Packaging substrate manufacturing method and packaging substrate

Abstract

The application provides a packaging substrate manufacturing method and a packaging substrate, and belongs to the technical field of packaging substrates. The packaging substrate manufacturing method comprises the following steps: providing a packaging substrate, pressing an insulating layer on the packaging substrate; curing and baking the packaging substrate to cure the insulating layer; annealing and baking the packaging substrate, wherein the annealing and baking temperature is lower than the glass transition temperature of the insulating layer; laser drilling the packaging substrate; and treating the packaging substrate with a chemical solution to remove the glue residue generated by the laser drilling. Through the annealing treatment of the packaging substrate, the internal stress of the insulating layer is released, the cracking defect of the insulating layer is improved, and the product reliability and yield are improved.

Description

Technical Field

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

[0002] According to the existing technology and process flow, after the substrate is processed by pre-lamination, ABF (Ajinomoto Buildup Film) is laminated. After the ABF film is laminated, it is cured and baked. Then, blind holes are processed through a laser station. After the laser processing is completed, it is sent to the glue removal station for production. After the substrate passes through the glue removal station, it is examined under a microscope and it is found that there is a problem of cracking in the ABF film.

[0003] Figure 1 This is a schematic diagram of the removal of adhesive residue from a pre-existing encapsulation substrate that has not undergone annealing and baking. The arrows indicate the direction of stress. The inventors discovered that the cracking defect of the ABF film 3' mainly occurs in areas where the ABF film 3' is relatively thin and in locations with a low residual copper ratio (the percentage of the area of ​​the copper layer 2' on the surface of substrate 1' to the total surface area of ​​substrate 1'). The main reason is that after the ABF film 3' is pressed onto the substrate 1', the material expands due to heat during the high-temperature curing and baking process. After baking, because the internal stress is not completely released, the internal stress contracts during the cooling process. The internal stress in the areas where the ABF film 3' is thin and the residual copper ratio is low is less than the internal stress accumulation in other areas. When the substrate 1' is processed in the adhesive residue removal process, the chemical solution attacks and erodes the surface of the ABF film 3', causing tiny pits to be etched on the surface of the ABF film 3'. This allows the stress stored inside the ABF film 3' to be released through these etched surfaces, thus leading to the cracking phenomenon of the ABF film 3'. Summary of the Invention

[0004] This application provides a method for manufacturing a packaging substrate. By annealing the packaging substrate, the internal stress of the insulating layer is released, the defects of insulating layer cracking are improved, and the product reliability and yield are increased.

[0005] This application provides a method for manufacturing a packaging substrate, including:

[0006] An encapsulation substrate is provided, on which an insulating layer is laminated;

[0007] The packaging substrate is cured and baked to cure the insulating layer;

[0008] The packaging substrate is annealed and baked at a temperature lower than the glass transition temperature of the insulating layer.

[0009] Laser drilling is performed on the packaging substrate;

[0010] The encapsulation substrate is treated with a chemical solution to remove adhesive residue generated during laser drilling.

[0011] In some embodiments, the annealing baking temperature is greater than or equal to 100°C, and the isothermal baking time ranges from 40 minutes to 50 minutes.

[0012] In some embodiments, the curing and baking process for the insulating layer includes:

[0013] The insulating layer is subjected to initial curing and baking treatment. The curing and baking temperature range is 120℃-140℃, and the curing and baking time range is 25 minutes-35 minutes.

[0014] The insulating layer is subjected to a secondary curing and baking process. The secondary curing and baking temperature range is 170℃-190℃, and the curing and baking time ranges from 25 minutes to 35 minutes.

[0015] In some embodiments, the packaging substrate is designed with a residual copper ratio of 60% or greater per layer.

[0016] In some embodiments, the residual copper on the packaging substrate covers the entire board area and is evenly distributed.

[0017] In some embodiments, during the step of treating the packaging substrate with a chemical solution, the chemical etching amount is less than or equal to 0.6 μm.

