JP2023058363A - Plasma processing apparatus and plasma processing method - Google Patents

Abstract

To improve the yield of products when a substrate held on a holding sheet is subjected to plasma processing.SOLUTION: A plasma processing apparatus includes: a chamber; a plasma generation part which generates plasma in the chamber; a stage 111 which is provided inside the chamber and has a mounting surface on which a transfer carrier 10 is mounted; an imaging part 131 which is disposed outside the chamber and images an imaging area from a first direction crossing the mounting surface through a window part 130 provided in a side face of the chamber, the imaging area including an opposing area that is an inner peripheral side wall of a frame 2 of the transfer carrier 10 mounted on the stage 111 and that is an area opposing the window part 130; a control part which controls the plasma generation part and the imaging part; and a determination part which determines, based on imaging data imaged by the imaging part 131, whether the mounted state of the transfer carrier 10 is good or bad.SELECTED DRAWING: Figure 4E

Description

The present invention relates to a plasma processing apparatus and a plasma processing method, and more particularly to a plasma processing method for plasma processing a substrate held by a holding sheet.

Plasma dicing is known as a method of dicing a substrate, in which a substrate on which a mask is formed is subjected to plasma etching to divide the substrate into individual chips. In Japanese Patent Laid-Open No. 2002-100002, a substrate is placed on a stage provided in a plasma processing apparatus while being held by a carrier provided with a frame and a holding sheet covering an opening of the carrier, in order to improve the handling of the substrate during transportation or the like. It teaches that the plasma treatment is performed by placing the

Japanese Patent Publication No. 2014-513868

The holding sheet is thin and flexible. Therefore, the transport carrier holding the substrate may be placed on the stage with the holding sheet wrinkled. If plasma processing is performed while wrinkles remain on the holding sheet, abnormal discharge may occur in the wrinkled portions, or the temperature of the wrinkled portions may rise, making it difficult to perform plasma processing normally.

Plasma processing is usually performed while a transport carrier is placed on a stage and attracted to the stage by an electrostatic attraction mechanism called an electrostatic chuck. At this time, the holding sheet holding the substrate may be placed on the stage in a wrinkled state. Due to wrinkles on the holding sheet, the holding sheet is attracted to the stage in a state in which a part of the holding sheet is lifted from the stage. Therefore, contact between the substrate and the stage through the holding sheet becomes insufficient.

If plasma processing is performed with insufficient contact between the substrate and the stage through the holding sheet, the etching of the substrate becomes non-uniform, resulting in variations in processed shape and unprocessed portions. Furthermore, a local temperature rise of the substrate may occur, or an abnormal discharge may occur. This temperature rise and abnormal discharge may damage the substrate, the holding sheet, and the ESC electrode that constitutes the electrostatic chuck. As a result, the product yield is lowered.

One aspect of the present invention is a plasma processing apparatus that performs plasma processing on a substrate held by a transfer carrier that includes a frame and a holding sheet, comprising: a chamber; a plasma generation unit that generates plasma in the chamber; A stage provided in a chamber and having a mounting surface on which the transport carrier is mounted; an imaging unit that captures an image of an imaging area including a facing area that is an inner peripheral side wall of the frame of the transport carrier and faces the window from a first direction that intersects with the mounting surface; The present invention relates to a plasma processing apparatus comprising: a control section that controls a generating section and the imaging section; and a determination section that determines the placement state of the transport carrier based on imaging data captured by the imaging section.

According to another aspect of the present invention, a substrate held by a transfer carrier having a frame and a holding sheet is provided with a chamber, a plasma generating section for generating plasma in the chamber, and the transfer carrier provided in the chamber. a stage having a mounting surface on which a carrier is mounted; a mounting step of mounting the carrier on the stage of a plasma processing apparatus; The step includes an imaging step of imaging the transport carrier placed on the stage, and the imaging step is arranged outside the chamber and through a window provided on the side surface of the chamber, the stage a step of capturing an image of an imaging area including a facing area that is an inner peripheral side wall of the frame of the transport carrier placed on the substrate and that is an area facing the window from a first direction that intersects with the mounting surface; The present invention relates to a plasma processing method, wherein, in the determining step, the placement state of the transport carrier is determined based on image data captured in the imaging step.

According to the present invention, the plasma processing is performed after confirming the state of contact between the substrate and the stage via the holding sheet, so the yield of the product is improved.

FIG. 2A is a top view schematically showing a transport carrier holding a substrate according to an embodiment of the present invention, and FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is a conceptual diagram which shows the basic structure of the plasma processing apparatus which concerns on embodiment of this invention in a cross section. 4 is a flow chart showing some steps of a plasma processing method according to an embodiment of the present invention; It is a conceptual diagram showing each process in the plasma processing method concerning the embodiment of the present invention. It is a conceptual diagram showing each process in the plasma processing method concerning the embodiment of the present invention. It is a conceptual diagram showing each process in the plasma processing method concerning the embodiment of the present invention. It is a conceptual diagram which shows each process in the plasma processing method which concerns on embodiment of this invention, and has shown the case where the mounting state of a conveyance carrier is a 1st state (good). It is a conceptual diagram which shows each process in the plasma processing method which concerns on embodiment of this invention, and has shown the case where the mounting state of a conveyance carrier is a 2nd state (defective). 4 is a conceptual diagram showing the positional relationship between the cover and the stage in each step of the plasma processing method according to the embodiment of the present invention; FIG.

