JP2017054854A - Plasma processing method and manufacturing method for electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma processing method capable of removing attachments adhering to the back surface of a cover.SOLUTION: A plasma processing method comprises a mounting step of mounting a transporting carrier for holding a substrate on a stage, a distance adjusting step of adjusting the distance between a cover and the stage to a first distance at which the cover covers a frame in no contact with the transporting carrier, a plasma processing step of performing plasma processing on the substrate mounted on the stage after the distance adjusting step, a carry-out step of carrying out the substrate together with the transporting carrier from the reaction chamber after the plasma processing step, and a removing step of generating plasma inside the reaction chamber after the carry-out step to remove attachments adhering to the cover. The distance between the cover and the stage in the removal step is a second distance longer than the first distance.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a plasma processing method and an electronic component manufacturing method, and more particularly to a plasma processing method using a plasma processing apparatus including a cover above a stage.

  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 and divided into individual chips. Patent Document 1 places a substrate on a stage in a state in which the substrate is held by a conveyance carrier including a holding sheet and a frame disposed on the outer peripheral portion of the holding sheet for improving handling of the substrate in conveyance or the like. Teaching to perform plasma treatment.

  In this case, when the transport carrier is directly exposed to plasma, a holding sheet made of a resin material and an adhesive for fixing the holding sheet to the frame are heated. Due to this heat, there is a concern that the carrier may be damaged such that the holding sheet is stretched (deformed) or the adhesive is lowered, and the holding sheet is peeled off from the frame.

  Therefore, in Patent Document 1, a dielectric cover having a window is disposed above the stage in the reaction chamber of the plasma processing apparatus. The cover includes a main body for covering the frame and a window formed to penetrate the main body in the thickness direction. During the plasma treatment, the main body covers the frame and the holding sheet so that they are not exposed to the plasma, and the window exposes the substrate. Of the exposed substrate, the portion where the resist mask is not formed is etched by plasma.

JP 2009-94436 A

In the plasma processing step, in order to vertically etch the surface of the substrate, for example, an etching step using a fluorine-based gas plasma such as SF ₆ and a fluorocarbon gas plasma such as perfluorocyclobutane (C ₄ F ₈ ) are used. The protective film deposition step may be repeated alternately. When a plasma treatment is continuously performed on a plurality of substrates using such a method, deposits accumulate in the reaction chamber as the number of treatments increases, causing substrate contamination or impossible etching. There is a case.

  The deposit is a substance containing carbon, for example, and adheres to a surface (hereinafter referred to as a back surface of the cover) facing the cover stage. This substance is, for example, a reaction product derived from a fluorocarbon gas used in the above protective film deposition step. During the plasma processing, the cover is disposed so as not to contact the frame and the holding sheet and as close to the stage as possible in order to protect the frame and the holding sheet from plasma.

  In the protective film deposition step, the fluorocarbon gas introduced into the reaction chamber is decomposed into ions and radicals in the plasma, and some of them enter between the cover and the stage and come into contact with the back surface of the cover. Thereby, the reaction product containing carbon derived from fluorocarbon gas adheres to the back surface of the cover.

  In the etching step, the fluorine-based gas introduced into the reaction chamber is decomposed into ions and radicals in the plasma, and similarly, some of them enter between the cover and the stage. Usually, in the etching step, a bias voltage is applied to the stage. This increases the speed at which the fluorine gas decomposition component collides with the substrate placed on the stage and promotes the etching reaction. However, since the back surface of the cover is spaced apart from the stage and above the stage, even if a bias voltage is applied to the stage, it is difficult to obtain the effect of promoting the etching reaction on the back surface of the cover. Therefore, the decomposition product of the fluorine-based gas that has entered between the cover and the stage cannot sufficiently remove the reaction product attached to the back surface of the cover in the protective film deposition step. As a result, each time the plasma treatment step is repeated, the reaction product accumulates on the back surface of the cover. The accumulated reaction product is eventually peeled off from the back surface of the cover and falls on the stage or the substrate or floats in the reaction chamber. As a result, the substrate is contaminated or desired etching cannot be performed.

  One aspect of the present invention is to place a substrate held by a transport carrier including a holding sheet and a frame disposed on an outer peripheral portion of the holding sheet, on a stage provided inside a reaction chamber, A plasma processing method for plasma-treating the substrate by covering the frame with a cover disposed above and having a window for exposing the substrate, wherein the transport carrier holding the substrate includes the carrier A placing step for placing on a stage; a distance adjusting step for adjusting a distance between the cover and the stage to a first distance that covers the frame without the cover contacting the transport carrier; and the distance adjusting. After the step, a plasma processing step for performing the plasma processing on the substrate placed on the stage, and after the plasma processing step, An unloading step of unloading from the reaction chamber together with a carrier carrier; and a removing step of removing the deposits attached to the cover by generating plasma in the reaction chamber after the unloading step. The present invention relates to a plasma processing method, wherein a distance between the cover and the stage in the process is a second distance that is larger than the first distance.

