Method for manufacturing copper columns on packaging carrier plate and packaging carrier plate

Abstract

The invention provides a method for manufacturing copper columns on a packaging substrate and the packaging substrate, and the method comprises the steps: sequentially covering a copper deposition layer and a graphical dry film on the surface of the packaging substrate, and vertically and continuously electroplating n first copper column groups of which the heights form an arithmetic progression on the graphic surfaces of the inner layer and the outer layer of a groove between the dry films; and the packaging carrier plate is rotated by 180 degrees, second copper column sets arranged in the height arithmetic progression are vertically and continuously electroplated on the first copper column sets correspondingly, the corresponding copper columns of the second copper column sets and the first copper column sets form target copper columns, and the heights of the target copper columns are the same. According to the invention, the first copper column group with equal height is arranged on the surface of the packaging carrier plate, and the second copper column group with equal height is arranged after up-down rotation, so that the single vertical continuous electroplating process does not exceed the single maximum copper plating amount, and the target copper column height is increased; meanwhile, increasing the height of the target copper column is beneficial to expanding the application range of the double-sided packaging process; in addition, redundant copper columns are arranged in the large plate before cutting, the residual copper rate of the whole plate is increased, the risk of plate burning and leakage is reduced, and the uniformity of the target copper columns is improved.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor integrated circuit manufacturing technology, and in particular relates to a method for fabricating copper pillars on a packaging substrate and the packaging substrate itself. Background Technology

[0002] With the increasing demand for System-in-Package (SiP) and Heterogeneous Integration, traditional substrates are evolving from single-sided to double-sided packaging. In conventional structures, after the top surface of the substrate is used for die mounting and wire bonding / flip-chip bonding, the bottom surface is only interconnected with the motherboard printed circuit board (PCB) via a land grid array (LGA or ball grid array). However, in emerging double-sided packaging architectures, the bottom surface also needs to support the chip. Therefore, copper pillars must be pre-formed on the bottom surface of the substrate to maintain sufficient height for reliable electrical connection with the motherboard PCB after molding.

[0003] Currently, major international packaging substrate manufacturers are all in the development and verification stage for this copper pillar structure, and there is no mature mass production process yet. The specifications in double-sided packaging architectures generally require copper pillar heights greater than 100 micrometers, far exceeding the maximum single-pass copper plating capacity of existing electroplating solutions. Furthermore, when using traditional vertical continuous plating (VCP) to thicken to over 100 micrometers in a single pass, the excessively high local current density easily leads to fatal defects such as burning, plating skips, and plating non-uniformity, resulting in a sharp drop in packaging yield.

[0004] Therefore, there is an urgent need for a process solution that can stably form uniform, high-yield high-copper pillars on the surface of the packaging substrate.

[0005] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating the understanding of those skilled in the art. It should not be assumed that the above technical solutions are known to those skilled in the art simply because these solutions have been described in the background section of this application. Summary of the Invention

[0006] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a method for manufacturing copper pillars using a packaging substrate and a packaging substrate, so as to solve the problem that it is difficult to form uniform and high-yield high copper pillars using a packaging substrate in the prior art.

[0007] To achieve the above objectives, the present invention provides a method for fabricating copper pillars using a substrate, the method comprising:

[0008] A packaging substrate for electroplating copper pillars is provided, wherein a patterned solder resist layer is provided on the outer patterned surface of the packaging substrate;

[0009] A copper plating layer is compliantly coated onto the surface of the packaging substrate using vertical chemical copper plating.

[0010] A patterned dry film is formed on the surface of the copper plating layer;

[0011] The outer patterned surface exposed in the grooves between the patterned dry films is formed by a vertical continuous electroplating process on two surfaces or one surface parallel to the side wall of the electroplating tank, forming n first copper pillar groups with an arithmetic sequence of height from top to bottom, where n is an integer greater than or equal to 2.

[0012] The encapsulation carrier plate in the electroplating tank is rotated 180° about the central axis in the direction perpendicular to the side wall of the electroplating tank. Using the same process parameters, n second copper pillar groups are formed on two surfaces or one surface parallel to the side wall of the electroplating tank through a vertical continuous electroplating process. The height of each second copper pillar group is the same as that of the first copper pillar group. Each copper pillar in the second copper pillar group and the copper pillar of the first copper pillar group at the corresponding position constitute a target copper pillar. The height of each target copper pillar is the same.

