure with high plasma generation efficiency and a power coining means (method) for the electrode, and the second problem can be processed at a time. It is to be able to increase the amount of the object to be processed, and the third problem is that it is possible to easily respond to the supply means of the object to be processed, the size change of the processing space, and the correspondence of the electrodes accompanying them. The fourth problem is to provide a plasma processing method and apparatus capable of uniform plasma processing.

The present invention for solving the above problems has the following configuration.
1. A plurality of objects to be processed are stored in a magazine with a space between them and placed in a chamber, and high frequency power in different frequency bands is applied to both sides of the magazine in the chamber (up and down depending on the magazine opening direction). Further, a pair of electrodes are arranged in a face-to-face structure, and at least two gas supply ports for supplying gas toward the electrode direction are provided outside the both electrodes of the chamber. Is provided with at least two gas discharge control ports, and the gas converted into plasma by the electrodes is supplied from both sides of the workpiece (up / down depending on the magazine opening direction), and then the gas supply direction By creating a gas flow in both sides (up and down depending on the magazine opening direction), plasma treatment is performed under a uniform gas flow on both the front and back surfaces of the workpiece. The plasma processing method comprising and.

2. One of the power applied to the pair of electrodes is a current in a frequency band of 1 KHz to 200 KHz, preferably 40 KHz, and the other of the power is a current in a frequency band of 1 MHz or more, preferably 13.56 MHz. The plasma processing method according to 1 above.

3. 3. The plasma processing method according to 1 or 2 above, wherein the pair of electrodes are formed by arranging thin wires side by side on the same plane.

4). 4. The plasma processing method according to any one of 1 to 3, further comprising an electrode position adjusting mechanism that changes the position of the electrode in accordance with the size of the magazine.

5. The processing object disposing means for storing a plurality of objects to be processed in a magazine at intervals, and disposing them in the chamber, and different frequencies on both sides of the magazine in the chamber (up and down depending on the magazine opening direction) A plasma generating means in which a pair of electrodes to which a high frequency power of a band is applied is arranged in a face-to-face structure; and a gas supply port for supplying gas toward the electrodes at least outside the both electrodes of the chamber Two places are provided, and at least two gas discharge adjustment ports are provided in approximately two directions in the center of the chamber, and the gas converted into plasma by the electrodes is on both sides of the workpiece (up / down depending on the magazine opening direction). Gas distribution means for supplying gas from the direction and then performing gas flow in both sides of the gas supply direction (up and down depending on the opening direction of the magazine). And a plasma processing apparatus which is a structure in which a plasma treatment is performed under a uniform gas flow to both sides of the back.

6). One of the power applied to the pair of electrodes is a current in a frequency band of 1 KHz to 200 KHz, preferably 40 KHz, and the other of the power is a current in a frequency band of 1 MHz or more, preferably 13.56 MHz. The plasma processing apparatus according to 5 above.

7). 7. The plasma processing apparatus as described in 5 or 6 above, wherein the pair of electrodes has thin wires arranged in parallel on the same plane.

8). 8. The plasma processing apparatus according to any one of 5 to 7, further comprising an electrode position adjusting mechanism that changes an electrode position in accordance with a size of the magazine.

  If the thin wire in the present invention is a conductive material including a flexible conductive material such as a wire or a self-holding rigid conductive material such as a rod, the cross-sectional shape is circular, elliptical, It can be any square. In addition, the juxtaposition on the same plane is not limited to the case where they are strictly arranged on a straight line, but is within the range of the outer diameter (φ0.5 to 20 mm) of the thin wire as shown in FIGS. It may be displaced in any direction as long as it is within 20 mm.

  According to the first to fifth aspects of the present invention, plasma is generated by applying power from two power sources having different frequency bands, and the electrodes to be arranged are devised, so that plasma is generated efficiently. It is possible to make it. In addition, the circuit configuration can be simplified as compared with the conventional apparatus adopting the dual power supply system, which is beneficial for reducing the manufacturing cost of the apparatus. Further, since the magazine can be used to arrange the processing object in the chamber, the amount that can be processed at a time can be remarkably increased as compared with the conventional apparatus. It is possible to arrange and discharge the processed material in the chamber in a short time, and a significant improvement in processing efficiency can be expected.