A plasma processing apparatus according to an embodiment of the present invention is a plasma processing apparatus that performs plasma processing on a substrate held by a transfer carrier that includes a frame and a holding sheet, and includes a chamber and a plasma for generating plasma in the chamber. a generator, a stage provided in the chamber and having a mounting surface on which the transport carrier is mounted, and a stage disposed outside the chamber and mounted on the stage through a window provided on the side surface of the chamber. an imaging unit that captures an image of an imaging region including a facing region that is an inner peripheral side wall of a frame of the transport carrier and faces the window from a first direction that intersects with the mounting surface, a plasma generation unit, and an imaging unit and a determination unit that determines the placement state of the transport carrier based on the imaging data captured by the imaging unit.

Determination of the placement state of the transport carrier by the determination unit is performed based on image data obtained by imaging the placement state of the transport carrier on the stage. The placement state can be determined based on the state of the inner peripheral side wall of the frame of the transport carrier. The imaging unit captures an image of the mounting state of the transport carrier including the inner peripheral side wall of the frame from a first direction slightly inclined from the mounting surface of the transport carrier (main surface of the substrate). When the material of the frame is, for example, a metal material, it reflects light well, so it is easy to distinguish between the frame and the substrate or holding sheet by image analysis from the imaging data. Here, when a part of the substrate or the holding sheet is lifted from the stage, the inner peripheral side wall of the frame is hidden behind the lifted substrate or the holding sheet when viewed from the first direction slightly inclined from the mounting surface. This makes it difficult to identify the frames in the imaging data. Therefore, it is possible to easily determine the mounting state of the transport carrier based on the state of the inner peripheral side wall of the frame in the imaging data.

Therefore, in the case where the angle formed by the first direction and the mounting surface has a separation area where the holding sheet or substrate is lifted from the mounting surface and is separated from the mounting surface, the holding sheet or substrate in the separation area causes the imaging section to move. The angle may be set such that imaging of at least a portion of the opposing region by is prevented.

The determination unit determines the placement state of the transport carrier based on the information of the facing area included in the imaging data. The determination unit determines, for example, whether the placement state of the transport carrier corresponds to either the first state or the second state. It is assumed that the first state is good placement, and the second state is bad placement. For example, if the area of the facing area occupying the imaging area is equal to or larger than a predetermined value, it can be determined that the mounting state is in a good first state, and if it is less than the predetermined value, it can be determined that the mounting state is in a second state with a defective mounting. Information on the facing area may include information such as the area of the facing area, the brightness of the facing area, and the shape of the facing area.

Further, the determination unit may determine the placement state of the transport carrier based on the information on the substrate surface included in the imaging data. Examples of substrate surface information used for determination include the state of reflection of light on the substrate surface and the distortion of a pattern formed on the substrate surface. Specifically, if the holding sheet is wrinkled due to a poor placement state of the transport carrier, the wrinkles may increase the amount of reflected light from the substrate surface. Further, if the holding sheet is wrinkled due to a poor placement condition of the transport carrier, the pattern formed on the substrate surface is distorted by the wrinkles.

When the determination unit determines that the placement state is the first state (good), the control unit causes the plasma generation unit to generate plasma. Plasma processing is performed using the generated plasma. On the other hand, when the determination unit determines that the placement state is in the second state (defective), the control unit performs, for example, improvement processing for the placement state, and then attempts to place the transport carrier on the stage again. . After the improvement process, the control unit causes the imaging unit to image the imaging area and the determination unit to determine the placement state of the transport carrier based on the imaging data again. If the placement state is determined to be the first state (good) by the determination unit again, the control unit causes the plasma generation unit to generate plasma.

In this way, by determining the placement state based on the information of the opposing region in the imaging data, it is possible to suppress plasma processing in a state in which the holding sheet has a wrinkled or separated region such as a lift, thereby increasing the yield of the product. can be improved.

As improvement processing after the mounting state is determined to be the second state (defective), for example, when using a suction mechanism that generates a suction force on the mounting surface when fixing the transport carrier to the stage, the suction mechanism A method of repeating the generation and stopping of the adsorption force a plurality of times can be mentioned. The attraction force may be repeatedly generated and stopped while plasma is being generated by the plasma generator.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, one embodiment of the transport carrier used in the present invention will be described with reference to FIGS. 1(a) and 1(b). FIG. 1(a) is a top view schematically showing the substrate 1 and the transport carrier 10 holding it, and FIG. 1(b) shows the substrate 1 and the transport carrier 10 shown in FIG. It is a cross-sectional view along line -B. As shown in FIG. 1( a ), the transport carrier 10 has a frame 2 and a holding sheet 3 . The holding sheet 3 is fixed to the frame 2 at its outer peripheral portion. The substrate 1 is adhered to the holding sheet 3 and held by the transport carrier 10 . Although FIG. 1 illustrates the case where both the frame 2 and the substrate 1 are substantially circular, the shape is not limited to this.

(substrate)
A substrate 1 is an object for plasma processing. For the substrate 1, for example, after forming a circuit layer such as a semiconductor circuit, an electronic component element, or MEMS on one surface of the main body, the back surface of the main body opposite to the circuit layer is ground to reduce the thickness. It is made by By singulating the substrate 1, an electronic component (not shown) having the circuit layer is obtained.

