Exposure method and exposure apparatus

Abstract

This invention discloses an exposure method and an exposure apparatus. The exposure method includes the following steps: S100, forming a first photoresist coating on each of the two surfaces of a substrate; S200, exposing a pattern on the first photoresist coating on the first surface of the substrate, and forming a mark on the first photoresist coating on the second surface of the substrate corresponding to the position of the exposed pattern on the first surface; S300, forming a second photoresist coating on the first surface of the substrate; S400, based on the mark on the first photoresist coating on the second surface of the substrate, exposing a pattern on the first photoresist coating on the second surface of the substrate, and forming a mark on the second photoresist coating on the first surface of the substrate corresponding to the position of the exposed pattern on the second surface; S500, based on the mark on the second photoresist coating on the first surface, exposing a pattern on the second photoresist coating on the first surface. The exposure method and exposure apparatus of this invention can efficiently prepare photolithographic layers with relatively thick thicknesses.

Description

Technical Field

[0001] This invention belongs to the field of circuit board manufacturing technology, specifically relating to an exposure method and exposure equipment. Background Technology

[0002] A circuit board, also known as a printed circuit board, can be made of ceramic, polymer, or metal materials, etc. The manufacturing process of a circuit board includes an exposure method, in which photoresist is coated on the substrate to obtain a photolithographic layer. By exposing the photolithographic layer, a photolithographic layer with an exposure etching pattern is obtained on the substrate, which facilitates the arrangement of circuits on the substrate. When the substrate is a ceramic material, due to the special properties and uses of circuit boards made of ceramic substrates (such as ceramic plates), ceramic plates are usually small in size, but the thickness of the photolithographic layer coated on the ceramic plate is large, about three times the thickness of the photolithographic layer on other conventional substrates.

[0003] Therefore, conventional exposure components may encounter problems such as incomplete exposure or excessively long exposure times when exposing and etching patterns on photoresist layers on ceramic substrates.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide an exposure method and exposure equipment that can efficiently prepare a thick photolithographic layer.

[0006] To achieve the above objectives, a specific embodiment of the present invention provides the following technical solution: an exposure method for exposing a photolithographic layer, wherein the photolithographic layer comprises multiple photoresist coatings, and the exposure method includes the following steps:

[0007] S100: A first photoresist coating is formed on each of the two surfaces of the substrate;

[0008] S200, Expose a pattern on the first layer of photoresist coating on the first side of the substrate, and form a mark on the first layer of photoresist coating on the second side of the substrate that corresponds to the position of the exposed pattern on the first side;

[0009] S300, A second photoresist coating is formed on the first surface of the substrate;

[0010] S400, Based on the mark on the first layer of photoresist coating on the second side of the substrate, expose the pattern on the first layer of photoresist coating on the second side of the substrate, and form a mark on the second layer of photoresist coating on the first side of the substrate corresponding to the position of the exposed pattern on the second side;

[0011] S500, based on the markings on the second layer of photoresist coating on the first side, expose a pattern on the second layer of photoresist coating on the first side.

[0012] In one or more embodiments of the present invention, step S500 includes:

[0013] S510. A second photoresist coating is formed on the second surface of the substrate to cover the markings on the first photoresist coating on the second surface.

[0014] S520. Based on the mark on the second layer of photoresist coating on the first side, expose a pattern on the second layer of photoresist coating on the first side, and form a mark on the second layer of photoresist coating on the second side of the substrate that corresponds to the position of the exposed pattern on the first side.

[0015] In one or more embodiments of the present invention, the exposure method further includes:

[0016] An Nth photoresist coating is formed on the first surface of the substrate, covering the markings on the (N-1)th photoresist coating on the first surface;

[0017] Based on the markings on the (N-1)th photoresist layer of the second side, a pattern is exposed on the (N-1)th photoresist layer of the second side, and a marking corresponding to the position of the exposed pattern on the Nth photoresist layer of the first side of the substrate is formed.

[0018] In one or more embodiments of the present invention, the exposure method further includes:

[0019] An Nth photoresist coating is formed on the second surface of the substrate, covering the markings on the (N-1)th photoresist coating on the second surface;

[0020] Based on the markings on the Nth layer of photoresist coating on the first side, a pattern is exposed on the Nth layer of photoresist coating on the first side, and a marking corresponding to the position of the exposed pattern on the Nth layer of photoresist coating on the second side of the substrate is formed.

[0021] In one or more embodiments of the present invention, the marker includes at least three non-collinear reference points.

