Packaging substrate exposure method, manufacturing method and packaging substrate

Abstract

The embodiment of the invention provides a packaging substrate exposure method, a manufacturing method and a packaging substrate, and the method comprises the steps: providing a substrate, enabling the substrate to be provided with a metal layer, enabling the substrate and the metal layer to be coated with printing ink, enabling the printing ink located on the metal layer to be a first printing ink layer, enabling the printing ink located on the substrate to be a second printing ink layer, and enabling the first printing ink layer to be provided with a windowing region; exposing the first ink layer by using a first exposure process; the second ink layer is exposed through a second exposure process, the optical wavelength of the second exposure process is not smaller than that of the first exposure process, and the exposure energy of the second exposure process is larger than that of the first exposure process. According to the invention, the first ink layer and the second ink layer are exposed separately, and the second ink layer is exposed by using light with longer wavelength and higher exposure energy, so that lateral erosion caused by poor light curing reaction at the bottom of the ink layer is reduced, and the problems that a windowing becomes smaller and edges become rounded are avoided.

Description

Technical Field

[0001] This application relates to the field of packaging substrate technology, and in particular to a packaging substrate exposure method, a manufacturing method, and a packaging substrate. Background Technology

[0002] A typical finished packaging substrate consists of three parts: a substrate, a solder mask, and a metal layer. The metal layer is typically 15-25 μm high, the solder mask on the metal layer is typically 20-30 μm high, and the solder mask on the substrate is typically 35-55 μm high. The solder mask is produced through five steps: ink coating, pre-baking, leveling, image transfer, and curing. The most critical step is image transfer, which is further divided into exposure and development. The main components of the ink are: acrylate (30-35%), barium sulfate (25-30%), naphtha (petroleum) heavy aromatic solvent (10-15%), and photoinitiator (5-10%). Exposure involves irradiating the ink at the desired location with light of wavelengths between 355-420 nm, causing the photoinitiator to react and release free radicals, which promotes the photopolymerization reaction of the acrylate, encapsulating the barium sulfate, naphtha (petroleum) heavy aromatic solvent, and other substances. Next, development is performed using a 1% weakly alkaline sodium carbonate solution to dissolve the acrylic ester and other components that have not undergone photopolymerization. Then, the ink is washed off by spraying to expose the underlying metal or substrate.

[0003] However, photoinitiators are sensitive to light with wavelengths of 355-420 nm, but this wavelength of light has weak penetration into ink. This results in a very complete photocuring reaction for the 20-30 μm thick ink on the metal layer, but a poor photocuring reaction at the bottom for the 35-55 μm thick ink on the substrate. During development and spraying, the bottom ink may be washed away, leading to lateral etching (see reference). Figure 1 To ensure complete reaction of the bottom ink, a longer wavelength of light is required. Since the photoinitiator is not sensitive to this wavelength, the light intensity also needs to be increased. However, this approach introduces another problem: the photoinitiator in the illuminated area reacts excessively, and the over-released free radicals cause the lateral ink to react as well, leading to smaller window openings and rounded edges (see reference). Figure 2 ). Summary of the Invention

[0004] This application provides a packaging substrate exposure method, manufacturing method, and packaging substrate. By exposing the first ink layer and the second ink layer separately, and by using longer wavelength light and greater exposure energy to expose the second ink layer, the side etching caused by poor photocuring reaction at the bottom of the ink layer is reduced. It also avoids the problem of excessive release of free radicals causing the lateral ink to react, resulting in smaller openings and rounded edges.

[0005] The first aspect of this application provides a method for exposing a packaging substrate, including: A substrate is provided, wherein a metal layer is provided on the substrate, and ink is coated on both the substrate and the metal layer. The ink on the metal layer is a first ink layer, and the ink on the substrate is a second ink layer. The first ink layer is provided with a window area. The first ink layer is exposed using a first exposure process; The second ink layer is exposed using a second exposure process, wherein the wavelength of light in the second exposure process is not less than the wavelength of light in the first exposure process, and the exposure energy of the second exposure process is greater than the exposure energy of the first exposure process.

[0006] In some embodiments, when the first ink layer is exposed, the exposed area at the junction of the first ink layer and the second ink layer is offset towards the area of ​​the second ink layer by a first predetermined distance. When the second ink layer is exposed, the exposed area at the outer edge of the second ink layer is offset by a second predetermined distance towards the area of ​​the first ink layer.

[0007] In some embodiments, the range of the first set distance is 50-1000 μm; the range of the second set distance is 10-50 μm.

[0008] In some embodiments, the first exposure process has a light wavelength range of 355-420 nm and an exposure energy range of 200-250 mJ; the second exposure process has a light wavelength range of 355-800 nm and an exposure energy range of 400-500 mJ.

