Etching device

Abstract

To provide an etching device capable of forming a plurality of through holes in an insulating substrate with high throughput.SOLUTION: An etching device 1 is for forming a plurality of through holes in an insulating substrate W. The etching device 1 includes a chamber 2, a mask 3, a bias application unit 4, and a plasma generation unit 5. The insulating substrate W is carried into the chamber 2. The mask 3 has a plurality of first openings 3a, and faces the insulating substrate W. The bias application unit 4 applies a negative voltage to the mask 3. The plasma generation unit 5 generates plasma, and supplies positive ion in the plasma to the insulating substrate W through the plurality of first openings 3a of the mask 3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an etching apparatus. [Background technology]

[0002] In the field of fan-out panel level packaging, an interposer is conventionally provided between a chip and a substrate. The interposer is a glass-based substrate. The glass-based substrate has a plurality of through holes formed therein, and the through holes are filled with a conductive material. The interposer realizes electrical connection between the chip and the substrate.

[0003] When manufacturing such an interposer, a technique has been proposed in which through-holes are formed in a glass substrate by laser processing and wet etching (Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2019-530629 [Patent Document 2] Japanese Patent Publication No. 2020-66551 [Patent Document 3] Japanese Patent Application Publication No. 2017-61401 Summary of the Invention [Problem to be solved by the invention]

[0005] Laser processing can cause microcracks in glass substrates. For this reason, it is desirable to process glass substrates at a low speed or to process glass substrates using a pulsed laser. However, these methods require a relatively long time to form multiple through holes. In particular, when the number of through holes exceeds several million, laser processing results in low throughput.

[0006] Therefore, an object of the present disclosure is to provide an etching apparatus that can form a plurality of through holes in an insulating substrate with high throughput. [Means for solving the problem]

[0007] A first aspect is an etching apparatus for forming a plurality of through holes in an insulating substrate, comprising: a chamber into which the insulating substrate is loaded; a mask having a plurality of first openings and facing the insulating substrate; a bias application unit that applies a negative voltage to the mask; and a plasma generation unit that generates plasma and supplies positive ions in the plasma to the insulating substrate through the plurality of first openings in the mask.

[0008] A second aspect is an etching apparatus according to the first aspect, wherein the mask includes an insulating plate having a plurality of second openings formed therein and a conductive film, the conductive film being provided on the inner surface of each of the plurality of second openings in the insulating plate and including a first conductive portion that forms the first opening, and the bias application unit applies the negative voltage to the conductive film.

[0009] A third aspect is an etching apparatus according to the second aspect, wherein the conductive film is formed on a first main surface of the insulating plate facing the insulating substrate and includes a second conductive portion connecting the first conductive portions to each other.

[0010] A fourth aspect is an etching apparatus according to the second or third aspect, wherein a portion of the first conductive portion protrudes beyond a second main surface of the insulating plate opposite to a first main surface on the insulating substrate side.

[0011] A fifth aspect is the etching apparatus according to any one of the second to fourth aspects, wherein the mask further includes a protective film that faces the first conductive portion and protects the first conductive portion from the plasma.

[0012] A sixth aspect is an etching apparatus according to any one of the second to fifth aspects, wherein the mask is provided between the insulating plate and the insulating substrate and further includes a replacement part that is detachable from the insulating plate and the conductive film, the replacement part having an opening that forms the first opening together with the opening of the first conductive part, and the diameter of the opening of the replacement part is smaller than the diameter of the opening of the first conductive part.

[0013] A seventh aspect is an etching apparatus according to any one of the second to sixth aspects, further comprising a heater that emits heating light toward the insulating substrate, and the mask is provided between the insulating plate and the insulating substrate and includes an absorbing portion that has a higher absorption rate for the light than the absorption rate of the insulating substrate.

[0014] An eighth aspect is an etching apparatus according to any one of the first to seventh aspects, including a plurality of conductive rollers that support the mask and transport the mask and the insulating substrate, and the bias application unit applies the negative voltage to the rollers. [Effects of the Invention]

[0015] According to the first aspect, a negative voltage is applied to the mask, so that cations can be supplied to the insulating substrate more effectively, and therefore the etching apparatus can form through-holes in the insulating substrate with higher efficiency.

[0016] According to the second aspect, the cations can be concentrated and attracted to the first opening, and therefore the cations can be more effectively supplied to the insulating substrate through the first opening.

[0017] According to the third aspect, it is possible to suppress wear of the second conductive portion due to cations.

[0018] According to the fourth aspect, the life of the conductive film, and therefore the life of the mask, can be extended.

[0019] According to the fifth aspect, the life of the mask can be extended.

[0020] According to the sixth aspect, the opening of the first conductive portion is wide, so that a larger number of cations can pass through to the insulating substrate side. Furthermore, when the replacement portion wears out, the replacement portion can be replaced.

[0021] According to the seventh aspect, heat is generated in the absorbing portion by absorbing light, and the heat is transferred to the insulating substrate, so that the insulating substrate can be heated more effectively.

