Method for removing foreign matter from a substrate and substrate processing method

Abstract

The present invention provides a method for removing foreign matter present in recesses of a substrate and a substrate processing method. [Solution] A method for removing foreign matter from a surface-treated substrate includes: a substrate treatment step of polishing the substrate before removing the foreign matter from the substrate; a coating step of applying a viscous adhesive liquid to the surface of the substrate, including recesses; an effect step of hardening the adhesive liquid applied to the surface of the substrate by heating the substrate to form a hardened layer; an irradiation step of irradiating the hardened layer with light to melt a part of the hardened layer or soften at least a part of the hardened layer; and a peeling step of peeling the hardened layer from the substrate.

Description

Technical Field

[0001] The present invention relates to a method for removing foreign matter on a substrate and a substrate processing method.

Background Art

[0002] In the manufacturing process of semiconductor devices, planarization technology for the surface of semiconductor devices is becoming increasingly important. As a planarization technology, chemical mechanical polishing (CMP) is known. In this chemical mechanical polishing, using a polishing apparatus, a polishing liquid (slurry) containing abrasive grains such as silica (SiO₂) and / or ceria (CeO₂) is supplied to a polishing pad, and a substrate such as a semiconductor wafer is brought into sliding contact with the polishing pad to perform polishing.

[0003] Removal of foreign matter on the substrate caused by substrate processing such as polishing is performed. In order to remove foreign matter such as polishing debris present in depressions or grooves of the substrate, Patent Document 1 discloses that the wafer after CMP is immersed in a 50% monomethanolamine aqueous solution for 10 minutes.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0005] If foreign matter such as polishing debris or residual slurry is present in the recessed portion of the substrate, a layer on the substrate that is assumed in advance may not be formed, or a decrease in yield may be caused due to poor conduction in subsequent manufacturing processes. In the polishing method of Patent Document 1, foreign matter present in the recessed portion of the substrate may not be sufficiently removed in some cases.

[0006] This invention has been made in view of the circumstances described above, and one of its objectives is to provide a novel method for removing foreign matter present in recesses of a substrate. [Means for solving the problem]

[0007] According to one embodiment of the present invention, a method for removing foreign matter from a substrate includes applying a viscous adhesive liquid to the surface of the substrate including recesses, curing the adhesive liquid applied to the surface of the substrate to form a cured layer, and peeling the cured layer from the substrate. [Brief explanation of the drawing]

[0008] [Figure 1] This is a flowchart showing the flow of a substrate processing method according to one embodiment. [Figure 2] This is a schematic cross-sectional view showing a substrate before processing in the substrate processing process. [Figure 3] This is a schematic cross-sectional view of a substrate to illustrate the substrate processing and preparation processes. [Figure 4] This is a schematic cross-sectional view of the substrate to illustrate the coating process. [Figure 5] This is a schematic cross-sectional view of the substrate to illustrate the curing process. [Figure 6] This is a schematic cross-sectional view of the substrate to illustrate the irradiation process. [Figure 7] This is a schematic cross-sectional view of the substrate to illustrate the peeling process. [Figure 8] This is a schematic plan view showing the configuration of a substrate processing apparatus according to one embodiment. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below with reference to the accompanying drawings. In the accompanying drawings, the same or Similar elements are denoted by the same or similar reference numerals, and redundant descriptions of the same or similar elements may be omitted in the description of each embodiment. Furthermore, features shown in each embodiment are applicable to other embodiments insofar as they do not contradict each other.

[0010] Figure 1 is a flowchart showing the flow of a substrate processing method according to this embodiment, which includes a method for removing foreign matter from the substrate.

[0011] In this specification, "substrate" includes not only semiconductor substrates, glass substrates, liquid crystal substrates, and printed circuit boards, but also magnetic recording media, magnetic recording sensors, mirrors, optical elements, micro-mechanical elements, or partially fabricated integrated circuits, and any other object to be processed. Substrates include any shape, including polygons and circles.

[0012] The method of this embodiment is performed to remove foreign matter present in recesses of a substrate. The substrate to which this method is applied preferably includes recesses, but it is not necessary to know whether or not recesses are present. Foreign matter present in recesses of a substrate may not be removable by methods such as immersing the substrate in a cleaning solution or scrubbing the substrate with a brush, but it can be removed by the method of this embodiment. Here, the recesses of the substrate may be formed as part or all of a pattern designed on the substrate, or they may be recesses formed unintentionally over part or all of the substrate, such as undulations in the substrate or undulations in a resin or other film on the substrate. A preferred example is a semiconductor substrate, where the recesses are grooves or holes in a pattern area designed on the substrate. Since such recesses can be part of a fine pattern, foreign matter located in these recesses is particularly difficult to remove by methods such as immersion in a cleaning solution. The pattern area of ​​the substrate is an area equipped with wiring and functional chips, and is used as a device formed on the substrate; it is equipped with wiring and functional chips that are meaningful to the function of the device.