[0018] In some embodiments, the step of annealing and baking the packaging substrate includes:

[0019] The encapsulated substrate is placed in the cavity of a freestanding oven for annealing and baking.

[0020] In some embodiments, the vacuum level inside the cavity of the freestanding oven is less than 50 mtorr, and the temperature uniformity inside the cavity of the freestanding oven is within the range of ±3°C.

[0021] In some embodiments, the encapsulation substrate is placed horizontally in the freestanding oven, and there is a certain gap between adjacent encapsulation substrates. The freestanding oven uses a horizontal airflow method to bake the encapsulation substrate.

[0022] This application also provides a packaging substrate, which is obtained by the packaging substrate manufacturing method described in any of the above embodiments.

[0023] The packaging substrate manufacturing method of this application embodiment cures the insulating layer of the packaging substrate by curing and baking, and then anneals and bakes the packaging substrate to release the internal stress of the insulating layer. This reduces the problem of cracking of the insulating layer due to internal stress after the packaging substrate is treated with chemicals, thereby improving the defect of insulating layer cracking and improving product reliability and yield. Attached Figure Description

[0024] 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.

[0025] Figure 1 This is a schematic diagram illustrating the process of removing adhesive residue from a packaging substrate that has not undergone annealing and baking in the prior art.

[0026] Figure 2 This is a flowchart illustrating a method for fabricating a packaging substrate according to an embodiment of this application.

[0027] Figure 3 This is a schematic diagram of removing adhesive residue from the encapsulation substrate after annealing and baking, as described in this application embodiment.

[0028] Figure 4 This is a schematic diagram illustrating the annealing and baking of the packaging substrate in an independent oven during the packaging substrate fabrication method of this application embodiment.

[0029] Reference numerals in the prior art for packaging substrate structures that have not undergone annealing and baking:

[0030] Substrate 1'; Copper layer 2'; ABF film 3'.

[0031] Reference numerals in the embodiments of this application:

[0032] 1. Encapsulation substrate; 2. Copper layer; 3. Insulating layer; 4. Dimples; 5. Independent oven. Detailed Implementation

[0033] 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.

[0034] This application provides a method for manufacturing a packaging substrate. By annealing the packaging substrate, the internal stress of the insulating layer is released, the defects of insulating layer cracking are improved, and the product reliability and yield are increased.

[0035] refer to Figure 2 and Figure 3 , Figure 2 This is a flowchart of a packaging substrate fabrication method according to an embodiment of this application. Figure 3 This is a schematic diagram illustrating the removal of adhesive residue from the encapsulation substrate after annealing and baking, as described in this application embodiment. The encapsulation substrate fabrication method includes:

[0036] 10. Provide a packaging substrate 1, and press an insulating layer 3 onto the packaging substrate 1;

[0037] 20. The packaging substrate 1 is cured and baked to cure the insulating layer 3;

[0038] 30. Anneal and bake the packaging substrate 1 at a temperature lower than the glass transition temperature of the insulating layer 3.

[0039] 40. Perform laser drilling on the packaging substrate 1;

[0040] 50. Treat the packaging substrate 1 with a chemical solution to remove adhesive residue generated during laser drilling.

[0041] It should be noted that during the curing and baking of the packaging substrate 1, the insulating layer 3 expands due to heat. Because the copper layer 2 remains on the packaging substrate 1 and is unevenly distributed, the thickness of the insulating layer 3 varies in different areas. This results in uneven expansion of the insulating layer 3 during the curing and baking process, leading to a complex stress distribution inside the insulating layer 3. As the packaging substrate 1 cools, the internal stress of the insulating layer 3 contracts. The internal stress in areas where the insulating layer 3 is thinner and has a lower residual copper content is less than the internal stress accumulation in other areas. Annealing and baking the packaging substrate 1 releases the internal stress of the insulating layer 3, alleviating its internal stress concentration. When the packaging substrate 1 is treated with chemicals, although the chemicals will still attack and etch the surface of the insulating layer 3, causing tiny pits 4 to be etched on the surface of the insulating layer 3, the internal stress of the insulating layer 3 is released through annealing and baking, alleviating its internal stress concentration. This significantly reduces the risk of cracking of the insulating layer 3 due to the release of internal stress from the pits 4.