[0013] The surface of the encapsulation substrate with the target copper pillar after electroplating is ground until smooth;

[0014] Remove the dry film;

[0015] Remove the exposed copper plating layer.

[0016] Optionally, the encapsulation carrier board of the copper pillar to be electroplated is a large board before the cutting process, and redundant copper pillars prepared at the same time as the target copper pillar are designed in the preset area of ​​the large board.

[0017] When performing the milling process after setting the target copper pillar, the redundant copper pillars are removed simultaneously.

[0018] Optionally, by setting the electroplating plate on the side wall of the electroplating tank in the vertical continuous electroplating process into n regions with current densities distributed in a preset ratio, a first copper column group and a second copper column group with heights arranged in an arithmetic sequence can be obtained.

[0019] Optionally, n is 3.

[0020] Optionally, the resulting target copper pillar is higher than the patterned dry film set before the vertical continuous electroplating process.

[0021] Optionally, the height of each of the target copper pillars is greater than 100 micrometers.

[0022] Alternatively, the copper plating layer can be removed by a flash etching process.

[0023] Optionally, after removing the copper plating layer, an automated optical inspection is performed, using a high-resolution camera to scan the surface of the packaging substrate to detect any defects.

[0024] Optionally, after automatic optical inspection, if the inspection is qualified, surface treatment, milling, electrical testing, and appearance inspection are performed to obtain the final packaging substrate.

[0025] The present invention also provides a packaging carrier board, which is obtained by fabricating copper pillars using any of the above-described methods for packaging carrier boards, and the packaging carrier board includes:

[0026] The target copper pillars are located on the bottom and / or top surfaces of the encapsulation carrier, corresponding to a preset outer layer pattern surface, and all the target copper pillars have the same height.

[0027] The pads are located on the top and / or bottom surfaces of the packaging substrate, corresponding to a preset outer layer pattern surface.

[0028] As described above, the method for fabricating copper pillars using the encapsulation carrier plate of the present invention, and the encapsulation carrier plate itself, have the following beneficial effects:

[0029] This invention increases the height of the target copper pillars by setting n first copper pillar groups with equal heights on the surface of the encapsulation carrier board, and then setting n second copper pillar groups with equal heights on the first copper pillar groups after rotating them up and down. This increases the height of the target copper pillars in the end without exceeding the maximum copper plating amount of existing electroplating chemicals in a single vertical continuous electroplating process.

[0030] This invention increases the achievable height of the target copper pillar, which is beneficial to improving the maturity of double-sided packaging technology and expanding the application range of double-sided packaging technology;

[0031] This invention improves the overall copper residual rate when setting the target copper pillars by simultaneously setting redundant copper pillars in the pattern setting of the large board before the cutting process, thereby reducing the risk of board burning and board leakage, and further improving the uniformity that the target copper pillars can achieve.

[0032] This invention improves the uniformity of high copper pillars without increasing the risk of process defects by setting up areas in the electroplating bath with current density distributed according to a preset ratio. Attached Figure Description

[0033] Figure 1 The diagram shows a schematic of the structure of a packaging substrate in the prior art.

[0034] Figure 2 The diagram shows a structural schematic of a packaging carrier plate with copper pillars in the prior art.

[0035] Figure 3 This diagram illustrates the problems that arise in the prior art when the height of a copper pillar exceeds 100 micrometers.

[0036] Figure 4 This is a schematic diagram of the structure of the encapsulation carrier plate shown in step 1 of the method for fabricating a copper pillar using an encapsulation carrier plate in Embodiment 1 of the present invention.

[0037] Figure 5 This is a schematic diagram of a large plate structure with redundant copper pillars, shown as an example of step 1 in the method of fabricating copper pillars using a carrier plate in Embodiment 1 of the present invention.

[0038] Figure 6 This is a schematic diagram of the structure presented in step 2 of the method for fabricating a copper pillar using a substrate in Embodiment 1 of the present invention, showing the application of a copper plating layer.