[0013] In this specification, "foreign matter" refers to unwanted substances present on the substrate and is not particularly limited. Foreign matter may be abrasive particles of slurry remaining on the substrate after polishing is complete, or polishing debris generated during polishing. Alternatively, foreign matter may be substances unintentionally mixed into the substrate. If foreign matter is present in recesses of the substrate, it may prevent the formation of layers on the substrate as anticipated, or cause a decrease in yield due to poor conductivity in subsequent manufacturing processes. The method of this embodiment is particularly suitable for removing slurry or polishing debris remaining in recesses of the pattern area of ​​the substrate.

[0014] As shown in Figure 1, in step S101, a substrate processing step is performed to process the substrate. The processing performed in the substrate processing step is preferably polishing. In other words, the substrate may be polished before removing foreign matter from the substrate. The type of polishing is not particularly limited, for example, CMP. Polishing is performed by bringing a member containing an abrasive material into contact with the surface of the substrate to be polished, and by the relative movement of the member and the surface to be polished. In polishing, a liquid such as slurry is supplied to the surface to be polished, and polishing debris may be generated from the surface to be polished. Therefore, foreign matter such as slurry or polishing debris may remain in the recesses of the surface to be polished after polishing. In the method of this embodiment, such foreign matter can be suitably removed. Note that the processing performed in the substrate processing step is not particularly limited as long as there is a possibility that foreign matter will be present on the substrate after processing, for example, grinding may be performed.

[0015] The method for removing foreign matter from a substrate according to this embodiment may include a preparation step of preparing a substrate with a treated surface before applying the adhesive liquid described later. This makes it possible to remove foreign matter that has been generated or entered into recesses of the substrate due to the substrate treatment. The substrate treatment step may be included in the preparation step. In addition, the substrate may not be treated in the preparation step, and a treated substrate may be procured.

[0016] FIG. 2 is a schematic cross-sectional view showing an example of a substrate before polishing is performed. In the illustrated example, the substrate WF includes a base substrate 30, a seed layer 40, a wiring layer 50, and an insulating film 60. In the substrate WF, the seed layer 40 and the wiring layer 50 are laminated in this order on the base substrate 30, and the insulating film 60 is disposed so as to cover the base substrate 30, the seed layer 40, and the wiring layer 50. The base substrate 30 is preferably plate-shaped, and is a substrate that serves as a support or base for layers formed in the processing of the substrate WF. The aspect of the base substrate 30 is not particularly limited, and may include glass, resin, or silicon. The base substrate 30 may be a glass substrate, a resin substrate, or a silicon wafer. The wiring layer 50 is formed in a desired pattern and is formed of a conductor such as metal. The seed layer 40 is a seed layer for electrolytic plating, and may include titanium, copper, or the like. The insulating film 60 is formed of an insulator, and may include a resin or the like.

[0017] The wiring layer 50 on the substrate WF can be formed, for example, by forming the seed layer 40 on the base substrate 30 by electroless copper plating or the like, then forming a resist on the seed layer 40 in a predetermined pattern using photolithography, and performing electrolytic copper plating. Thereafter, the resist is removed, and a part of the seed layer 40 is removed by etching. Further, the insulating film 60 is formed so as to cover the seed layer 40, the wiring layer 50, and the base substrate 30, and the recess 61 can be formed in the insulating film 60 by a laser or the like. Note that the above-described configuration and manufacturing method of the substrate WF are merely examples, and the structure and manufacturing method of the substrate WF are not particularly limited as long as a recess in which foreign matter can exist is formed.

[0018] FIG. 3 is a schematic cross-sectional view showing an example of the substrate WF after polishing is performed in the substrate processing step. In the illustrated example, in the flat plate-shaped substrate WF, the surface on the side opposite to the base substrate 30 in the thickness direction is polished as a surface to be polished. The surface to be polished constitutes the surface P1 including the recess 61 in the substrate WF. By polishing, the foreign matter S1 may remain in the recess 61 of the substrate WF. The foreign matter S1 may be an abrasive such as abrasive grains, or polishing debris separated from the substrate WF. Alternatively, in the case of CMP polishing, the foreign matter S1 may be residual slurry.

