JP6598370B2 - Coating material recovery method and semiconductor device manufacturing method - Google Patents

Description

The present invention relates to a recovery method and a manufacturing how a semiconductor device including the same coating material.

In recent years, polyimide resins have been used as surface protective films and interlayer insulating films for various parts in the semiconductor manufacturing industry, the microelectronics industry, and the like. Polyimide resin is superior to inorganic insulating films such as SiO ₂ and SiN in covering the substrate with large unevenness. In addition, the polyimide resin film can be easily thickened and can have a thickness of 1 μm or more. Furthermore, the polyimide-based resin has advantages such as higher heat resistance than other organic materials and excellent electrical and mechanical properties.
For this reason, polyimide resins are often used as materials for interlayer insulating films such as MOS and bipolar ICs. Recently, they are widely used as materials for α-ray shielding films and buffer coat films of memory elements.

The polyimide resin film is formed by applying a polyimide solution (polyimide precursor mixed solution) onto a wafer by spin coating and further performing a heat treatment. However, the polyimide solution has a very high viscosity (around 3000 Cp) compared to other liquids such as a resist solution.
Therefore, at the time of polyimide application to the wafer surface, the applied polyimide liquid scatters and becomes mist due to rotation of the wafer, and wraps around the back surface of the wafer while drifting in the spin coater processing cup (processing chamber where spin coating is performed). The problem is that it adheres and stains the backside of the wafer.

  As a preventive measure, for example, as in the spin coating apparatus 200 shown in FIG. 3, a wall (back surface wrap prevention ring) 206 is provided so as to cover the back surface of the wafer in the spin coating process. A method is disclosed in which a misted polyimide is prevented from entering the back surface of the wafer by flowing an airflow toward the surface (Patent Document 1). In addition, a method of forcibly evacuating the polyimide that has been scattered and misted is disclosed (Patent Document 2).

JP 2012-134361 A JP 11-238667 A

  However, when trying to prevent the polyimide liquid from wrapping around the back surface of the wafer by the above-described method, it is necessary to provide an exhaust mechanism and a mechanism for generating an air flow, and the cost for securing and installing the installation space is required. It will be required.

  The present invention has been made in view of the above circumstances, and in the spin coating process, a part of a coating material such as polyimide applied to the substrate wraps around the back side of the substrate to generate an exhaust mechanism or an air flow. It is an object of the present invention to provide a method for recovering a coating material, which can be prevented without using a mechanism.

  In addition, the present invention prevents a part of a coating material such as polyimide applied to the substrate from going around to the back side of the substrate without using an exhaust mechanism or a mechanism for generating an air current in the spin coating process. An object of the present invention is to provide a spin coating apparatus that enables the above.

As a result of repeated studies, the present inventor has come up with the following invention.
[1] In a spin coating process in which a coating material is applied on a rotating substrate to form a film, a rod-like member standing around the substrate is coated with a coating material that has been scattered and misted around the substrate. A method for recovering a coating material, characterized by being entangled and caught.
[2] The method for recovering a coating material according to [1], wherein the rod-shaped member is rotated about its axis.
[3] The coating material recovery method according to [2], wherein the rotation direction of the rod-shaped member is aligned with the rotation direction of the substrate.
[4] The method for recovering a coating material according to any one of [2] or [3], wherein the rotational speed of the rod-shaped member is made larger than the rotational speed of the substrate.
[5] Any one of [1] to [4], wherein the bar-like member is installed such that the position of the upper end thereof is the same height as the substrate surface or lower than the substrate surface. A method for recovering a coating material according to any one of the above.
[6] The method for collecting a coating material according to [5], wherein the rod-shaped member is installed so that a difference in height between the position of the upper end portion and the substrate surface is within 3 mm.
[7] The plurality of rod-shaped members are installed so as to be in an axially symmetric positional relationship with respect to the rotation axis of the substrate. [1] As described in any one of [6], Collection method of coating material.
[8] The method for recovering a coating material according to any one of [1] to [7], wherein the rod-shaped member has a convex portion on a side surface.
[9] The method for recovering a coating material according to any one of [1] to [7], wherein the rod-shaped member has a recess on a side surface.
[10] A method for manufacturing a semiconductor device, wherein the method for recovering a coating material according to any one of [1] to [9] is used.
[11] A spin coating apparatus that forms a film by applying a coating material on a rotating substrate, the coating chamber, and a support base that supports the substrate at a position spaced from the floor surface in the coating chamber; It comprises means for rotating the substrate via the support, means for applying a coating material on the substrate, and a rod-like member standing on the floor surface in the coating chamber. Spin coating device.