  According to the second and sixth aspects of the invention, plasma can be generated efficiently regardless of the electrode material and the like.

  According to the third and seventh aspects of the present invention, the plasma gas flow in the chamber is remarkably improved, and in particular, since the electrode does not become a barrier to the plasma gas flow, a new plasma to the object to be processed can be obtained. The gas contact rate is improved, and the processing performance can be remarkably improved. In addition, according to the electrode structure disclosed in the present invention, the degree of freedom of the arrangement structure of the objects to be processed in the chamber is improved, and the amount of objects to be processed that can be processed at one time is significantly increased. It has become possible to deal with plasma processing of a wide variety of workpieces with different sizes and shapes.

  According to the fourth and eighth aspects of the present invention, it is possible to easily respond to the supply means of the object to be processed, the size change of the processing space, and the correspondence of the electrodes associated therewith.

  In the following description, a case will be described in which counter-structured electrodes are arranged in a face-to-face structure on both sides of a magacin set in the chamber, but depending on the magazine opening direction (gas flow introduction direction)・ It is arranged in the downward direction.

A plasma processing method and apparatus according to the present invention will be described in detail with reference to the accompanying drawings.
First, according to FIG. 1, the whole plasma processing apparatus according to the present invention will be outlined. The main body device 100 includes a chamber 110 having a configuration described later. By opening the door 120 of the chamber 110, the magazine 130 in which a large number of objects to be processed can be loaded and unloaded. In a preferred embodiment, an operation panel 140 for operating the apparatus is disposed on the front surface of the main body apparatus 100.

  The power supply apparatus 200 supplies power with a frequency of 40 KHz and 13.56 MHz as a preferred mode, but in short, if the power of the KHz band frequency and the power of the MHz band frequency are combined according to the object to be processed, etc. Well, as described above, many commercial products are known for the high frequency power supply device in this band, and a commercially available high frequency power supply device designed for plasma generation as shown in Patent Documents 1 to 8 is used. can do.

  The vacuum pump 300 eliminates the gas in the chamber 110, the supplied process gas, the purge gas, etc., and the capacity varies depending on the capacity of the chamber 110 (the number of objects to be cleaned at one time). It will be a thing. As the vacuum pump 300, various commercially available vacuum pumps can be used.

  Process gas (for example, oxygen gas or argon gas) and purge gas (for example, nitrogen gas) are supplied in the form of gas cylinders 400 to 402, but the use of other supply forms is not limited.

  The plasma processing method and apparatus according to the present invention are characterized by the structure of the discharge electrode disposed in the chamber 110, the structure for supplying and discharging the gas, the structure of the magazine for disposing and unloading the workpiece. This will be described in detail below.

  FIG. 2 schematically shows an embodiment of the plasma processing apparatus according to the present invention. The arrangement of each member such as an electrode in the chamber 30 is clearly shown. It has already been described that the chamber 30 is sealed and released by opening and closing the door 120 (see the chamber 110 and the door 120 in FIG. 1).

  Arrangement / unloading of the workpiece 10 is performed via the magazine 20, and the configuration of the magazine 20 will be described in detail later.

  For example, the electrode 40 to which high frequency power of 13.56 MHz is applied and the electrode 50 to which high frequency power of 40 KHz is applied, for example, have a composite electrode structure, that is, a multi-electrode structure. 41 and 51 are arranged in a face-to-face relationship with the magazine 20 interposed therebetween.

  Reference numeral 60 denotes a gas introduction plate. Preferably, at least an area where the electrode exists is provided with a through hole (including a slit) so that the gas flow is directed toward the electrode portion. In order to guide it to be supplied in the direction of the workpiece 10, the internal space of the chamber 30 is partitioned.

