JP6516125B2 - Plasma processing method and method of manufacturing electronic component - Google Patents

Description

  The present invention relates to a plasma processing method and a method of manufacturing an electronic component, and more particularly to improvement of productivity in the case of manufacturing an electronic component by plasma processing a substrate held by a resin sheet.

  As a method for dicing a substrate, plasma dicing is known in which a substrate on which a resist mask is formed is subjected to plasma etching to be divided into individual chips. Patent documents 1 and 2 teach holding a substrate on a conveyance carrier provided with an annular frame and a resin sheet covering the opening in order to improve the handling property of the substrate in conveyance and the like. The substrate is placed on the stage while being held by the transport carrier and subjected to plasma processing.

  In this case, the resin sheet is usually attracted to the stage by an electrostatic attraction mechanism called an electrostatic chuck. The electrostatic adsorption mechanism includes an electrostatic chucking electrode (hereinafter referred to as an ESC electrode) disposed inside the stage. When a voltage is applied to the ESC electrode, a coulomb force is generated between the ESC electrode and the carrier, and a Johnson-Rahbek force is generated between the stage and the carrier. The electrostatic adsorption mechanism causes the resin sheet to be adsorbed to the stage by these electrostatic forces.

JP, 2009-94436, A Japanese Patent Application Publication No. 2014-513868

  When a plurality of substrates held on a resin sheet are subjected to continuous plasma processing, the number of processed wafers increases, and the depth (etching rate) with which etching can be performed within a predetermined time tends to decrease. In addition, on the stage after the plasma processing is performed on the substrate held by the resin sheet, the deposit is generated so as to transfer the shape of the resin sheet. And it turned out that the said deposit | attachment is affecting the reduction of an etching rate.

  During the plasma processing, the resin sheet is subjected to heat from plasma irradiation, an electric field generated by the ESC electrode, and a leakage current. Therefore, it is considered that various additives such as plasticizers contained in the resin sheet are discharged from the resin sheet during plasma treatment, float on the surface of the resin sheet, and adhere to the stage. In particular, many deposits resulting from the resin sheet are generated from the portion of the resin sheet where the substrate is held. As described above, the phenomenon that various additives contained in the resin float on the surface of the resin is called bleed out.

  Here, usually, the stage is cooled (for example, to 15 ° C. or less). The resin sheet is heated by plasma irradiation to suppress thermal damage. By cooling the stage, the resin sheet adhered to the stage by electrostatic adsorption is also cooled. However, if a deposit is present between the resin sheet and the stage, the cooling effect of the resin sheet is reduced. If the resin sheet is not sufficiently cooled, the cooling effect of the substrate held thereby is also reduced. Therefore, the etching rate is reduced and the productivity is reduced. In addition, when the substrate is continuously processed, it is necessary to stop the process in order to remove the deposits on the stage, which further reduces the productivity.

One aspect of the present invention is a plasma processing method in which a substrate held by a resin sheet is placed on a stage provided inside a reaction chamber to perform plasma processing, and the substrate is a surface of the stage and A cover having a mounting step of mounting on the stage and a window portion for exposing at least a part of the substrate mounted on the stage such that the resin sheet is in contact with the resin sheet; A step of partially covering , a plasma treatment step of performing plasma treatment on the substrate exposed from the cover, an unloading step of unloading the substrate together with the resin sheet from the reaction chamber after the plasma treatment step; After the unloading step, plasma is generated in the reaction chamber, and the removing step is for removing the substance discharged from the resin sheet and adhering to the surface of the stage. The provided, the distance between the cover and the stage in the removal step is greater than the distance between the cover and the stage in the plasma treatment step, a plasma treatment method.

Another aspect of the present invention is a process of preparing a substrate held by a resin sheet, and the substrate is placed on the stage such that the surface of the stage provided inside the reaction chamber is in contact with the resin sheet. A step of mounting, a cover having a window portion for exposing at least a portion of the substrate mounted on the stage, a step of covering at least a portion of the resin sheet, and exposure from the cover A dicing process of subjecting the substrate to plasma processing to separate the substrate, and an unloading process of unloading the substrate together with the resin sheet from the reaction chamber after the dicing process, and after the unloading process by generating a plasma in the reaction chamber, wherein a resin sheet is discharged and a removing step of removing the substance adhering to the surface of the stage, before in the removing step The distance between the cover and the stage is greater than the distance between the cover and the stage in the dicing step, the method for manufacturing the electronic component.

  According to the present invention, since the etching rate is high and stable, the productivity is improved. In addition, even when the substrate is continuously processed, the adhered matter can be removed without stopping the process, which further improves the productivity.

It is an upper side figure (a) which shows the conveyance career concerning one embodiment of the present invention roughly, and a sectional view (b) in the BB line. It is a conceptual diagram of the plasma processing apparatus concerning one embodiment of the present invention. It is a graph which shows the change of plasma dicing speed. It is sectional drawing which shows the plasma processing part concerning one Embodiment of this invention notionally. It is a flowchart which shows the plasma processing method which concerns on one Embodiment of this invention. It is a conceptual diagram which shows a part of operation | movement of the plasma processing part which concerns on one Embodiment of this invention ((a)-(e)). It is a conceptual diagram which shows a part of other operation | movement of the plasma processing part which concerns on one Embodiment of this invention ((f)-(k)). 7 is a flowchart illustrating a plasma processing method according to another embodiment of the present invention.