  In another aspect of the present invention, a substrate held by a transport carrier including a holding sheet and a frame disposed on an outer peripheral portion of the holding sheet is placed on a stage provided inside a reaction chamber, A method of manufacturing an electronic component in which the frame is covered with a cover that is disposed above a stage and includes a window for exposing the substrate, and the substrate is subjected to plasma processing. A step of preparing a substrate held by a transfer carrier provided with a frame disposed on the outer periphery, a mounting step of mounting the transfer carrier holding the substrate on the stage, the cover and the stage, A distance adjustment step of adjusting the distance to a first distance that covers the frame without the cover contacting the transport carrier; and after the distance adjustment step, the step The substrate placed on a substrate is subjected to plasma treatment to separate the substrate, and after the dicing step, the separated substrate is unloaded from the reaction chamber together with the transport carrier. An unloading step, and after the unloading step, plasma is generated in the reaction chamber to remove deposits attached to the cover, and the cover and the stage in the removing step are removed. The present invention relates to a method for manufacturing an electronic component, wherein the distance is a second distance that is greater than the first distance.

  According to the present invention, it is possible to remove the deposits attached to the back surface of the cover, so that the yield of electronic components is improved.

It is sectional drawing which shows notionally an example of the plasma processing apparatus used for this invention. It is a conceptual diagram which shows from the mounting process to the plasma processing process which concerns on one Embodiment of this invention ((a)-(g)). It is a conceptual diagram which shows from the carrying-out process to the removal process which concerns on one Embodiment of this invention ((h)-(m)). It is sectional drawing which shows notionally some operation | movement of the plasma processing apparatus shown in FIG. It is the top view (a) which shows roughly an example of the conveyance carrier used for this invention, and sectional drawing (b) in the BB line. It is sectional drawing which shows notionally another example of the plasma processing apparatus used for this invention. It is a conceptual diagram which shows the positional relationship of a cover and a stage in the plasma processing process and removal process using the plasma processing apparatus shown in FIG. 6 ((a), (b)).

  In the plasma processing method according to the present invention, a substrate held by a transport carrier including a holding sheet and a frame disposed on an outer peripheral portion of the holding sheet is placed on a stage provided inside a reaction chamber, This is a plasma processing method for plasma processing a substrate by covering the frame with a cover that is disposed above and includes a window portion for exposing the substrate. That is, a placing step of placing the transport carrier holding the substrate on the stage, and a distance adjusting step of adjusting the distance between the cover and the stage to the first distance that covers the frame without the cover contacting the transport carrier And after the distance adjusting step, a plasma processing step for performing plasma processing on the substrate placed on the stage, and after the plasma processing step, an unloading step for unloading the substrate from the reaction chamber together with the transfer carrier, and unloading After the step, a removing step of generating plasma inside the reaction chamber to remove the deposits attached to the cover is included. In the removing step, the distance between the cover and the stage (second distance d2) is set larger than the distance between the cover and the stage during plasma processing (first distance d1). Thereby, since plasma can enter into the back surface of the cover, the deposits attached to the back surface of the cover are removed.

  The electronic component manufacturing method according to the present invention is a method of dicing a substrate using the plasma processing method. That is, in the method of manufacturing an electronic component according to the present invention, a step of preparing a substrate held by a conveyance carrier provided with a holding sheet and a frame disposed on an outer peripheral portion of the holding sheet, and a conveyance carrier that holds the substrate, After the placing step for placing on the stage, the distance adjusting step for adjusting the distance between the cover and the stage to the first distance that the cover covers the frame without contacting the carrier, and after the distance adjusting step, A dicing process for performing plasma processing on the placed substrate and separating the substrate into individual pieces; an unloading step for unloading the separated substrate together with the carrier from the reaction chamber after the dicing step; and an unloading step And a removing step of generating plasma inside the reaction chamber to remove deposits attached to the cover. As described above, since the deposits attached to the back surface of the cover can be removed, the yield of electronic components is improved.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
First, an embodiment of a plasma processing apparatus used in the present invention will be described in detail with reference to FIG. FIG. 1 is a conceptual diagram showing a cross section of a plasma processing apparatus. The plasma processing apparatus shown in FIG. 1 fluctuates the distance between the cover and the stage by moving the cover up and down.

  The plasma processing apparatus 100A includes a stage 111. Above the stage 111, a main body part 124B that covers at least a part of the frame 2 and the holding sheet 3 and a cover 124 that has a window part 124W for exposing at least a part of the substrate 1 are disposed. Window portion 124W is formed by an opening that penetrates main body portion 124B in the thickness direction.