[0022] A specific embodiment of the present invention also provides an exposure apparatus applied to the above-described exposure method, the exposure apparatus comprising:

[0023] A worktable, having a surface for supporting workpieces;

[0024] An exposure mechanism includes a connecting frame movably mounted on a worktable and an exposure component mounted on the connecting frame, the exposure component being used to expose a workpiece on the worktable.

[0025] In one or more embodiments of the present invention, the exposure mechanism further includes a vision component mounted on a connecting frame for identifying the position of the workpiece to determine the exposure position on the workpiece.

[0026] In one or more embodiments of the present invention, the workbench is provided with a mounting groove, and a marking light is provided in the mounting groove for marking the side of the workpiece facing the workbench.

[0027] In one or more embodiments of the present invention, the connecting frame includes a first frame spaced apart on both sides of the workpiece and a second frame fixedly connected between the first frame, the first frame being slidably connected to the worktable, and the exposure assembly being slidably mounted on the second frame.

[0028] In one or more embodiments of the present invention, the work surface includes multiple working areas, each working area is provided with at least three non-collinear marker lights, and each working area corresponds to a workpiece.

[0029] Compared with the prior art, the exposure method and exposure equipment of the present invention divide the thick photolithography layer into several photoresist coatings. After exposing one photoresist coating, a new photoresist coating is applied and then exposed again. That is, the coating is formed and exposed in stages, thereby ensuring that the existing exposure components can fully expose each photoresist coating, thereby improving the exposure processing efficiency of the photolithography layer. In addition, the exposure method and exposure equipment of the present invention can efficiently prepare thick photolithography layers. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a flowchart of an exposure method in an example of the present invention;

[0032] Figure 2 This is a schematic diagram of the exposure method steps in one embodiment of the present invention;

[0033] Figure 3 This is a partial perspective view of an exposure device according to an embodiment of the present invention;

[0034] Figure 4 This is a top view of the positions of the worktable and the workpiece in an exposure device according to an embodiment of the present invention.

[0035] Explanation of key figure labels:

[0036] 1. Workbench; 11. Tabletop; 2. Exposure mechanism; 21. Connecting frame; 211. First frame; 212. Second frame; 22. Exposure assembly; 23. Vision assembly; 3. Marker light; 4. Workpiece. Detailed Implementation

[0037] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0038] As mentioned in the background art, when the substrate is ceramic material, due to the special properties and uses of the ceramic substrate circuit board, the ceramic board is usually small in size, but the thickness of the photolithography layer applied on the ceramic board is large, about 3 times the thickness of the photolithography layer on other conventional substrates.

[0039] For example, if the thickness of the photolithography layer on other substrates is 1 unit, then the thickness of the photolithography layer on a ceramic substrate is 3 to 3.5 units. Existing commonly used exposure units are designed for photolithography layers with a thickness of 1.2 units or less. In this case, without changing the exposure unit, the only solution is to extend the exposure time. Exposure processing proceeds from the surface of the photolithography layer inwards. After the surface layer is exposed, it hinders the energy transmission from the exposure unit to the inwards, causing the exposure rate of the inner layers to be lower than that of the surface layer. Especially as the thickness of the exposed surface layer increases, the exposure rate of the inner layers becomes increasingly slower, resulting in increasingly longer exposure times. That is, the exposure time for a photolithography layer with a thickness of 3 to 3.5 units is far greater than the exposure time for a photolithography layer with a thickness of 1 unit by 3 to 3.5 times. Even with extended exposure time, it is impossible to fully expose the inner layers of the photolithography layer.

[0040] like Figure 1 As shown, an exposure method in one example of the present invention is used to expose a photolithographic layer, the photolithographic layer comprising multiple photoresist coatings, and the exposure method includes the following steps:

[0041] S100: A first photoresist coating is formed on each of the two surfaces of the substrate;

[0042] S200, Expose a pattern on the first layer of photoresist coating on the first side of the substrate, and form a mark on the first layer of photoresist coating on the second side of the substrate that corresponds to the position of the exposed pattern on the first side;

[0043] S300, A second photoresist coating is formed on the first surface of the substrate;

[0044] S400, Based on the mark on the first layer of photoresist coating on the second side of the substrate, expose the pattern on the first layer of photoresist coating on the second side of the substrate, and form a mark on the second layer of photoresist coating on the first side of the substrate corresponding to the position of the exposed pattern on the second side;

[0045] S500, based on the markings on the second layer of photoresist coating on the first side, expose a pattern on the second layer of photoresist coating on the first side.