[0042] It should also be noted that the insulating layer 3 is usually made of polymer materials, many of which undergo rapid changes in properties near their glass transition temperature (Tg). To avoid deformation or alteration of the properties of the insulating layer 3, the annealing temperature should be lower than the glass transition temperature of the insulating layer 3. For example, when the insulating layer 3 is an ABF film, its glass transition temperature is approximately 150°C, and the annealing temperature should be lower than 150°C.

[0043] The packaging substrate manufacturing method of this application embodiment cures the insulating layer 3 by curing and baking the packaging substrate 1, and then anneals and bakes the packaging substrate 1 to release the internal stress of the insulating layer 3. This reduces the problem of cracking of the insulating layer 3 due to internal stress after the packaging substrate 1 is treated with chemicals, thereby improving the defect of cracking of the insulating layer 3 and improving product reliability and yield.

[0044] In some embodiments, the annealing temperature is greater than or equal to 100°C, for example, 100°C, 115°C, 125°C, or 135°C; the isothermal time for annealing is in the range of 40-50 minutes, for example, 40 minutes, 45 minutes, or 50 minutes. It should be noted that the annealing temperature needs to be greater than or equal to 100°C and less than the glass transition temperature of the insulating layer 3. For example, if the insulating layer 3 is an ABF film with a glass transition temperature of approximately 150°C, then the annealing temperature should be between 100°C and 150°C.

[0045] The inventors of this application discovered through research that, when using ABF as the insulating layer 3 material, following industry-standard curing and baking conditions (130℃×30min+180℃×30min) and a typical residual copper rate (60%), the annealing and baking temperature and isothermal time have a significant impact on the probability of cracking defects in the insulating layer 3.

[0046] 1. Control the annealing and baking time to 45 minutes, and the annealing and baking temperature is variable:

[0047] When the annealing temperature is below 100℃, the cracking rate of insulation layer 3 decreases with increasing annealing temperature. At room temperature (no annealing), the cracking rate of insulation layer 3 is approximately 65%; at 80℃, it is approximately 21%; at 90℃, it is approximately 13%; and when the annealing temperature approaches 100℃, the cracking rate approaches 0%.

[0048] No cracking defects were found in insulation layer 3 when the annealing temperature was 100℃, 115℃, 125℃, and 135℃ (greater than or equal to 100℃). This indicates that the annealing baking temperature of 100℃ is the critical temperature for eliminating cracking in insulation layer 3. Therefore, in order to improve the cracking defect in insulation layer 3 and increase product reliability and yield, the annealing baking time needs to be set above 100℃.

[0049] The relationship between annealing baking temperature change and cracking rate of insulation layer 3 is shown in Table 1:

[0050]

[0051] Table 1

[0052] 2. Control the annealing and baking temperature at 100℃, and the constant temperature time for annealing and baking is a variable:

[0053] When the annealing baking time is less than 40 minutes, even if the annealing temperature is 100℃, the insulation layer 3 will occasionally crack: when the annealing baking time is 30 minutes, the cracking rate of the insulation layer 3 is about 7%; when the annealing baking time is 35 minutes, the cracking rate of the insulation layer 3 is about 4%. It is speculated that this is because the annealing baking time is not long enough, resulting in insufficient stress release inside the insulation layer 3.

[0054] When the annealing baking time was 40 minutes, 45 minutes and 50 minutes, no cracking defect was found in the insulation layer 3. This indicates that the constant temperature time of 40 minutes for annealing baking is the critical time to eliminate the cracking of the insulation layer 3. Therefore, in order to improve the cracking defect of the insulation layer 3, improve product reliability and yield, and reduce production time and cost, the annealing baking time needs to be controlled between 40 minutes and 50 minutes, preferably 45 minutes.