[0022] According to the eighth aspect, a negative voltage can be applied to the mask at a plurality of locations, making it possible to make the potential distribution on the mask more uniform. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a side view schematically showing an example of the configuration of an etching apparatus according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view schematically illustrating an example of a part of the configuration of a mask. [Figure 3] FIG. 2 is a plan view schematically illustrating an example of a part of a configuration of a mask. [Figure 4] FIG. 1 is a diagram schematically illustrating the movement of cations. [Figure 5] FIG. 10 is a cross-sectional view schematically showing a first alternative example of the configuration of the mask. [Figure 6] FIG. 10 is a cross-sectional view schematically showing a second alternative example of the mask configuration. [Figure 7] FIG. 10 is a diagram schematically illustrating a third alternative example of the mask configuration. [Figure 8] FIG. 10 is a diagram schematically illustrating a fourth alternative example of the mask configuration. [Figure 9] FIG. 10 is a side view schematically showing an example of the configuration of an etching apparatus according to a second embodiment. [Figure 10] 10A and 10B are diagrams illustrating an example of the configuration of a roller, a mask, and an insulating substrate. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, the embodiments will be described in detail with reference to the drawings. In the drawings, the dimensions and numbers of parts are exaggerated or simplified as necessary for ease of understanding. Parts having similar configurations and functions are designated by the same reference numerals, and duplicate explanations will be omitted below.

[0025] In the following description, the same components are denoted by the same reference numerals, and their names and functions are also the same. Therefore, detailed descriptions of them may be omitted to avoid duplication.

[0026] Furthermore, in the following description, even if ordinal numbers such as "first" or "second" are used, these terms are used for convenience to facilitate understanding of the contents of the embodiments, and are not limited to the order that may result from these ordinal numbers.

[0027] When expressions indicating relative or absolute positional relationships (e.g., "in one direction," "along one direction," "parallel," "orthogonal," "center," "concentric," "coaxial," etc.) are used, unless otherwise specified, the expressions not only strictly represent the positional relationship but also represent a state in which there is a relative displacement in terms of angle or distance within a range in which tolerance or equivalent functionality is obtained. When expressions indicating an equal state (e.g., "identical," "equal," "homogeneous," etc.) are used, the expressions not only represent a state in which there is strict quantitative equality but also represent a state in which there is a difference in which tolerance or equivalent functionality is obtained, unless otherwise specified. When expressions indicating a shape (e.g., "rectangular shape" or "cylindrical shape," etc.) are used, the expressions not only represent a geometrically strict shape but also represent a shape with, for example, irregularities or chamfers within a range in which equivalent effects are obtained, unless otherwise specified. When the expressions "comprise," "include," "have," "includes," "includes," or "have" are used to describe one component, the expressions are not exclusive expressions that exclude the presence of other components. When the phrase "at least one of A, B, and C" is used, the phrase includes A only, B only, C only, any two of A, B, and C, and all of A, B, and C.

[0028] First Embodiment <Etching equipment> FIG. 1 is a side view schematically illustrating an example of the configuration of an etching apparatus 1 according to the first embodiment. The etching apparatus 1 is a dry etching apparatus that forms a plurality of through holes in an insulating substrate W. For example, the insulating substrate W is a glass substrate having a plate-like shape. The etching apparatus 1 dry-etches the insulating substrate W to form a plurality of through holes in the insulating substrate W. The etching apparatus 1 can also be said to be a through-hole forming apparatus. In a process subsequent to the etching apparatus 1, for example, a conductive member is provided in the through holes in the insulating substrate W to form an interposer.

[0029] The etching apparatus 1 includes a chamber 2, a mask 3, a bias application unit 4, and a plasma generation unit 5.

[0030] Chamber 2 has a hollow box shape. The internal space of chamber 2 corresponds to a processing chamber in which insulating substrate W is etched. Chamber 2 has a loading / unloading port 21. In the example of FIG. 1, loading / unloading port 21 is formed in the side wall of chamber 2. A passage 22 is connected to loading / unloading port 21. An unprocessed insulating substrate W is loaded into chamber 2 through passage 22. The insulating substrate W undergoes etching processing in chamber 2. The processed insulating substrate W is unloaded from chamber 2 through passage 22.

[0031] In the example of FIG. 1, a plurality of rollers 25 are provided within the chamber 2. The plurality of rollers 25 transport the insulating substrate W. The plurality of rollers 25 are arranged at intervals along the transport direction D1 of the insulating substrate W. In the example of FIG. 1, the transport direction D1 is a horizontal direction. Each roller 25 is provided to be rotatable around a rotation axis, which will be described below. The rotation axis is a rotation axis along a horizontal width direction D2 that is perpendicular to the transport direction D1. Each roller 25 is rotated synchronously by a roller rotation drive unit (not shown). The roller rotation drive unit includes, for example, a motor. The roller rotation drive unit is controlled by the control unit 9.

[0032] The insulating substrate W can be transported in a horizontal position. Here, the horizontal position refers to a position in which the thickness direction of the insulating substrate W is aligned with the vertical direction. The insulating substrate W is supported by rollers 25. The underside of the insulating substrate W may be in contact with the rollers 25, or a mounting plate (not shown) may be provided between the insulating substrate W and the rollers 25. In the latter case, the insulating substrate W is transported while placed on the mounting plate. The roller rotation drive unit synchronously rotates the multiple rollers 25 in the loading direction, thereby moving the insulating substrate W loaded through the loading / unloading port 21 to a processing position within the chamber 2. FIG. 1 shows the insulating substrate W stopped at the processing position. Meanwhile, the roller rotation drive unit synchronously rotates the multiple rollers 25 in the unloading direction, which is opposite to the loading direction, thereby unloading the insulating substrate W from the chamber 2 through the loading / unloading port 21.

[0033] The mask 3 faces the insulating substrate W in the vertical direction. The mask 3 has, for example, a plate-like shape and is provided with its thickness direction aligned vertically. In the example of FIG. 1, the mask 3 is provided above the insulating substrate W. The mask 3 faces the insulating substrate W at least when the insulating substrate W is positioned at the processing position. In this example, the mask 3 is transported together with the insulating substrate W. That is, the mask 3 is fixed to the insulating substrate W, and the mask 3 and the insulating substrate W are transported together. The lower surface of the mask 3 may be in contact with the upper surface of the insulating substrate W, or may face the upper surface of the insulating substrate W with a small gap therebetween. In the latter case, a fixing member (for example, a spacer) is provided to fix the relative positions of the insulating substrate W and the mask 3.