[0039] Figure 7 This is a schematic diagram of the structure presented in step 3 of the method for fabricating a copper pillar using a substrate in Embodiment 1 of the present invention, showing the patterned dry film.

[0040] Figure 8 This is a schematic diagram showing the structure of the first copper pillar group formed in step 4 of the method for manufacturing copper pillars using a substrate in Embodiment 1 of the present invention.

[0041] Figure 9 This is a schematic diagram showing the structure of the encapsulation carrier plate after rotation in step 5 of the method for manufacturing copper pillars using an encapsulation carrier plate in Embodiment 1 of the present invention.

[0042] Figure 10 This is a schematic diagram showing the structure of the second copper pillar group in step 5 of the method for manufacturing copper pillars using a substrate in Embodiment 1 of the present invention.

[0043] Figure 11 This is a schematic diagram showing the structure after the target copper pillar is formed in step 5 of the method for making a copper pillar by encapsulating a carrier plate in Embodiment 1 of the present invention.

[0044] Figure 12 This is a schematic diagram showing the structure after grinding the plate in step 6 of the method for manufacturing a copper pillar using a packaged carrier plate in Embodiment 1 of the present invention.

[0045] Figure 13 This is a schematic diagram of the structure after removing the dry film in step 7 of the method for fabricating a copper pillar using a substrate in Embodiment 1 of the present invention, as shown in Embodiment 1 of the present invention.

[0046] Figure 14This is a schematic diagram of the structure after removing the copper plating layer in step 8 of the method for fabricating a copper pillar using a substrate in Embodiment 1 of the present invention.

[0047] Figure 15 The diagram shown is a schematic diagram of the packaging carrier plate in Embodiment 1 of the present invention.

[0048] Figure 16 The diagram shown is a schematic diagram of the packaging carrier plate in Embodiment 2 of the present invention.

[0049] Figure 17 The diagram shown is a schematic diagram of the packaging carrier plate in Embodiment 3 of the present invention.

[0050] Explanation of icon numbers

[0051] 10. Substrate; 11. Copper pillar; 12. Solder pad;

[0052] 20. Packaging substrate; 21. Outer layer pattern; 22. Solder mask layer; 23. Copper plating layer; 24. Dry film; 25. Target copper pillar;

[0053] 30. Large board; 31. Slat; 32. Carrier board unit;

[0054] 40. Electroplating tank; 41. Side wall; 42. First copper column group; 43. Second copper column group; 44. Central shaft; 45. Electroplating plate. Detailed Implementation

[0055] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0056] In the detailed description of embodiments of the present invention, for ease of explanation, the schematic diagrams illustrating the device structure may be partially enlarged without adhering to the general scale, and the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. Furthermore, in actual manufacturing, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0057] For ease of description, spatial relation terms such as “below,” “under,” “lower than,” “below,” “above,” and “upper” may be used herein to describe the relationship between one element or feature shown in the accompanying drawings and other elements or features. It will be understood that these spatial relation terms are intended to include directions other than those depicted in the accompanying drawings for devices in use or operation.

[0058] In the context of this application, the structure described above the first feature may include embodiments in which the first and second features are in direct contact, or embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0059] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex. The quantity range given in the present invention includes the two boundary values ​​of the quantity range by default unless otherwise specified.

[0060] With the increasing demand for system-in-package (SiP) and heterogeneous integration, traditional packaging substrates are shifting from... Figure 1 The single-sided package shown is as follows Figure 2 The development of double-sided packaging is shown. In single-sided packaging, such as... Figure 1 The substrate 10 shown has only pads 12 on its top and bottom surfaces for supporting chips or connecting to the motherboard PCB, whereas in double-sided packaging... Figure 2 The same surface of substrate 10 (shown as the bottom surface) needs to simultaneously support the chip and connect to the motherboard PCB. Therefore, while forming pads 12 to support the chip, copper pillars 11 need to be formed on the same surface of substrate 10 to maintain a reliable electrical connection with the motherboard PCB. Currently, major international packaging substrate manufacturers are developing copper pillar structures, but mature mass production processes are not yet available. Double-sided packaging requires the copper pillars 11 to be over 100 micrometers high, which exceeds the capabilities of existing electroplating technologies. When using traditional electroplating methods to thicken to over 100 micrometers in one go, such as... Figure 3 As shown, problems such as burning, pulverization and adhesion caused by excessive current density at the top of the first and second copper pillars 11 from left to right, uneven thickness due to different heights of the third and fourth copper pillars 11, and incomplete plating due to the failure to form the fifth copper pillar 11 can easily occur, which seriously affect the packaging yield.