The size of the substrate 1 is not particularly limited, and is, for example, about 50 mm to 300 mm in maximum diameter. The thickness of the substrate 1 is normally about 25 to 150 μm, which is very thin. Therefore, the substrate 1 itself has almost no rigidity (self-supporting property). Therefore, the outer peripheral portion of the holding sheet 3 is fixed to the substantially flat frame 2, and the substrate 1 is adhered to the holding sheet 3. As shown in FIG. This facilitates handling such as transportation of the substrate 1 . The shape of the substrate 1 is also not particularly limited, and may be circular or square, for example. Further, the substrate 1 may be provided with an orientation flat (orientation flat) and a notch such as a notch (none of which are shown).

The material of the main body of the substrate is also not particularly limited, and examples thereof include semiconductors, dielectrics, metals, and laminates thereof. Examples of semiconductors include silicon (Si), gallium arsenide (GaAs), gallium nitride (GaN), and silicon carbide (SiC). Dielectrics include resin films such as polyimide, low dielectric constant films (Low-k films), silicon dioxide (SiO ₂ ), silicon nitride (Si ₃ N ₄ ), lithium tantalate (LiTaO ₃ ), lithium niobate ( LiNbO ₃ ) and the like can be exemplified.

A mask having a desired shape is formed on the surface of the substrate 1 that is not adhered to the holding sheet 3 (not shown). The portion where the mask is formed is protected from plasma etching. A portion where no mask is formed can be etched by plasma from the front surface to the back surface. As the mask, for example, a resist mask formed by exposing and developing a resist film can be used. Also, the mask may be formed by, for example, opening a resin film or resin film formed on the surface of the substrate 1 by laser scribing.

(flame)
The frame 2 is a frame body having an opening with an area equal to or larger than that of the entire substrate 1, and has a predetermined width and a substantially constant thin thickness. The frame 2 has enough rigidity to carry the holding sheet 3 and the substrate 1 while holding them.

The shape of the opening of the frame 2 is not particularly limited, but may be, for example, circular, rectangular, hexagonal, or other polygonal shape. The frame 2 may be provided with notches 2a and corner cuts 2b for positioning. Examples of materials for the frame 2 include metals such as aluminum and stainless steel, and resins. On one side of the frame 2, one side of the holding sheet 3 is attached near the outer periphery thereof.

(holding sheet)
The holding sheet 3 has, for example, a surface having an adhesive (adhesive surface 3a) and a surface having no adhesive (non-adhesive surface 3b). The outer peripheral edge of the adhesive surface 3a is adhered to one surface of the frame 2 and covers the opening of the frame 2. As shown in FIG. Further, the substrate 1 is adhered to the portion of the adhesive surface 3a exposed through the opening of the frame 2. As shown in FIG.

The adhesive surface 3a is preferably made of an adhesive component whose adhesive strength is reduced by irradiation with ultraviolet rays (UV). This is because the individualized substrates (electronic components) can be easily peeled off from the adhesive surface 3a and easily picked up by performing ultraviolet irradiation after dicing. For example, the holding sheet 3 is obtained by applying a UV curable acrylic pressure-sensitive adhesive to a thickness of 5 to 20 μm on one side of a film-like substrate.

The material of the film-like substrate is not particularly limited, and examples thereof include polyolefins such as polyethylene and polypropylene, and thermoplastic resins such as polyesters such as polyethylene terephthalate. The base material contains rubber components for adding stretchability (e.g., ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), etc.), plasticizers, softeners, antioxidants, conductive materials, etc. may be blended with various additives. Moreover, the thermoplastic resin may have a functional group that exhibits photopolymerization reaction, such as an acrylic group. The thickness of the substrate is, for example, 50-150 μm. During plasma processing, the transport carrier 10 is placed on the stage so that the stage and the non-adhesive surface 3b are in contact with each other.

(Plasma processing device)
Next, the basic structure of the plasma processing apparatus 100 according to the embodiment of the present invention will be described with reference to FIG. FIG. 2 schematically shows a cross section of the basic structure of the plasma processing apparatus 100. As shown in FIG.

The plasma processing apparatus 100 has a stage 111 . The transport carrier 10 is mounted on the stage 111 so that the surface of the holding sheet 3 holding the substrate 1 faces upward. The stage 111 has a size that allows the entire transport carrier 10 to be placed thereon. A cover 124 that covers at least a portion of the frame 2 and the holding sheet 3 and has a window portion 124W for exposing at least a portion of the substrate 1 is arranged above the stage 111 .

The stage 111 and cover 124 are arranged in the processing chamber (vacuum chamber 103). The vacuum chamber 103 has a generally cylindrical shape with an open top, and the top opening is closed by a dielectric member 108 that is a lid. Examples of the material forming the vacuum chamber 103 include aluminum, stainless steel (SUS), and aluminum whose surface is anodized. Examples of materials forming the dielectric member 108 include dielectric materials such as yttrium oxide (Y ₂ O ₃ ), aluminum nitride (AlN), alumina (Al ₂ O ₃ ), and quartz (SiO ₂ ). An antenna 109 as an upper electrode is arranged above the dielectric member 108 . Antenna 109 is electrically connected to first high-frequency power supply 110A. The stage 111 is arranged on the bottom side inside the vacuum chamber 103 .

A gas inlet 103 a is connected to the vacuum chamber 103 . A process gas source 112 and an ashing gas source 113, which are plasma generating gas supply sources, are connected to the gas inlet 103a by pipes. Further, the vacuum chamber 103 is provided with an exhaust port 103b, and the exhaust port 103b is connected to a decompression mechanism 114 including a vacuum pump for decompressing the gas in the vacuum chamber 103 by exhausting the gas.