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 upper opening, and the upper opening is closed by a dielectric member 108 that is a lid. Examples of the material constituting the vacuum chamber 103 include aluminum, stainless steel (SUS), and aluminum whose surface is anodized. Examples of the material constituting 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 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 plasma generating gas, are connected to the gas inlet 103a by pipes. The vacuum chamber 103 is provided with an exhaust port 103b, and a pressure reducing mechanism 114 including a vacuum pump for exhausting and depressurizing the gas in the vacuum chamber 103 is connected to the exhaust port 103b.

  The stage 111 includes a substantially circular electrode layer 115, a metal layer 116, a base 117 that supports the electrode layer 115 and the metal layer 116, and an outer peripheral portion 118 that surrounds the electrode layer 115, the metal layer 116, and the base 117. Is provided. The outer peripheral portion 118 is made of a metal having 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 disposed on the upper surface of the outer peripheral portion 118. The outer peripheral ring 129 serves to protect the upper surface of the outer peripheral portion 118 from plasma. When the outer diameter of the outer peripheral ring 129 is larger than the outer diameter of the outer peripheral portion 118, the outer peripheral ring 129 controls the flow of these gases so that various gases supplied into the vacuum chamber 103 are unevenly distributed above the stage 111. To do. The electrode layer 115 and the outer peripheral ring 129 are made of, for example, the dielectric material described above.

  Inside the electrode layer 115, an electrode part (hereinafter referred to as an ESC electrode) 119 constituting an electrostatic attraction mechanism and a high-frequency electrode part 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 adsorption mechanism is composed of an ESC electrode 119 and a DC power supply 126.

  The metal layer 116 is made of, for example, aluminum having an alumite coating on the surface. In the metal layer 116, a coolant channel 127 as a cooling unit is formed. The refrigerant flow path 127 cools the stage 111. By cooling the stage 111, the holding sheet 3 mounted on the stage 111 is cooled, and the cover 124 partially touching the stage 111 is also cooled. The refrigerant in the refrigerant flow path 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 that penetrate the stage 111 are arranged. The support part 122 is driven up and down by an up-and-down mechanism 123A. When the transport carrier 10 is transported into the vacuum chamber 103, it is delivered to the support part 122 that has been lifted to a predetermined position. The support unit 122 supports the frame 2 of the transport carrier 10. The transport carrier 10 is mounted at a predetermined position of the stage 111 by lowering the upper end surface of the support unit 122 to the same level or lower as the stage 111.

  A plurality of lifting rods 121 are connected to the end of the cover 124 so that the cover 124 can be lifted and lowered. The elevating rod 121 is driven up and down by the elevating mechanism 123B. The raising / lowering operation of the cover 124 by the raising / lowering mechanism 123B can be performed independently of the raising / lowering mechanism 123A.

  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 decompression mechanism 114, a refrigerant circulation 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 executed in the plasma processing method according to the present embodiment will be described with reference to FIGS. In FIG. 2 and FIG. 3, a device that varies the distance between the cover 124 and the stage 111 by moving the cover 124 up and down by the lifting rod 121 as in the plasma processing apparatus 100 </ b> A is used. It is not a thing. FIG. 2 is a conceptual diagram illustrating the operation from the placing process to the plasma processing process of the plasma processing apparatus, and FIG. 3 is a conceptual diagram illustrating the operation from the unloading process to the removal process of the plasma processing apparatus.

  In the placing process and the plasma processing process, the stage 111 is cooled to, for example, about 15 ° C. by the refrigerant that is constantly circulating in the refrigerant flow path 127. Until the transport carrier 10 is carried into the reaction chamber 103, the cover 124 is cooled by its lower end 124L coming into contact with the stage 111 (FIG. 2A). Next, the lifting rod 121 is driven, and the cover 124 is raised to a predetermined position (FIG. 2B). Subsequently, a gate valve (not shown) is opened and the transport carrier 10 is carried in. When the transport carrier 10 reaches a predetermined position above the stage 111, the plurality of support portions 122 rise (FIG. 2C) and support the transport carrier 10. 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 that holds the substrate 1 faces upward.

  When the transport carrier 10 is transferred to the support portion 122, the gate valve is closed and the reaction chamber 103 is placed in a sealed state. Next, the support part 122 starts to descend (FIG. 2D). The carrier carrier 10 is placed on the stage 111 when the upper end surface of the support part 122 is lowered to the same level or lower as the stage 111 (FIG. 2E). Subsequently, the lifting rod 121 is driven. The lifting rod 121 lowers the cover 124 to a predetermined position (FIG. 2 (f)). At this time, the distance (first distance d1) between the cover 124 and the stage 111 is adjusted so that the cover 124 can cover the frame 2 without contacting the transport carrier 10 (distance adjustment step). Although the distance d1 is not specifically limited, For example, it is about 0.5 mm-1.5 mm. The distance d1 is the shortest distance between the stage 111 and the portion of the main body 124B facing the stage 111.