[0009] In some embodiments, the upper surfaces of the first ink layer and the second ink layer are flush.

[0010] In some embodiments, the thickness of the first ink layer ranges from 20 to 30 μm, and the thickness of the second ink layer ranges from 35 to 55 μm.

[0011] A second aspect of this application provides a method for manufacturing a packaging substrate, including: Exposure is performed using the exposure method described in any of the above embodiments, followed by development to transfer the desired finished image onto ink; The ink is photocured and heat-cured to ensure it is completely dry and becomes a solder resist.

[0012] In some embodiments, the step of coating the substrate and the metal layer with ink includes: Use a rubber roller to evenly apply ink to the surfaces of the substrate and the metal layer; The ink on the substrate and the metal layer is baked in an atmospheric oven at 80°C for 45 minutes to allow the ink on the substrate and the metal layer to dry initially. The ink that has been partially dried is leveled to ensure that the upper surfaces of the first ink layer and the second ink layer are flush.

[0013] In some embodiments, the rubber roller is provided with a V-shaped groove.

[0014] A third aspect of this application provides a packaging substrate, which is obtained by the packaging substrate manufacturing method described in any of the above embodiments.

[0015] The packaging substrate exposure method of this application embodiment exposes the first ink layer and the second ink layer separately, and exposes the second ink layer with longer wavelength light and greater exposure energy. This reduces the side etching caused by poor photocuring reaction at the bottom of the ink layer, and avoids the excessive release of free radicals causing the lateral ink to react as well, resulting in problems such as smaller openings and rounded edges. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the cross-section of a packaging substrate exposed to short-wavelength light in the prior art.

[0018] Figure 2 This is a schematic diagram of the cross-section of a packaging substrate exposed to long-wavelength light in the prior art.

[0019] Figure 3 This is a schematic flowchart of the packaging substrate exposure method according to an embodiment of this application.

[0020] Figure 4This is a cross-sectional schematic diagram of the ink exposure method of the packaging substrate according to an embodiment of this application.

[0021] Figure label: Substrate 1; Metal layer 2; First ink layer 3; Window area 31; Second ink layer 4. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0023] refer to Figure 3 and Figure 4 , Figure 3 This is a schematic flowchart of the packaging substrate fabrication method according to an embodiment of this application. Figure 4 This is a cross-sectional schematic diagram of the ink exposure method for the packaging substrate according to an embodiment of this application. The dashed line represents the junction of the first ink layer 3 and the second ink layer 4. L1 is the left boundary of the exposure of the second ink layer 4 on the left, L2 is the left boundary of the exposure of the first ink layer 3 on the left, L3 is the right boundary of the exposure of the second ink layer 4 on the left, L4 is the right boundary of the exposure of the first ink layer 3 on the left, L5 is the left boundary of the exposure of the first ink layer 3 on the right, L6 is the left boundary of the exposure of the second ink layer 4 on the left, L7 is the right boundary of the exposure of the first ink layer 3 on the right, and L8 is the right boundary of the exposure of the second ink layer 4 on the right.

[0024] An embodiment of this application provides a method for exposing a packaging substrate, comprising: S1. A substrate 1 is provided, on which a metal layer 2 is provided. Both the substrate 1 and the metal layer 2 are coated with ink, and the ink on the metal layer 2 is a first ink layer 3, and the ink on the substrate 1 is a second ink layer 4. The first ink layer 3 is provided with a window area 31.

[0025] S2. Expose the first ink layer 3 using the first exposure process.

[0026] S3. Using a second exposure process, expose the second ink layer 4. The wavelength of light in the second exposure process is not less than the wavelength of light in the first exposure process, and the exposure energy of the second exposure process is greater than the exposure energy of the first exposure process.

[0027] It should be noted that, due to the inconsistent thicknesses of the first ink layer 3 (20-30μm) and the second ink layer 4 (35-55μm), if short-wavelength light is used for exposure, the first ink layer 3 will react completely while the bottom of the second ink layer 4 will not be completely photocured. During the developing process, the ink at the bottom of the second ink layer 4 may be washed away, leading to lateral etching (see reference). Figure 1 If long-wavelength light is used for exposure, the photoinitiator is not sensitive to this wavelength, so the light intensity needs to be increased. This leads to excessive reaction of the photoinitiator in the illuminated area, and the excessively released free radicals also react with the lateral ink, resulting in smaller window openings and rounded edges (see reference). Figure 2 Therefore, this application uses a first exposure process (shorter wavelength, lower energy light) to expose the first ink layer 3, ensuring that the first ink layer 3 reacts completely and avoiding lateral etching or over-reaction of the photoinitiator in the first ink layer 3; and uses a second exposure process (longer wavelength, higher energy light) to expose the second ink layer 4, ensuring that the second ink layer 4 reacts completely without lateral etching. Since the second exposure process does not expose the first ink layer 3, it avoids problems such as the window area 31 becoming smaller and the edges becoming rounded due to over-reaction of the photoinitiator in the first ink layer 3.