  The plasma processing method according to the present invention includes a mounting step of mounting the substrate held by the resin sheet on the stage such that the surface of the stage provided in the plasma processing apparatus is in contact with the resin sheet; It comprises a plasma processing step of performing plasma processing on the placed substrate, and an unloading step of unloading the substrate together with the resin sheet from the reaction chamber after the plasma processing step. Furthermore, after the unloading step, plasma is generated again in the reaction chamber where the carrier 10 is not present. Thereby, it is possible to bleed out from the resin sheet and remove the substance (adhesion) attached to the surface of the stage. Therefore, the cooling effect of the substrate placed on the stage next is unlikely to be impaired. Therefore, high power can be supplied into the reaction chamber, and the etching rate (plasma dicing speed in the case of dicing the substrate by plasma processing) can be increased. As a result, the time required for plasma processing (for example, dicing) is shortened, and the productivity is improved. In addition, when the deposit adheres unevenly, the temperature of the substrate placed next on the stage may not be uniform within the substrate surface. In this case, the in-plane distribution of etching with respect to the substrate also becomes uneven, which may cause variations in processing shape. That is, by providing the removing step, it is also possible to suppress the decrease in yield due to the deposit on the stage.

  On the other hand, a minute amount of component (bleed out component) which bleeds out from the resin sheet during plasma processing intervenes so as to fill a minute gap between the resin sheet and the stage, and adhesion of the resin sheet and thus the substrate to the stage In some cases, the (adsorbability) may be enhanced, or the heat conduction between the resin sheet and the stage may be enhanced. That is, in the plasma processing step in the plasma processing method according to the present invention, while the resin sheet is electrostatically adsorbed on the surface of the stage, the plasma processing is performed on the substrate placed on the stage, and It may be a step of interposing a bleed out component between the resin sheet and the stage. Thereby, the etching of the substrate is more likely to be uniform. The effect of the bleed-out component as described above is observed when the amount of the bleed-out component is small.

  The removal step is preferably performed under an oxygen atmosphere. In other words, it is preferable to remove the deposit by oxygen plasma. This is because deposits are efficiently removed. In particular, organic substances are efficiently removed by the oxygen plasma. The oxygen atmosphere means that the content of oxygen relative to the total gas contained in the reaction chamber is 50 to 100% by volume (the same applies hereinafter). Among them, the oxygen content is preferably 80 to 100% by volume from the viewpoint of removal efficiency.

  A method of manufacturing an electronic component according to the present invention is a method of dicing a substrate using the above-described plasma processing method. That is, in the method of manufacturing an electronic component according to the present invention, a process of preparing a substrate held by a resin sheet, the above-mentioned placing process, a dicing process of singulating the substrate by the plasma treatment, and the unloading process And the removing step in this order. As described above, the efficiency of the plasma processing is improved by performing the removal step, and thus the productivity of the electronic component is improved.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, one embodiment of the carrier used in the present invention will be described with reference to FIGS. 1 (a) and (b). FIG. 1A is a top view schematically showing the transport carrier 10, and FIG. 1B is a cross-sectional view of the transport carrier 10 taken along line B-B shown in FIG. Although FIG. 1 illustrates the case where both the frame 2 and the substrate 1 are substantially circular, the present invention is not limited to this.

  As shown in FIG. 1A, the transport carrier 10 includes a substrate 1, a frame 2 and a resin sheet 3. An outer peripheral portion of the resin sheet 3 is fixed to the frame 2. The substrate 1 is attached to the resin sheet 3 and held by the transport carrier.

(flame)
The frame 2 is a frame having an opening of the same area as or larger than the whole of the substrate 1 and has a predetermined width and a substantially constant thin thickness. The frame 2 has such rigidity that it can be transported while holding the resin sheet 3 and the substrate 1.

  The shape of the opening of the frame 2 is not particularly limited, but may be, for example, a circle, a rectangle, or a polygon such as a hexagon. The frame 2 may be provided with a notch 2a and a corner cut 2b for positioning. Examples of the material of the frame 2 include metals such as aluminum and stainless steel, and resins. The outer peripheral edge of one surface of the resin sheet 3 is adhered to one surface of the frame 2.

(Resin sheet)
The resin sheet 3 includes, for example, a surface having an adhesive (adhesive surface 3a) and a surface not having an adhesive (non-adhesive surface 3b). The outer peripheral edge of the adhesive surface 3 a is attached to one surface of the frame 2 and covers the opening of the frame 2. Further, the substrate 1 is attached to a portion of the adhesive surface 3 a exposed from the opening of the frame 2.

  The adhesive surface 3a is preferably made of an adhesive component whose adhesive force is reduced by the irradiation of ultraviolet light. By performing ultraviolet irradiation after dicing, the singulated substrate (electronic component) is easily peeled off from the adhesive surface 3 a and is easy to pick up. For example, the resin sheet 3 is obtained by apply | coating a UV curable acrylic adhesive to the thickness of 5-20 micrometers on the single side | surface of a film-form base material.