  Subsequently, a plasma processing step is performed on the substrate 1. At this time, a voltage is applied to the ESC type electrode. As a result, the transport carrier 10 is electrostatically attracted to the stage 111 and cooled. In the plasma processing step, the cover 124 is preferably in a position where the lower end 124 </ b> L of the cover contacts the stage 111. During the plasma processing step, the lower end 124L is brought into contact with the stage 111 and cooled, whereby thermal damage to the substrate 1 and the holding sheet 3 due to the radiant heat of the cover 124 can be suppressed. At this time, the temperature of the holding sheet 3 is controlled to, for example, 50 ° C. or more and 150 ° C. or less. On the other hand, when the cover 124 is cooled, the reaction product easily adheres to the back surface of the main body portion 124B of the cover due to the carbon fluoride gas used in the protective film deposition step described later. However, since the removal process is performed by separating the cover 124 and the stage 111 at an appropriate distance after the plasma treatment process, the plasma generated in the removal process is sufficiently irradiated to the back surface of the main body 124B. As a result, the deposit on the back surface of the main body 124B is removed.

  The main body 124B has, for example, a donut shape having a substantially circular outer contour, and has a constant width and a thin thickness. The inner diameter of the main body portion 124B (the diameter of the window portion 124W) is smaller than the inner diameter of the frame 2, and the outer diameter of the main body portion 124B 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 main body 124 </ b> B can cover at least a part of the frame 2 and the holding sheet 3. On the other hand, at least a part of the substrate 1 is exposed from the window portion 124W. The main body 124B is made of, for example, a dielectric such as ceramics (for example, alumina or aluminum nitride) or quartz, or a metal such as aluminum or aluminum whose surface is anodized.

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

  Subsequently, high frequency power is supplied from the first high frequency power supply 110A to the antenna 109 to generate plasma P1 in the vacuum chamber 103 (FIG. 2G). The generated plasma P1 is composed of ions, electrons, radicals, and the like. Next, high-frequency power is supplied from the second high-frequency power source 110B to the high-frequency electrode 120, and plasma processing for the substrate 1 is started. The incident energy of ions on the substrate 1 can be controlled by a bias voltage applied to the high-frequency electrode 120 from the second high-frequency power source 110B. The portion from the front surface to the back surface of the portion exposed from the resist mask formed on the substrate 1 is etched by the physicochemical reaction with the generated plasma P1, and the substrate 1 is separated into pieces.

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 a plasma P 1 of a fluorine-containing gas such as sulfur hexafluoride (SF ₆ ) in the vacuum chamber 103. In this case, for example, the pressure of the reaction chamber 103 is controlled to 10 to 50 Pa by the decompression mechanism 114 while SF ₆ gas is supplied from the process gas source 112 at 100 to 800 sccm. The antenna 109 is supplied with a high frequency power of 1000 to 5000 W and a frequency of 13.56 MHz, and the high frequency electrode 120 is supplied with a high frequency power of 50 to 1000 W and a frequency of 13.56 MHz.

In the plasma processing step, in order to etch the surface of the substrate 1 vertically, an etching step using a plasma of a fluorine-based gas such as SF ₆ and a plasma of a fluorocarbon gas such as perfluorocyclobutane (C ₄ F ₈ ). The protective film deposition step is repeated alternately. At this time, the fluorocarbon gas used in the protective film deposition step may enter between the cover 124 and the stage 111, causing a reaction product containing carbon to adhere to the back surface of the cover 124 (FIG. 4A). reference).

  The substrate 1 is separated into pieces by the etching, and an electronic component 4 (chip) is obtained. Subsequently, ashing is executed. An ashing process gas (for example, oxygen gas or a mixed gas of oxygen gas and fluorine gas) is introduced into the vacuum chamber 103 from the ashing gas source 113. On the other hand, the vacuum mechanism 114 is evacuated to maintain the vacuum chamber 103 at a predetermined pressure. By applying 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 portion 124W of the cover 124 is completely removed. .

  When ashing is completed, the gas in the vacuum chamber 103 is discharged, and the gate valve is opened. The transport carrier 10 holding the electronic component 4 is unloaded from the reaction chamber 103 by the transfer mechanism that has entered from the gate valve (unloading step). When the transport carrier 10 is unloaded, the gate valve is quickly closed.