  In this embodiment, process gas or the like is supplied in the form of cylinders 400 to 402 as described above, but is supplied into the chamber 30 through the gas supply ports 31 and 32 according to control of a valve (not shown), and gas is discharged. Since the gas is discharged from the adjusting ports 33 and 34, the gas supplied from the gas supply ports 31 and 32 is dispersed by the gas introduction plate 60 as the gas flow in the chamber 30. It flows in the direction of the electrodes 41 and 51, and then flows through the gap between the processed object 10 and the processed object 10 in a stacked state in the magazine 20, and the left and right flows merge in the vicinity of the center and flow to the side. Then, the gas is discharged from the gas discharge adjusting port 33 disposed above the chamber 30 and the gas discharge adjusting port 34 disposed below. However, the gas discharge adjusting ports 33 and 34 are not limited to the upward and downward directions, and may be provided on both side surfaces of the chamber 30 that are substantially perpendicular to the gas flow direction. That is, it is sufficient that the chamber 30 has almost two directions in the center.

  Reference numeral 35 denotes a vacuum suction discharge port for vacuum suction performed for discharging the gas in the chamber 30.

  For the chamber 30, the type of gas used as a plasma generating gas (process gas), such as oxygen gas or argon gas, and the amount used (pressure) thereof, for example, can be determined by taking into account conventional technology. That's fine. That is, they are not directly related to the present invention, and therefore the essence of the present invention is not influenced by the difference in the type of gas and the amount (pressure) thereof.

  As the frequency of power applied to the electrodes, for example, a range of 1 KHz to 200 KHz, preferably 40 KHz, a frequency band of 1 MHz or more, preferably a frequency band of 13.56 MHz, or a frequency band of 2.45 GHz is selected. Which frequency band is used is not an essential element for the present invention.

Hereinafter, how the workpiece 10 is disposed in the chamber 30 will be described.
There are many types of workpieces 10 in terms of size and external shape. Therefore, depending on the position of the workpiece 10 in the chamber 30, the number that can be processed at one time is limited, resulting in a significant reduction in processing efficiency. Is inevitable. In particular, it is extremely inefficient to arrange and carry out the workpieces 10 to and from the chamber 30 one by one.

  Therefore, in the present invention, attention is paid to the fact that the shape of the object to be processed 10 is basically a flat plate, and a configuration in which these are horizontally stacked at a constant interval (see 3-1 in FIG. 3). The upper surface and the lower surface of the workpiece 10 are simultaneously plasma-processed by the plasma flow in the direction of the arrow A or the direction of the arrow B by a configuration in which they are arranged vertically at regular intervals (see 3-2 in FIG. 3). This makes it possible not only to dramatically increase the amount of the workpieces 10 that can be processed at one time, but also to use the magazine 20 to improve the efficiency of arrangement and unloading to the chamber 30. Dramatically improved.

  In FIG. 3, since there is a structural problem in arranging the electrodes and the like in the magazine arrangement / unloading direction, particularly the front surface position of the chamber 110 in FIG. The position of the arrow B is natural. Of course, the idea of incorporating electrodes and the like into the door 120 in FIG.

The magazine 20 will be specifically described.
The magazine 20 will be described in detail with reference to FIGS.
The magazine 20 shown in FIG. 4 is an example of a bottomless box type, and hangers 21 for suspending the workpiece 10 are connected in multiple stages on both side surfaces of the inner wall. The slit 22 is formed so that the intermediate part of the hanger part 21 and the hanger part 21 becomes a through-hole.

  In the above embodiment, the slit 22 can be provided on the upper surface portion and the lower surface portion. Moreover, although it demonstrated that it was a bottomless structure, depending on the kind etc. of the to-be-processed object 10 to accommodate, it can also be set as a bottomed structure, and in order to ensure the flow of gas in the provided low part, A slit 22 is preferably provided.

  As is clear from the above description, it is important for the magazine 20 to stably suspend a large number of objects to be processed 10 and to determine the interval between the objects to be processed 10 in a stacked state. It is better not to adopt a configuration that hinders the movement of plasma particles. Therefore, the combination of the continuous hanger portion 21 and the slit 22 is not an absolutely necessary constituent element. As described above, if the strength sufficient to accommodate a large number of workpieces 10 is ensured, the slit 22 A configuration in which the entire surface is in a released state without providing the above is a preferable mode. Furthermore, the fact that the hanger portion 21 has a ridge configuration means that the hanger portion 21 becomes an obstacle to plasma movement. For example, there are various configurations other than the configuration in which the hanger portion 21 is a thin ridge. A configuration is preferably employable.