A window 130 is provided on the side of the vacuum chamber 103 on the side of the transport carrier 10 . The window 130 is made of transparent glass, for example, and through the window 130, the state where the transport carrier 10 is placed on the stage 111 can be visually recognized.

The imaging unit 131 is arranged close to the window 130 of the vacuum chamber 103 . The imaging unit 131 is, for example, a CCD camera. The image capturing unit 131 captures an image of the transport carrier 10 through the window 130 and acquires image data. The imaging area includes a facing area that is an inner peripheral sidewall of the frame 2 and faces the window 130 . By performing image analysis of the imaging area, particularly the opposing area, in the imaging data, it is possible to determine whether the state of placement of the transport carrier 10 on the stage 111 is good or bad. Determination of whether the placement state is good or bad can be made by a determination unit provided in a control unit, which will be described later.

The stage 111 includes a substantially circular electrode layer 115 , a metal layer 116 , a base 117 supporting the electrode layer 115 and the metal layer 116 , and an outer peripheral portion 118 surrounding the electrode layer 115 , the metal layer 116 and the base 117 . Prepare. The outer peripheral portion 118 is made of a metal having electrical conductivity and etching resistance, and protects the electrode layer 115, the metal layer 116 and the base 117 from plasma. An annular outer ring 129 is arranged on the upper surface of the outer peripheral portion 118 . The outer ring 129 serves to protect the upper surface of the outer peripheral portion 118 from plasma. The electrode layer 115 and the outer ring 129 are made of, for example, the dielectric material described above.

Inside the electrode layer 115, an ESC electrode 119 forming an electrostatic attraction mechanism and a high frequency electrode section 120 electrically connected to the second high frequency power source 110B are arranged. A DC power supply 126 is electrically connected to the ESC electrode 119 . The electrostatic attraction mechanism is composed of ESC electrode 119 and DC power supply 126 . The holding sheet 3 is pressed against the stage 111 and fixed by the electrostatic adsorption mechanism. A case where an electrostatic adsorption mechanism is provided as a fixing mechanism for fixing the holding sheet 3 to the stage 111 will be described below as an example, but the present invention is not limited to this. Fixation of the holding sheet 3 to the stage 111 may be performed by a clamp (not shown).

The metal layer 116 is made of, for example, aluminum with an alumite coating formed on its surface. A coolant channel 127 is formed in the metal layer 116 . Coolant flow path 127 cools stage 111 . By cooling the stage 111 , the holding sheet 3 mounted on the stage 111 is cooled, and the cover 124 partly in contact with the stage 111 is also cooled. This prevents the substrate 1 and the holding sheet 3 from being damaged by being heated during plasma processing. The refrigerant in refrigerant flow path 127 is circulated by refrigerant circulation device 125 .

A plurality of support portions 122 that penetrate the stage 111 are arranged near the outer periphery of the stage 111 . The support portion 122 is driven up and down by a lifting mechanism 123A. When the transport carrier 10 is transported into the vacuum chamber 103, it is handed over to the support part 122 which has been raised to a predetermined position. The support portion 122 supports the frame 2 of the transport carrier 10 . The transport carrier 10 is mounted at a predetermined position on the stage 111 by lowering the upper end surface of the support portion 122 to the same level as the stage 111 or lower.

A plurality of elevating rods 121 are connected to the ends of the cover 124 so that the cover 124 can be elevated. The lifting rod 121 is driven up and down by a lifting mechanism 123B. The lifting operation of the cover 124 by the lifting mechanism 123B can be performed independently of the lifting mechanism 123A.

The lifting rod 121 and the lifting mechanism 123B constitute a relative position changer and change the relative distance between the cover 124 and the stage 111. FIG. For example, the determining unit determines the placement state of the transport carrier 10 on the stage 111 while the cover 124 and the stage 111 are positioned in a state where the cover 124 is raised so as not to interfere with imaging of the opposing region by the imaging unit 131. The distance may be performed with the first distance d1. As a result of the determination, when the placement state is determined to be the first state (good), the relative position changing unit lowers the cover 124 to reduce the distance between the cover 124 and the stage 111 to the second distance d2. change. Thereafter, plasma processing is performed with the distance between the cover 124 and the stage 111 being the second distance d2. However, the method for changing the distance by the relative position changer is not limited to the method using the lifting rod 121 .

Dielectric member 108, antenna 109, first high-frequency power supply 110A, second high-frequency power supply 110B, process gas source 112, decompression mechanism 114, and high-frequency electrode section 120 constitute a plasma generation section.

The control device 128 includes a first high-frequency power source 110A, a second high-frequency power source 110B, a process gas source 112, an ashing gas source 113, a pressure reduction mechanism 114, a refrigerant circulation device 125, an elevating mechanism 123A, an elevating mechanism 123B, and an electrostatic adsorption mechanism. It controls the operation of the elements that make up the plasma processing apparatus 100 . The control device 128 also has a determination unit, and determines whether the placement state of the transport carrier 10 on the stage 111 is good or bad based on the imaging data acquired by the imaging unit 131 .

(Plasma treatment method)
Next, basic steps of the plasma processing method according to this embodiment will be described with reference to FIGS. 3 and 4. FIG. FIG. 3 is a flow chart showing some steps of the plasma processing method.