[0034] A plurality of first openings 3a are formed in the mask 3. Each first opening 3a penetrates the mask 3 in its thickness direction. The first openings 3a may also be called through holes. The plurality of first openings 3a are arranged two-dimensionally dispersed in a plan view. Plan view here refers to viewing an object with the line of sight aligned vertically. Each first opening 3a has, for example, a circular shape in a plan view. The diameter of the first openings 3a may be set to several tens of μm (for example, 30 μm) or less. The number of first openings 3a in the mask 3 is, for example, one million or more.

[0035] As will be described later, positive ions in the plasma generated by the plasma generating unit 5 pass through the first openings 3a of the mask 3 and act on the insulating substrate W. As a result, the insulating substrate W is etched directly below each first opening 3a.

[0036] The mask 3 is conductive. FIG. 2 is a cross-sectional view schematically illustrating an example of a portion of the configuration of the mask 3. FIG. 3 is a plan view schematically illustrating an example of a portion of the configuration of the mask 3. In the example of FIGS. 2 and 3, the mask 3 includes an insulating plate 31 and a conductive film 32. The insulating plate 31 has a plate-like shape and is disposed with its thickness direction aligned vertically. The insulating plate 31 is insulating and is formed, for example, from resin or glass. One of the main components of glass is, for example, silicon dioxide. Hereinafter, the two main surfaces of the insulating plate 31 will be referred to as the first main surface 31a and the second main surface 31b, respectively. The first main surface 31a is the main surface of the insulating plate 31 facing the insulating substrate W, and the second main surface 31b is the surface opposite the first main surface 31a. A plurality of second openings are formed in the insulating plate 31. Hereinafter, the inner circumferential surface of each second opening in the insulating plate 31 will be referred to as the inner circumferential surface 31c. One peripheral edge of the inner peripheral surface 31c is connected to the first main surface 31a, and the other peripheral edge of the inner peripheral surface 31c is connected to the second main surface 31b. In other words, the second opening penetrates the insulating plate 31 in its thickness direction.

[0037] 2, the conductive film 32 includes a first conductive portion 321 and a second conductive portion 322. The first conductive portion 321 is provided on each inner circumferential surface 31c of the insulating plate 31. For example, the first conductive portion 321 has a cylindrical shape, and the outer circumferential surface of the first conductive portion 321 is joined to the inner circumferential surface 31c. The inner circumferential surface of the first conductive portion 321 forms the first opening 3a of the mask 3. In other words, the inner circumferential surface of the first conductive portion 321 is exposed inside the chamber 2. Here, as an example, the second opening of the insulating plate 31 has a circular shape in a plan view, and the first conductive portion 321 has a cylindrical shape.

[0038] The second conductive portion 322 is provided on the first main surface 31a of the insulating plate 31. The second conductive portion 322 has a plate-like shape, and one main surface thereof is joined to the first main surface 31a. The second conductive portion 322 electrically connects the multiple first conductive portions 321 to each other. The second conductive portion 322 may be provided over the entire first main surface 31a, or may be provided partially.

[0039] The conductive film 32 is conductive and is made of, for example, a metal. The metal includes, for example, at least one of copper, silver, and aluminum. The conductive film 32 is provided on the insulating plate 31 by, for example, vapor deposition or plating. The conductive film 32 is provided in a state of being bonded to the insulating plate 31.

[0040] The bias application unit 4 applies a negative voltage to the mask 3. Specifically, the bias application unit 4 applies a negative voltage to the mask 3 during etching of the insulating substrate W. In the example of FIG. 1, the bias application unit 4 includes a contact member 41, wiring 42, and a DC power supply 43. The contact member 41 is conductive and is provided within the chamber 2. Specifically, the contact member 41 is provided at a position where it contacts the conductive film 32 of the mask 3 stopped at the processing position. For example, the contact member 41 contacts a part of the second conductive portion 322 of the mask 3. The contact member 41 may include, for example, a conductive brush. The brush contacts the conductive film 32 (e.g., the second conductive portion 322), thereby electrically connecting the contact member 41 and the conductive film 32. In the example of FIG. 1, the mask 3 is wider than the insulating substrate W in a plan view. In other words, the mask 3 extends horizontally beyond the insulating substrate W. The second conductive portion 322 is also present in a portion of the mask 3 that protrudes beyond the insulating substrate W, and the contact member 41 may come into contact with the second conductive portion 322 at this portion.

[0041] The wire 42 is connected to the contact member 41 and the low potential output terminal of a DC power supply 43. The high potential output terminal of the DC power supply 43 is grounded.

[0042] The DC power supply 43 outputs a DC voltage between the high potential output terminal and the low potential output terminal. Since the high potential output terminal is grounded, a negative voltage is applied to the low potential output terminal. The output of the DC power supply 43 is controlled by the control unit 9. The control unit 9 causes the DC power supply 43 to output a DC voltage while the contact member 41 is in contact with the mask 3. As a result, a negative voltage (for example, 500 eV or less) is applied to the mask 3 (specifically, the conductive film 32).