  The material of the film-like substrate is not particularly limited, and examples thereof include polyolefins such as polyethylene and polypropylene, and polyesters such as polyethylene terephthalate. The base material may be a rubber component (for example, ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), etc.) for adding elasticity, a plasticizer, a softener, an antioxidant, a conductive material, etc. These various additives may be blended. The thickness of the substrate is, for example, 50 to 150 μm. During the plasma processing, the transport carrier 10 is placed on the stage so that the stage and the non-adhesive surface 3 b are in contact with each other. At the time of plasma treatment, at least a part of the various additives as described above (in particular, organic substances) bleed out from the substrate and adhere to the surface of the stage.

(substrate)
The substrate 1 is an object of plasma processing. 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 substrate 1 is thinned by thinning the back surface of the main body opposite to the circuit layer. It is produced by doing. By separating the substrate 1, an electronic component (not shown) having the circuit layer can be obtained.

  The size of the substrate 1 is not particularly limited, and for example, the maximum diameter is about 50 mm to about 300 mm, and the thickness is about 25 to about 150 μm. The shape is also not particularly limited, and is, for example, circular or square. Further, the substrate 1 may be provided with notches such as an orientation flat (ori-flat) and a notch (all not shown).

The material of the main body of the substrate is also not particularly limited, and examples thereof include semiconductors, dielectrics, metals, and laminates of these. Examples of the semiconductor include silicon (Si), gallium arsenide (GaAs), gallium nitride (GaN), silicon carbide (SiC) and the like. As a dielectric, silicon dioxide (SiO ₂ ), silicon nitride (Si ₃ N ₄ ), polyimide, lithium tantalate (LiTaO ₃ ), lithium niobate (LiNbO ₃ ), etc. can be exemplified.

  On the surface of the substrate 1 not attached to the resin sheet 3, a resist mask is formed in a desired shape (not shown). The portion where the resist mask is formed is protected from etching by plasma. The portion from which the resist mask is not formed can be etched by plasma from the front surface to the back surface.

First Embodiment
Next, an outline of a plasma processing method according to an embodiment of the present invention will be described with reference to FIG. FIG. 2 shows a conceptual view of a plasma processing apparatus 20 used in a plasma processing method according to an embodiment of the present invention. In FIG. 2, M <b> 1 to M <b> 4 represent the operation (entry and exit of each part) of the transport mechanism 203.

  The plasma processing apparatus 20 includes, for example, a cassette unit 300 for storing the carrier 10 holding the substrate 1, a preparation unit 200 including a carrier mechanism 203 for carrying the carrier 10, and the plasma processing unit 100. Have. The preparation unit 200 is interposed between the cassette unit 300 and the plasma processing unit 100, and the carrier 10 carried out of the cassette unit 300 is carried into the plasma processing unit 100 via the preparation unit 200. . The cassette unit 300 includes, for example, a cassette 301 for storing a plurality of transport carriers 10. The transport mechanism 203 includes, for example, a transport fork 201 and a transport arm 202 that supports the transport fork 201. The plasma processing unit 100 includes a stage 111 on which the carrier 10 is placed. The plasma processing unit 100 plasma-processes the substrate 1 placed on the stage 111 to separate the substrate 1 into pieces. The configuration other than the stage 111 of the plasma processing unit 100 will be described later.

The process from the lot start to the end in the case of using such a plasma processing apparatus 20 is as follows.
First, the carrier 10 to be subjected to plasma processing is selected from among the plurality of carrier carriers. The selected transport carrier 10 is carried out of the cassette unit 300 by the transport mechanism 203 (M1). Position adjustment, inspection of the presence or absence of the substrate 1, and the like are performed in the preparation unit 200 as needed for the transported carrier 10 that has been carried out. Subsequently, the carrier 10 is carried into the plasma processing unit 100 (M2).

  Here, in order to improve the efficiency of the plasma processing, it is preferable that the plasma processing unit 100 be kept in vacuum when the carrier 10 is carried in and out. Therefore, when the cassette unit 300 is under the atmosphere, the preparation unit 200 is sealed after the transport carrier 10 is carried in and is decompressed by a vacuum pump (not shown). After the preparation unit 200 is decompressed, a gate valve (not shown) of the plasma processing unit 100 is opened, and the carrier 10 is carried into the plasma processing unit 100 and placed on the stage 111. At this time, the transport fork 201 holds the transport carrier from the side of the surface of the resin sheet 3 which does not hold the substrate 1. The transport carrier 10 is placed on the stage 111 such that the resin sheet 3 and the stage of the plasma processing unit 100 are in contact with each other. After mounting the carrier 10, the carrier mechanism 203 is withdrawn from the plasma processing unit 100, and the gate valve is closed again.

  In the plasma processing unit 100, plasma processing (etching and ashing) is performed on the substrate placed on the stage 111. When the plasma processing is completed, the gate valve of the plasma processing unit 100 is opened again, and the transport carrier 10 is unloaded from the plasma processing unit 100 by the transport mechanism 203 (M3). When unloading is complete, the gate valve is closed. The transported carrier 10 carried out is inspected and the like in the preparation unit 200 as needed, and then stored in the cassette 301 of the cassette unit 300 (M4).

  On the other hand, in the plasma processing unit 100 in which the carrier 10 is carried out and the gate valve is closed, the process gas is supplied again, and the plasma processing is started. This plasma treatment is performed to remove the deposit derived from the resin sheet attached to the stage 111. When the deposits on the stage 111 are removed, the gas inside the plasma processing unit 100 is evacuated and is again in a vacuum state. After the plasma processing unit 100 becomes vacuum, the transport carrier 10 holding the other substrate 1 is carried into the plasma processing unit 100 by the transport mechanism 203, and the plasma processing is repeated.