[0028] The packaging substrate exposure method of this application exposes the first ink layer 3 and the second ink layer 4 separately, and exposes the second ink layer 4 with longer wavelength light and greater exposure energy. This reduces the side etching caused by poor photocuring reaction at the bottom of the ink layer, and avoids the excessive release of free radicals causing the lateral ink to react as well, resulting in problems such as smaller openings and rounded edges.

[0029] In some embodiments, reference Figure 4 When exposing the first ink layer 3, the exposed area at the junction of the first ink layer 3 and the second ink layer 4 is offset by a first set distance towards the area of ​​the second ink layer 4. The junction of the first ink layer 3 and the second ink layer 4 refers to the boundary area where they contact each other. This first set distance offset is to prevent unexposed portions of the first ink layer 3 due to exposure accuracy issues, ensuring that the entire first ink layer 3 can be fully exposed. In actual operation, considering factors such as the exposure accuracy of the equipment, ink characteristics, and design requirements, the range of the first set distance is selected as 50-1000 μm (e.g., 50 μm, 100 μm, 500 μm, 1000 μm) to ensure that the entire first ink layer 3 can be fully exposed.

[0030] When exposing the second ink layer 4, the exposed area at the outer edge of the second ink layer 4 is offset towards the area of ​​the first ink layer 3 by a second predetermined distance. The outer edge of the second ink layer 4 refers to the edge region of the second ink layer 4 that is far from the first ink layer 3. Because higher energy and longer wavelengths cause the ink to extend from the exposed area to the unexposed area, the offset by the second predetermined distance is to make the exposed second ink layer 4 closer to its original shape and size. In actual operation, the range of the second predetermined distance is selected as 10-50 μm (e.g., 10μm, 20μm, 30μm, 50μm) based on a comprehensive consideration of factors such as the exposure accuracy of the equipment, ink characteristics, and design requirements, so that the exposed second ink layer 4 is close to its original shape and size.

[0031] It should be noted that the reference Figure 4 Exposure is performed using the first exposure process, covering areas L2-L4 and L5-L7. L4-L5 is the standard windowed area, with no compensation for the window size. The position of L2 is the location offset to the left by a first set distance from the boundary between the left first ink layer 3 and the left second ink layer 4 (i.e., the compensated position). The position of L7 is the location offset to the right by a first set distance from the boundary between the right first ink layer 3 and the right second ink layer 4 (i.e., the compensated position). At this point, the ink in areas L3-L4 and L5-L6 (the entire first ink layer 3) is fully reacted, while the ink in areas L2-L3 and L6-L7 is fully reacted. The upper ink layer (partial second ink layer 4) reacts completely, while the bottom ink layer does not react completely. Subsequently, a second exposure process is used for exposure, covering the L1-L3 and L6-L8 regions. The L1 position is the position after the exposed area of ​​the outer edge of the left second ink layer 4 is shifted by a second set distance towards the area of ​​the left first ink layer 3 (i.e., the compensated position). The L8 position is the position after the exposed area of ​​the outer edge of the right second ink layer 4 is shifted by a second set distance towards the area of ​​the right first ink layer 3 (i.e., the compensated position). At this time, the ink in the L1-L3 and L6-L8 regions reacts completely.

[0032] In some embodiments, the upper surfaces of the first ink layer 3 and the second ink layer 4 are flush to avoid uneven exposure caused by inconsistent ink heights.

[0033] In some embodiments, the thickness of the first ink layer 3 ranges from 20 to 30 μm, and the thickness of the second ink layer 4 ranges from 35 to 55 μm. This avoids the problem of reduced insulation caused by excessively thin ink layers, and also avoids the problem of incomplete reaction of the bottom ink layers caused by excessively thick ink layers.

[0034] In some embodiments, the first exposure process has a light wavelength range of 355-420 nm and an exposure energy range of 200-250 mJ; the second exposure process has a light wavelength range of 355-800 nm and an exposure energy range of 400-500 mJ.

[0035] A second aspect of this application provides a method for manufacturing a packaging substrate, including: Exposure is performed using the exposure method of any of the above embodiments, followed by development to transfer the desired finished image onto ink; The ink is photocured and heat-cured to ensure it is completely dry and becomes a solder resist.