[0043] The plasma generating unit 5 generates plasma and supplies cations in the plasma to the main surface (top surface in FIG. 1) of the insulating substrate W through the multiple first openings 3a in the mask 3. As shown in FIG. 1, the etching apparatus 1 is also provided with a gas introduction unit 6. The gas introduction unit 6 supplies gas for plasma generation to the plasma generating unit 5. The gas for plasma generation includes, for example, at least one of a fluorine-containing gas having elemental fluorine and a rare gas. The rare gas includes, for example, argon gas. The fluorine-containing gas includes, for example, at least one of a fluorocarbon gas (CxFy) and a sulfur fluorocarbon gas (SFx).

[0044] In the example of FIG. 1, the plasma generation unit 5 is provided in the chamber 2, and the gas introduction unit 6 supplies gas into the chamber 2. In the example of FIG. 1, the gas introduction unit 6 includes a gas introduction pipe 61 and a valve 62. The downstream port of the gas introduction pipe 61 opens into the chamber 2. The upstream end of the gas introduction pipe 61 is connected to a gas supply source (not shown). The valve 62 is provided in the gas introduction pipe 61. The valve 62 is controlled by the control unit 9, and switches the opening and closing of the gas introduction pipe 61. When the control unit 9 opens the valve 62, the gas is supplied into the chamber 2 through the gas introduction pipe 61. The gas is converted into plasma by the plasma generation unit 5.

[0045] In the example of FIG. 1, the plasma generating unit 5 includes a conductive member 51. The conductive member 51 is provided in the chamber 2. Specifically, the conductive member 51 is provided in a position vertically facing the mask 3 stopped at the processing position. In other words, the conductive member 51 is provided on the opposite side of the mask 3 from the insulating substrate W. In other words, the mask 3 is located between the conductive member 51 and the insulating substrate W. In the example of FIG. 1, the conductive member 51 is provided above the mask 3. A voltage for generating plasma is applied to the conductive member 51. The application of this voltage turns the gas around the conductive member 51 into plasma.

[0046] In the example of FIG. 1, the plasma generation unit 5 generates plasma by an inductive coupling method. Specifically, the conductive member 51 functions as an inductively coupled antenna. In the example of FIG. 1, the conductive member 51 has a U-shape. The conductive member 51 is disposed with the bottom of the U facing the mask 3, and both ends of the conductive member 51 penetrate the chamber 2. In the example of FIG. 1, both ends of the conductive member 51 penetrate the ceiling of the chamber 2.

[0047] 1, the downstream port of the gas introduction pipe 61 of the gas introduction unit 6 is provided closer to the conductive member 51 than the mask 3 in the vertical direction. In other words, the downstream port of the gas introduction pipe 61 is provided above the transfer port 21. In addition, the downstream port of the gas introduction pipe 61 is provided at a position aligned horizontally with the conductive member 51. This allows the gas for plasma that flows out from the downstream port of the gas introduction pipe 61 to easily flow around the conductive member 51.

[0048] The conductive member 51 is connected to a high-frequency power supply 54 through an impedance matching circuit 53. More specifically, one end of the conductive member 51 is connected to a first output terminal of the high-frequency power supply 54 through the impedance matching circuit 53, and the other end of the conductive member 51 is connected to a second output terminal of the high-frequency power supply 54. In the example of Fig. 1, the second output terminal is grounded. The high-frequency power supply 54 is controlled by the control unit 9, and outputs a high-frequency voltage of, for example, 13.56-60 MHz.

[0049] When the high-frequency power supply 54 applies a high-frequency voltage to both ends of the conductive member 51, a high-frequency induction magnetic field for generating plasma is generated around the conductive member 51, and this acts on the gas for plasma, ionizing the gas and turning it into plasma. Such inductively coupled plasma has a spatial density of electrons of 3×10 10 pieces / cm 3 This is a high density plasma.

[0050] In the example of FIG. 1, a plurality of conductive members 51 are provided. The plurality of conductive members 51 are arranged side by side in the horizontal direction. As shown in FIG. 1, the plurality of conductive members 51 may be arranged side by side in the transport direction D1. Alternatively, the plurality of conductive members 51 may be arranged side by side in the width direction D2. This allows the plasma generating unit 5 to generate plasma over a wider range. As shown in FIG. 1, the conductive members 51 may be arranged in a position where both ends thereof are arranged side by side in the transport direction D1.

[0051] 1, the plasma generating unit 5 also includes a dielectric member 52. The dielectric member 52 is provided corresponding to the conductive member 51. The dielectric member 52 covers the conductive member 51 and protects the conductive member 51 from plasma. The dielectric member 52 has a U-shaped hollow shape, and the conductive member 51 is provided in the hollow portion.

[0052] In the example of FIG. 1, the etching apparatus 1 is provided with a pressure reduction unit 7. The pressure reduction unit 7 includes a suction pipe 71 and a suction unit 72. The upstream port of the suction pipe 71 opens inside the chamber 2. In the example of FIG. 1, the upstream port of the suction pipe 71 is provided on the side wall of the chamber 2 on the opposite side of the conductive member 51 from the downstream port of the gas introduction pipe 61. The suction unit 72 is provided on the suction pipe 71. The suction unit 72 is controlled by the control unit 9, and sucks gas from inside the chamber 2 through the suction pipe 71. The suction unit 72 includes, for example, a pump (vacuum pump). The control unit 9 operates the suction unit 72 to reduce the pressure inside the chamber 2 to within a pressure range suitable for etching.

[0053] In the example of FIG. 1, the etching apparatus 1 is provided with a heater 8. The heater 8 is controlled by a control unit 9 and heats the insulating substrate W. The heater 8 adjusts the temperature of the insulating substrate W to within a predetermined temperature range suitable for etching. In the example of FIG. 1, the heater 8 is provided in a position aligned vertically with the insulating substrate W, and is provided on the opposite side of the insulating substrate W from the mask 3 (below in the figure). Also, in the example of FIG. 1, the heater 8 is provided below the bottom of the chamber 2. The heater 8 is, for example, an optical heater (a radiation heater).