  Here, the unloading process of the transport carrier 10 may be performed by a procedure reverse to the procedure of mounting the transport carrier 10 on the stage 111 as described above. That is, as shown in FIG. 3, after the plasma processing step (FIG. 3 (h)), the cover 124 is raised to a predetermined position (FIG. 3 (i)). Next, the applied voltage to the ESC type electrode (not shown) is set to zero, the suction of the transport carrier 10 to the stage 111 is released, and the support part 122 is raised (FIG. 3 (j)). When the support unit 122 is raised to a predetermined position and the transport carrier 10 is transferred to the transport mechanism, the support unit 122 is lowered until the end of the support unit 122 is equal to or lower than the level of the stage 111, and the gate valve is opened. The carrier 10 is carried out (FIG. 3 (k)).

  After the transport carrier 10 is unloaded and the gate valve is closed, the removal process is started. That is, again, gas is supplied into the vacuum chamber 103 to generate plasma P2 (FIG. 3 (l)). In the removing step, the distance between the cover 124 and the stage 111 (second distance d2) is set larger than the distance between the cover 124 and the stage 111 (first distance d1) in the plasma processing step. This makes it easier for the plasma P2 to enter the back surface of the main body portion 124B of the cover as compared with the plasma processing step. For this reason, the adhering matter adhering to the back surface of the main body portion 124B of the cover is etched and removed by the plasma P2.

  The distance d2 between the cover 124 and the stage 111 in the removal process is not particularly limited as long as it is larger than the distance d1. When the distance between the cover 124 and the stage 111 when the cover 124 is at the transfer position of the transport carrier 10 is a third distance d3 (see FIG. 3 (k)), the distance d2 is the same as the distance d3. (D2 = d3> d1), may be larger than the distance d3 (d2> d3> d1), or may be between the distance d3 and the distance d1 (d3> d2> d1). The distance d2 is preferably larger from the viewpoint of enhancing the effect of removing deposits, but is preferably not more than the distance d3 from the viewpoint of productivity.

  The removal process may be performed after the carry-out process, once the cover 124 is lowered until it contacts the stage 111 and the cover 124 is cooled. At this time, after the preparation for generating the plasma P2 is completed, the removal process is started while raising the cover 124 again to the distance d2 or while raising the cover 124 again. Further, the removal step may be performed after the unloading step without cooling the cover 124 (without lowering the cover 124 until it comes into contact with the stage 111). At this time, the cover 124 may be slightly raised (when d2> d3) or lowered (when d2 <d3) so that the distance to the stage 111 is the distance d2, or may not be raised or lowered. (D2 = d3). In this case, although it is advantageous from the viewpoint of productivity, it is preferable that the cover 124 is quickly lowered after the removal step is completed, the lower end 124L is brought into contact with the stage 111, and the cover 124 is cooled.

  Specifically, the distance d2 is preferably larger than 1.5 mm, and more preferably 2 mm or longer. When the distance d2 is within this range, the plasma P2 is more likely to enter the back surface of the main body 124B of the cover, and the effect of removing deposits is further enhanced. The upper limit value of the distance d2 is not particularly limited, and may be set as appropriate in consideration of productivity.

  In the removing step, it is preferable to change the distance d2 while the plasma P2 is generated. That is, it is preferable to raise and lower the cover 124 and / or the stage 111 (in this case, the cover 124) while the plasma P2 is generated. As the cover 124 and / or the stage 111 moves up and down, the distribution of the plasma P2 changes, and the plasma P2 is easily irradiated onto the back surface of the main body portion 124B of the cover without unevenness. Therefore, the deposits are further easily removed.

  It is preferable that the cover 124 is not cooled during the removing process in that the effect of removing the deposit is further enhanced. In the present embodiment, the lower end 124L of the cover is brought into contact with the stage 111 during the plasma processing step to cool the cover 124, while the cover 124 is disposed higher than during the plasma processing step during the removal step. Thus, the cover 124 and the stage 111 can be brought into a non-contact state, and the cooling of the cover 124 can be stopped. That is, according to the present embodiment, by changing the position of the cover 124 relative to the stage 111, the distance between the cover 124 and the stage 111 in the plasma processing step and the removal step can be set appropriately. The cover 124 can be placed in an appropriate cooling state or non-cooling state according to each process.

  When the plasma processing apparatus includes a mechanism for moving the cover 124 up and down by the lifting rod 121 arranged near the outer periphery of the stage 111 as described above, during the plasma processing, as shown in FIG. The lower end 124L is in contact with the upper surface of the stage 111 (electrode layer 115). At this time, for example, when the fluorocarbon gas used in the protective film deposition step comes into contact with the upper surface of the outer ring 129 or the gap 130 between the cover 124 and the outer ring 129, the upper surface of the outer ring 129 and the gap 130 contain carbon. Deposit 5b adheres. The upper surface and the gap 130 of the outer peripheral ring 129 are unlikely to be exposed to plasma, like the back surface of the cover main body 124B. For this reason, the plasma treatment process may be completed with the deposit 5b remaining there.