[0036] The packaging substrate fabrication method of this application embodiment exposes the first ink layer 3 and the second ink layer 4 separately, and exposes the second ink layer 4 with longer wavelength light and greater exposure energy. This reduces the side etching caused by poor photocuring reaction at the bottom of the ink layer, and avoids the excessive release of free radicals causing the lateral ink to react as well, resulting in problems such as smaller openings and rounded edges.

[0037] In some embodiments, the step of coating ink on the substrate 1 and the metal layer 2 includes: Use a rubber roller to evenly apply ink to the surfaces of substrate 1 and metal layer 2.

[0038] The ink on substrate 1 and metal layer 2 is baked in an atmospheric oven at 80°C for 45 minutes to allow the ink on substrate 1 and metal layer 2 to dry initially.

[0039] After the ink has partially dried, it is leveled to ensure that the upper surfaces of the first ink layer 3 and the second ink layer 4 are flush. Leveling the partially dried ink is typically done using a steel plate flattening machine to effectively prevent uneven exposure caused by inconsistent ink height.

[0040] In some embodiments, the rubber roller is provided with a V-shaped groove, and the width and depth of the V-shaped groove are consistent at all points so that the ink is evenly applied to the substrate 1 and the metal layer 2.

[0041] A third aspect of this application provides a packaging substrate, which is obtained by the packaging substrate manufacturing method of any of the above embodiments.

[0042] In the packaging substrate of this application embodiment, the first ink layer 3 and the second ink layer 4 are exposed separately during processing. The second ink layer 4 is exposed with longer wavelength light and greater exposure energy. This reduces the side etching caused by poor photocuring reaction at the bottom of the ink layer, and avoids the excessive release of free radicals causing the lateral ink to react as well, resulting in problems such as smaller openings and rounded edges, thereby improving the quality of the packaging substrate.

[0043] In the description of this application, it should be understood that terms such as “first” and “second” are used only to distinguish similar objects and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0044] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0045] It should be understood that the terms "thickness," "upper," "lower," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In the description of the present invention, unless otherwise stated, "a plurality of" means two or more.

[0046] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand this application. At the same time, those skilled in the art will find that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method of exposing a package substrate, the method comprising: The application relates to a packaging substrate manufacturing method. A substrate is provided, wherein a metal layer is arranged on the substrate, and ink is coated on the substrate and the metal layer, and the ink on the metal layer is a first ink layer, and the ink on the substrate is a second ink layer, and a window area is arranged on the first ink layer; The first ink layer is exposed by using a first exposure process; The second ink layer is exposed by using a second exposure process, wherein the light wavelength of the second exposure process is not less than the light wavelength of the first exposure process, and the exposure energy of the second exposure process is greater than the exposure energy of the first exposure process.

2. The package substrate exposure method according to claim 1, wherein When the first ink layer is exposed, the exposure area at the junction of the first ink layer and the second ink layer is offset to the area of the second ink layer by a first set distance; When the second ink layer is exposed, the exposure area at the outer edge of the second ink layer is offset to the area of the first ink layer by a second set distance.

3. The package substrate exposure method according to claim 2, wherein The first set distance ranges from 50 to 1000 mu m, and the second set distance ranges from 10 to 50 mu m.

4. The package substrate exposure method according to claim 1, wherein The light wavelength of the first exposure process ranges from 355 to 420 nm, and the exposure energy ranges from 200 to 250 mJ; the light wavelength of the second exposure process ranges from 355 to 800 nm, and the exposure energy ranges from 400 to 500 mJ.

5. The package substrate exposure method according to any one of claims 1 to 4, wherein The upper surfaces of the first ink layer and the second ink layer are flush.

6. The package substrate exposure method according to any one of claims 1 to 4, wherein The thickness of the first ink layer ranges from 20 to 30 mu m, and the thickness of the second ink layer ranges from 35 to 55 mu m.

7. A method for fabricating a package substrate, the method comprising: The application also relates to a packaging substrate manufacturing method. The substrate is exposed by using the exposure method in any one of claims 1 to 6, and then developed to transfer a required finished product image to the ink; The ink is photocured and thermally cured, so that the ink is completely dried to be solder resist.

8. The method of claim 7, wherein The step of coating the ink on the substrate and the metal layer comprises the following steps: The rubber roller is used to uniformly coat the ink on the surface of the substrate and the metal layer; The ink on the substrate and the metal layer is baked in an atmospheric oven at a temperature of 80 DEG C for 45 minutes, so that the ink on the substrate and the metal layer is preliminarily dried; The preliminarily dried ink is leveled to ensure that the upper surfaces of the first ink layer and the second ink layer are flush.

9. The method of claim 8, wherein The rubber roller is provided with a V-shaped groove.

10. A package substrate, characterized by, The packaging substrate is obtained by the packaging substrate manufacturing method in any one of claims 7 to 9.

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