JP2013207210A - Plasma processing apparatus and plasma processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma processing apparatus and a plasma processing method which improve the accuracy of the end point detection of etching process even when a thickness dimension of an etching target layer is large for a pattern dimension and a pattern is fine.SOLUTION: According to one embodiment, a plasma processing apparatus includes: a processing container that has a plasma generation region therein and may maintain an atmosphere decompressed so as to be lower than the atmospheric pressure; a gas supply part supplying a process gas to the plasma generation region; a plasma generation part supplying electromagnetic energy to the plasma generation region thereby generating plasma; a decompression part decompressing the interior of the processing container to a predetermined pressure; a placement part provided in the processing container and on which a processed product is placed; a peripheral member provided on the placement part; and an end point detection plate provided at a position of the peripheral member that faces the plasma generation region.

Description

  Embodiments described herein relate generally to a plasma processing apparatus and a plasma processing method.

  In the manufacture of semiconductor devices, flat panel displays, photomasks, etc., when a pattern is formed by an etching process, the end of pattern formation, that is, the end point of the etching process is detected.

  In such an etching end point detection, the detection end point is detected by causing detection light to enter the substrate to be etched and monitoring the intensity of the reflected interference light (see, for example, Patent Document 1). .

  However, if the technique disclosed in Patent Document 1 is used, the end point of the etching process is detected when the thickness dimension of the etching target layer is larger than the pattern dimension and the pattern is fine. There is a risk that accuracy will be significantly reduced.

JP 2004-119514 A

  The problem to be solved by the present invention is that it is possible to improve the accuracy of detecting the end point of the etching process even when the thickness dimension of the etching target layer is larger than the pattern dimension and the pattern is fine. A plasma processing apparatus and a plasma processing method are provided.

  According to the present embodiment, a processing vessel that has a plasma generation region inside and can maintain an atmosphere reduced in pressure from atmospheric pressure, a gas supply unit that supplies a process gas to the plasma generation region, and the plasma A plasma generation unit that generates plasma by supplying electromagnetic energy to a generation region, a decompression unit that depressurizes the inside of the processing container to a predetermined pressure, and an object to be processed provided in the processing container are placed. A plasma processing apparatus comprising: a mounting portion; a peripheral member provided on the mounting table; and an end point detection plate provided at a position of the peripheral member facing the plasma generation region. Provided.

  According to another embodiment of the present invention, plasma is generated in an atmosphere that is depressurized from the atmosphere, and a process gas supplied toward the plasma is excited to generate a plasma product, and the plasma product A plasma processing method for performing an etching process on an object to be processed by using the above-mentioned, and detecting the end point of interference light from the end point detection plate provided at the position facing the plasma of the peripheral member provided on the mounting table. There is provided a plasma processing method comprising: a step of detecting by a section; and a step of detecting an end point of etching based on the intensity of the interference light.

  According to the embodiment of the present invention, even when the thickness dimension of the etching target layer is larger than the pattern dimension and the etching target pattern is fine, the accuracy of detecting the end point of the etching process is improved. A plasma processing apparatus and a plasma processing method are provided.

Schematic cross-sectional view for illustrating the plasma processing apparatus according to the first embodiment Schematic diagram showing the end point detector in FIG. Schematic diagram related to the endpoint detection method in the comparative example The figure which represented the change of the intensity | strength of reflected light L2 typically. Schematic sectional view according to the endpoint detection method in the first embodiment Schematic cross-sectional view for illustrating the plasma processing method according to the second embodiment

Hereinafter, embodiments will be illustrated with reference to the drawings. In addition, in each drawing, the same code | symbol is attached | subjected to the same component and detailed description is abbreviate | omitted suitably. In the present specification, “pattern dimension” refers to the etching depth of the etching target layer.
[First Embodiment]
Here, as an example, a substrate manufacturing apparatus that can be used when manufacturing a phase shift mask will be described.

  FIG. 1 is a schematic cross-sectional view for illustrating the plasma processing apparatus according to the first embodiment.

  The plasma processing apparatus includes a processing container 1, a gas supply unit 2, a plasma generation unit 3, and a decompression unit 8.