  When the plasma processing step is completed and the elevating rod 121 rises to carry the carrier 10 out of the reaction chamber, the deposit 5b adhering to the gap 130 is stimulated by the movement of the cover 124 that rises together with the elevating rod 121. It enters directly under the lower end 124L of the cover 124 (FIG. 4B). When the carrying carrier is unloaded, the lifting rod 121 is lowered to cool the cover 124 and tries to bring the lower end 124L of the cover 124 into contact with the upper surface of the stage 111 again. At this time, the adhering material 5b has entered immediately below the lower end 124L, and thus the cover 124 cannot come into contact with the stage 111 (FIG. 4C). Therefore, the cooling of the cover 124 becomes insufficient.

  During the plasma processing, the upper surface of the cover 124 (the surface opposite to the back surface) is exposed to plasma. Therefore, the entire cover 124 is at a high temperature (for example, 250 ° C. or higher). Even after the plasma treatment is completed, the cover 124 is not immediately cooled and continues to dissipate heat to the surroundings. If the next substrate 1 is placed on the stage 111 as it is, the holding sheet 3 holding the substrate 1 may be thermally damaged. For this reason, it is desirable that the cover 124 is cooled by being brought into contact with the stage 111 as much as possible after the plasma treatment process is completed.

  The phenomenon shown in FIGS. 4B and 4C occurs after the plasma processing step until the cover 124 is raised to a predetermined position (FIG. 3 (i)) and the cover 124 is lowered (FIG. 3). (M)). However, this cooling failure is also eliminated by appropriately setting the distance (second distance d2) between the cover 124 and the stage 111 in the removal step performed between FIGS. 3 (i) to 3 (m). be able to.

  That is, by making the distance d2 between the cover 124 and the stage 111 in the removal process larger than the distance d1 between the cover 124 and the stage 111 in the plasma processing process, the plasma P2 is generated at the lower end of the cover 124 to which the deposit 5b adheres. It becomes easy to enter just below 124L. Therefore, the adhering material 5b adhering directly below the lower end 124L of the cover 124 can be removed together with the adhering material 5a adhering to the back surface of the cover 124.

  The removal step is preferably performed in an oxygen atmosphere in that the effect of removing the deposits is enhanced. The oxygen atmosphere means that the content of oxygen with respect to the total gas contained in the reaction chamber is 50 to 100% by volume (hereinafter the same). Especially, from a viewpoint of removal efficiency, it is preferable that oxygen content rate is 80-100 volume%, and it is more preferable that it is 95-100 volume%.

In the removal step, for example, the pressure in the reaction chamber 103 is controlled to 5 to 10 Pa by the decompression mechanism 114 while supplying O ₂ gas from 150 to 200 sccm and CF ₄ from 0 to 50 sccm from the ashing gas source 113. A high frequency power having a frequency of about 13.56 MHz of about 1 to 5 kW is supplied to the antenna 109 and a high frequency power having a frequency of 0 to 30 W of 13.56 MHz is supplied to the high frequency electrode 120. The removal process is performed under such conditions, for example, for 1-2 minutes.

  After the removing step, the cover 124 is lowered to a position where a part of the cover 124 comes into contact with the stage 111 (FIG. 3M), and the cover 124 is cooled. In this way, a series of steps is completed. In this state, the cover 124 stands by until the next substrate 1 is transported (FIG. 2A), and the processes shown in FIG. 5B and subsequent steps are performed again.

  In addition, before the support part 122 is lifted in the unloading process (for example, while the cover 124 of FIG. 3 (i) is being lifted or after being lifted), a charge eliminating process for discharging the holding sheet 3 may be provided. This is because it is difficult to smoothly peel the holding sheet 3 from the stage 111 when the charge at the time of plasma treatment remains on the holding sheet 3 and the holding sheet 3 remains adsorbed on the stage 111. The neutralization may be performed by supplying weak high-frequency power of, for example, about 200 W from the first high-frequency power supply 110A to generate weak plasma. At this time, the support portion 122 may be lifted by a minute distance to form a minute space between at least a part of the holding sheet 3 and the stage 111. Thereby, since weak plasma can also wrap around between the holding sheet 3 and the stage 111, the static elimination effect is further enhanced. Since the holding sheet 3 is smoothly peeled off from the stage 111 by the charge removal, troubles such as damage to the holding sheet 3 during carry-out are suppressed, and the yield of electronic components is further improved.