[0046] Understandably, for a workpiece with photolithographic layers on both sides of the substrate, specific patterns need to be exposed on both photolithographic layers, and the patterns on both sides must be aligned (the relative positional relationship of the patterns on the photolithographic layers on both sides of the substrate must be accurate and precise). However, the position of the pattern on one side of the substrate relative to the photolithographic layer on that side does not need to be particularly precise, as long as it is within a certain range. Therefore, the marking serves to determine the relative position of the patterns on the photolithographic layers on both sides of the substrate.

[0047] In this setup, the two opposite sides of the substrate can be considered as the first and second sides. The substrate is placed on a table, with the first side facing the exposure assembly and the second side covering the marker lamp on the table. While a specific pattern is exposed on the photoresist coating on the first side of the substrate, the marker lamp on the table illuminates a mark on the photoresist coating on the second side. This can be understood as the marker lamp causing the photoresist coating to react and change color, thus forming a mark that can be detected by the vision assembly. In other words, the position of the exposed pattern on the photoresist coating on the first side of the substrate corresponds to the mark on the photoresist coating on the second side. When the substrate is flipped over to expose the photoresist coating on the second side, the position of the exposed pattern on the photoresist coating on the first side can be determined based on the position of the mark on the second side, thus determining the position of the pattern to be exposed on the photoresist coating on the second side. This operation ensures alignment between the patterns on the first and second sides.

[0048] Because the photoresist coating on the same side is relatively thick, multiple photoresist coatings on the same side need to be exposed separately. When exposing each photoresist coating, it is necessary to ensure that it is aligned with the photolithographic pattern of the previous layer on that side and with the photolithographic pattern of the other side. Therefore, after applying the photoresist again, it is necessary to mark the position of the exposed pattern before exposure, and this mark corresponds to the pattern already exposed on the other side.

[0049] Furthermore, step S500 includes:

[0050] S510. A second photoresist coating is formed on the second surface of the substrate to cover the markings on the first photoresist coating on the second surface.

[0051] S520. Based on the mark on the second layer of photoresist coating on the first side, expose a pattern on the second layer of photoresist coating on the first side, and form a mark on the second layer of photoresist coating on the second side of the substrate that corresponds to the position of the exposed pattern on the first side.

[0052] It is understandable that when the pattern is exposed on the second layer of photoresist coating on the first side, a mark corresponding to the exposed pattern on the second layer of photoresist coating on the second side is formed on the second layer of photoresist coating on the first side, so as to facilitate the position of the exposed pattern when the second layer of photoresist coating on the second side is exposed in the future.

[0053] Furthermore, the exposure method also includes:

[0054] An Nth photoresist coating is formed on the first surface of the substrate, covering the markings on the (N-1)th photoresist coating on the first surface;

[0055] Based on the markings on the (N-1)th photoresist layer of the second side, a pattern is exposed on the (N-1)th photoresist layer of the second side, and a marking corresponding to the position of the exposed pattern on the Nth photoresist layer of the first side of the substrate is formed.

[0056] It is understandable that the above steps are steps for exposing the pattern on the (N-1)th layer of photoresist coating on the second side.

[0057] Furthermore, the exposure method also includes:

[0058] An Nth photoresist coating is formed on the second surface of the substrate, covering the markings on the (N-1)th photoresist coating on the second surface;

[0059] Based on the markings on the Nth layer of photoresist coating on the first side, a pattern is exposed on the Nth layer of photoresist coating on the first side, and a marking corresponding to the position of the exposed pattern on the Nth layer of photoresist coating on the second side of the substrate is formed.

[0060] It is understandable that the above steps are for exposing patterns on the Nth layer of photoresist coating on the first surface. By combining the above two steps, patterns can be exposed on multiple photoresist coatings on the first and second surfaces of the substrate until all multiple photoresist coatings on the first and second surfaces of the substrate have been exposed.

[0061] like Figure 2 As shown, taking the example of needing to expose three layers of photoresist coating on both sides, after the photoresist coating is applied to both sides of the substrate, the first side is exposed with a pattern, and the second side is marked. At this time, the pattern on the first side and the mark on the second side form a corresponding positional relationship.

[0062] Then, a second layer of photoresist is applied to the first surface, and the substrate is flipped so that the first surface faces the table. The exposure equipment exposes a pattern on the second surface according to the marked positions on the second surface. At this time, a mark is formed on the second layer of photoresist on the first surface. The mark is formed on the photoresist coating on the side facing the table, while the exposure pattern is formed on the photoresist coating on the side facing away from the table (i.e., the side facing the exposure equipment).