4A to 4F are conceptual diagrams showing the positional relationship between the cover and the stage in each step of the plasma processing method. 4A to 4F omit the description of the outer peripheral portion 118, the outer peripheral ring 129, the gas introduction path, and the like, in order to facilitate understanding of the invention.

A plasma processing method according to an embodiment of the present invention comprises a chamber, a plasma generation section for generating plasma in the chamber, a substrate held by a transfer carrier having a frame and a holding sheet, provided in the chamber, a stage having a mounting surface on which the transport carrier is placed; a placing step of placing the transport carrier on the stage of the plasma processing apparatus; and a determining step of determining the placement state of the transport carrier. The determination process includes an imaging process of imaging the transport carrier placed on the stage. The imaging process is arranged outside the chamber, and through the window provided on the side surface of the chamber, the facing area, which is the inner wall of the frame of the transport carrier placed on the stage and faces the window. is a step of imaging an imaging region including from a first direction that intersects with the placement surface. In the determination step, the placement state of the transport carrier is determined based on the imaging data captured in the imaging step.

(1) Preparation Step First, the transport carrier 10 is prepared. The transport carrier 10 is obtained by attaching the holding sheet 3 to one surface of the frame 2 and fixing it. At this time, as shown in FIG. 1(b), the adhesive surface 3a of the holding sheet 3 is made to face the frame. Next, by attaching the substrate 1 to the adhesive surface 3 a of the holding sheet 3 , the substrate 1 is held by the transport carrier 10 .

(2) Loading Step Next, the transport carrier 10 holding the substrate 1 is loaded into the vacuum chamber 103 .

FIG. 4A shows the positional relationship between the cover 124 and the stage 111 before loading the transport carrier. As shown in FIG. 4A, the lifting rod 121 and the support 122 are in the lowered position.

The elevating rod 121 and the supporting portion 122 are driven to raise the cover 124 to a predetermined position in the vacuum chamber 103, and the supporting portion 122 is kept in the raised state. FIG. 4B shows the positional relationship between cover 124 and stage 111 at this time. At this time, the distance between the cover 124 and the stage 111 is the first distance d1.

Subsequently, a shutter (not shown) is opened, and the transfer carrier 10 held by the transfer arm is carried into the vacuum chamber 103 via the transfer arm. When the transport carrier 10 reaches a predetermined position above the stage 111 , the transport carrier 10 is transferred to the support section 122 . The transport carrier 10 is placed on the upper end surface of the support portion 122 so that the surface of the holding sheet 3 holding the substrate 1 faces upward. FIG. 4C shows the positional relationship between cover 124 and stage 111 at this time.

(3) Placement Step When the transport carrier 10 is transferred to the support portion 122, the transport arm 221 is withdrawn, the shutter is closed, and the vacuum chamber 103 is sealed. After that, the support part 122 is lowered. The transport carrier 10 is mounted on the stage 111 by lowering the upper end surface of the support portion 122 to the same level as the stage 111 or lower. FIG. 4D shows the positional relationship between the cover 124 and the stage 111 at this time. Since the cover 124 is not lowered, the distance between the cover 124 and the stage 111 remains the first distance d1.

Subsequently, the transport carrier 10 placed on the stage 111 is fixed on the stage 111 . When the stage 111 is provided with the ESC electrode 119 , by applying a voltage to the ESC electrode 119 , an attraction force is generated between the holding sheet 3 of the transport carrier 10 and the stage 111 , and the holding sheet 3 and thus the transport carrier 10 are moved. , can be fixed to the stage 111 .

The ESC electrodes 119 are broadly classified into two types, unipolar and bipolar.
A monopolar ESC electrode 119 includes at least one electrode. When the unipolar ESC electrode 119 includes two or more electrodes, voltages of the same polarity are applied to all of them. The electrostatic chucking mechanism with the unipolar ESC electrode 119 uses Coulomb force as the chucking mechanism. By applying a voltage to the ESC electrode 119 , electric charge is induced on the surface of the stage 111 made of a dielectric by dielectric polarization, and the holding sheet 3 placed on the stage 111 is charged. As a result, a Coulomb force acts between the charge induced on the surface of the stage 111 and the charged holding sheet 3 , and the transport carrier 10 is attracted to the stage 111 . In order to charge the holding sheet 3, plasma is generated in the vacuum chamber 103 and the holding sheet 3 is exposed to the generated plasma.

On the other hand, the bipolar ESC electrode 119 has a positive electrode and a negative electrode, and voltages with different polarities are applied to the positive electrode and the negative electrode. For example, a comb-shaped electrode is used as the bipolar ESC electrode 119 . A voltage of V1 is applied from the DC power supply 126 to the positive terminal, and a voltage of -V1 is applied from the DC power supply 126 to the negative terminal.

As the adsorption mechanism of the electrostatic adsorption mechanism provided with the bipolar ESC electrode 119, there is a case of using the Coulomb force and a case of using the Johnson-Rahbek force. Depending on the adsorption mechanism, the structure of the ESC electrode 119 and the material (for example, ceramics) forming the ESC electrode 119 are appropriately selected. In any adsorption mechanism, by applying voltages of different polarities to the positive electrode and the negative electrode, an adsorption force is generated between the ESC electrode and the holding sheet 3 , and the transport carrier 10 can be adsorbed to the stage 111 . . In the case of the bipolar type, unlike the case of the unipolar type, it is not necessary to charge the holding sheet 3 in order to attract it.