[0055] The relationship between the annealing baking time and the cracking rate of insulation layer 3 is shown in Table 2:

[0056]

[0057] Table 2

[0058] In some embodiments, the curing and baking process of the insulating layer 3 includes: performing a primary curing and baking process on the insulating layer 3, with a curing and baking temperature range of 120℃-140℃ and a curing and baking time range of 25 minutes-35 minutes; and performing a secondary curing and baking process on the insulating layer 3, with a secondary curing and baking temperature range of 170℃-190℃ and a curing and baking time range of 25 minutes-35 minutes.

[0059] It should be noted that during the curing and baking process, to ensure complete curing of the insulation layer 3, a relatively high temperature and a long baking time are usually required. However, excessively high temperatures and long baking times may lead to over-curing, discoloration, and other adverse phenomena in the insulation layer 3 material, while also increasing energy consumption and production costs. Therefore, a two-stage curing and baking process is adopted, dividing the curing process into two stages. The first curing and baking, based on the characteristics of the insulation layer 3 material, aims to initially cure the insulation layer 3, forming a relatively stable structural foundation to prepare for the subsequent second curing process. During the second curing and baking, the temperature is increased to 170℃-190℃ to further promote the improvement and stability of the internal structure of the insulation layer 3, enabling it to reach a better performance state. The temperature and time parameters of the first and second curing and baking can be flexibly adjusted according to the specific characteristics of the material to adapt to the needs of different material combinations.

[0060] In some embodiments, the packaging substrate 1 is designed with a residual copper ratio of greater than or equal to 60% per layer. It should be noted that the residual copper ratio = area of ​​copper-containing layers on the substrate surface / area of ​​the entire substrate × 100%.

[0061] The inventors of this application also discovered through research that when using ABF as the insulating layer material, following industry-standard curing and baking conditions (140℃×30min+190℃×30min) and setting annealing baking (100℃-150℃×45min), the residual copper content of the packaging substrate 1 has a significant impact on the probability of cracking defects in the insulating layer 3: when the residual copper content of the packaging substrate 1 is 55% or less, there is a clear problem of cracking in the insulating layer 3, and the cracking rate of the insulating layer 3 increases as the residual copper content of the packaging substrate 1 decreases. However, when the residual copper content of the packaging substrate 1 is greater than or equal to 60%, no cracking defects in the insulating layer 3 are found. This indicates that a residual copper content of 60% in the packaging substrate 1 is the critical value for eliminating cracking in the insulating layer 3. Therefore, in order to improve the cracking defects in the insulating layer 3 and improve product reliability and yield, it is necessary to control the residual copper content of the packaging substrate 1 to be greater than or equal to 60%.

[0062] The relationship between the residual copper content of the packaging substrate 1 and the cracking rate of the insulating layer 3 is shown in Table 3:

[0063]

[0064] Table 3

[0065] Furthermore, in some embodiments, the residual copper on the packaging substrate 1 covers the entire board area and is uniformly distributed. It should be noted that by covering the entire board area with residual copper on the packaging substrate 1 and distributing it uniformly, the copper layer 2 is not locally or scattered on the packaging substrate 1, but is completely spread to all areas of the packaging substrate 1, and the distribution density, thickness and other parameters of the same layer are consistent, without obvious differences or local aggregation, which further reduces the stress concentration problem inside the insulating layer 3, thereby further reducing the risk of cracking of the insulating layer 3.

[0066] In some embodiments, during the step of treating the packaging substrate 1 with a chemical solution, the etching amount of the chemical solution is less than or equal to 0.6 μm. It should be noted that after the chemical solution etches the surface of the insulating layer 3, it will cause tiny pits 4 to be etched into the surface of the insulating layer 3. Areas with larger pits 4 are more prone to cracking of the insulating layer 3. Therefore, by controlling the etching amount of the chemical solution to be less than or equal to 0.6 μm, excessive etching of the surface of the insulating layer 3 by the chemical solution is avoided, further reducing the risk of cracking of the insulating layer 3.