  The processing container 1 is a sealed container so that a reduced pressure atmosphere can be maintained. The workpiece W is placed on the electrode 4 provided in the processing container 1, and an etching process is performed by the plasma product generated by the plasma generated in the plasma generation region P. Moreover, in this embodiment, the electrode 4 becomes a mounting part which mounts the to-be-processed object W, and can hold | maintain holding tools (not shown), such as a pusher pin. The electrode 4 is provided on the pedestal 4a, and an insulating ring 4b is provided on the periphery thereof.

The gas supply unit 2 introduces a processing gas into the plasma generation region P in the processing container 1 through a gas supply port 2 a provided on the ceiling or side wall of the processing container 1. The processing gas can be a gas containing fluorine. Examples of the gas containing fluorine include CF ₄ , CHF ₃ , C4F ₈ , SF ₆ , and a mixed gas thereof.

  A high frequency power source 5a is connected to the electrode 4 through a capacitor 5c. The side wall of the electrode 4 is surrounded by an insulating ring 4 b and is insulated similarly to the wall of the processing container 1. That is, the high frequency power supply 5a, the electrode 4, and the wall of the processing container 1 constitute a capacitive coupling electrode.

  A coil 20 is provided on the ceiling outside the processing container 1, and a high frequency power source 5b is connected to the coil 20 via a capacitor 5d. The coil 20 excites an electromagnetic field from a high frequency applied from the high frequency power source 5 b and introduces the electromagnetic field into the processing container 1 through the dielectric window 6. That is, the high frequency power supply 5b and the coil 20 constitute an inductive coupling electrode. Thus, the plasma processing apparatus in this embodiment is a two-frequency plasma etching apparatus having a capacitively coupled electrode and an inductively coupled electrode.

  In the present embodiment, the high frequency power source 5 a, the electrode 4, the coil 20, the wall of the processing container 1, the high frequency power source 5 b, and the dielectric window 6 constitute the plasma generating unit 3.

  The high frequency power source 5a has a frequency of about 100 KHz to 100 MHz and can apply a high frequency power of about 1 KW to the electrode 4 through a capacitor.

  The high frequency power source 5b has a frequency of about 100 KHz to 100 MHz, and can apply a high frequency power of about 200 W to the coil 20 via a capacitor.

  On the side wall of the processing container 1, a loading / unloading port 9 for loading / unloading the workpiece W into / from the processing container 1 is provided. A gate valve 9 a is provided at the carry-in / out port 9. The gate valve 9a has a door 9b, and opens / closes the loading / unloading port 9 by opening / closing the door 9b by a gate opening / closing mechanism (not shown). The door 9b is provided with a sealing member 9c such as an O-ring. When the loading / unloading port 9 is closed by the door 9b, the contact surface between the loading / unloading port 9 and the door 9b can be sealed.

  An exhaust port 8a is provided near the bottom in the processing container 1, and is connected to the decompression unit 8 via a pressure control unit 8b. The decompression unit 8 evacuates while controlling the pressure in the processing container 1 by the pressure control unit 8b, and decompresses until the pressure inside the processing container 1 becomes a predetermined pressure.

  A shutter (not shown) that divides a space for generating plasma may be provided in the processing container 1. In this case, during processing, the space for generating plasma is covered with a shutter, so that plasma damage to the inner wall of the processing container 1 and adhesion of by-products generated during processing can be suppressed. In addition, when opening the loading / unloading port 9, the space for generating plasma is covered with the shutter, so that it is possible to prevent particles from entering the space for generating plasma from the outside.

  A focus ring 7 is disposed around the workpiece W at the periphery of the upper end of the electrode 4. The inner peripheral shape of the focus ring 7 may be adapted to the outer peripheral shape of the workpiece W, and the shape when the focus ring 7 is viewed in plan may be, for example, an annular shape or a rectangular frame shape. The focus ring 7 is made of an insulating material that does not attract reactive ions, and makes the reactive ions effectively enter the workpiece W on the inside. In the present embodiment, the focus ring 7 is a peripheral member provided on the periphery of the workpiece W. Further, the focus ring 7 has a holding portion 7 a for holding the end point detection plate 10.

  The end point detection plate 10 can be detachably attached to the holding portion 7 a of the focus ring 7 and can be provided at a position facing the plasma generation region P on the focus ring 7. The end point detection plate 10 can be made of the same material as the etching target layer of the workpiece W. For example, when the etching target layer of the workpiece W is a light-transmitting material, the end point detection plate 10 can also be a light-transmitting material.

  That is, when the etching target layer of the workpiece W is being etched, the end point detection plate 10 is also etched in the same manner. The end point detection plate 10 will be described in detail later.