A bipolar ESC electrode can also function as a unipolar type depending on the method of applying voltage to the positive and negative electrodes. Specifically, by applying a voltage of the same polarity to the positive electrode and the negative electrode, it can be used as a unipolar ESC electrode.

When the ESC electrode 119 is of the bipolar type, a voltage is applied from the DC power source 126 to the ESC electrode 119 after the transfer carrier 10 is delivered to the support section 122 . As a result, the holding sheet 3 contacts the stage 111 and is attracted to the stage 111 at the same time, and the holding sheet 3 is fixed to the stage 111 . Note that application of voltage to the ESC electrode 119 may be started after the holding sheet 3 is placed on the stage 111 (after contact).

(4) Judging Step After the placing step, a judging step for judging the placement state of the transport carrier is performed. Here, an imaging unit 131 is used to photograph the placement state of the transport carrier 10 in the vacuum chamber 103 through a window 130 provided on the side surface of the chamber, and image analysis is performed on the imaging data. Accordingly, the placement state of the holding sheet 3 on the stage 111 and the placement state of the substrate 1 on the stage 111 via the holding sheet 3 are determined.

For example, as shown in FIG. 4D, the imaging unit 131 is arranged at a position on the side of the transport carrier 10 in a state of being placed on the stage 111, and is positioned from the mounting surface of the transport carrier (main surface of the substrate 1). The transport carrier 10 is photographed from a slightly inclined angle. The image capturing unit 131 particularly captures an image of the inner peripheral side wall of the frame 2 of the transport carrier 10 facing the window 130 . The imaging angle and imaging range of the imaging unit 131 are adjusted so that the imaging data includes the inner peripheral sidewall of the frame. More specifically, the imaging direction (first direction) of the imaging unit 131 is when the angle formed by the first direction and the mounting surface has a separation area in which the holding sheet or the substrate is lifted and separated from the mounting surface. In addition, the angle can be set such that the holding sheet or the substrate in the spaced region prevents the imaging unit from imaging at least part of the opposing region. The angle formed by the mounting surface of the transport carrier and the first direction is, for example, in the range of more than 0° and 30° or less.

As shown in FIG. 4D, when the substrate or the holding sheet is not lifted from the stage 111 and the transport carrier is placed in a good state (first state), the imaging data includes information on the inner peripheral side wall of the frame 2 . included. However, as shown in FIG. 4E, for example, when the holding sheet is wrinkled in a partial region and part of the holding sheet is lifted from the stage 111 (second state), the lifted portion causes at least the inner peripheral side wall of the frame to be deformed. Part of it is hidden and does not appear in the imaging data. Therefore, by obtaining the area (opposing area) corresponding to the inner peripheral side wall of the frame from the imaging data by image analysis, the placement state of the transport carrier can be determined. For example, the area of the region (opposing region) corresponding to the inner peripheral side wall of the frame in the imaging data is obtained. The placement state can be determined to be the second state (defective).

Further, as shown in FIG. 4E, when the substrate is thin and flexible, if the holding sheet is wrinkled, the substrate held in the wrinkled portion of the holding sheet may also be wrinkled. . When the substrate is wrinkled, the light reflection state of the substrate surface changes, or the pattern formed on the substrate surface is distorted. Therefore, the mounting state of the transport carrier can be determined by obtaining the information of the substrate surface from the imaging data by image analysis.

When it is determined that the transport carrier 10 is placed on the stage 111 in the first state (good), the process proceeds to the plasma etching step, which will be described later. On the other hand, if it is determined that the transport carrier 10 is placed on the stage 111 in the second state (defective), the transport carrier 10 is carried out of the vacuum chamber 103, and then the placement process is attempted again. Alternatively, the support part 122 is raised again, and the mounting process is attempted again from a state in which the transport carrier 10 is separated from the stage 111 . In the retry, while the supporter 122 is being raised or lowered, the supporter 122 may be moved slightly up and down. As a result, wrinkles in the holding sheet 3 are eliminated, and floating of the holding sheet is easily eliminated.

When the placement state of the transport carrier 10 is determined to be in the second state (defective) in the determination step, the placement state improvement step may be performed before the transport carrier 10 is unloaded from the vacuum chamber 103. good. In the improvement step, for example, voltage is intermittently applied to the ESC electrode 119, and generation and termination of the attraction force are repeated multiple times. While plasma is generated in the vacuum chamber 103, generation and termination of the attraction force may be repeated multiple times. The applied voltage (absolute value of the voltage applied to the positive and negative electrodes) V1 to the ESC electrode 119 in the improvement process is, for example, about 2500 V. For example, voltage application for 1 second and no voltage application for 1 second are repeated. . When plasma is generated, for example, Ar gas is supplied into the vacuum chamber 103 and high frequency power of 100 to 500 W and a frequency of 13.56 MHz is supplied to the antenna 109 .

After the improvement process, the determination process is performed again to determine the placement state of the transport carrier. In the determination process after the improvement process, when it is determined that the placement state of the transport carrier 10 on the stage 111 is the first state (good), the process proceeds to the plasma etching process, which will be described later. On the other hand, if it is determined that the transport carrier 10 is placed on the stage 111 in the second state (defective) in the determination process after the improvement process, the improvement process may be performed again.