[0054] The control unit 9 controls various components of the etching apparatus 1. The control unit 9 is configured, for example, by a general-purpose computer having electrical circuits. As an example, the control unit 9 is configured to include a CPU (Central Processor Unit) as a central processing unit that performs various arithmetic processing (data processing), a ROM (Read Only Memory) that stores basic programs and the like, a RAM (Random Access Memory) used as a work area when the CPU performs predetermined processing (data processing), a storage device configured by a nonvolatile storage device such as a flash memory or a hard disk drive, and a bus line connecting these components to each other. The storage device or RAM may store a program that defines the processing to be performed by the control unit 9. In this case, for example, the CPU may execute the program to control each component of the etching apparatus 1, and the processing defined by the program may be performed in the etching apparatus 1. In other words, the CPU may execute the program to implement a circuit in the control unit 9 that performs the processing defined by the program. However, some or all of the control performed by the control unit 9 (some or all of the circuitry implemented by the control unit 9) may be executed (implemented) by hardware such as a dedicated logic circuit. Furthermore, the control unit 9 may include a plurality of control configurations each made up of a calculation device and a storage unit. In other words, the functions of the control unit 9 may be realized by a plurality of control configurations working together.

[0055] Next, an example of the operation of the etching apparatus 1 will be outlined. The operation described below is realized under the control of the control unit 9. First, an unprocessed insulating substrate W having no through-holes is carried into the chamber 2. Specifically, the unprocessed insulating substrate W is moved to the processing position by synchronously rotating a plurality of rollers 25 in the carrying-in direction. Here, as an example, the mask 3 is transported integrally with the insulating substrate W while facing the insulating substrate W. With the insulating substrate W and mask 3 positioned at the processing position, the contact member 41 of the bias application unit 4 comes into contact with the conductive film 32 of the mask 3.

[0056] Next, the bias application unit 4 applies a negative voltage to the mask 3. Furthermore, the pressure reduction unit 7 sucks the gas inside the chamber 2 to reduce the pressure inside the chamber 2. The pressure reduction unit 7 adjusts the pressure inside the chamber 2 to within a predetermined pressure range until etching is completed. Furthermore, the heater 8 heats the insulating substrate W. The heater 8 adjusts the temperature of the insulating substrate W to within a predetermined temperature range until etching is completed.

[0057] Next, the gas inlet 6 supplies the gas to the plasma generator 5, which converts the gas into plasma. Positive ions (e.g., argon ions or fluorine ions) in the plasma are attracted toward the mask 3 by the negative voltage applied to the mask 3. FIG. 4 is a diagram schematically illustrating the movement of positive ions. As shown in FIG. 4, the positive ions are concentrated toward the first conductive portion 321. That is, because a negative DC voltage is applied to the first conductive portion 321 exposed in the chamber 2, the positive ions in the plasma are attracted to the first conductive portion 321 by a stronger electric attraction. Therefore, the positive ions move toward the mask 3 at a relatively high speed, and some of them act on the insulating substrate W through each of the first openings 3a. The positive ions can physically etch the insulating substrate W. If the positive ions are fluorine ions, they can also chemically etch the insulating substrate W. As a result, the insulating substrate W is etched directly below the multiple first openings 3a.

[0058] This allows multiple through-holes to be formed in the insulating substrate W. When the insulating substrate W is sufficiently etched, the etching apparatus 1 ends the etching. For example, when a predetermined etching time has elapsed since the start of etching, the etching apparatus 1 ends the etching. Specifically, the plasma generation unit 5 stops operating, the gas introduction unit 6 stops introducing gas, and the pressure reduction unit 7, heater 8, and bias application unit 4 also stop operating. Next, the multiple rollers 25 rotate synchronously in the unloading direction, and the processed insulating substrate W with multiple through-holes formed and the mask 3 are unloaded from the chamber 2 together. This causes the contact member 41 of the bias application unit 4 to separate from the conductive film 32 of the mask 3.

[0059] As described above, the etching apparatus 1 can form multiple through-holes in the insulating substrate W. Moreover, in the etching apparatus 1, the bias application unit 4 applies a negative DC voltage to the mask 3. This allows the etching apparatus 1 to etch the insulating substrate W at a higher etching rate (throughput). In other words, the conductive film 32 (particularly the first conductive portion 321) of the mask 3 can function as a DC electrode for plasma, and can attract cations with a strong electrical attraction. This allows for improved throughput. For example, the etching apparatus 1 can increase the etching rate to the order of μm / min.

[0060] Furthermore, in the above example, the second conductive portion 322 of the conductive film 32 is provided on the first main surface 31a of the insulating plate 31 on the insulating substrate W side. Therefore, cations are less likely to act on the second conductive portion 322. This makes it possible to improve the life of the second conductive portion 322, and therefore the life of the mask 3.

[0061] On the other hand, positive ions collide with the first conductive portion 321 of the conductive film 32, which can cause the first conductive portion 321 to wear. In the above example, the mask 3 is transported integrally with the insulating substrate W, so that the mask 3 can be easily replaced. In other words, an operator can replace the worn mask 3 with a new mask 3 outside the chamber 2. This reduces the workload.