  According to the method for recovering a coating material of the present invention, by standing a rod-shaped member around the substrate to be processed, it is possible to entangle and collect the floating mist-coated coating material, thereby It is possible to prevent the material from wrapping around the back surface of the wafer. This is because the floating misted polyimide has a high viscosity, and thus utilizes the property of being easily attached to the rod-shaped member.

  That is, when the rod-shaped member is erected around the substrate, the mist of the coating material that is directed toward the back surface of the substrate comes into contact with the rod-shaped member in the middle thereof. Since the coating material has a high viscosity, the portion in contact with the rod-shaped member is constrained to the position, and the subsequent portion is pulled toward the position so as to be directed to the position of the rod-shaped member. As a result, the entire application member made into a mass (a group) of mist is wound around (attached to) the rod-shaped member.

  Therefore, according to the coating material recovery method of the present invention, large-scale facilities such as an exhaust mechanism and a mechanism for generating an air flow are not required, and it is possible to reduce their installation space and installation cost.

  According to the spin coating apparatus of the present invention, by standing a rod-shaped member around the substrate to be processed, it is possible to entangle and collect the floating mist of the coating material. It is possible to prevent wraparound to the wafer back surface. This is because the floating mist-like coating material has a high viscosity, and therefore utilizes the property of being easily attached to the rod-shaped member.

  In other words, since the rod-shaped member is erected around the substrate, the mist of the coating material that is going to face the back surface of the substrate comes into contact with the rod-shaped member in the middle thereof. Since the coating material has a high viscosity, the portion in contact with the rod-shaped member is constrained to the position, and the subsequent portion is pulled toward the position so as to be directed to the position of the rod-shaped member. As a result, the entire application member made into a mass (a group) of mist is wound around (attached to) the rod-shaped member.

  Therefore, according to the spin coating apparatus of the present invention, large-scale facilities such as an exhaust mechanism and a mechanism for generating an air flow are not necessary, and it is possible to reduce the installation space and the cost for installation.

It is sectional drawing of the spin coating device based on one Embodiment of this invention. It is the perspective view and sectional drawing of the rod-shaped member of FIG. It is sectional drawing of the conventional spin coating apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, components having the same function may be denoted by the same reference numerals and description thereof may be omitted. Further, there are cases where the characteristic portions are shown in an enlarged manner for convenience, and the dimensional ratios of the respective constituent elements are not always the same as the actual ones.

  A method for collecting a coating material according to an embodiment of the present invention will be described. In the spin coating process in which a coating material is applied to a rotating substrate to form a film, the coating material recovery method according to the present embodiment is applied to the surroundings of the substrate by scattering the coating material around the substrate to form a mist. It is characterized in that it is entangled and caught (wound up) using a rod-shaped member set up in the above.

  FIG. 1 is a cross-sectional view of a spin coating apparatus 100 used for collecting a coating material. The spin coating apparatus 100 is an apparatus that applies a coating material P on a rotating substrate (wafer) W to form a protective film P1. Also, the spin coating apparatus 100 has a function of collecting the coating material P2 that has been scattered and mist out of the coated coating material P with a configuration that will be described later. The constituent elements other than the rod-like member 105 of the spin coating apparatus 100 are substantially the same as those provided in a known spin coating apparatus, and can be appropriately replaced.

  The spin coating apparatus 100 rotates a substrate W through a coating chamber (processing chamber) 101, a support table 102 that supports the substrate W at a position separated from the floor surface 101 a in the coating chamber 101, and the support table 102. Means 103, means 104 for applying the coating material P on the substrate W, and a rod-like member (pin) standing in the coating chamber 101 so as to extend from the floor surface 101a side to the periphery of the support base 102 105. On the back surface side of the substrate W, a back surface wrap prevention ring 106 that covers the back surface of the substrate W may be provided.

  The coating chamber 101 only needs to constitute at least a space that accommodates the substrate W and its support base 102 in the spin coating process. For example, as shown in FIG. 1, the coating chamber 101 includes a cup portion 101A and a lid portion 101B. What is constructed can be used.

  The support base 102 is preferably provided with a vacuum chuck and is configured to suck and fix the substrate W. A means (rotating shaft) 103 that rotates the substrate W together with the support table 102 is provided on the back surface of the support table 102 (the surface opposite to the substrate W placement surface). One end of the rotating shaft 103 is connected to the central portion of the back surface of the support base 102, and a motor or the like (not shown) required for rotational driving is provided inside or outside.