  Next, the end point detection unit 11 will be further illustrated with reference to FIG.

  The end point detection unit 11 causes the detection light to be incident on the main surface of the end point detection plate 10 (in the case illustrated in FIG. 1, the surface facing the region where plasma is generated) and changes the intensity of the reflected light. Is measured to detect the etching depth of the end point detection plate 10.

  The end point detection unit 11 is provided with a detection window 12, a light source 13, a spectroscopic unit 14, and a control unit 15.

  The detection window 12 is made of a light-transmitting material, and allows the detection light L3 from the light source 13 and the reflected light L4 reflected from the end point detection plate 10 to pass therethrough. The number of detection windows 12 is not limited to one, and two detection windows 12 may be provided separately for the detection window 12 that allows the detection light L3 to pass therethrough and the detection window 12 that allows the reflected light L4 to pass therethrough.

  The light source 13 emits detection light L3. The detection light L3 can be, for example, light having a wavelength of 400 nm or less, for example, ultraviolet light. Examples of the light source 13 include a mercury xenon lamp capable of obtaining a strong light amount in the ultraviolet region.

  The spectroscopic unit 14 separates light having a specific wavelength from the incident reflected light L4. Noise may enter the wavelength of the detection light L3 emitted from the light source 13 and it may be difficult to set it to a single wavelength. In such a case, if the spectroscopic unit 14 separates light of a specific wavelength, the accuracy of end point detection can be improved. The spectroscopic unit 14 is not always necessary, and may be provided as necessary.

  The control unit 15 monitors the intensity change of the reflected light L4a incident through the spectroscopic unit 14, compares the monitored intensity of the reflected light L4a with a pre-stored threshold value, and compares the comparison result with the operation of the manufacturing apparatus. This is sent to the process control unit 16 to be controlled.

  The process control unit 16 ends the etching process in the manufacturing apparatus based on the comparison result. For example, if the intensity of the reflected light L4a is lower than the threshold value, the etching end point is determined and the etching process is terminated. In addition, the process control unit 16 can control the control unit 15 to start detection or end detection in the end point detection unit 11. The process control unit 16 can also control the operation of each element provided in the manufacturing apparatus.

  The end point detection unit 11 can be provided with other optical elements such as a transmission unit such as an optical fiber for transmitting the detection light L4 and L4a to the control unit 15, and a lens for condensing the detection light L3 at the detection point.

  Next, an example of detecting information related to the end point of the etching process (hereinafter also referred to as “end point”) will be described.

  FIG. 3 is a schematic diagram according to the endpoint detection method in the comparative example.

  The workpiece W is provided with a light transmitting portion 201, a light shielding portion 202, and a resist 203 which are stacked in layers. The light transmitting portion 201 is made of a material that transmits light, such as quartz. The light shielding portion 202 is made of a material that shields light, such as chromium oxide (CrO), chromium nitride (CrN), silicon molybdenum (MoSi), and the like.

  Openings are formed in the resist 203 and the light shielding portion 202 by an existing plasma etching method. And the case where the part corresponding to the opening part 202a of the light-shielding part 202 in the translucent part 201 is etched until the desired depth is illustrated.

  Here, an endpoint detection method in the case where the light transmitting portion 201 is an etching target layer will be exemplified.

  In the comparative example shown in FIG. 3, the light transmitting part 201 is irradiated with the detection light L1 from the light source 13, and the reflected light L21 from the surface of the light transmitting part 201 and the reflected light L22 from the bottom surface of the light transmitting part 201 are used. The end point is calculated by obtaining the relationship between the change in intensity of the reflected light L2, which is interference light caused by the above, and the etching amount.

  FIG. 4 is a diagram schematically showing a change in intensity of the reflected light L2.

  In FIG. 4, the amount A etched during one period T of the reflected light L2 can be obtained by the following equation.

Here, S is the wavelength of the detection light L1, and n is the refractive index of the etching target layer.

次に、反射光Ｌ２の一周期Ｔにおける処理時間と、エッチングされる量Ａとからエッチングレートを求める。そして、求められたエッチングレートと、所望のエッチング深さとからエッチング処理に要する時間、すなわち、エンドポイントを求めることができる。

Next, an etching rate is obtained from the processing time in one cycle T of the reflected light L2 and the etching amount A. The time required for the etching process, that is, the end point can be obtained from the obtained etching rate and the desired etching depth.