  When the flow including the mounting step, the plasma processing step, and the unloading step is continuously performed on a plurality of transport carriers, the deposit removing step is performed when there is no transport carrier 10 in the plasma processing unit 100. If there is, it may be performed at any timing. In particular, after the plasma-treated transport carrier is unloaded in the Nth flow, the time before the transport carrier to be subjected to plasma processing is placed in the (N + 1) th flow is used, It is preferable to carry out the removal step. In order to perform the removal process using a time (for example, the transfer time of the transfer carrier 10, etc.) which is always required in a series of processes performed on one transfer carrier 10, a removal process is added Also, the increase in required time can be suppressed. In other words, productivity is not lost. Rather, by removing the deposit, the etching rate is high and stable even when a plurality of substrates are continuously processed, so the efficiency of plasma processing is improved and the productivity is enhanced.

  The removal process may be started immediately after, for example, the plasma processing is completed, the plasma-treated carrier 10 is unloaded from the plasma processing unit 100, and the gate valve is closed. In this case, since the plasma-treated transport carrier 10 is moving toward the cassette unit 300, the removal process starts at the timing immediately before the storage of the latest processed transport carrier 10 in the cassette unit 300 is completed. It will be done.

  In addition, the removal process may be started when the transport process of the transport carrier 10 which is the target of the next plasma process is started after the plasma processed transport carrier 10 is stored in the cassette 301. Specifically, the removal process can be performed while selecting the carrier 10 or while moving the carrier 10 from the preparation unit 200 to the plasma processing unit 100. In this case, the removal process is started at the timing immediately after the start of the selection operation of the transport carrier 10 to be subjected to the next plasma processing or the transport process.

  Note that the removing step may be performed each time the plasma processing on one carrier is completed or started, or may be performed on each of a plurality of carriers.

  In FIG. 3, when a plurality of substrates held by a resin sheet (made of polyolefin resin) are placed on a stage and plasma dicing is continuously performed, change in plasma dicing rate (etching depth per unit time) Indicates The substrate used is a Si substrate with a thickness of 100 μm, and a mask pattern is formed on the surface of the substrate. In the figure, a unit of plasma dicing speed (arb. Unit) means an arbitrary unit. When the removal step is not performed, the plasma dicing rate tends to decrease as the number of processed wafers increases. On the other hand, when the removal step is performed, it can be seen that although the plasma dicing rate slightly decreases immediately after the start, it tends to be stabilized at a constant high value thereafter. When the Si substrate not held by the resin sheet is directly placed on the stage and plasma dicing is continuously performed, the degree of decrease in plasma dicing speed is smaller than that when the removal step is not performed, and the removal step It is almost the same as when it was done. In other words, the deposit derived from the resin sheet has a great influence on the plasma dicing speed, but the influence is extremely reduced by the removal step.

When the removal step is not performed, the reason why the plasma dicing rate decreases as the number of processed wafers increases is considered as follows.
The singulation of the Si substrate by plasma dicing is performed by etching (deep etching) the opening of the mask of the Si substrate perpendicularly to the depth direction. The so-called Bosch process is usually used here. In the Bosch process, a plasma etching step for etching and a plasma protective film deposition step for protective film deposition are alternately repeated. In the etching step, the Si substrate exposed in the opening of the mask is etched in the depth direction to form a groove. In the protective film deposition step, the inner wall surface of the groove formed in the etching step is coated with a protective film. In the subsequent etching step, the protective film covering the bottom of the groove is removed, and the Si substrate exposed at the bottom is etched in the depth direction. At this time, since the side walls of the groove are still covered with the protective film, they are not easily etched in the etching step. By alternately repeating the etching step and the protective film deposition step, the substrate can be dug vertically in the depth direction at the opening of the mask.

  When the removal step is not performed, the deposit derived from the resin sheet adheres to the surface of the stage, and the cooling effect of the substrate is reduced. Therefore, the temperature of the substrate during plasma processing is increased. The temperature rise of the substrate has two opposite effects on the etching rate in the etching step.

  The first effect is the increase of the etch rate in the etch step. When the temperature of the substrate is high, the reactivity between the plasma and the Si substrate is enhanced.

The second effect is the reduction of the etch rate in the etch step.
The temperature rise of the substrate inhibits the deposition of the protective film in the protective film deposition step. When the temperature of the substrate is high, the desorption reaction of the deposit on the substrate is promoted. Therefore, it becomes difficult to form a protective film on the side surface of the groove. When the temperature of the substrate further rises, there will be a portion where the protective film is not formed on the side, ie, an exposed portion of the Si substrate. That is, when the temperature of the Si substrate rises, the area of the Si substrate exposed to the portion other than the bottom of the groove increases. When the area of the Si substrate exposed other than the bottom of the groove increases, in the etching step, the components (ions, radicals, etc.) in the plasma that contribute to the etching of the Si substrate are not on the bottom of the groove (that is, the side of the groove). It is consumed by the reaction with the exposed Si substrate and is not sufficiently supplied to the bottom of the groove. As a result, the etching rate to the bottom of the groove is reduced (loading effect).