[0061] To address the above problems, the present invention provides the following solution:

[0062] Example 1:

[0063] This embodiment provides a method for fabricating copper pillars using a packaging substrate, the method comprising:

[0064] Step 1: Provide a packaging substrate for the copper pillar to be electroplated, wherein the outer patterned surface of the packaging substrate is provided with a patterned solder resist layer;

[0065] Step 2: Apply a copper plating layer to the surface of the packaging substrate using a vertical chemical copper plating process;

[0066] Step 3: Apply a patterned dry film to the surface of the copper plating layer;

[0067] Step 4: The outer pattern surface exposed in the groove between the patterned dry films is formed by a vertical continuous electroplating process on two surfaces or one surface parallel to the side wall of the electroplating tank, forming a group of n first copper pillars with an arithmetic sequence of height from top to bottom, where n is an integer greater than or equal to 2.

[0068] Step 5: Rotate the encapsulation carrier plate in the electroplating tank 180° about the central axis in the direction perpendicular to the side wall of the electroplating tank. Using the same process parameters, form n second copper pillar groups on the first copper pillar group through a vertical continuous electroplating process on two surfaces or one surface parallel to the side wall of the electroplating tank. The second copper pillar group and the copper pillar of the first copper pillar group at the corresponding position together constitute a target copper pillar. The height of each target copper pillar is the same.

[0069] Step 6: Grind the surface of the encapsulation substrate with the target copper pillar after electroplating until the surface is smooth;

[0070] Step 7: Remove the dry film;

[0071] Step 8: Remove the exposed copper plating layer.

[0072] The method for fabricating copper pillars from the encapsulation substrate of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the above order does not strictly represent the order of the method for fabricating copper pillars from the encapsulation substrate protected by the present invention, and those skilled in the art can make changes according to the actual method steps.

[0073] First, such as Figure 4 As shown, in step 1, a packaging substrate 20 for the copper pillar to be electroplated is provided. The outer pattern 21 of the packaging substrate 20 is provided with a patterned solder resist layer 22.

[0074] In one embodiment, such as Figure 5 As shown, the encapsulation carrier 20 of the copper pillar to be electroplated is a large panel 30 before the cutting process. A redundant (dummy) copper pillar is designed in the preset area of ​​the large panel and is prepared at the same time as the target copper pillar 25.

[0075] When performing the milling process after setting the target copper pillar 25, the redundant copper pillars are removed simultaneously.

[0076] Specifically, such as Figure 5As shown, each large board 30 is composed of multiple strips 31, each strip 31 is composed of multiple carrier units 32, and each carrier unit 32 includes a package carrier 20; the preset area of ​​the large board 30 with redundant copper pillars is the position that will be removed according to the design during the subsequent milling process.

[0077] This invention improves the overall copper residual rate of the board when setting the target copper pillars 25 without adding extra process steps by setting the pattern in the large board 30 before the cutting process and setting redundant copper pillars at preset positions that will be removed later. This reduces the local current density, makes the heat and electric field distribution more uniform, provides more conductive paths and bubble escape paths, reduces the risk of board burning and board leakage, and further improves the uniformity that the target copper pillars 25 can achieve.

[0078] Then, as Figure 6 As shown, in step 2, a copper plating layer 23 is compliantly coated on the surface of the packaging substrate 20 by vertical chemical copper plating.

[0079] The present invention provides a conductive substrate for the subsequent copper pillars by setting a copper plating layer 23, thereby enhancing adhesion and providing a flat surface to improve the uniformity of electroplating, ensuring that the subsequent electroplated copper pillars can grow uniformly and firmly.