[0062] <First Alternative Mask Example> 5 is a cross-sectional view schematically showing a first modified example of the configuration of the mask 3. The mask 3 according to the first modified example differs from the mask 3 of FIG. 2 in the configuration of the conductive film 32. In the first modified example, a part of the first conductive portion 321 of the conductive film 32 protrudes beyond the second main surface 31b of the insulating plate 31. In other words, a part of the first conductive portion 321 is located on the opposite side of the second main surface 31b of the insulating plate 31 from the first main surface 31a (on the conductive member 51 side).

[0063] 5, the conductive film 32 also includes a plurality of third conductive portions 323. The third conductive portions 323 may be provided in a one-to-one correspondence with the first conductive portions 321. Each third conductive portion 323 has an annular shape in plan view, and its inner circumferential portion is connected to the corresponding first conductive portion 321. Each third conductive portion 323 is provided around the second opening in the second main surface 31b of the insulating plate 31. Each third conductive portion 323 is joined to the second main surface 31b of the insulating plate 31.

[0064] When positive ions collide with the first conductive portion 321, the first conductive portion 321 gradually wears down. As a result, the volume of the first conductive portion 321 may gradually decrease. However, a portion (protruding portion) of the first conductive portion 321 according to the first modified example is located closer to the conductive member 51 than the second main surface 31b. As a result, the life of the first conductive portion 321, and therefore the life of the mask 3, can be extended.

[0065] Furthermore, in the above example, third conductive portion 323 is provided. Therefore, the protruding portion of first conductive portion 321 is fixed to second main surface 31b of insulating plate 31 via third conductive portion 323. Therefore, the strength of first conductive portion 321 can be improved.

[0066] In the above example, the third conductive portions 323 are provided only around the second opening on the second main surface 31b of the insulating plate 31. In other words, the multiple third conductive portions 323 are spaced apart from one another on the second main surface 31b side. Therefore, compared to a structure in which the third conductive portions 323 are provided over the entire second main surface 31b of the insulating plate 31, it is possible to attract cations intensively to the first opening 3a of the mask 3.

[0067] <Second example of a mask> FIG. 6 is a cross-sectional view schematically illustrating a second modified example of the configuration of the mask 3. The mask 3 according to the second modified example differs from the mask 3 of FIG. 2 in the presence or absence of a protective film 33. In the second modified example, the mask 3 further includes a protective film 33. The protective film 33 faces the first conductive portion 321 of the conductive film 32. The protective film 33 is provided on the opposite side of the first conductive portion 321 from the insulating substrate W (the conductive member 51 side). The protective film 33 has a plate-like shape, e.g., an annular shape in plan view. The protective film 33 is provided in a one-to-one correspondence with the first conductive portion 321. Each protective film 33 surrounds the first opening 3a in plan view. In the example of FIG. 6, the inner peripheral portion of the protective film 33 faces the first conductive portion 321, and the outer peripheral portion of the protective film 33 faces the second main surface 31b of the insulating plate 31. The protective film 33 is in contact with the first conductive portion 321 and the second main surface 31b of the insulating plate 31. The protective films 33 are spaced apart from one another in a plan view.

[0068] The protective film 33 may be insulating or conductive. If the protective film 33 is conductive, the protective film 33 is electrically connected to the first conductive portion 321. Therefore, a negative voltage is also applied to the protective film 33. The protective film 33 may be made of a material that is less susceptible to etching than the material of the conductive film 32. As an example, the protective film 33 may be made of yttrium. The protective film 33 is formed by, for example, vapor deposition or plating.

[0069] The protective film 33 can protect a part of the first conductive portion 321 from cations, thereby extending the life of the mask 3. If the protective film 33 is made of a material that is more difficult to etch than the first conductive portion 321, the life of the mask 3 can be further extended.

[0070] In the above example, the protective films 33 are spaced apart from one another on the second main surface 31b. Therefore, when the protective films 33 are conductive, the cations can be attracted intensively to the first openings 3a of the mask 3.

[0071] <Third Alternative Mask Example> FIG. 7 is a diagram schematically illustrating a third modified example of the configuration of the mask 3. The mask 3 according to the third modified example differs from the mask 3 of FIG. 2 in the presence or absence of a replaceable part 35. In the third modified example, the mask 3 further includes a replaceable part 35. The replaceable part 35 is provided closer to the insulating substrate W than the conductive film 32. Specifically, the replaceable part 35 has a plate-like shape and is provided between the conductive film 32 and the insulating substrate W. The replaceable part 35 is provided with its thickness direction aligned with the vertical direction. The replaceable part 35 is separate from the conductive film 32 and is provided separable from the conductive film 32. In other words, the replaceable part 35 is not bonded to the conductive film 32.

[0072] The replacement part 35 has openings 35a that communicate in the vertical direction with openings 321a formed by the inner circumferential surface of the first conductive portion 321 of the conductive film 32. The openings 35a are provided in a one-to-one correspondence with the openings 321a. Each opening 35a penetrates the replacement part 35 in its thickness direction. The size of the openings 35a of the replacement part 35 is smaller than the size of the openings 321a in a plan view. In other words, in a plan view, the inner circumferential surface that forms the openings 35a of the replacement part 35 is located more inward than the inner circumferential surface of the first conductive portion 321. When the openings 321a and 35a have a circular shape in a plan view, the diameter of the opening 321a is smaller than the diameter of the opening 35a.

[0073] The replacement part 35 may be insulating or conductive. The replacement part 35 may be made of, for example, resin or metal. An example of a metal is yttrium. When the replacement part 35 is conductive, the replacement part 35 is electrically connected to the conductive film 32.

[0074] In such a mask 3, positive ions pass through the opening 321a in the first conductive portion 321 and the opening 35a in the replaceable portion 35, and collide with the main surface of the insulating substrate W. Therefore, the replaceable portion 35 also functions as a mask. In other words, the opening 35a and the opening 321a form the first opening 3a.