  That is, the temperature rise of the substrate acts to increase the etching rate in the etching step, and at the same time it acts to lower the rate. When the removal step is not performed, it is considered that the decrease in the etching rate to the bottom due to the loading effect outweighs the increase in the etching rate due to the temperature increase as the number of processed wafers increases. Therefore, the plasma dicing speed is reduced. As the plasma dicing rate decreases, productivity decreases. In addition, if the etching rate relative to the side surface is relatively increased, it is difficult to dig vertically and it becomes difficult to singulate into a desired shape.

Next, the plasma processing unit 100 according to an embodiment of the present invention will be described in detail with reference to FIG. FIG. 4 is a conceptual view showing a cross section of the plasma processing unit 100. As shown in FIG.
The plasma processing unit 100 includes a stage 111. The transport carrier 10 is mounted on the stage 111 such that the surface (adhesive surface 3 a) holding the substrate 1 of the resin sheet 3 faces upward. A cover 124 having a window 124 W for covering at least a part of the frame 2 and the resin sheet 3 and exposing at least a part of the substrate 1 is disposed above the stage 111.

The stage 111 and the cover 124 are disposed in the reaction chamber (vacuum chamber 103). The vacuum chamber 103 is generally cylindrical with an open top, and the top opening is closed by a dielectric member 108 which is a lid. As a material which comprises the vacuum chamber 103, aluminum, stainless steel (SUS), the aluminum which carried out the alumite processing of the surface etc. can be illustrated. The material constituting the dielectric member 108, yttrium oxide (Y ₂ O _3), aluminum nitride (AlN), alumina (Al ₂ O _3), a dielectric material such as quartz (SiO ₂₎ can be exemplified. An antenna 109 as an upper electrode is disposed above the dielectric member 108. The antenna 109 is electrically connected to the first high frequency power supply 110A. The stage 111 is disposed on the bottom side in 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 supply sources of a plasma generation gas, are connected to the gas introduction port 103a by piping, respectively. Further, an exhaust port 103 b is provided in the vacuum chamber 103, and a pressure reducing mechanism 114 including a vacuum pump for exhausting the gas in the vacuum chamber 103 and reducing the pressure is connected to the exhaust port 103 b.

  The stage 111 has 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. Equipped with Inside the electrode layer 115, an electrode portion (hereinafter referred to as an ESC electrode) 119 constituting an electrostatic adsorption mechanism and a high frequency electrode 120 electrically connected to the second high frequency power source 110B are disposed. A DC power supply 126 is electrically connected to the ESC electrode 119. The electrostatic adsorption mechanism is constituted by the ESC electrode 119 and the DC power supply 126. The electrode layer 115 is made of, for example, the above-described dielectric material.

  The metal layer 116 is made of, for example, aluminum or the like having an alumite coating formed on the surface. A coolant channel 127 is formed in the metal layer 116. The coolant channel 127 cools the stage 111. As the stage 111 is cooled, the resin sheet 3 mounted on the stage 111 is cooled, and the cover 124 which is partially in contact with the stage 111 is also cooled. The refrigerant in the refrigerant flow passage 127 is circulated by the refrigerant circulation device 125.

  In the vicinity of the outer periphery of the stage 111, a plurality of support portions 122 penetrating the stage 111 are disposed. The support portion 122 is driven to move up and down by the lift mechanism 123A. When the transport carrier 10 is transported into the vacuum chamber 103, it is delivered to the support 122 raised to a predetermined position. The support portion 122 supports the frame 2 of the transport carrier 10. By lowering the upper end surface of the support portion 122 to the same level as the stage 111 or less, the transport carrier 10 is mounted at a predetermined position of the stage 111.

  A plurality of lifting rods 121 are connected to the end of the cover 124, and the cover 124 can be moved up and down. The lifting rod 121 is driven to move up and down by the lifting mechanism 123B. The lifting and lowering operation of the cover 124 by the lifting and lowering mechanism 123B can be performed independently of the lifting and lowering mechanism 123A.

  The controller 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 reducing mechanism 114, a refrigerant circulating device 125, an elevating mechanism 123A, an elevating mechanism 123B, and an electrostatic adsorption mechanism. The operation of the elements constituting the plasma processing unit 100 is controlled.

  Specific steps performed by the plasma processing method according to the present embodiment will be described using FIGS. 5 and 6. FIG. 5 is a flowchart showing a plasma processing method, and FIG. 6 is a conceptual view showing a part of the operation of the plasma processing unit.

  Prior to the start of the placement step (S1), the plurality of transport carriers 10 are accommodated in the cassette 301 provided in the cassette unit 300. The transport mechanism 203 is activated, and the transport fork 201 enters the cassette unit 300 to hold one of the plurality of transport carriers 10. Next, the transport fork 201 withdraws from the cassette unit 300 while holding the transport carrier 10. The preparation unit 200 into which the carrier 10 is carried is sealed and vacuumed by a vacuum pump. When it is confirmed that the preparation unit 200 has become vacuum, the gate valve of the plasma processing unit 100 is opened, and the mounting step (S1) is started.