  If the structure which can be employ | adopted according to the above is enumerated as an example, the hanger member which has the several hanger part 21 will be a structure which is a comb-like board as a whole, and the whole hanger member including the hanger part 21 is formed with a metal wire etc. Examples include the configuration. The hanger member described above may be assembled by a frame formed of a metal wire or the like.

The posture in the chamber 30 of the magazine 20 of the embodiment shown in FIG. 4 will be described.
In the posture of the magazine 20 shown in 5-1 of FIG. 5, since the workpieces 10 are in a state of being flatly stacked, gas flow from the directions of A1, A1, and A2, A2 is possible. As will be described later, electrodes are arranged on the sides of A1, A1, and A2, A2.

  In the posture of the magazine 20 shown in 5-2 of FIG. 5, since the objects to be processed 10 are arranged in the vertical direction, the gas flow from the directions of A3, A3 and B1, B1 is possible. As will be described later, electrodes are arranged on the sides of A3 · A3 and B1 · B1.

Next, the electrode will be described.
The electrodes 40 and 50 and the electrodes 41 and 51 shown in FIG. 2 form an electrode unit and are arranged to face each other in the gas flow direction.

  The structure of the electrode unit is shown, for example, in FIGS. 6 and 7. For example, the electrodes in which conductive thin wires are connected in a U shape are arranged side by side (more preferably, alternately arranged) on the same plane. In the illustrated embodiment, for example, 40 KHz power is applied to the electrodes 40 and 41, and high frequency power of 13.56 MHz is applied to the electrodes 50 and 51, for example. As a material for forming the electrode, for example, a conductive material such as aluminum can be preferably used. For example, an aluminum wire or a round bar having a diameter of 0.5 to 20 mm is preferably used, but the material and the size are not limited thereto. Absent. Further, it is possible to adopt a configuration in which the electrode material and size are different depending on the applied frequency band.

  Since the present invention can apply a high frequency in parallel to the object to be processed 10 by arranging the electrodes facing each other, both surfaces of the object to be processed 10 in the magazine 20 can be simultaneously plasma processed uniformly. It is.

  FIG. 9 shows a configuration in which electrodes 40 (41) and electrodes 50 (51) are alternately arranged on a frame 45 formed of a non-conductive material. In the illustrated embodiment, thin wires (wires, rods, etc.) having different thicknesses are used as electrodes, but at least one electrode, preferably both electrodes, are connected to parallel thin wires, for example, strip-shaped plates. Can be used.

  FIG. 10 shows a configuration in which square electrodes 40 (41) and 50 (51) made of fine wires of different sizes are arranged concentrically and fixed by respective conductive frames 45 and 46, respectively. It is shown. As shown in the figure, the frames 45 and 46 are not limited to the configuration in which the frames 45 and 46 are arranged in a vertical and horizontal cross shape. Needless to say, one of the conductive frames 45 (46) acts to energize one of the electrodes.

  It is not desirable that the frame for fixing or maintaining the posture of the electrodes 40 (41) and 50 (51) occupy a large area with respect to the direction of gas flow, and it is preferable to eliminate factors that obstruct gas flow as much as possible. . Therefore, it is preferable that the frame for the electrode has a large arrangement space with respect to the direction of gas flow, or has a perforated structure in which an opening is provided in itself.

  The structure of the electrode unit is not limited as long as the thin wires constituting each electrode are arranged in parallel on the same plane (including the case where they are substantially on the same plane), as shown in FIGS. The present invention is not limited to a combination of straight thin lines, and may be a combination of curved thin lines such as a square shape or a spiral shape as shown in FIG.