If the mounting state is determined to be the second state (defective) even after a plurality of improvement processes, the transport carrier 10 is carried out from the vacuum chamber 103, and then the mounting process is attempted again. Alternatively, the support part 122 is raised again, and the mounting process is attempted again from a state in which the transport carrier 10 is separated from the stage 111 .

In the determination process, the placement state of the transport carrier is determined by raising the cover 124 so that the imaging unit 131 does not interfere with the imaging of the opposing area by the cover 124, and the distance between the cover 124 and the stage 111 is determined. is performed at the first distance d1. In this case, since the placement state of the transport carrier is determined in a state where the cover is sufficiently spaced from the transport carrier, it is possible to prevent subsequent processing errors due to the poor placement state. can be prevented. For example, it is possible to avoid a transport error due to contact with the cover during unloading when the placement state is not good. As a result, substrate yield and production efficiency can be further improved.

(5) Plasma treatment process In the judgment process, if the placement state is judged to be good, the lift rod 121 is driven to lower the cover 124 to a predetermined position. As a result, the distance between cover 124 and stage 111 is changed to second distance d2, which is smaller than first distance d1. FIG. 4F shows the positional relationship between the cover 124 and the stage 111 at this time. The second distance d2 is adjusted so that the cover 124 can cover the frame 2 without contacting the holding sheet 3 . As a result, portions of the frame 2 and the holding sheet 3 that do not hold the substrate 1 are partially covered with the cover 124 and the substrate 1 is exposed through the window 124W of the cover 124 . Although the second distance d2 is not particularly limited, it is, for example, approximately 0.5 mm to 1.5 mm. The second distance d2 is the shortest distance between the stage 111 and the part of the cover 124 that faces the holding sheet of the transport carrier placed on the stage 111 .

The cover 124 is, for example, donut-shaped with a substantially circular outer contour, with a constant width and a thin thickness. The inner diameter of the cover 124 (the diameter of the window portion 124W) is smaller than the inner diameter of the frame 2, and the outer diameter of the cover 124 is larger than the outer diameter of the frame 2. Therefore, when the transport carrier 10 is mounted at a predetermined position on the stage and the cover 124 is lowered, the cover 124 can cover at least part of the frame 2 and the holding sheet 3 . At least a portion of the substrate 1 is exposed through the window portion 124W. The cover 124 is made of, for example, a dielectric such as ceramics (eg, alumina, aluminum nitride, etc.) or quartz, or a metal such as aluminum or aluminum whose surface is anodized.

When the support portion 122 and the cover 124 are placed in place, process gas is introduced into the vacuum chamber 103 from the process gas source 112 through the gas introduction port 103a. On the other hand, the decompression mechanism 114 exhausts the gas inside the vacuum chamber 103 through the exhaust port 103b to maintain the inside of the vacuum chamber 103 at a predetermined pressure. Subsequently, high-frequency power is supplied to the antenna 109 from the first high-frequency power supply 110A to generate plasma P in the vacuum chamber 103 . The generated plasma P is composed of ions, electrons, radicals, and the like. A portion exposed from the resist mask formed on the substrate 1 is removed (etched) from the front surface to the back surface by a physicochemical reaction with the generated plasma P, and the substrate 1 is singulated.

Here, for example, high-frequency power of 100 kHz or higher may be supplied from the second high-frequency power supply 110B to the high-frequency electrode section 120 . The energy of the ions incident on the substrate 1 can be controlled by high-frequency power applied to the high-frequency electrode section 120 from the second high-frequency power supply 110B. By applying high frequency power to the high frequency electrode part 120, a bias voltage is generated on the surface of the stage 111, and this bias voltage accelerates the ions incident on the substrate 1, thereby increasing the etching rate.

Conditions for etching (conditions for generating plasma) are set according to the material of the substrate 1 and the like. For example, when the substrate 1 is Si, the substrate 1 is etched by generating plasma in the vacuum chamber 103 using sulfur hexafluoride (SF ₆ ) or the like as a raw material. In this case, for example, the pressure in the vacuum chamber 103 is controlled to 10-50 Pa by the decompression mechanism 114 while supplying 100-800 sccm of SF ₆ gas from the process gas source 112 . At this time, high frequency power of 1000 to 5000 W and a frequency of 13.56 MHz is supplied to the antenna 109, and high frequency power of 50 to 1000 W and 100 kHz or higher (for example, 400 to 500 kHz or 13.56 MHz) is supplied to the high frequency electrode unit 120. supply.

In order to suppress the temperature rise of the transport carrier 10 during etching, it is preferable to set the temperature of the coolant circulated in the stage 111 to -20 to 20° C. by the coolant circulation device 125 . Thereby, if the contact state between the holding sheet 3 and the stage 111 is good, the temperature of the holding sheet 3 during plasma processing is controlled to, for example, 60° C. or lower. Therefore, thermal damage to the holding sheet 3 is suppressed.

In plasma dicing, the surface of the substrate 1 exposed from the resist mask is preferably etched vertically. In this case, as described above, the etching step using fluorine-based gas plasma such as SF ₆ and the protective film deposition step using fluorocarbon gas plasma such as perfluorocyclobutane (C ₄ F ₈ ) are alternately repeated. may

After the substrate 1 is singulated by etching, ashing is performed. A process gas for ashing (for example, oxygen gas, mixed gas of oxygen gas and fluorine-containing gas, etc.) is introduced from the ashing gas source 113 into the vacuum chamber 103 . On the other hand, the vacuum mechanism 114 evacuates the inside of the vacuum chamber 103 to maintain a predetermined pressure. When the high frequency power is supplied from the first high frequency power supply 110A, oxygen plasma is generated in the vacuum chamber 103, and the surface of the singulated substrate 1 (electronic component) exposed from the window 124W of the cover 124 is damaged. The resist mask is completely removed.