  Thereafter, the process control unit 16 or the operator who controls the process ends the processing in the plasma processing apparatus based on the obtained end point of the etching processing.

  Thus, in the comparative example, the reflected light L2 that is the interference light between the reflected light L22 from the bottom of the etching target layer (translucent portion 201) and the reflected light L21 from the surface is obtained. Then, the etching amount A is calculated from the change in intensity of the reflected light L2, the etching rate is calculated, and the time required for the desired etching process, that is, the end point is detected.

  By the way, the etching target layer may have a large thickness dimension and a fine pattern. For example, when a fine pattern is formed using a quartz substrate as an etching target layer, the thickness dimension of the quartz substrate is the thickness dimension of the etching target layer, and thus the thickness dimension is large, but the etching depth is small. When such an end point of the etching target layer is detected, the light of the detection light L12 that passes through the etching target layer becomes long, so that it is easily absorbed and attenuated in the etching target layer. As a result, the intensity of the reflected light L12 is reduced, and the reflected light L2 that is the interference light between the reflected light L11 and the reflected light L12 is difficult to be taken, so that accurate detection may be difficult. As a result, it becomes difficult to detect endpoints in real time during etching.

  Further, for example, when considering the wavelength length so that the detection light L1 is not absorbed in the etching target layer, the wavelength of the detection light L1 depends on the difference between the etching depth and the thickness dimension of the etching target layer. It is necessary to decide. However, when the pattern size or pattern design of the etching target layer is varied according to the application, the wavelength of the detection light L1 must be determined according to each, and productivity is reduced.

Here, an endpoint detection method in the first embodiment will be exemplified with reference to FIG.
FIG. 5 is a schematic cross-sectional view according to the endpoint detection method in the first embodiment.

  The end point detection plate 10 can be provided at a position facing the plasma generation region P on the peripheral member of the workpiece W. In this embodiment, the focus ring 7 is a peripheral member.

  The end point detection plate 10 can be made of the same material as the etching target layer of the workpiece W.

  That is, when the etching target layer of the workpiece W is being etched, the end point detection plate 10 is also etched in the same manner. In other words, it is possible to indirectly detect the etching amount of the etching target layer of the workpiece W by monitoring the etching amount of the end point detection plate 10. As a result, when it is detected that the etching depth of the end point detection plate 10 has reached a predetermined depth, the etching end point of the etching target layer of the workpiece W can be set.

  In this embodiment, the end point detection plate 10 is irradiated with the detection light L3 from the light source 13, and interference is caused by the reflected light L41 from the surface of the light transmitting part 201 and the reflected light L42 from the bottom surface of the light transmitting part 201. The end point of the translucent portion 201 is detected by monitoring the change in the intensity of the reflected light L4 that is light.

  Since the thickness dimension of the end point detection plate 10 is very small with respect to the thickness dimension of the etching target layer, the reflected light L42 from the bottom surface of the end point detection plate 10 has a short optical path and is difficult to attenuate. As a result, it becomes easy to detect the reflected light L4, which is interference light between the reflected light L41 and the reflected light L42, and highly accurate endpoint detection can be performed. As a result, the end point can be detected in real time during etching without obtaining the end point from the etching rate by calculation as in the comparative example.

  Thus, in the plasma processing apparatus of the present embodiment, the end point detection plate 10 is provided on the peripheral member of the workpiece W, so that the etching end point of the workpiece W can be detected in real time.

  Even when the pattern size or pattern design of the etching object is varied depending on the application, the thickness dimension H of the end point detection plate 10 is always constant, so that the wavelength of the detection light L3 does not need to be changed. Therefore, productivity is improved.

  Here, the thickness dimension H of the end point detection plate 10 needs to be larger than the etching depth of the etching target layer, but can be smaller than the thickness dimension of the etching target layer.

That is, the thickness dimension H of the end-point detection plate 10, the thickness dimension T of the workpiece W, and the etching depth E of the workpiece W can satisfy the following expressions.