  In the case of a plate-like electrode like the electrode of a conventional device, the whole plate becomes an electrode, so that plasma cannot be generated efficiently. However, the electrode according to the present invention is constituted by a combination of fine wires. The plasma can be efficiently generated around the periphery, that is, between the electrode gaps. For example, as shown to 8-1 of FIG. 8, according to the structure by which the electrode 40 (41) and the electrode 50 (51) are arrange | positioned on the same plane, as shown to 8-2 of FIG. The range where the discharge effect extends is overlapped around each electrode, and plasma can be generated efficiently. Therefore, high-density plasma can be efficiently sent to the magazine by allowing gas to flow efficiently through the gaps between the electrodes. By arranging the electrodes in the direction of gas flow, active plasma can always be supplied in the magazine. It is possible to apply to a processed material uniformly.

Next, the adjustment configuration of the present invention will be described.
The magazine of the conventional apparatus is manufactured with various shapes and dimensions depending on the type of the object to be processed 10, and when plasma processing is performed, the distance from the electrode to the magazine may be too far, and the effect may be reduced. By using a structure that can be adjusted, the magazine 10 of any shape and size can be used.

  FIG. 11 shows an example of a mechanism for adjusting the electrode position. In this embodiment, the base 71 of the electrode 70 moves along the rail 72. The number of rails 72 is preferably two or more.

  The electrodes 70 are movable in the direction of the arrows along the rails 72. When a magazine 20 having a narrow width is provided as shown in 11-2 of FIG. 11, the respective electrodes are moved inward. Thus, the distance between the electrode and the object to be processed can be adjusted.

It is also possible to arrange the rails 72 on the ceiling side of the chamber 30 and suspend the electrodes 70.
The gas introduction plate 60 may be configured to be movable together with the electrode 70, but the gas introduction plate 60 is preferably configured to be fixed at a specific position in the chamber 30 as shown in FIG.

  The electrode position adjusting mechanism has a different configuration depending on the electrode arrangement structure (see FIG. 5). For example, in the configuration in which the electrodes are arranged above and below the magazine, the rail 72 is positioned in the vertical direction, so that some kind of stopper structure for fixing at a specific height is required.

  The invention shown in claims 4 and 8 is characterized in that it has a mechanism for changing the electrode unit of the pair structure arranged with the magazine sandwiched in accordance with the size of the magazine arranged in the chamber. A known configuration may be employed as a mechanical mechanism for adjusting the electrode position.

Next, gas distribution will be described.
As described with reference to FIG. 2, in the present invention, several vacuum outlets are provided for each purpose. For example, when the chamber 30 is evacuated from atmospheric pressure, the outlet 35 provided on the back surface of the chamber 30. In addition, gas discharge adjustment ports 33 and 34 for fine adjustment are provided in the top and bottom of the chamber 30. In addition, you may arrange | position unevenly up and down, right and left.

  As shown in FIG. 12, by arranging the gas discharge adjusting ports 33 and 34 for finely adjusting the exhaust gas on the top and bottom, the high-density plasma flow from the directions of the arrows A and A is directed to the directions of the arrows B and B. Therefore, the gas flow is not stagnated. Therefore, it is possible to efficiently perform the plasma treatment on both surfaces of the workpiece 10.

  In order to efficiently introduce the process gas into the electrodes 40 (41) and 50 (51), a so-called gas projector is used as the gas introduction plate 60 (see FIG. 2) provided with a large number of through holes. explain.

  In FIG. 13, reference numeral 61 denotes a hollow box, which is disposed outside or inside the chamber 30, and is disposed in the chamber 30 so as to be in close contact with the outer wall or the inner wall of the chamber 30 via a packing member or the like. A large number of apertures 62 are provided on one side surface of the box 61 with a width corresponding to the area of the electrode as indicated by phantom lines, and the gas supplied from the direction of the arrow is the aperture 62. Will flow directly to the electrode. Instead of the simple opening 62, a configuration in which a small cylinder or nozzle is arranged may be used.

  According to the above-described configuration, the gas flow rate toward the electrode is remarkably large compared to the configuration in which the gas is supplied through the opening provided in the wall surface of the chamber 30, and an amount of plasma corresponding to the amount of the supplied gas is generated. be able to. Since the pressure in the chamber 30 is delicate and adjusted to an optimum pressure, there is a limit to the amount of gas that can be supplied into the chamber 30, and therefore, the amount of raw gas that has not been converted to plasma, that is, raw gas, Considering the ratio with the amount of plasma gas flowing through the electrode portion, the introduction of gas by the gas introduction plate 60 having a simple configuration may increase the amount of gas that is not converted to plasma. In the example using, this can be solved greatly.