[0075] According to the mask 3 of the third modified example, the openings 321a of the first conductive portion 321 are relatively large, allowing a larger number of cations to pass through to the replacement part 35 side. Some of the cations collide with the replacement part 35, while the remaining cations collide with the main surface of the insulating substrate W. The insulating substrate W is etched as a result of the cations acting on it. Meanwhile, the replacement part 35 is gradually worn away as a result of the cations colliding with it. This replacement part 35 is not bonded to the conductive film 32 and is detachable from the insulating plate 31 and the conductive film 32. Therefore, the replacement part 35 that has worn out after being used to process the insulating substrate W can be replaced with a new replacement part 35, for example, after being carried out of the chamber 2.

[0076] <Fourth Alternative Mask Example> FIG. 8 is a diagram schematically illustrating a fourth modified example of the configuration of the mask 3. The mask 3 according to the fourth modified example differs from the mask 3 of FIG. 2 in the presence or absence of an absorbing portion 34. In the fourth modified example, the mask 3 further includes an absorbing portion 34. The absorbing portion 34 is provided closer to the insulating substrate W than the conductive film 32. Specifically, the absorbing portion 34 has a plate-like shape and is provided between the conductive film 32 and the insulating substrate W. The absorbing portion 34 is provided with its thickness direction aligned with the vertical direction.

[0077] The absorbing portion 34 has an opening 34a that is vertically connected to an opening formed by the inner circumferential surface of the first conductive portion 321 of the conductive film 32. The opening 34a penetrates the absorbing portion 34 in its thickness direction. The opening 34a of the absorbing portion 34 and the opening 321a of the conductive film 32 form the first opening 3a of the mask 3.

[0078] The absorbing portion 34 may be provided so as to be separable from the conductive film 32, or may be provided in a state where it is joined to the conductive film 32.

[0079] Here, the heater 8 is an optical heater (in other words, a radiant heater) that emits heating light toward the insulating substrate W. The heating light is, for example, infrared light. In the example of FIG. 1, the heater 8 is provided outside the bottom of the chamber 2. For this reason, a material with high transmittance for the heating light is applied to the bottom of the chamber 2. The bottom is formed of, for example, glass.

[0080] On the other hand, the transmittance of the insulating substrate W may also be high. For example, when the insulating substrate W is made of glass, the insulating substrate W transmits the heating light. Therefore, the heating light is incident on the absorbing portion 34. The transmittance of the insulating substrate W may be, for example, 60% or more, 80% or more, or 90% or more.

[0081] On the other hand, the absorptance of the absorbing portion 34 for the heating light is higher than that of the insulating substrate W. The absorptance of the absorbing portion 34 is also higher than that of the conductive film 32. For example, the light absorptance of the absorbing portion 34 may be 40% or more, 60% or more, 80% or more, or 90% or more. For example, the absorbing portion 34 is made of diamond-like carbon. The absorbing portion 34 is provided by, for example, sputtering or the like.

[0082] The heating light from the heater 8 is absorbed by the absorbing portion 34 and converted into heat. The heat is transferred to the insulating substrate W. Therefore, the insulating substrate W can be effectively heated. In the example of FIG. 8, the absorbing portion 34 is in contact with the insulating substrate W, and therefore the heat generated by the absorbing portion 34 is easily transferred to the insulating substrate W.

[0083] Furthermore, since the absorbing portion 34 is provided between the conductive film 32 and the insulating substrate W, it is in contact with the main surface of the insulating substrate W on the side that is hit by the cations. This makes it possible to more effectively increase the temperature of the main surface of the insulating substrate W to be etched. This allows the temperature of the main surface of the insulating substrate W to be raised to a temperature suitable for etching more quickly, allowing the etching process to be started at an earlier timing.

[0084] The reflectance of the conductive film 32 (particularly the second conductive portion 322) with respect to the heating light may be higher than the reflectance of the absorbing section 34. For example, the reflectance of the conductive film 32 may be, for example, 60% or more, 80% or more, or 90% or more. In this way, a portion of the heating light that has passed through the absorbing section 34 is reflected by the conductive film 32 and then passes through the absorbing section 34 again. This makes it possible to improve the amount of light absorbed by the absorbing section 34 and to increase the amount of heat generated in the absorbing section 34. Therefore, the insulating substrate W can be heated more effectively.

[0085] In FIG. 7, when the absorption rate of the replacement part 35 is higher than the absorption rate of the insulating substrate W, the replacement part 35 can function as the absorption part 34.

[0086] Second Embodiment FIG. 9 is a side view schematically illustrating an example of the configuration of an etching apparatus 1 according to the second embodiment. The etching apparatus 1 according to the second embodiment differs from the etching apparatus 1 according to the first embodiment in the positions of the components. In the example of FIG. 9, the roller 25 is in contact with the mask 3, and the insulating substrate W is positioned above the mask 3. For example, the insulating substrate W is placed on the mask 3. The plasma generation unit 5 is provided on the opposite side of the mask 3 from the insulating substrate W, and therefore, in the example of FIG. 9, it is provided below the mask 3. Also, in the example of FIG. 9, the gas introduction pipe 61 is provided below the passage 22, and the downstream port of the gas introduction pipe 61 is provided below the mask 3. For example, the downstream port of the gas introduction pipe 61 is provided in a position horizontally aligned with the conductive member 51. Meanwhile, the heater 8 is provided above the insulating substrate W, and in the example of FIG. 9, it is provided above the ceiling of the chamber 2. When the heater 8 emits light for heating, the ceiling of the chamber 2 is translucent to the light. In the example of FIG. 9, the upstream opening of the suction pipe 71 is provided at a position below the roller 25.