[0080] Next, as Figure 7 As shown, step 3 is performed, in which a patterned dry film 24 is formed on the surface of the copper plating layer 23.

[0081] In one embodiment, after lamination, exposure, and vertical development, a patterned dry film 24 is obtained to ensure that copper is not plated on non-copper pillar areas in subsequent processes.

[0082] Then, proceed to step 4, as follows: Figure 8 As shown, the outer pattern 21 exposed in the groove between the patterned dry films 24 forms a group of n first copper pillars 42 arranged in an arithmetic sequence from top to bottom on two surfaces or one surface parallel to the side wall 41 of the electroplating tank 40 through a vertical continuous plating process (VCP). n is an integer greater than or equal to 2.

[0083] Specifically, each first copper pillar group 42 includes more than one copper pillar. The attached figure shows only one copper pillar in each first copper pillar group 42. In fact, depending on the actual needs, other numbers of copper pillars can be set in each first copper pillar group 42.

[0084] Specifically, the heights form an arithmetic sequence. The "height" in "heights form an arithmetic sequence" refers to the preset process height of the copper pillars. For example, if there are three groups of first copper pillars 42, the preset process height of each copper pillar in the first copper pillar group 42 with the smallest height is H. The preset process heights of each copper pillar in the other two groups of first copper pillars 42 are H+d, H+2d, and so on. The preset process height of the copper pillars refers to the height of the copper pillars that should be obtained under ideal conditions when performing a vertical continuous electroplating process using preset process equipment and process parameters. The actual height of the copper pillars may deviate slightly from the preset process height due to minor disturbances caused by factors such as the actual process environment.

[0085] In one embodiment, n is 3.

[0086] This invention achieves a dual optimization between increasing the achievable height of the copper pillar and reducing process costs by setting n to 3. This avoids overly complex process improvements due to setting too many different electroplating parameter areas in the electroplating tank 40, while simultaneously meeting the current requirements for copper pillar height in double-sided packaging. Specifically, n can also be set to other numbers according to actual needs, all of which are within the scope of this invention.

[0087] Next, proceed to step 5, as follows: Figure 9 As shown, the encapsulation carrier plate 20 inside the electroplating tank 40 is rotated 180° about the central axis 44 in a direction perpendicular to the side wall 41 of the electroplating tank 40, as... Figure 10 As shown, using the same process parameters, n second copper pillar groups 43 are formed on two surfaces or one surface parallel to the side wall 41 of the electroplating tank 40 within the first copper pillar group 42 through a vertical continuous electroplating process. These second copper pillar groups 43 are arranged in an arithmetic sequence with the same height from top to bottom. Each copper pillar in the second copper pillar group 43 and the copper pillar in the corresponding position of the first copper pillar group 42 together constitute a target copper pillar. The height of each target copper pillar 25 is the same.

[0088] This invention sets up n first copper pillar groups 42 with equal heights on the surface of the encapsulation carrier 20. After rotating it up and down, second copper pillar groups 43 with the same equal heights are set on the first copper pillar groups 42 using the same process parameters. The equal heights set in the two steps are complementary and added together by rotating the encapsulation carrier 20, ensuring that the target copper pillars 25 formed by the copper pillars at corresponding positions in each first copper pillar group 42 and second copper pillar group 43 have the same height. This increases the final height of the target copper pillars 25 without exceeding the maximum copper plating amount of existing electroplating solutions in a single vertical continuous electroplating process, and ensures the height uniformity among the target copper pillars 25. This is beneficial for improving the maturity of double-sided encapsulation technology and expanding its application range. Furthermore, this invention breaks the constraint of needing to use expensive and limited-use special electroplating solutions to meet the height requirements of double-sided encapsulation technology. The encapsulation carrier 20 can be prepared using existing materials in the factory, reducing costs while achieving double-sided encapsulation, saving time on changing electroplating solutions on the production line, and solving the limitations of electroplating solutions.

[0089] Specifically, each second copper pillar group 43 includes more than one copper pillar. The attached figure shows only one copper pillar in each second copper pillar group 43. In fact, depending on the actual needs, other numbers of copper pillars can be set in each second copper pillar group 43.