A process for plasma-treating an object to be processed using the apparatus described above will be described.
A:. Arrangement of magazines (objects to be processed) The objects to be processed 10 are stored in the magazine 20 by automatic operation or manual operation and placed in a standby state, and are sequentially arranged in the chamber 110 for each magazine 20. The As a matter of course, the cleaning apparatus 100 may be configured to store a plurality of magazines 20 and perform cleaning simultaneously. In such a configuration, the cleaning apparatus 100 may have a plurality of chambers 110.

  When the placement of the magazine 20 in the chamber 30 (110) is completed, the door 120 is closed and the chamber 110 becomes a sealed space.

B: Preliminary process When the chamber 110 becomes a sealed space by closing the door 120, the vacuum pump 300 is operated, and the gas in the chamber 110 is discharged to be in a vacuum state.

C: Plasma Processing Step In the plasma processing step, first, a process gas prepared in the gas cylinder 400, such as oxygen gas, is supplied into the chamber 110, and then the electrodes 40 and 41 and the power source 50 are operated by the operation of the power supply device 200. A voltage is applied to each of 51. In the treatment with oxygen gas, the surface of the workpiece 10 is treated by a chemical reaction with the oxygenated gas, and the surface of the workpiece 10 is hydrophilized. In the process in which argon gas is supplied as a process gas, inorganic substances such as an oxide film formed on the surface of the object to be processed 10 are removed by a sputtering effect.

The gas used in the plasma processing step is not particularly limited, and various known and publicly used gases such as Ar, O ₂ , CF ₄ , N ₂ , and a mixed gas thereof can be selectively used. It is. The supply amount of the process gas and the time required for the processing step vary depending on the size of the chamber 110 or the number of objects 10 to be processed.

D: Purging Step After the plasma processing step has passed for a predetermined time, the application of high-frequency power to the electrodes is stopped, the vacuum pump 300 is stopped, and a purge gas prepared in the gas cylinder 402, for example, nitrogen gas is supplied. Return to atmospheric pressure.

E :. About discharge of magazine (object to be processed) When the inside of the chamber 110 is returned to atmospheric pressure, the door 120 is opened, the cleaned object 10 to be processed is discharged from the chamber 110 together with the magazine 20, and a series of processing steps is completed. Become.

Plasma treatment as a pretreatment for chip mounting and wire bonding was performed under the following conditions.
Used apparatus: The apparatus shown in FIGS. 1 and 2 was used.
Process gas used: Argon gas
Gas supply rate: 10 / ml / min
Chamber pressure: 5Pa
Power: 13.56MHz, 200W
40KHz, 600W
Processing time: 5 minutes Size and amount of workpieces: 180mm x 40mm on each level (shelf) with 20 levels
× BGA board with a thickness of 0.5 mm (consisting of 5 to 6 parts)
Was stored for one sheet.

  The effect was judged by the average contact angle of water on the surface of the treated object. The average contact angle before the treatment was 100 degrees, whereas that after the treatment was 15 degrees or less, and it was confirmed that the treatment ability was excellent.

Plasma treatment as a pretreatment for molding was performed under the following conditions.
Used apparatus: The apparatus shown in FIGS. 1 and 2 was used.
Process gas used: Argon gas and oxygen gas mixed
Gas supply rate: Argon gas 50 ml / min
Oxygen gas 100ml / min
Chamber pressure: 130Pa
Power: 13.56MHz, 100W
40KHz, 300W
Processing time: 3 minutes Size and amount of workpieces: 180 mm x 15 mm x 20 tiers (shelf)
× Lead frame with a thickness of 0.5 mm
N) was stored for one sheet.

  The effect was judged by the average contact angle of water on the surface of the treated object. The average contact angle before the treatment was 100 degrees, whereas that after the treatment was 15 degrees or less, and it was confirmed that the treatment ability was excellent.