  In addition, a cooling process is provided in which the cooling gas is introduced into the vacuum chamber 103 and the cover 124 is cooled after the ashing is completed and before the support portion 122 is raised (FIGS. 3H to 3J). May be. Thereby, the thermal damage of the holding sheet 3 due to the radiant heat from the cover 124 is further easily suppressed. From the viewpoint of suppressing thermal damage to the holding sheet 3, the cover 124 is raised to a predetermined position and the cover 124 is moved away from the holding sheet 3 (FIG. 3 (i)), and then the above cooling process is performed. preferable.

  Next, an embodiment of the substrate 1 and the carrier 10 used in the present invention will be described with reference to FIGS. 5 (a) and 5 (b). FIG. 5A is a top view schematically showing the transport carrier 10 and the substrate 1 held thereon, and FIG. 5B is a cross-sectional view taken along line BB shown in FIG. It is sectional drawing in a line. 5A and 5B illustrate the case where the frame 2 and the substrate 1 are both substantially circular, the present invention is not limited to this.

  As shown in FIG. 5A, the transport carrier 10 includes a frame 2 and a holding sheet 3. The outer periphery of the holding sheet 3 is fixed to the frame 2. The substrate 1 is attached to the holding sheet 3 and held on the transport carrier.

(flame)
The frame 2 is a frame having an opening having 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 such a rigidity that it can be conveyed while holding the holding 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 vicinity of the outer peripheral edge of one surface of the holding sheet 3 is attached to one surface of the frame 2.

(Holding sheet)
The holding 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 adhered to one surface of the frame 2 and covers the opening of the frame 2. In addition, the substrate 1 is attached to a portion exposed from the opening of the frame 2 of the adhesive surface 3a.

  The pressure-sensitive adhesive surface 3a is preferably made of a pressure-sensitive adhesive component whose adhesive force decreases when irradiated with ultraviolet rays. By performing ultraviolet irradiation after dicing, the separated substrate (electronic component) is easily peeled off from the adhesive surface 3a, so that it is easy to pick up. 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 polyesters such as polyethylene terephthalate. The base material may contain various additives such as a rubber component, a plasticizer, a softener, an antioxidant, and a conductive material. The thickness of the substrate is, for example, 50 to 150 μm.

(substrate)
The substrate 1 is an object of plasma processing. For example, the substrate 1 is formed by forming a circuit layer such as a semiconductor circuit, an electronic component element, or a MEMS on one surface of the main body, and then grinding the surface opposite to the circuit layer of the main body to reduce the thickness. It is produced by this. By separating the substrate 1 into pieces, an electronic component (not shown) having the circuit layer is obtained.

  The magnitude | size of the board | substrate 1 is not specifically limited, For example, the largest diameter is about 50 mm-300 mm, and thickness is about 25-150 micrometers. The shape is not particularly limited, and is, for example, circular or square. The substrate 1 may be provided with notches (not shown) such as an orientation flat (orientation flat) and a notch.

The material of the main body portion of the substrate 1 is not particularly limited, and examples thereof include a semiconductor, a dielectric, a metal, or a laminate thereof. Examples of the semiconductor include silicon (Si), gallium arsenide (GaAs), gallium nitride (GaN), and silicon carbide (SiC). Examples of the dielectric include silicon dioxide (SiO ₂ ), silicon nitride (Si ₃ N ₄ ), polyimide, lithium tantalate (LiTaO ₃ ), lithium niobate (LiNbO ₃ ), and the like.

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

(Second Embodiment)
In the present embodiment, a plasma processing apparatus 100B illustrated in FIG. 6 is used instead of the plasma processing apparatus 100A. The plasma processing apparatus 100B includes a bellows (expandable tube) between the point where the cover 124 is connected to the reaction chamber 103, the point where the end of the elevating rod 131 is connected to the stage 111, and the bottom surface of the reaction chamber 103. ) The configuration is the same as that of the plasma processing apparatus 100A except that 132 is disposed. FIG. 6 is a conceptual diagram showing a cross section of the plasma processing apparatus 100B.

  The plasma processing apparatus 100 </ b> B varies the distance between the cover 124 and the stage 111 by moving the stage 111 up and down. The stage 111 is lifted and supported by a lift rod 131. The bellows 132 is a bellows-like tube having substantially the same diameter as that of the stage 111, and part of the elevating rod 131 and the support portion 122 is disposed inside the bellows 132. Inside the bellows 132 are further various wirings (not shown) (for example, wiring connecting the second high frequency power supply 110B and the high frequency electrode 120, wiring connecting the DC power supply 126 and the ESC electrode 119, etc.), the refrigerant circulation device 125, and the refrigerant flow path. A pipe or the like that connects to 127 is arranged. The internal space of the bellows 132 and the space into which the process gas is introduced in the vacuum chamber 103 are separated. 7A and 7B show the positional relationship between the cover 124 and the stage 111 in the plasma processing step and the removal step using the plasma processing apparatus 100B. As shown in FIG. 7A, in the plasma processing step, the distance between the cover and the stage is kept at d1. In the removing step, the stage 111 is lowered than in the plasma processing step, and the distance d2 between the cover 124 and the stage 111 is made larger than the distance d1, as shown in FIG. 7B.