[0019] As shown in Figure 1, step S102 is performed after step S101. In step S102, a coating process is performed. In the coating process, a viscous adhesive liquid is applied to the surface P1 of the substrate WF that includes the recessed portions. The method for applying the adhesive liquid is not particularly limited, and the application can be carried out using a coating apparatus such as a spin coater. In the present embodiment, an adhesive liquid that cures by heating or the like is used. The viscosity of the adhesive liquid to be applied is not particularly limited as long as the adhesive liquid can enter the recess 61. The viscosity of the adhesive liquid is preferably 1 mPa·s or more. If the viscosity of the adhesive liquid is low, a cured layer having sufficient thickness and uniformity may not be formed during curing of the adhesive liquid described later. The viscosity of the adhesive liquid is preferably 1000 mPa·s or less. If the viscosity of the adhesive liquid is high, the adhesive liquid will hardly enter the recess 61. Therefore, the viscosity of the adhesive liquid is preferably 1 mPa·s or more and 1000 mPa·s or less.

[0020] It is preferable that the adhesive liquid is meltable or softenable by light after being cured. From the viewpoint of more reliably forming a cured layer having sufficient thickness and uniformity in the curing step described later, the adhesive liquid preferably contains a photoresist.

[0021] Figure 4 is a schematic cross-sectional view showing an example of the substrate WF after the adhesive liquid is applied. The adhesive liquid 70 covers the surface P1 of the substrate WF including the recess 61, and the adhesive liquid 70 enters the recess 61 and comes into contact with the foreign matter S1. In the illustrated example, the foreign matter S1 in the recess 61 is surrounded by the adhesive liquid 70. Before the coating process, the substrate WF that has been processed in the substrate processing step may be cleaned by being immersed in a cleaning liquid.

[0022] As shown in Figure 1, step S103 is performed after step S102. Step In step S103, a curing process is performed. In the curing process, the adhesive liquid 70 applied to the surface P1 of the substrate WF, including the recesses 61, is cured to form a cured layer. The curing method in the curing process is not particularly limited, and a method appropriate to the properties of the adhesive liquid 70 may be used. The curing of the adhesive liquid 70 may be performed by heating the substrate WF, particularly by baking, using a heating device. This allows curing to be performed without requiring complex work. From the viewpoint of ensuring the temperature necessary for curing while suppressing adverse effects on metals such as copper on the substrate WF, it is preferable to place the substrate WF at a temperature of 200°C to 300°C for curing the adhesive liquid 70. The curing of the adhesive liquid 70 may also be performed by placing the substrate WF in a furnace set to such a temperature.

[0023] Figure 5 is a schematic cross-sectional view showing an example of a substrate WF after the adhesive liquid 70 has hardened. The adhesive liquid 70 hardens to form a hardened layer 71. The hardened layer 71 can come into contact with foreign matter S1. In the illustrated example, the foreign matter S1 in the recess 61 is surrounded by the hardened layer 71.

[0024] As shown in Figure 1, step S104 is performed after step S103. In step S104, an irradiation step is performed. In the irradiation step, light is irradiated onto the cured layer 71, causing a portion of the cured layer 71 to melt or at least a portion of the cured layer 71 to soften. The wavelength of the light and the type of light source are not particularly limited as long as this melting or softening facilitates the peeling of the cured layer 71, which will be described later. The light may be visible light or ultraviolet light. In the irradiation step, it is preferable to irradiate the entire substrate WF or the entire pattern area of ​​the substrate WF with light, but it is also possible to irradiate any part of the substrate WF with light. From the viewpoint of facilitating the peeling of the cured layer 71 by melting or softening, it is preferable that the adhesive liquid 70 be a positive-type photoresist. Note that the irradiation step may be omitted if the peeling step described later can be performed.

[0025] Figure 6 is a schematic cross-sectional view showing an example of a substrate WF after the hardened layer 71 has been irradiated with light during the irradiation process. The irradiation process may form an intermediate layer 72 between the hardened layer 71 and the surface P1 of the substrate WF, including the recesses 61, by melting or softening the hardened layer 71. The intermediate layer 72 makes it easier for the hardened layer 71 to separate from the surface P1 and peel off. Note that Figure 6 is only one example of how peeling is promoted by the irradiation process; for example, peeling may also be promoted by the softening of the entire hardened layer 71.