［数２］を満たすものであれば、終点検出板１０の厚み寸法Ｈはいかなる値も適用可能である。ただし、後述するように、終点検出板１０の厚み寸法Ｈは、終点検出板１０に対するエッチング条件に影響を及ぼさないような厚み寸法とすることができる。例えば、６ｍｍの石英基板がエッチング対象層であり、そのエッチング深さが１６８ｎｍと微細である場合、終点検出板１０は１ｍｍ以下１６８ｎｍ以上の石英板を用いることができる。さらに、メンテナンス性を考慮すると、エッチング処理によって消耗した終点検出板１０の取替えはできるだけ少なくしたほうがよく、厚み寸法Ｈは、例えばエッチング深さＥの整数倍とすることができる。

Any value can be applied to the thickness dimension H of the end point detection plate 10 as long as [Equation 2] is satisfied. However, as will be described later, the thickness dimension H of the end point detection plate 10 can be set to a thickness that does not affect the etching conditions for the end point detection plate 10. For example, when a 6 mm quartz substrate is an etching target layer and the etching depth is as fine as 168 nm, the endpoint detection plate 10 can be a quartz plate having a thickness of 1 mm or less and 168 nm or more. Further, in consideration of maintainability, it is better to replace the end point detection plate 10 consumed by the etching process as much as possible, and the thickness dimension H can be an integral multiple of the etching depth E, for example.

  Here, it is preferable that the etching conditions for the end point detection plate 10 and the etching conditions for the etching target layer of the workpiece W are as similar as possible.

  Therefore, the height of the main surface of the end point detection plate 10 can be made substantially the same as the height of the main surface of the etching target layer. In this case, since the distance from the region where plasma is generated to both main surfaces can be made substantially the same, the deactivation and reaction rate of the plasma product can be considered to be almost the same. As a result, the etching conditions for the end point detection plate 10 and the etching conditions for the etching target layer of the workpiece W can be made equal.

  Further, it is conceivable that the temperature condition of the end point detection plate 10 and the temperature condition of the etching target layer are the same. For example, a temperature control mechanism such as a small heater or a refrigerant flow path can be arranged on the peripheral member provided with the end point detection plate 10 to control the temperature so as to be equal to the temperature condition of the etching target layer.

  Further, the end point detection plate 10 is arranged as close to the workpiece W as possible so that the plasma density on the main surface of the end point detection plate 10 is equal to the plasma density on the main surface of the etching target layer. It is preferable. For example, when the peripheral member having the end point detection plate 10 is the focus ring 7, the end point detection plate 10 may be disposed closer to the workpiece W than the half of the width when the focus ring 7 is viewed in plan. it can.

  Further, the peripheral member having the end point detection plate 10 can be placed on the same electrode 4 as the electrode 4 on which the workpiece W is placed. For example, the peripheral member can be the focus ring 7 as in the present embodiment. Since the focus ring 7 is installed on the same electrode 4 as the electrode 4 on which the workpiece W is placed, etching such as plasma density distribution and temperature distribution on the end point detection plate 10 provided on the focus ring 7 is performed. The conditions can be the same as the etching conditions in the etching target layer of the workpiece W.

  As described above, if the etching conditions for the end point detection plate 10 and the etching conditions for the etching target layer of the workpiece W are the same, the end point detection plate 10 can be connected to the end point of the etching target layer even indirectly. It is possible to detect an endpoint with high accuracy as a measurement point.

  Furthermore, the number of the end point detection plates 10 is not limited to one, and if a plurality of end point detection plates 10 are arranged on the peripheral member, the object to be processed is based on the distribution of the etching rate detected from each of the plurality of end point detection plates 10. The etching uniformity on W can be measured.

According to the present embodiment, even when the thickness dimension of the etching target layer is large and the pattern is fine, it is possible to improve the accuracy of detecting the end point of the etching process.
[Second Embodiment]
Hereinafter, the plasma processing method according to the second embodiment will be described with reference to FIG.

  FIG. 6 is a schematic cross-sectional view for illustrating the plasma processing method according to the second embodiment.

  Here, as an example, the case of manufacturing a phase shift mask is illustrated.

  First, a workpiece W having a light transmitting part 201 and a light shielding part 202 is prepared. The light transmitting portion 201 is made of a material that transmits light, such as quartz. The light shielding portion 202 is made of a material that shields light, such as chromium oxide (CrO), chromium nitride (CrN), silicon molybdenum (MoSi), and the like.

  As shown in FIG. 6A, a patterned resist 203 serving as an etching mask is formed on the surface of the light shielding portion 202. The resist patterning is performed by an existing method. At this time, the light shielding portion 202 is exposed in the resist opening 203a.