(6) Unloading Step When the ashing is completed, the gas in the vacuum chamber 103 is discharged, the shutter is opened, and the transport carrier 10 holding the singulated substrate 1 is moved from the plasma processing apparatus 100 by the transport arm 221. carried out. The unloading process of the transport carrier 10 may be performed in reverse order to the procedure of mounting the substrate 1 on the stage 111 as described above. That is, after the cover 124 is raised to a predetermined position, the voltage applied to the ESC electrode 119 is set to zero to release the adsorption of the transport carrier 10 to the stage 111 and raise the support portion 122 . After the support portion 122 is raised to a predetermined position, the transport carrier 10 is unloaded.

INDUSTRIAL APPLICABILITY The plasma processing method of the present invention is useful when performing plasma processing on a substrate held by a transport carrier using a plasma processing apparatus.

1: Substrate 1A: Peripheral part 1B: Central part 2: Frame 2a: Notch 2b: Corner cut 3: Holding sheet 3a: Adhesive surface 3b: Non-adhesive surface 10: Transport carrier 100: Plasma processing device 103 : vacuum chamber, 103a: gas inlet, 103b: exhaust port, 108: dielectric member, 109: antenna, 110A: first high-frequency power supply, 110B: second high-frequency power supply, 111: stage, 112: process gas source, 113 : ashing gas source, 114: decompression mechanism, 115: electrode layer, 116: metal layer, 117: base, 118: outer peripheral portion, 119: ESC electrode, 120: high frequency electrode portion, 121: elevating rod, 122: support portion , 123A, 123B: lifting mechanism, 124: cover, 124W: window, 125: refrigerant circulation device, 126: DC power supply, 127: refrigerant flow path, 128: control device, 129: outer ring 130: window (window) , 131: imaging unit

Claims (9)

A plasma processing apparatus for performing plasma processing on a substrate held by a transfer carrier having a frame and a holding sheet,
a chamber;
a plasma generator that generates plasma in the chamber;
a stage provided in the chamber and having a mounting surface on which the transport carrier is mounted;
In a region of the inner peripheral side wall of the frame of the transport carrier placed on the stage and facing the window through the window provided on the side surface of the chamber, which is arranged outside the chamber. an imaging unit that captures an image of an imaging region including a certain facing region from a first direction that intersects with the mounting surface;
a control unit that controls the plasma generation unit and the imaging unit;
A plasma processing apparatus comprising: a determination unit that determines a placement state of the transport carrier based on imaging data captured by the imaging unit. The first direction is such that when the holding sheet or the substrate has a spaced region separated from the mounting surface, the spaced region prevents the imaging unit from imaging at least part of the facing region. is set and
2. The plasma processing apparatus according to claim 1, wherein said determination unit determines the mounting state of said transport carrier based on information of said facing area included in said imaging data. the imaging area includes a surface of the substrate held by the transport carrier;
2. The plasma processing apparatus according to claim 1, wherein said determination unit determines the mounting state of said transport carrier based on information about said surface included in said imaging data. The control unit causes the plasma generation unit to generate plasma when the determination unit determines that the placement state of the transport carrier is the first state,
4. The plasma processing apparatus according to any one of claims 1 to 3, wherein when said determination unit determines that said placement state of said transport carrier is in a second state, processing for improving said placement state is performed. . 5. The method according to claim 4, wherein after the improvement process, the control unit causes the image pickup unit to image the image pickup region and the determination unit to judge the placement state of the transport carrier based on the image pickup data. plasma processing equipment. further comprising an adsorption mechanism for generating an adsorption force on the mounting surface,
6. The plasma processing apparatus according to claim 4, wherein said improving process includes repeating generation and stopping of adsorption force by said adsorption mechanism a plurality of times. A substrate held by a transport carrier comprising a frame and a holding sheet is placed in a chamber, a plasma generator for generating plasma in the chamber, and a mounting surface provided in the chamber on which the transport carrier is placed. A mounting step of mounting on the stage of a plasma processing apparatus comprising a stage having
and a determination step of determining the placement state of the transport carrier,
The determination step includes an imaging step of imaging the transport carrier placed on the stage,
In the imaging step, the inner peripheral sidewall of the frame of the transport carrier placed on the stage is arranged outside the chamber and is mounted on the stage through a window provided on the side surface of the chamber. A step of imaging an imaging region including a facing region that is a region facing from a first direction intersecting the mounting surface,
The plasma processing method, wherein, in the determining step, the mounting state of the transport carrier is determined based on image data captured in the imaging step. The first direction is such that when the holding sheet or the substrate has a spaced region separated from the mounting surface, the spaced region prevents at least part of the facing region from being imaged in the imaging step. is set and
8. The plasma processing method according to claim 7, wherein in said determination step, the mounting state of said transport carrier is determined based on information of said facing area included in said imaging data. the imaging area includes a surface of the substrate held by the transport carrier;
8. The plasma processing method according to claim 7, wherein in said determination step, the placement state of said transport carrier is determined based on information on said surface included in said imaging data.

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