[0090] In one embodiment, such as Figures 8-10 As shown, by setting the electroplating plate 45 on the side wall 41 of the electroplating tank 40 in the vertical continuous electroplating process as n regions with current densities distributed according to a preset ratio (e.g., ... Figures 8-10 From the three regions A, B, and C in the diagram, we can obtain the first copper column group 42 and the second copper column group 43, which are arranged in an arithmetic sequence.

[0091] This invention improves the uniformity of high-quality copper pillars by setting regions within the electroplating tank 40 with a preset ratio of current density, without increasing the risk of process defects. Assuming the heights of the copper pillars in the n first copper pillar groups 42 form an arithmetic sequence (e.g., heights H, H+d, H+2d respectively), experiments can determine the ratio of current density provided by the electroplating plate 45 on the sidewall 41 of the electroplating tank 40 to the locations of the copper pillars in each of the n first copper pillar groups 42 with an arithmetic sequence. This experimentally obtained current density ratio that achieves the arithmetic sequence of copper pillar heights is called the "preset ratio." Specifically, based on the experimentally obtained correspondence between the current density of the electroplating tank 40 and the copper pillar height, the current density of each region on the sidewall 41 of the electroplating tank 40 is set according to this correspondence, so that the copper pillar heights of each first copper pillar group 42 and each second copper pillar group 43 are all in an arithmetic sequence, thereby obtaining target copper pillars 25 with good quality and the required height.

[0092] Specifically, other parameters of the electroplating process (such as electroplating time, electrode spacing of electroplating tank 40, nozzle spray flow rate and angle, current waveform, shielding plate, etc.) can be set in zones according to actual needs to achieve copper pillars arranged in an arithmetic sequence of heights, all of which are within the protection scope of this invention.

[0093] In one embodiment, such as Figure 11 As shown, the resulting target copper pillar 25 is higher than the patterned dry film 24 set before the vertical continuous electroplating process.

[0094] Because a grinding process is required after electroplating, and a dry film 24 grinding plate is needed to protect the outer pattern 21, the surface of the dry film 24 is relatively smooth. If the height of the target copper pillar 25 is lower than the height of the dry film 24, the grinding surface is prone to slippage, causing uneven grinding. Therefore, to facilitate grinding, after multiple electroplating processes, the height of the target copper pillar 25 needs to be higher than the thickness of the dry film 24, in order to further improve the surface flatness of the encapsulation substrate 20 after setting the target copper pillar 25, thereby improving the product quality of the encapsulation substrate 20.

[0095] In one embodiment, the height of each of the target copper pillars 25 is greater than 100 micrometers.

[0096] Since the height of the copper pillars in the current double-sided packaging process cannot be higher than 100 micrometers, the present invention sets the height of the target copper pillar 25 to be higher than 100 micrometers, which can better reflect the advantages of the present invention in increasing the height of the copper pillars. Specifically, other suitable heights of the target copper pillar 25 can also be set according to actual needs, all of which are within the protection scope of the present invention.

[0097] Then, as Figure 12 As shown, in step 6, the surface of the encapsulation carrier 20 with the target copper pillar 25 after electroplating is ground until the surface is smooth.

[0098] Next, as Figure 13 As shown, proceed to step 7 to remove the dry film 24.

[0099] The present invention exposes the copper plating layer 23 by removing the dry film 24 after setting the target copper pillar 25.

[0100] Finally, as Figure 14 As shown, step 8 is performed to remove the exposed copper plating layer 23.

[0101] In one embodiment, the copper plating layer 23 is removed by a flash etching process.

[0102] In one embodiment, after removing the copper plating layer 23, an automated optical inspection (AOI) is performed, using a high-resolution camera to scan the surface of the package carrier 20 to detect any defects.

[0103] In one embodiment, after automatic optical inspection, if the inspection is qualified, surface finishing, milling, electrical testing, and visual inspection are performed to obtain the final packaging substrate 20.