  In the present embodiment, the cooling unit (refrigerant flow path 127) disposed inside the stage 111 mainly contributes to cooling the transport carrier 10. The cover 124 may be cooled, for example, by contacting the side wall of the vacuum chamber 103 that is cooled by a cooling device (not shown). Alternatively, the cover 124 may be cooled by providing a refrigerant flow path (not shown) inside the cover 124 and circulating the refrigerant by a refrigerant circulation device (not shown). At this time, a through-hole that connects the flow path inside the cover and the refrigerant circulation device arranged outside the vacuum chamber 103 may be provided on the side wall of the vacuum chamber 103. In addition, from the viewpoint of suppressing a reduction in the removal effect, it is preferable to stop the cooling mechanism for the cover and the stage so that the cover 124 is not cooled during the removal process.

  The plasma processing method of the present invention is useful when performing plasma processing using a plasma processing apparatus including a cover above the stage.

1: Substrate, 2: Frame, 2a: Notch, 2b: Corner cut, 3: Holding sheet, 3a: Adhesive surface, 3b: Non-adhesive surface, 4: Electronic component, 5, 5a, 5b: Deposit, 10: Transport Carrier, 100A, 100B: Plasma processing apparatus, 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: decompression mechanism, 115: electrode layer, 116: metal layer, 117: base, 118: outer periphery, 119: ESC Electrode, 120: high-frequency electrode, 121: cover lifting rod, 122: support, 122a: upper end surface, 123A, 123B: lifting mechanism, 124: cover 124B: body portion, 124W: window portion, 124L: lower end of cover, 125: refrigerant circulation device, 126: DC power supply, 127: refrigerant flow path, 128: control device, 129: outer ring, 130: gap, 131: stage Lifting rod, 132: Bellows

Claims (7)

A substrate held by a transport carrier comprising a holding sheet and a frame arranged on the outer periphery of the holding sheet is placed on a stage provided inside the reaction chamber, and is arranged above the stage, and A plasma processing method for plasma-treating the substrate by covering the frame with a cover having a window for exposing the substrate,
A placing step of placing the transport carrier holding the substrate on the stage;
A distance adjusting step of adjusting a distance between the cover and the stage to a first distance that covers the frame without the cover contacting the transport carrier;
A plasma processing step for performing the plasma processing on the substrate placed on the stage after the distance adjustment step;
An unloading step of unloading the substrate from the reaction chamber together with the transfer carrier after the plasma treatment step;
A removal step of generating plasma inside the reaction chamber after the unloading step to remove deposits attached to the cover;
The plasma processing method, wherein a distance between the cover and the stage in the removing step is a second distance that is larger than the first distance.   The plasma processing method according to claim 1, wherein the second distance is 2 mm or more.   The plasma processing method according to claim 1, wherein in the removing step, the second distance is changed.   The plasma processing method according to claim 1, wherein the cover is cooled in the plasma processing step.   The plasma processing method according to claim 1, wherein the cover is not cooled in the removing step. A cooling unit is provided inside the stage,
The plasma processing method according to claim 1, wherein the cover is cooled by bringing a part of the cover into contact with the stage. A substrate held by a transport carrier comprising a holding sheet and a frame arranged on the outer periphery of the holding sheet is placed on a stage provided inside the reaction chamber, and is arranged above the stage, and A method of manufacturing an electronic component that covers the frame with a cover having a window for exposing the substrate, and plasma-treats the substrate,
Preparing a substrate held on a transport carrier comprising a holding sheet and a frame disposed on the outer periphery of the holding sheet;
A placing step of placing the transport carrier holding the substrate on the stage;
A distance adjusting step of adjusting a distance between the cover and the stage to a first distance that covers the frame without the cover contacting the transport carrier;
After the distance adjusting step, performing a plasma treatment on the substrate placed on the stage, and a dicing step for dividing the substrate into pieces,
After the dicing step, the substrate that has been separated into pieces is unloaded from the reaction chamber together with the transfer carrier, and
A removal step of generating plasma inside the reaction chamber after the unloading step to remove deposits attached to the cover;
The method for manufacturing an electronic component, wherein a distance between the cover and the stage in the removing step is a second distance that is larger than the first distance.

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