Next, as shown in FIG. 6B, a pattern is formed in the light shielding portion 202 corresponding to the opening 203a of the pattern of the resist 203 by the first etching process. The first etching process can be performed by a plasma process. The processing gas to be used can be a gas with which the material of the light-shielding part 202 easily reacts, for example, a chlorine-based gas such as Cl ₂ , HCl, or CCl ₄ , or a mixed gas with another gas.

  A pattern is formed in the light shielding portion 202 by the first etching process. At this time, the surface of the translucent part 201 is exposed in the opening 202a of the light shielding part.

Then, as shown in FIG. 6C, a pattern is formed in the light transmitting portion 201 corresponding to the opening 202a of the light shielding portion by the second etching process. The second etching process can also be performed by a plasma etching process. The processing gas to be used is a gas in which the material of the light transmitting portion 201 is easily reacted and the material of the light shielding portion 202 is difficult to react, for example, a fluorine-based gas such as CF ₄ , CHF ₃ , C4F ₈ , SF ₆ , or other It can be a mixed gas with gas.

  In the second etching process, the end point can be detected by the end point detector 11 exemplified in the first embodiment.

  For example, the end point detection plate 10 is irradiated with the detection light L3 from the light source 13 and reflected as interference light by the reflected light L41 from the surface of the light transmitting part 201 and the reflected light L42 from the bottom surface of the light transmitting part 201. By monitoring the change in the intensity of the light L4, the end point of the light transmitting portion 201 is detected. In addition, in order to detect the end point of the translucent part 201 with high accuracy, as described above, in the second etching process, the end point detection plate 10 is processed under conditions equivalent to the conditions for the translucent part 201. Is preferably initiated. Therefore, in the first etching process, an insulating cover is provided on the end point detection plate 10 so that the end point detection plate 10 is not etched, or the end point detection plate 10 is removed during the first etching process. You may make it attach in a 2nd etching process.

  Thus, in the plasma processing apparatus of the present embodiment, the end point detection plate 10 is provided on the peripheral member of the workpiece W, so that the etching end point of the workpiece W can be detected in real time.

  Even when the pattern size or pattern design of the etching object is varied depending on the application, the thickness dimension H of the end point detection plate 10 is always constant, so that the wavelength of the detection light L3 does not need to be changed. Therefore, productivity is improved.

  As described above, after detecting the end point of the second etching process, the resist 203 is removed by an existing ashing method as shown in FIG. For example, there are methods such as wet ashing using chemicals and dry ashing using plasma.

  A phase mask can be manufactured as described above.

  According to the present embodiment, even when the thickness dimension of the etching target layer is large and the pattern is fine, it is possible to improve the accuracy of detecting the end point of the etching process.

The embodiment has been illustrated above. However, the present invention is not limited to these descriptions.

Regarding the above-described embodiment, those in which those skilled in the art appropriately added, deleted, or changed the design, or added the process, omitted, or changed the conditions also have the features of the present invention. As long as it is within the scope of the present invention.

  For example, the shape, dimensions, material, arrangement, number, and the like of each element included in the plasma processing apparatus, the workpiece W, and the like are not limited to those illustrated, and can be changed as appropriate.

  For example, the end point detection unit 11 may detect the end point by making detection light incident from the back surface of the end point detection plate 10. In this case, a transmission path of incident light and reflected light and a light source 13 are provided inside the focus ring 7 as a peripheral member, and reflected light reflected from the main surface of the end point detection plate 10 and reflected from the back surface of the end point detection plate 10. It is possible to detect reflected light which is interference light with light.

  Further, the end point detection plate 10 need not always be exposed to plasma during the etching process of the workpiece W. For example, during etching of another layer that is not the etching target layer for detecting the end point, the end point detection plate 10 is covered with an insulating cover made of the same material as the peripheral member, and the etching target layer is etched. At the start of processing, the cover can be removed and the end point detection plate 10 can be exposed to plasma.

  Alternatively, during etching of another layer that is not the etching target layer for detecting the end point, a chip made of the same material as that of the peripheral member is fitted in the holding portion 7a in place of the end point detecting plate 10, and the end is detected. When the etching target layer for detecting the point is etched, the end point detection plate 10 may be carried into the processing container and installed on the peripheral member. In this manner, the end point detection plate 10 can be etched under the same conditions as the etching target layer without being etched by plasma while the other layers are etched.