  The means (nozzle) 104 for applying the coating material P is configured such that the spout is located immediately above the central portion of the substrate W, and the coating material P is dropped toward the central portion of the substrate W. As the coating material P, a liquid having a very high viscosity compared to the resist liquid, such as a polyimide liquid, is used.

  The rod-shaped member 105 is erected so that one end (lower end) 105a is fixed to the floor surface 101a in the coating chamber 101, and the longitudinal direction L is substantially perpendicular to the floor surface 101a. The rod-shaped member 105 has a cartridge type structure, and can be exchanged for a new one every predetermined number of sheets. The material of the rod-shaped member 105 is not particularly limited, but it is preferable to use a metal such as aluminum, a resin such as Teflon (registered trademark), or polypropylene.

  It is preferable that the position of the upper end portion 105b of the rod-shaped member 105 is set to be the same height (level) as the processing surface (substrate surface) W1 of the substrate W or lower than the substrate surface W1. Furthermore, it is more preferable if the height difference between the position of the upper end portion of the rod-shaped member 105 and the substrate surface W1 is set to be within 3 mm. Note that if the position of the upper end portion of the rod-shaped member 105 is higher than the substrate surface W1, an air flow generated by the rotation of the rod-shaped member may affect the substrate surface W1 (surface to be processed), which is not preferable. .

  The distance between the upper end portion 105b of the rod-shaped member 105 and the outer peripheral portion W2 of the substrate W is preferably 20 mm or more and 50 mm or less. If the distance between the upper end portion 105b of the rod-shaped member and the outer peripheral portion W2 of the substrate is less than 20 mm, it is not preferable because it is directly scattered on the rod-shaped member in the coating liquid state at the initial stage of substrate rotation. If the distance exceeds 50 mm, a part of the misted coating agent may come around to the back side of the substrate without coming into contact with the rod-shaped member 105, which is not preferable.

  It is preferable that the rod-shaped member 105 has a structure that can rotate around its longitudinal axis. In this case, it is assumed that a rotation drive mechanism that controls the rotation direction, rotation speed, and the like of the rod-shaped member 105 is attached inside or outside the coating chamber 101.

  In order to increase the efficiency of entwining and catching the coating material, it is preferable that a plurality of the rod-like members 105 are erected, and more preferably four or more. In this case, in order to evenly entrap and catch the coating material P in all directions of scattering, the plurality of rod-shaped members 105 are installed so as to be in an axially symmetrical positional relationship with respect to the rotation axis of the substrate W. Is preferred.

  The side surface of the rod-shaped member 105 may have a smooth shape, but it is preferable that the side surface of the rod-shaped member 105 has a concavity and convexity that improves the adsorption effect for the purpose of entanglement of the scattered and misted coating material. An example of the shape of such a rod-shaped member 105 is shown in FIG. 2A and 2B are a perspective view and a cross-sectional view of the rod-shaped member 105 in the case where a convex portion (projection) 105c is provided on the side surface of the rod-shaped member 105, respectively.

  2A and 2B show examples in which the cylindrical convex portions are configured to be linearly aligned in the vertical direction, the shape and arrangement of the convex portions are limited to this. Not. The shape of the convex portion may be, for example, a conical shape or a prismatic shape, and a plurality of types of shapes may be mixed. For example, the protrusions may be arranged in a spiral, randomly distributed, or locally distributed in a part.

  Further, the side surface of the rod-shaped member 105 may have a structure having a recess (for example, a filter structure). The shape and arrangement of the recesses in this case are not particularly limited as in the case of the projections.

  The rod-shaped member 105 has a structure that can be attached to and detached from the spin coating apparatus 100. The rod-shaped member 105 may have a structure that allows the whole to be detachable regardless of the presence or absence of unevenness on the side surface, and constitutes a central portion as shown in FIGS. 2 (a) and 2 (b). The core portion 105 </ b> A and the shell portion 105 </ b> B surrounding the core portion 105 </ b> A may have a double structure, and only the shell portion 105 </ b> B may be detachable.

  As described above, according to the coating material recovery method according to the present embodiment, the spin coating apparatus having the configuration shown in FIG. 1 is used, that is, around the substrate to be processed in the spin coating process. By erecting the rod-shaped member, the mist-like coating material floating in the coating chamber can be caught and collected. Thereby, wraparound of the coating material to the back surface of the substrate can be prevented. This is because the floating mist-like coating material has a high viscosity, and therefore utilizes the property of being easily attached to the rod-shaped member.