[0063] Subsequently, a second layer of photoresist is applied to the second surface. The markings on the original first layer of photoresist are covered, so the markings need to be formed again. Therefore, the substrate is flipped over again and placed on the table with the second surface facing the table. The exposure equipment exposes the pattern on the second layer of photoresist on the first surface according to the position of the markings on the first surface, and at this time, the markings are formed on the second layer of photoresist on the second surface.

[0064] This process continues until all three layers of photoresist coating on the first and second sides are fully exposed.

[0065] Understandably, this setup is intended to ensure that the positions of the exposed patterns on each photoresist layer in the photolithography layers on opposite sides of the substrate are relatively aligned.

[0066] Specifically, the markings include at least three non-collinear reference points. The principle that three non-collinear points can define a plane allows for the determination of the position of the exposure pattern on each layer of photoresist coating.

[0067] In this embodiment, the substrate is a ceramic substrate; specifically, the ceramic substrate can be a ceramic plate, and the raw material of the photolithography layer can be a commonly used photoresist.

[0068] like Figure 3 and 4 As shown, a specific embodiment of the present invention also provides an exposure apparatus that can be applied to the above-described exposure method. The exposure apparatus includes a worktable 1 and an exposure mechanism 2. The worktable 1 has a table surface 11 for supporting a workpiece 4. The exposure mechanism 2 includes a connecting frame 21 movably mounted on the worktable 1 and an exposure assembly 22 mounted on the connecting frame 21. The exposure assembly 22 is used to expose the workpiece 4 on the table surface 11. That is, the exposure assembly 22 is used to expose the photoresist coating on the side of the workpiece 4 facing away from the table surface 11.

[0069] It is understood that the connecting frame 21 can move relative to the table 11, thereby adjusting the position of the exposure component 22 and its exposure position. Specifically, the worktable 1 may be equipped with a drive unit (not shown in the figure), which is connected to the connecting frame 21 (e.g., via a common connector) to control the movement of the connecting frame 21. The drive unit can be an electric cylinder, a pneumatic cylinder, etc. The drive unit can be connected to a host computer, which is beneficial for the automation of the equipment.

[0070] The exposure component 22 may include a laser source, an optical modulator (DMD), and a lens assembly. The laser source forms a light spot with a specific pattern after being reflected by the DMD, and the light spot is projected onto the photoresist coating of the workpiece 4 after passing through the lens assembly.

[0071] Specifically, the connecting frame 21 includes a first frame 211 spaced apart on both sides of the workpiece 4, and a second frame 212 fixedly connected between the first frame 211. The first frame 211 is slidably connected to the worktable 1, and the exposure assembly 22 is slidably mounted on the second frame 212.

[0072] The drive unit can be connected to the first frame 211, thereby driving the first frame 211 to slide relative to the worktable 1. A drive unit can also be installed on the second frame 212, connected to the exposure assembly 22 (e.g., via a common connector), thereby controlling the movement of the exposure assembly 22 on the second frame 212. The drive unit can be an electric cylinder, a pneumatic cylinder, etc. The drive unit can be connected to a host computer, which facilitates equipment automation. The direction of movement of the exposure assembly 22 on the second frame 212 can be perpendicular to the direction of movement of the first frame 211 on the worktable 1.

[0073] Specifically, the exposure mechanism 2 also includes a vision component 23 mounted on the connecting frame 21 for identifying the position of the workpiece 4 in order to determine the exposure position on the workpiece 4.

[0074] Understandably, when the vision component 23 can capture images of a certain area on the table 11, and based on the image content, determine whether there is a workpiece 4 in that area (including determining the position of the workpiece 4), and whether there is a photoresist coating on the substrate of the workpiece 4, etc., the vision component 23 can be a common shooting or photographing device on the market. The vision component 23 and the exposure component 22 can have their own processing system, or they can be connected to a host computer. The processing system or the host computer can control the vision component 23 and process the image information it captures; the processing system or the host computer can control the exposure process of the exposure component 22.

[0075] When there are no markings on the photoresist coating that needs to be exposed, the exposure mechanism 2 exposes the photoresist coating on the substrate according to the information from the vision component 23.

[0076] When there are markings on the photoresist coating that needs to be exposed, the position of the exposure mechanism 2 can be determined according to the position of the markings, and the exposure mechanism 2 can be adjusted to move to the designated area for exposure processing.

[0077] Furthermore, the worktable 1 has a mounting groove on its surface 11, and a marking lamp 3 (i.e., a common UV mark lamp) is installed in the mounting groove to mark the side of the workpiece 4 facing the worktable 11. Since both the photolithography layer and the photoresist coating are photosensitive materials, the marking lamp 3 can be used to irradiate them, thereby forming a mark on the photoresist coating. For example, forming a color portion on the photoresist coating that is different from the color of the photoresist coating itself is a mark.