  Further, the peripheral member is not limited to the focus ring 7 and may be any member provided around the workpiece W on the placement unit. For example, it is good also considering the surrounding area of the to-be-processed object W in the baffle plate installed in the mounting part or a mounting part as a peripheral member.

  Further, the material of the end point detection plate 10 may be different from that of the workpiece W. In this case, a material having a high etching rate with respect to the processing gas used when etching the etching target layer of the workpiece W can be used. At this time, since the etching rate of the end point detection plate 10 is higher than the etching rate of the etching target layer, if the etching rate of the end point detection plate 10 is monitored, the end point of the workpiece W can be detected more precisely. it can.

  Further, the incident angle of the detection light may be perpendicular to the end point detection plate 10 or may be incident with an inclination.

  Further, as an example, the end point of the translucent portion 201 is performed by the end point detection method of the present invention, but the present invention can also be applied to the end point detection of other layers such as the light shielding portion 202 and the resist 203.

  Moreover, although the case where the to-be-processed object W was a phase shift mask was illustrated as an example, it can be made to apply suitably when the pattern to be etched is fine. For example, the present invention can also be applied when etching a glass substrate or a nanoimprint substrate used for a flat panel display or the like.

  Moreover, each element with which each embodiment mentioned above is combined can be combined as much as possible, and what combined these is also included in the scope of the present invention as long as the characteristics of the present invention are included.

DESCRIPTION OF SYMBOLS 1 Processing container 2 Gas supply part 2a Gas supply port 3 Plasma generation part 4 Electrode 4a Base 4b Insulation ring 5a High frequency power supply 5b High frequency power supply 5c Capacitor 5d Capacitor 6 Dielectric window 7 Focus ring 7b Holding part 8 Decompression part 8a Exhaust port 8b Pressure Control unit 9 Loading / unloading port 9a Gate valve 9b Door 9c Sealing member 10 End point detection plate 11 End point detection unit 12 Detection window 13 Light source 14 Spectrometer unit 15 Control unit 16 Process control unit 20 Coil 100 Plasma processing apparatus 201 Translucent unit 202 Light shielding Part 202a Light-shielding part opening 203 Resist 203a Resist opening L1 Detected light L2 Reflected light L3 Detected light L4 Reflected light P Plasma generation area W Substrate H Thickness dimension of end-point detection plate T Thickness dimension of workpiece E Etching depth

Claims (8)

A processing vessel having a plasma generation region inside and capable of maintaining an atmosphere depressurized from atmospheric pressure;
A gas supply unit for supplying a process gas to the plasma generation region;
A plasma generator for generating plasma by supplying electromagnetic energy to the plasma generation region;
A decompression section for decompressing the inside of the processing container to a predetermined pressure;
A placement unit for placing an object to be processed provided in the processing container;
Peripheral members provided on the mounting portion;
A plasma processing apparatus, comprising: an end point detection plate provided at a position of the peripheral member facing the plasma generation region.   The plasma processing apparatus according to claim 1, wherein the peripheral member is a focus ring surrounding a periphery of an object to be processed.   The processing container is provided with an end point detection unit that makes detection light incident on the surface of the end point detection plate facing the plasma generation region and detects the end point of the etching process based on the reflected light from the end point detection plate. The plasma processing apparatus according to claim 1, wherein the apparatus is a plasma processing apparatus.   The processing container is provided with an end point detection unit that makes detection light incident on a surface of the end point detection plate facing the mounting table and detects an end point of the etching process based on the detection light reflected from the end point detection plate. The plasma processing apparatus according to claim 1, wherein the apparatus is a plasma processing apparatus.   The plasma processing apparatus according to claim 1, wherein the end point detection plate is made of the same material as the object to be processed.   The plasma processing apparatus according to claim 1, wherein a height of a main surface of the end point detection plate is the same height as a main surface of the object to be processed. The plasma according to claim 1, wherein a thickness dimension H of the end point detection plate, a thickness dimension T of the object to be processed, and an etching depth E of the object to be processed satisfy the following expressions. Processing equipment.

Plasma that generates plasma in an atmosphere depressurized from the atmosphere, excites a process gas supplied toward the plasma to generate a plasma product, and performs an etching process on the object to be processed using the plasma product A processing method,
A step of detecting interference light from an end point detection plate provided at a position facing the plasma of a peripheral member provided on the mounting table by an end point detection unit;
Detecting an end point of etching based on the intensity of the interference light;
A plasma processing method comprising:

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