[0026] As shown in Figure 1, step S105 is performed after step S104. In step S105, a peeling step is performed. In the peeling step, the hardened layer 71 is peeled off from the substrate WF. The foreign matter S1 is removed from the recess 61 by the peeling step. The peeling method in the peeling step is not particularly limited as long as the hardened layer 71 is separated from the substrate WF together with the foreign matter S1. With the method of this embodiment, even when a general cleaning solution has difficulty flowing into or out of the recess 61, and it is difficult to remove the foreign matter S1 from the recess 61 with the cleaning solution, the foreign matter S1 can be removed. The hardened layer 71 can be physically peeled off from the substrate WF. This makes it possible to separate the hardened layer 71, which is integrally formed with the foreign matter S1, from the substrate WF, and effectively remove the foreign matter S1 in the recess 61. In this case, the hardened layer 71 may be grasped and peeled off by machine, instrument, or by hand, or the hardened layer 71 may be freed by immersing the substrate WF in a liquid such as a cleaning solution.

[0027] Figure 7 is a schematic cross-sectional view showing an example of a substrate WF after the peeling process. The hardened layer 71 is removed from the substrate WF, and foreign matter S1 is removed from the recesses 61. If an intermediate layer 72 is formed by the irradiation process, the intermediate layer 72 may also be removed. After the peeling process, the substrate WF may be processed, such as by film deposition, or any other manufacturing process may be performed besides processing the substrate WF.

[0028] This embodiment provides a novel method for removing foreign matter S1 present in the recesses 61 of the substrate WF. The method for removing foreign matter on the substrate according to this embodiment may include the above-described coating step, curing step, and peeling step, and preferably includes an irradiation step as appropriate. i. In the substrate processing method of this embodiment, the substrate processing step can be performed before or after the method for removing foreign matter from the substrate as described above. This reduces the risk of not obtaining the expected results or of adverse effects from foreign matter S1 such as poor conductivity in the processing of the substrate WF or other manufacturing processes using the substrate WF.

[0029] Figure 8 is a schematic plan view showing an example of a substrate processing apparatus according to this embodiment. In the illustrated example, the substrate processing apparatus 10 is configured as a semiconductor manufacturing apparatus. The substrate processing apparatus 10 comprises a substantially rectangular housing 1, a load / unload unit 2, a polishing unit 3, a cleaning unit 4, a transport device 5, a foreign matter removal unit 100, and a control device 900. The load / unload unit 2, the polishing unit 3, the cleaning unit 4, and the foreign matter removal unit 100 are arranged inside the housing 1 and may be partitioned by a partition wall. The load / unload unit 2 comprises an arbitrary number (four in the illustrated example) of front loading sections 20 on which wafer cassettes for stocking a large number of substrates WF are placed, and a load / unload device 21 for transporting substrates WF from the front loading section 20 to the transport device 5 and from the transport device 5 to the front loading section 20. The transport device 5 comprises a linear transporter or a swing transporter, etc., and transports substrates WF between each unit of the substrate processing apparatus 10. The polishing unit 3 is equipped with a polishing device 300 and polishes the substrate WF. The cleaning unit 4 is equipped with a cleaning device 400 and cleans the substrate WF. The foreign matter removal unit 100 is equipped with a substrate transport device 110 which has an arm for transporting the substrate WF, a coating device 120 which applies adhesive liquid to the substrate WF in the coating process, an irradiation device 130 which irradiates the substrate WF with light in the irradiation process, and a heating device 140 such as a furnace which heats the substrate WF in the curing process. Peeling in the peeling process can be performed using the arm of the substrate transport device 110. The control device 900 is equipped with a processing device including a CPU and memory and is configured to control each part of the substrate processing device 10 which includes each element of the polishing device 300 and the foreign matter removal unit 100. The substrate WF loaded from the load / unload unit 2 is appropriately cleaned by the cleaning device 400, polished by the polishing device 300, and foreign matter is removed from the substrate by the foreign matter removal unit 100 before being discharged from the load / unload unit 2. The configuration of the apparatus and other equipment used to perform the method of removing foreign matter from the substrate in this embodiment is not particularly limited, as long as it can be carried out.

[0030] The embodiments described above can also be described in the following forms. [Embodiment 1] According to Embodiment 1, a method for removing foreign matter on a substrate is proposed, the method comprising: applying a viscous adhesive liquid to the surface of the substrate including recesses; curing the adhesive liquid applied to the surface of the substrate to form a cured layer; and peeling the cured layer from the substrate. According to Embodiment 1, a novel method for removing foreign matter present in recesses of a substrate can be provided. Furthermore, even when general cleaning liquids have difficulty flowing into or out of recesses, making it difficult to remove foreign matter from recesses with cleaning liquids, foreign matter can be removed.