Schematic of the processing apparatus according to the present invention Schematic of a chamber performing a processing method according to the present invention Schematic showing the posture of the workpiece in the chamber Schematic showing an example of a magazine according to the present invention Schematic showing the attitude of the magazine according to the present invention Schematic front view showing an example of an electrode according to the present invention Schematic plan view showing an example of an electrode according to the present invention Action explanatory diagram of electrode according to the present invention The schematic perspective view which shows the other example of the electrode which concerns on this invention Schematic front view showing another example of the electrode according to the present invention Schematic front view showing an example of an adjuster for electrode positions Conceptual diagram showing the gas flow for the workpiece Schematic perspective view showing an example of a gas guide member according to the present invention Schematic showing a chamber of a plasma processing apparatus as a reference example

Explanation of symbols

10-processed object 20-magazine 21-hanger part 22-slit 30-chamber 31-gas supply port (hole)
32-gas supply port (hole)
33-Gas discharge adjustment port (hole)
34-Gas discharge adjustment port (hole)
35-Vacuum suction outlet (hole)
40-electrode 41-electrode 45-frame 46-frame 50-electrode 51-electrode 60-gas introduction plate 61-hollow box 62-opening 70-electrode 71-base 72-rail 100-device main body 110-chamber 120-door 130-magazine 140-operation panel 200-power supply device 300-vacuum pump 400-cylinder 401-cylinder 402-cylinder

Claims (8)

A plurality of objects to be processed are stored in a magazine at intervals and arranged in a chamber, and high frequency power in different frequency bands is applied to both sides of the magazine in the chamber (up and down depending on the magazine opening direction). The pair of electrodes are arranged in a face-to-face structure, and at least two gas supply ports for supplying gas toward the electrode direction are provided outside the both electrodes of the chamber. The gas discharge adjusting port is provided at least in two places, and the gas converted into plasma by the electrode is supplied from both side surfaces (up and down depending on the magazine opening direction), and then the gas supply direction By creating a gas flow in both sides (up / down depending on the magazine opening direction), plasma treatment is performed under a uniform gas flow on both the front and back surfaces of the workpiece. The plasma processing method comprising and. One of the power applied to the pair of electrodes is a current in a frequency band of 1 KHz to 200 KHz, preferably 40 KHz, and the other of the power is a current in a frequency band of 1 MHz or more, preferably 13.56 MHz. The plasma processing method according to claim 1. 3. The plasma processing method according to claim 1, wherein the pair of electrodes are formed by arranging thin wires side by side on the same plane. The plasma processing method according to claim 1, further comprising an electrode position adjusting mechanism that changes the position of the electrode in accordance with the size of the magazine. The processing object disposing means for storing a plurality of objects to be processed in a magazine at intervals, and disposing them in the chamber, and different frequencies on both sides of the magazine in the chamber (up and down depending on the magazine opening direction) A plasma generating means in which a pair of electrodes to which a high frequency power of a band is applied is arranged in a face-to-face structure; and a gas supply port for supplying gas toward the electrodes at least outside the both electrodes of the chamber Two places are provided, and at least two gas discharge adjustment ports are provided in approximately two directions in the center of the chamber, and the gas converted into plasma by the electrodes is on both sides of the workpiece (up / down depending on the magazine opening direction). Gas distribution means for supplying gas from the direction and then performing gas flow in both sides of the gas supply direction (up and down depending on the opening direction of the magazine). And a plasma processing apparatus which is a structure in which a plasma treatment is performed under a uniform gas flow to both sides of the back. One of the power applied to the pair of electrodes is a current in a frequency band of 1 KHz to 200 KHz, preferably 40 KHz, and the other of the power is a current in a frequency band of 1 MHz or more, preferably 13.56 MHz. The plasma processing apparatus according to claim 5. The plasma processing apparatus according to claim 5 or 6, wherein the pair of electrodes are formed by arranging thin wires side by side on the same plane. The plasma processing apparatus according to claim 5, further comprising an electrode position adjusting mechanism that changes the position of the electrode in accordance with the size of the magazine.

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