[0087] FIG. 10 is a diagram showing an example of the configuration of the rollers 25, the mask 3, and the insulating substrate W. FIG. 10 shows the rollers 25, the mask 3, and the insulating substrate W as viewed along the conveyance direction D1. As shown in FIG. 10, a pair of rollers 25 are arranged side by side in the width direction D2. One roller 25 contacts one end of the mask 3 in the width direction D2, and the other roller 25 contacts the other end of the mask 3 in the width direction D2. Multiple pairs of such rollers 25 are arranged side by side in the conveyance direction D1. Multiple first openings 3a of the mask 3 are provided in the region between the pair of rollers 25 in the width direction D2. Conversely, the rollers 25 are arranged in positions that avoid this region.

[0088] In the second embodiment, the roller 25 is conductive and contacts the conductive film 32 of the mask 3. In the example of FIG. 10, the conductive film 32 further includes a fourth conductive portion 324 and a fifth conductive portion 325. In the example of FIG. 10, the fifth conductive portion 325 is provided on the second main surface 31b of the insulating plate 31 and contacts the roller 25. This electrically connects the fifth conductive portion 325 to the roller 25. In the example of FIG. 10, the pair of fifth conductive portions 325 contact the pair of rollers 25, respectively. The fifth conductive portion 325 may extend along the conveyance direction D1. That is, the fifth conductive portion 325 may have an elongated shape with the conveyance direction D1 as the longitudinal direction in a plan view.

[0089] The fourth conductive portion 324 penetrates the insulating plate 31 in its thickness direction, and connects the second conductive portion 322 and the fifth conductive portion 325. The fourth conductive portion 324 may have, for example, a cylindrical shape. The fourth conductive portion 324 can function as a via.

[0090] The bias application unit 4 applies a negative voltage to the roller 25. As a result, the negative voltage is applied to the conductive film 32 in contact with the roller 25. The bias application unit 4 may include, for example, a conductive contact member (e.g., a brush) that contacts the roller 25. The contact member is connected to the low-potential output terminal of the DC power supply 43 through wiring 42. In this example, since the roller 25 contacts the conductive film 32 of the mask 3, the roller 25 functions as the contact member 41 of the bias application unit 4. A negative voltage may be applied to all of the multiple rollers 25, or to some of the rollers 25.

[0091] As described above, in the second embodiment, the conductive roller 25 contacts the conductive film 32 of the mask 3, and therefore the roller 25 is used to apply a negative voltage. When a negative voltage is applied to multiple rollers 25, the negative voltage can be applied to the mask 3 at multiple locations (rollers 25). This makes it possible to make the potential distribution of the mask 3 more uniform. Consequently, the etching apparatus 1 can etch the insulating substrate W more uniformly.

[0092] Although the etching apparatus 1 has been described in detail above, the above description is merely an example in all respects, and this disclosure is not limited thereto. Furthermore, the various modifications described above can be combined and applied as long as they are not mutually inconsistent. It is understood that numerous modifications not exemplified can be envisioned without departing from the scope of this disclosure. [Explanation of symbols]

[0093] 1. Etching equipment 3. Mask 31 Insulating plate 31a 1st main surface 31b 2nd principal surface 32 Conductive film 321 1st conductive part 322 Second conductive part 33 Protective film 34 Absorption section 35 Replacement part 3a 1st opening 4. Bias application section 5. Plasma generation unit 8 Heater W insulating substrate

Claims

1. An etching apparatus for forming a plurality of through holes in an insulating substrate, a chamber into which the insulating substrate is carried; a mask having a plurality of first openings and facing the insulating substrate; a bias applying unit that applies a negative voltage to the mask; a plasma generating unit that generates plasma and supplies positive ions in the plasma to the insulating substrate through the plurality of first openings of the mask; An etching apparatus comprising:

2. 2. The etching apparatus according to claim 1, The mask is an insulating plate having a plurality of second openings formed therein; Conductive film and Including, the conductive film is provided on an inner circumferential surface of each of the plurality of second openings in the insulating plate and includes a first conductive portion that forms the first opening; The bias application unit applies the negative voltage to the conductive film.

3. 3. The etching apparatus according to claim 2, the conductive film is formed on a first main surface of the insulating plate facing the insulating substrate and includes a second conductive portion connecting the first conductive portions to each other.

4. 4. The etching apparatus according to claim 2 or 3, a portion of the first conductive portion protrudes beyond a second main surface of the insulating plate opposite to a first main surface on the insulating substrate side.

5. 4. The etching apparatus according to claim 2 or 3, The etching apparatus, wherein the mask further includes a protective film that faces the first conductive portion and protects the first conductive portion from the plasma.

6. 4. The etching apparatus according to claim 2 or 3, The mask is a replacement part provided between the insulating plate and the insulating substrate, the replacement part being detachable from the insulating plate and the conductive film; the refill portion has an opening that, together with an opening in the first conductive portion, forms the first opening; The diameter of the opening in the refill portion is smaller than the diameter of the opening in the first conductive portion.

7. 4. The etching apparatus according to claim 2 or 3, a heater that emits light for heating toward the insulating substrate; The mask is an absorbing portion provided between the insulating plate and the insulating substrate, the absorbing portion having a higher absorption rate for the light than the absorption rate of the insulating substrate.

8. 4. The etching apparatus according to claim 1, a plurality of conductive rollers that support the mask and transport the mask and the insulating substrate; The bias application unit applies the negative voltage to the roller.

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