  In the placement step (S 1), the transport mechanism 203 transports the transport carrier 10 into the plasma processing unit 100 and places it on the stage 111. At this time, in the vacuum chamber 103, in order to support the transport carrier 10, the plurality of supports 122 stand by in a raised state. The cover 124 also stands by at the raised position (FIG. 6A). The transport carrier 10 is transported into the vacuum chamber 103 by the transport mechanism (not shown), and is delivered to the plurality of supports 122 (FIG. 6B). The transport carrier 10 is placed on the upper end surface 122 a of the support portion 122 such that the surface (adhesive surface 3 a) of the resin sheet 3 holding the substrate 1 faces upward.

  When the transport carrier 10 is placed on the upper end surface 122 a of the support portion 122, the transport fork 201 withdraws. When it is confirmed that the transport fork 201 has been withdrawn, a gate valve (not shown) separating the plasma processing unit 100 and the preparation unit 200 is closed, and the plasma processing unit 100 is placed in a sealed state. Subsequently, plasma processing is performed on the substrate 1 (plasma processing step: S2).

  In the plasma processing step (S2), first, the support portion 122 starts to descend. The upper end surface 122a of the support portion 122 is lowered to the same level as the stage 111 or less, and the carrier 10 is placed on the stage 111 (FIG. 6C). Subsequently, the elevating rod 121 is driven by the elevating mechanism 123B. The lift rod 121 lowers the cover 124 to a predetermined position (FIG. 6 (d)).

  At this time, the stage 111 is cooled to, for example, about 15 ° C. by the refrigerant constantly circulated in the refrigerant channel 127. Further, a voltage is applied to the ESC type electrode 119. The bleed out from the resin sheet 3 is more likely to be noticeable due to the electric field formed by the ESC electrode and the leakage current generated from the ESC electrode. However, since the removal step is performed after the plasma treatment step, the efficiency of the plasma treatment is hardly reduced by the above bleed out.

  When the cover 124 is placed in the predetermined lowered position, the frame 2 and the portion not holding the substrate 1 of the resin sheet 3 are covered by the cover 124 without contacting the cover 124, and the substrate 1 is a window of the cover 124 It is exposed from the part 124W.

  The cover 124 is, for example, a donut shape having a substantially circular outline, and has a certain width and a small thickness. The inner diameter of the cover 124 (the diameter of the window 124 W) 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 a part of the frame 2 and the resin sheet 3. At least a part of the substrate 1 is exposed from the window portion 124W. At this time, the cover 124 does not contact any of the frame 2, the resin sheet 3 and the substrate 1. The cover 124 is made of, for example, a dielectric such as ceramics (for example, alumina, aluminum nitride or the like) or quartz, or a metal such as aluminum or aluminum whose surface is anodized.

  When the support 122 and the cover 124 are in place, the process gas is introduced into the vacuum chamber 103 from the process gas source 112 through the gas inlet 103 a. On the other hand, the pressure reducing mechanism 114 exhausts the gas in the vacuum chamber 103 from the exhaust port 103 b and maintains the inside of the vacuum chamber 103 at a predetermined pressure.

  Subsequently, high frequency power is applied to the antenna 109 from the first high frequency power supply 110A, and plasma P1 is generated in the vacuum chamber 103 (FIG. 6 (e)). The generated plasma P1 is composed of ions, electrons, radicals, and the like. The surface to the back surface of the exposed portion from the resist mask formed on the substrate 1 is removed (etched) by the physicochemical reaction with the generated plasma P1, and the substrate 1 is singulated.

  Here, high frequency power of, for example, 100 kHz or more may be input from the second high frequency power supply 110 </ b> B to the high frequency electrode 120. The incident energy of the ions to the substrate 1 can be controlled by the high frequency power applied from the second high frequency power supply 110 B to the high frequency electrode 120. When high frequency power is applied to the high frequency electrode 120, a bias voltage is generated on the surface of the stage 111, and ions entering the substrate 1 are accelerated by the bias voltage, and the etching rate is increased. On the other hand, when high frequency power is applied to the high frequency electrode 120, the bleed out from the resin sheet 3 tends to be more remarkable. However, after the plasma treatment step, the bleed-out component attached to the stage 111 is removed by the removal step, so that even if the plasma treatment is repeatedly performed while applying high-frequency power to the high-frequency electrode 120, bleeding to the stage 111 is performed. Accumulation of out components is suppressed. Therefore, even when the plasma processing is repeatedly performed to apply high frequency power to the high frequency electrode 120 in order to perform etching at high speed, the effect of cooling the substrate 1 is not easily impaired, and a problem caused by temperature rise of the substrate (for example, plasma The reduction of dicing speed is suppressed.

The etching conditions are set in accordance with the material of the substrate 1 and the like. For example, when the substrate 1 is Si, the substrate 1 is etched by generating a plasma P1 of a fluorine-containing gas such as sulfur hexafluoride (SF ₆ ) in the vacuum chamber 103. In this case, for example, while the SF ₆ gas is supplied at 100 to 800 sccm from the process gas source 112, the pressure of the reaction chamber 103 is controlled to 10 to 50 Pa by the pressure reducing mechanism 114. The antenna 109 is supplied with high frequency power of 13.56 MHz at a frequency of 1000 to 5000 W, and is supplied with high frequency power of 13.56 MHz at a frequency of 50 to 1000 W to the high frequency electrode 120.