[0031] [Embodiment 2] According to embodiment 2, the substrate is prepared with the surface treated before applying the adhesive liquid in embodiment 1. According to embodiment 2, foreign matter generated in or remaining in recesses during the processing of the substrate can be removed.

[0032] [Embodiment 3] In embodiment 3, in embodiment 1 or 2, the hardening of the adhesive liquid is performed by heating the substrate. In embodiment 3, the hardening of the adhesive liquid can be performed without requiring complex work.

[0033] [Embodiment 4] According to Embodiment 4, in any of Embodiments 1 to 3, the method further includes irradiating the hardened layer with light to melt a portion of the hardened layer or to soften at least a portion of the hardened layer. According to Embodiment 4, the hardened layer can be made easier to peel off.

[0034] [Embodiment 5] According to Embodiment 5, in Embodiment 4, the adhesive liquid includes a photoresist. According to Embodiment 5, due to the properties of the photoresist, the cured layer can be melted or softened, and a layer of adhesive liquid with sufficient thickness and uniformity can be formed on the substrate more reliably, and peeling can be performed more reliably.

[0035] [Embodiment 6] According to embodiment 6, in any of embodiments 1 to 5, the cured layer is physically peeled off from the substrate. According to embodiment 6, foreign matter can be removed integrally with the cured layer.

[0036] [Form 7] According to Form 7, in any of Forms 1 to 6, the viscosity of the adhesive liquid is 1 mPa·s or more and 1000 mPa·s or less. According to Form 7, the adhesive liquid can easily penetrate into recesses and be applied with sufficient thickness and uniformity, and foreign matter can be removed more reliably when peeling off the hardened layer.

[0037] [Embodiment 8] According to Embodiment 8, a substrate processing method is proposed, which includes processing a substrate and removing foreign matter from the substrate by any of the methods in Embodiments 1 to 7. According to Embodiment 8, the risk of adverse effects from foreign matter, such as poor conductivity, in substrate processing or other manufacturing processes using the substrate can be reduced.

[0038] [Embodiment 9] According to embodiment 9, in embodiment 8, the substrate is polished before removing foreign matter on the substrate. According to embodiment 9, foreign matter such as slurry or polishing debris that is generated in or remains in the recesses by polishing can be removed.

[0039] Although several embodiments of the present invention have been described above, the embodiments described above are for the purpose of facilitating understanding of the present invention and do not limit it. The present invention can be modified and improved without departing from its spirit, and of course, equivalents thereof are included in the present invention. Furthermore, any combination or omission of the components described in the claims and specification is possible to the extent that at least some of the above-mentioned problems can be solved or at least some of the effects can be achieved. [Explanation of symbols]

[0040] 10 Substrate Processing Equipment 30 Substrate 40 Seed Layer 50 wiring layers 60 insulating film 61 Recesses in the substrate 70 Adhesive liquid 71 Hardened layer 72 Middle Class 100 Foreign object removal unit 110 Substrate transport device 120 Coating device 130 Irradiation device 140 Heating device 300 Polishing equipment P1 Surface including recess of substrate S1 Foreign object WF board

Claims

1. Applying a viscous adhesive liquid to the surface of the substrate, including the recesses, The adhesive liquid applied to the surface of the substrate is cured to form a cured layer, The hardened layer is peeled off from the substrate. A method for removing foreign matter from a substrate, including [specific example].

2. The method according to claim 1, further comprising preparing the substrate whose surface has been treated before applying the adhesive liquid.

3. The method according to claim 1 or 2, wherein the curing of the adhesive liquid is performed by heating the substrate.

4. The method according to claim 1 or 2, further comprising irradiating the hardened layer with light to melt a portion of the hardened layer or to soften at least a portion of the hardened layer.

5. The method according to claim 4, wherein the adhesive liquid includes a photoresist.

6. The method according to claim 1 or 2, wherein the cured layer is physically peeled off from the substrate.

7. The method according to claim 1 or 2, wherein the viscosity of the adhesive liquid is 1 mPa·s or more and 1000 mPa·s or less.

8. Processing the circuit board, A substrate processing method comprising removing foreign matter from the substrate by the method described in claim 1 or 2.

9. The substrate processing method according to claim 8, wherein, in the above process, the substrate is polished before removing foreign matter from the substrate.

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