  That is, when the coating material is dropped onto the rotating wafer, the excessive coating material is scattered to the outside of the substrate by centrifugal force to be mist, and flows toward the coating chamber (processing chamber) wall surface. And the flow which reached the wall surface turns into a flow which returns to the board | substrate side, and mist goes to the board | substrate back surface. According to the configuration of the present invention, since the rod-shaped member is erected around the substrate, the mist of the coating material that is going to face the back surface of the substrate comes into contact with the rod-shaped member in the middle thereof. Since the coating material has a high viscosity, the portion in contact with the rod-shaped member is constrained to the position, and the subsequent portion is pulled toward the position so as to be directed to the position of the rod-shaped member. As a result, the entire application member made into a mass (a group) of mist is wound around (attached to) the rod-shaped member.

In addition, by rotating the rod-shaped member around its axis, it becomes easy to entangle and catch the coating material, and the collection efficiency of the coating material can be improved. It can prevent powerfully.
In particular, when the rotation direction of the rod-shaped member is aligned with the rotation direction of the substrate, the recovery efficiency of the coating material is further improved when the rotation speed of the rod-shaped member is larger than the rotation speed of the substrate (usually about 2000 to 2600 rpm). As a result, wraparound of the coating material to the back surface of the substrate can be prevented more strongly.

Therefore, according to the coating material recovery method using the spin coating apparatus according to the present embodiment, large-scale equipment such as an exhaust mechanism and a mechanism for generating an air flow is not necessary, and the installation space and the installation Costs can be reduced.
Therefore, the semiconductor device manufacturing method using the coating material forming method according to the present embodiment can be applied to various semiconductor devices including a power semiconductor device and a spin coating process.

  The present invention can be widely used in a process of spin-coating a highly viscous material such as polyimide as a material for forming a surface protective film or an interlayer insulating film such as a power semiconductor device.

DESCRIPTION OF SYMBOLS 100 ... Spin coating apparatus, 101 ... Coating chamber, 101a ... Floor surface,
101A ... cup part, 101B ... lid part, 102 ... support base,
103 ... means for rotating (rotating shaft), 104 ... means for applying (nozzle),
105 ... Bar-shaped member, 105a ... Lower end, 105b ... Upper end,
105c ... convex part (projection part), 106 ... back surface wrap prevention ring,
200... Spin coating device, 206.
207 ... Exhaust mechanism, L ... Longitudinal direction, LP ... Coating material, P1 ... Protective film,
P2 ... coating material, W ... substrate (wafer), W1 ... surface to be processed (substrate surface),
W2 ... Peripheral portion.

Claims (10)

In a spin coating process in which a film is formed by applying a coating material on a rotating substrate,
The coating material is a method of collecting the coating material that is entangled using the rod-shaped member that is set up around the substrate, the coating material scattered and misted around the substrate ,
A method for recovering a coating material, wherein the rod-shaped member is rotated about its axis . In a spin coating process in which a film is formed by applying a coating material on a rotating substrate,
The coating material is a method of collecting the coating material that is entangled using the rod-shaped member that is set up around the substrate, the coating material scattered and misted around the substrate ,
The rod-shaped member is installed so that the position of the upper end thereof is the same height as the substrate surface or lower than the substrate surface,
A method for recovering a coating material, wherein the rod-shaped member is rotated about its axis . Recovery method of applying material according to claim 1 or 2, characterized in that the direction of rotation of the rod-shaped member, aligned with the rotational direction of the substrate. The method for recovering a coating material according to any one of claims 1 to 3 , wherein a rotational speed of the rod-shaped member is made larger than a rotational speed of the substrate. In a spin coating process in which a film is formed by applying a coating material on a rotating substrate,
The coating material is a method of collecting the coating material that is entangled using the rod-shaped member that is set up around the substrate, the coating material scattered and misted around the substrate ,
A method for recovering a coating material, wherein the bar-shaped member is installed so that the position of the upper end portion thereof is the same height as the substrate surface or lower than the substrate surface . 6. The method for recovering a coating material according to claim 2 , wherein the rod-shaped member is installed so that a difference in height between the position of the upper end portion and the substrate surface is within 3 mm.   The method for recovering a coating material according to any one of claims 1 to 6, wherein the plurality of rod-shaped members are installed so as to have an axially symmetrical positional relationship with respect to the rotation axis of the substrate. .   The method for collecting a coating material according to claim 1, wherein the rod-shaped member has a convex portion on a side surface.   The method for recovering a coating material according to any one of claims 1 to 7, wherein the rod-shaped member has a concave portion on a side surface.   A method for manufacturing a semiconductor device, wherein the method for recovering a coating material according to claim 1 is used.

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