[0067] In some embodiments, reference Figure 4The annealing and baking step for the packaging substrate 1 includes placing the packaging substrate 1 into the cavity of the independent oven 5 for annealing and baking. It is understood that the independent oven 5 can more precisely control the temperature and temperature uniformity of the annealing and baking of the packaging substrate 1, thereby improving the quality of annealing and baking.

[0068] Furthermore, in some embodiments, the vacuum degree inside the cavity of the freestanding oven 5 is less than 50 mtorr, and the temperature uniformity inside the cavity of the freestanding oven 5 is within the range of ±3°C.

[0069] Furthermore, in some embodiments, the packaging substrate 1 is placed horizontally in the independent oven 5, and there is a certain gap between adjacent packaging substrates 1. The independent oven 5 uses a horizontal air supply method to bake the packaging substrate 1.

[0070] It is understandable that by setting the vacuum and temperature uniformity within the independent oven 5 cavity, adopting a horizontal hot air supply method, placing the packaging substrate 1 horizontally within the independent oven 5, and maintaining a certain gap between adjacent packaging substrates 1, the uniformity of annealing and baking of the packaging substrate 1 within the cavity can be ensured, and the temperature difference during annealing and baking of the packaging substrate 1 can be reduced.

[0071] This application also provides a packaging substrate, which is obtained by the packaging substrate manufacturing method of any of the above embodiments.

[0072] The packaging substrate of this application embodiment is processed using the packaging substrate manufacturing method of the above embodiment. Annealing and baking the packaging substrate releases the internal stress of the insulating layer, reducing the problem of cracking of the insulating layer due to internal stress after chemical treatment of the packaging substrate. This improves the defect of insulating layer cracking, thereby increasing product reliability and yield.

[0073] 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. Unless otherwise stated, "a plurality of" means two or more.

[0074] 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 for manufacturing a packaging substrate, characterized in that, include: An encapsulation substrate is provided, on which an insulating layer is laminated; The packaging substrate is cured and baked to cure the insulating layer. The packaging substrate is annealed and baked at a temperature lower than the glass transition temperature of the insulating layer. Laser drilling is performed on the packaging substrate; The encapsulation substrate is treated with a chemical solution to remove adhesive residue generated during laser drilling. The steps for curing and baking the insulating layer include: The insulating layer is subjected to initial curing and baking treatment. The curing and baking temperature range is 120℃-140℃, and the curing and baking time range is 25 minutes-35 minutes. The insulating layer is subjected to a secondary curing and baking process. The secondary curing and baking temperature range is 170℃-190℃, and the curing and baking time ranges from 25 minutes to 35 minutes. The packaging substrate is designed with a residual copper rate of 60% or more per layer; the residual copper of the packaging substrate covers the entire board area and is evenly distributed.

2. The method for manufacturing a packaging substrate according to claim 1, characterized in that, The annealing baking temperature is greater than or equal to 100°C, and the constant temperature baking time range is 40 minutes to 50 minutes.

3. The method for manufacturing a packaging substrate according to claim 1, characterized in that, In the step of treating the encapsulation substrate with a chemical solution, the chemical etching amount is less than or equal to 0.6 μm.

4. The method for manufacturing a packaging substrate according to claim 1, characterized in that, The step of annealing and baking the packaging substrate includes: The encapsulated substrate is placed in the cavity of a freestanding oven for annealing and baking.

5. The method for manufacturing a packaging substrate according to claim 4, characterized in that, The vacuum level inside the cavity of the freestanding oven is less than 50 mtorr, and the temperature uniformity inside the cavity of the freestanding oven is within ±3℃.

6. The method for manufacturing a packaging substrate according to claim 4, characterized in that, The packaging substrate is placed horizontally in the freestanding oven, with a certain gap between adjacent packaging substrates. The freestanding oven uses a horizontal air supply method to bake the packaging substrate.

7. A packaging substrate, characterized in that, The packaging substrate is obtained by the packaging substrate manufacturing method according to any one of claims 1 to 6.

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