  In order to suppress the temperature rise of the transport carrier 10 during etching, the temperature of the refrigerant circulated in the stage 111 is preferably set to -20 to 20 ° C. by the refrigerant circulation device 125. Thereby, the temperature of the resin sheet 3 in plasma processing is controlled to 150 degrees C or less. Therefore, the thermal damage of the resin sheet 3 is suppressed. When the temperature of the resin sheet 3 is, for example, 50 ° C. or more and 150 ° C. or less, the organic matter is easily bled out of the resin sheet 3.

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

  The substrate is singulated by etching, and the electronic component 4 (chip) is manufactured. Subsequently, ashing is performed. A process gas for ashing (for example, oxygen gas, mixed gas of oxygen gas and gas containing fluorine, etc.) is introduced into the vacuum chamber 103 from an ashing gas source 113. On the other hand, the evacuation by the decompression mechanism 114 is performed to maintain the inside of the vacuum chamber 103 at a predetermined pressure. By the application of high frequency power from the first high frequency power supply 110A, oxygen plasma is generated in the vacuum chamber 103, and the resist mask on the surface of the electronic component 4 exposed from the window 124W of the cover 124 is completely removed. .

  When the ashing is completed, the gas in the vacuum chamber 103 is exhausted and the gate valve is opened. The transport carrier 10 holding the electronic component 4 is carried out of the plasma processing unit 100 by the transport mechanism 203 which has entered from the gate valve (S3). When the carrier 10 is carried out, the gate valve is quickly closed. The carried carrier 10 is once carried into the preparation unit 200 and, if necessary, inspected and the like, then carried into the cassette unit 300 and stored in the cassette 301.

  Here, the unloading process of the transport carrier 10 may be performed in a procedure reverse to the procedure of mounting the substrate 1 on the stage 111 as described above. That is, as shown in FIG. 7, after raising the cover 124 to a predetermined position (FIG. 7 (g)), the voltage applied to the ESC type electrode 119 is made zero, and the carrier carrier 10 is moved to the stage 111. The suction is released, and the support portion 122 is raised (FIG. 7 (h)). After the support portion 122 ascends to a predetermined position, the transport carrier 10 is unloaded by the transport mechanism 203 (FIG. 7 (i)). FIG. 7 is a conceptual view showing another part of the operation of the plasma processing unit.

  Here, it is preferable to provide a charge removing step (S5) for removing the resin sheet 3 as shown in FIG. 8 before or during the rising of the support part 122 (between FIG. 7 (g) to (h)). . When the electric charge at the time of the plasma processing remains on the resin sheet 3 and the resin sheet 3 remains adsorbed on the stage 111, it is difficult to peel the resin sheet 3 smoothly from the stage 111. The static elimination is performed by supplying weak high frequency power of about 200 W, for example, from the first high frequency power supply 110A to generate weak plasma. Since the resin sheet 3 is peeled off smoothly from the stage 111 by the static elimination, troubles such as damage to the resin sheet 3 at the time of unloading are suppressed, and the efficiency of the plasma processing is further improved. FIG. 8 is a flowchart showing another plasma processing method.

  The static elimination step (S5) is preferably performed in the same atmosphere as the subsequent removal step (S4). This is because the time required for the inside of the vacuum chamber 103 to become an environment suitable for the removal process (that is, the atmosphere in the vacuum chamber 103 in the removal process) is shortened, and the efficiency of plasma processing is further improved. When the removal step is performed, for example, in an oxygen atmosphere, the charge removal step is also preferably performed in an oxygen atmosphere. That is, for the static elimination, it is preferable to use a gas containing oxygen as a gas for generating plasma, and it is particularly preferable to use only oxygen. In other words, the oxygen content in the vacuum chamber 103 in the static elimination step is preferably 80 to 100% by volume.

In the charge removal step, for example, while the O ₂ gas is supplied at 200 to 500 sccm from the ashing gas source 113, the pressure in the reaction chamber 103 is controlled to 8 to 12 Pa by the pressure reducing mechanism 114. Then, it is performed by supplying a high frequency power of 13.56 MHz with a frequency of 100 to 200 W to the antenna 109.

  Further, after the end of ashing (FIG. 7F), a cooling process may be provided to cool the cover 124 by introducing a cooling gas into the vacuum chamber 103 until the support portion 122 is lifted. This is because the cover 124 has a high temperature by being exposed to plasma in the plasma treatment process. By cooling the cover 124, thermal damage of the resin sheet 3 due to the radiant heat from the cover 124 is easily suppressed. From the viewpoint of suppressing the thermal damage of the resin sheet 3, after the cover 124 is raised to a predetermined position and the cover 124 is moved away from the resin sheet 3 (FIG. 7 (g)), the above-mentioned cooling process may be performed. preferable.

  The cooling step is also preferably performed in the same atmosphere as the subsequent removal step (S4). This is because the time required for the inside of the vacuum chamber 103 to become an environment suitable for the removal step is shortened, and the efficiency of plasma processing is further improved. When the removal step is performed, for example, in an oxygen atmosphere, the cooling step is also preferably performed in an oxygen atmosphere. That is, it is preferable to use a gas containing oxygen as the cooling gas, and in particular, it is preferable to use only oxygen. In other words, the oxygen content in the vacuum chamber 103 in the cooling step is preferably 80 to 100% by volume.