[0078] The worktable 1 is equipped with at least three non-collinear marker lights 3. Each workpiece 4 must cover at least three non-collinear marker lights 3, thereby forming at least three non-collinear reference points (called mark points) on the photoresist coating of the workpiece 4. These at least three non-collinear reference points constitute one mark. Figure 4 The dotted circle on workpiece 4 represents the marking light 3 covered by workpiece 4. Specifically, the marking light 3 can be a commonly used ultraviolet marking light or other marking lights, as long as it can mark the photoresist coating.

[0079] like Figure 4 As shown, the worktable 11 includes multiple working areas, each with at least three non-collinear marker lights 3, and each working area corresponds to one workpiece 4. That is, multiple workpieces 4 can be placed on the worktable 11 at one time. An exposure mechanism 2 can be installed on the worktable 1, and multiple vision components 23 and exposure components 22 can be installed on each connecting frame 21, so that multiple workpieces 4 can be exposed at one time.

[0080] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0081] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An exposure method for exposing a photolithographic layer, the photolithographic layer comprising a plurality of photoresist coatings, characterized in that, The exposure method includes the following steps: S100: A first photoresist coating is formed on each of the two surfaces of the substrate; S200, Expose a pattern on the first layer of photoresist coating on the first side of the substrate, and form a mark on the first layer of photoresist coating on the second side of the substrate that corresponds to the position of the exposed pattern on the first side; S300, A second photoresist coating is formed on the first surface of the substrate; S400, Based on the mark on the first layer of photoresist coating on the second side of the substrate, expose the pattern on the first layer of photoresist coating on the second side of the substrate, and form a mark on the second layer of photoresist coating on the first side of the substrate corresponding to the position of the exposed pattern on the second side; S500, based on the markings on the second layer of photoresist coating on the first side, expose a pattern on the second layer of photoresist coating on the first side.

2. The exposure method according to claim 1, characterized in that, Step S500 includes: S510. A second photoresist coating is formed on the second surface of the substrate to cover the markings on the first photoresist coating on the second surface. S520. Based on the mark on the second layer of photoresist coating on the first side, expose a pattern on the second layer of photoresist coating on the first side, and form a mark on the second layer of photoresist coating on the second side of the substrate that corresponds to the position of the exposed pattern on the first side.

3. The exposure method according to claim 2, characterized in that, The exposure method further includes: An Nth photoresist coating is formed on the first surface of the substrate, covering the markings on the (N-1)th photoresist coating on the first surface; Based on the markings on the (N-1)th photoresist layer of the second side, a pattern is exposed on the (N-1)th photoresist layer of the second side, and a marking corresponding to the position of the exposed pattern on the Nth photoresist layer of the first side of the substrate is formed.

4. The exposure method according to claim 3, characterized in that, The exposure method further includes: An Nth photoresist coating is formed on the second surface of the substrate, covering the markings on the (N-1)th photoresist coating on the second surface; Based on the markings on the Nth layer of photoresist coating on the first side, a pattern is exposed on the Nth layer of photoresist coating on the first side, and a marking corresponding to the position of the exposed pattern on the Nth layer of photoresist coating on the second side of the substrate is formed.

5. The exposure method according to any one of claims 1 to 4, characterized in that, The markers include at least three non-collinear reference points.

6. An exposure apparatus, applied to the exposure method according to any one of claims 1 to 5, characterized in that, The exposure equipment includes: A worktable, having a surface for supporting workpieces; An exposure mechanism includes a connecting frame movably mounted on a worktable and an exposure component mounted on the connecting frame, the exposure component being used to expose a workpiece on the worktable.

7. The exposure apparatus according to claim 6, characterized in that, The exposure mechanism also includes a vision component mounted on a connecting frame for identifying the position of the workpiece to determine the exposure position on the workpiece.

8. The exposure apparatus according to claim 6, characterized in that, The workbench has a mounting groove on its surface, and a marking light is installed in the mounting groove to mark the side of the workpiece facing the workbench.

9. The exposure apparatus according to claim 6, characterized in that, The connecting frame includes a first frame spaced apart on both sides of the workpiece and a second frame fixedly connected between the first frames. The first frame is slidably connected to the worktable, and the exposure assembly is slidably mounted on the second frame.

10. The exposure apparatus according to claim 6, characterized in that, The work surface includes multiple working areas, each working area is provided with at least three non-collinear marker lights, and each working area corresponds to one workpiece.

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