After the charge removal step (S5) and / or the cooling step is performed as necessary, the carrier 10 is carried out (S3). At this time, the deposit 5 derived from the resin sheet 3 is attached to the surface of the stage 111 (FIG. 7 (i)). Then, after the carrier 10 is carried out and the gate valve is closed, the gas is again supplied into the vacuum chamber 103 to generate the plasma P2 (Fig. 7 (j), S4). At this time, for example, while the O ₂ gas is supplied at 200 to 1000 sccm from the ashing gas source 113, the pressure of the reaction chamber 103 is controlled to 8 to 12 Pa by the pressure reducing mechanism 114. The antenna 109 is supplied with high frequency power of 13.56 MHz at a frequency of 500 to 1000 W.

  As a result, the resin sheet 3 is bled out, and the deposit 5 attached to the surface of the stage 111 is removed (FIG. 7 (k)). The removal of the deposit 5 is preferably performed by oxygen plasma as described above. After removing the deposit 5 attached to the stage 111, the gas inside the plasma processing unit 100 is exhausted and vacuumed again. Thus, the series of steps is completed. When the plasma processing is continuously performed on a plurality of transport carriers, the steps from the placing step (S1) to the removing step (S4) may be repeated, or from the placing step (S1) to the unloading step After repeating the process a plurality of times, the removal process (S4) may be performed.

  On the other hand, while the series of plasma processing is being performed, the next substrate 1 to be subjected to plasma processing is prepared in portions other than the plasma processing unit 100. That is, in the manufacturing process of the electronic component 4, after the removing step, the support portion 122 and the cover 124 are lifted again (FIG. 6 (a)), the other carrier 10 is carried in, and the mounting step, plasma treatment A process, an unloading process and a removing process are performed.

  The plasma processing method of the present invention is useful as a method of plasma processing a substrate held by a resin sheet.

  1: Substrate, 2: Frame, 2a: Notch, 2b: Corner cut, 3: Resin sheet, 3a: Adhesive surface, 3b: Non-adhesive surface, 4: Electronic parts, 5: Adherence, 10: Transport carrier, 20: Plasma processing apparatus, 100: plasma processing unit, 103: vacuum chamber, 103a: gas inlet, 103b: exhaust port, 108: dielectric member, 109: antenna (plasma source), 110A: first high frequency power source, 110B: Second high frequency power source 111: stage 112: process gas source 113: ashing gas source 114: pressure reducing mechanism 115: electrode layer 116: metal layer 117: base 118: peripheral portion 119: ESC Electrode 120: High frequency electrode 121: Lifting rod 122: Support portion 122a: Upper end surface 123A, 123B: Lifting mechanism 124: Cover, 124W Window, 125: refrigerant circulating apparatus, 126: DC power supply, 127: refrigerant passage, 128: controller

Claims (10)

A plasma processing method of placing a substrate held by a resin sheet on a stage provided inside a reaction chamber and performing plasma processing,
Placing the substrate on the stage such that the surface of the stage is in contact with the resin sheet;
Covering at least a part of the resin sheet with a cover having a window for exposing at least a part of the substrate placed on the stage;
Performing a plasma process on the substrate exposed from the cover ;
An unloading step of unloading the substrate together with the resin sheet from the reaction chamber after the plasma processing step;
After the unloading step, generating a plasma in the reaction chamber to remove a substance discharged from the resin sheet and adhering to the surface of the stage ;
The plasma processing method , wherein a distance between the cover and the stage in the removing step is larger than a distance between the cover and the stage in the plasma processing step . The flow including the disposing step, the plasma processing step, and the unloading step is performed on each of the plurality of substrates held by the plurality of resin sheets,
The plasma processing method according to claim 1, wherein the removing step is performed after the unloading step in the Nth (N is an integer) flow, and before the placing step in the (N + 1) th flow.   The plasma processing method according to claim 1, wherein the removing step is performed under an oxygen atmosphere.   The plasma processing method according to claim 3, wherein after the plasma processing step, a gas containing oxygen is supplied into the reaction chamber until the start of the removal step.   The plasma processing method according to claim 4, wherein only oxygen is supplied into the reaction chamber after the plasma processing step until the start of the removal step.   The plasma processing method according to any one of claims 1 to 5, wherein a high frequency power of 100 kHz or more is applied to the stage in the plasma processing step.   The plasma processing method according to any one of claims 1 to 6, wherein the temperature of the resin sheet is controlled to 150 ° C or lower in the plasma processing step. After the plasma treatment step, a charge removal step for removing the charge of the resin sheet is provided between the discharge step and the discharge step.
The plasma processing method according to any one of claims 3 to 7, wherein the charge removal step is performed under an oxygen atmosphere.   The plasma processing method according to any one of claims 1 to 8, wherein the substance discharged from the resin sheet contains an organic substance. Preparing a substrate held by the resin sheet;
Placing the substrate on the stage such that the surface of the stage provided inside the reaction chamber and the resin sheet are in contact with each other;
Covering at least a part of the resin sheet with a cover having a window for exposing at least a part of the substrate placed on the stage;
Performing a plasma process on the substrate exposed from the cover to singulate the substrate;
An unloading step of unloading the substrate from the reaction chamber together with the resin sheet after the dicing step;
After the unloading step, generating a plasma in the reaction chamber to remove a substance discharged from the resin sheet and adhering to the surface of the stage ;
A method of manufacturing an electronic component , wherein a distance between the cover and the stage in the removing step is larger than a distance between the cover and the stage in the dicing step .

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