[0104] Specifically, automated optical inspection refers to scanning the board surface with a high-resolution camera, comparing it with the CAD design, and detecting defects such as circuit gaps, short circuits, copper slag, and hole breaks; surface treatment refers to coating the exposed copper pads with a protective layer to prevent oxidation and ensure solderability, such as hot air leveling, chemical nickel plating, organic solder mask, immersion tin, and immersion silver; milling refers to using a high-speed spindle and milling cutter to mill a large board into individual strips according to the programmed path; electrical testing refers to open and short circuit testing, using a flying probe tester or fixture tester to probe all electrical connection networks point by point to ensure there are no open circuits or short circuits; visual inspection refers to manually or automatically inspecting the board surface for defects such as stains, scratches, solder mask detachment, blurred characters, and board warping.

[0105] Specifically, other necessary processing steps can be performed after obtaining the target copper pillar 25, all of which are within the protection scope of this invention.

[0106] The conventional mSAP (Modified Semi-Additive Process) flow involves a pre-process, followed by laser drilling, then vertical chemical copper plating, film lamination, exposure, vertical development, vertical continuous electroplating, film removal, flash etching, and the application of a solder mask layer 22, before final processing. However, when fabricating copper pillars using the mSAP process, the pre-process involves applying a solder mask layer 22, followed by vertical chemical copper plating, film lamination, exposure, and vertical development, then vertical continuous electroplating, grinding, film removal, flash etching, and finally surface treatment and final processing. This invention improves the mSAP process by creating copper pillars in the electroplating tank 40 twice, forming copper pillars with heights in an arithmetic progression. This increases the final height of the target copper pillar 25, allowing it to meet the height requirements of double-sided packaging processes.

[0107] This embodiment also provides a packaging carrier 20, which is obtained by any of the above-described methods for fabricating copper pillars using a packaging carrier, such as... Figure 15 As shown, the packaging carrier 20 includes:

[0108] The target copper pillar 25 is located on the top surface of the encapsulation carrier 20, corresponding to the surface of the preset outer layer pattern 21, and each target copper pillar 25 has the same height.

[0109] The pad 12 is located on the top and / or bottom surface of the packaging substrate 20, corresponding to the surface of the preset outer layer pattern 21.

[0110] The present invention obtains the target copper pillar 25 by adopting the aforementioned method, so that the target copper pillar 25 formed on the packaging carrier 20 using existing materials in the carrier factory can be used for double-sided packaging process to package the chip on the same surface of the carrier 20, while being electrically connected to the PCB through the target copper pillar 25. Double-sided packaging with higher integration is achieved without the use of special electroplating solution, thereby reducing the cost of double-sided packaging and improving the efficiency of double-sided packaging.

[0111] In one embodiment, a solder mask layer is provided on the outer layer pattern 21 of the packaging substrate 20 at locations where the target copper pillars 25 and solder pads 12 are not located. Alternatively, the solder mask layer may be omitted, both of which are within the scope of this invention.

[0112] Example 2:

[0113] This embodiment provides a packaging carrier 20, which has other features that are basically the same as those in Embodiment 1, except that:

[0114] In this embodiment, as Figure 16 As shown, the target copper pillar 25 is located only on the bottom surface of the encapsulation carrier 20, corresponding to the surface of the preset outer layer pattern 21.

[0115] Example 3:

[0116] This embodiment provides a packaging carrier 20, which has other features that are basically the same as those in Embodiment 1, except that:

[0117] In this embodiment, as Figure 17 As shown, the target copper pillar 25 is located on both the top and bottom surfaces of the encapsulation carrier 20, corresponding to the surface of the preset outer layer pattern 21.

[0118] Specifically, the pad 12 is used to enable the package carrier 20 to carry the bare die, and the target copper pillar 25 is used to electrically connect the package carrier 20 to the PCB (Printed Circuit Board).

[0119] In summary, the method for fabricating copper pillars on the packaging substrate and the packaging substrate of the present invention can increase the height of the final target copper pillars by setting n first copper pillar groups with equal heights on the surface of the packaging substrate, and then setting n second copper pillar groups with equal heights on the first copper pillar groups after rotating up and down. This increases the height of the target copper pillars without exceeding the maximum copper plating amount of existing electroplating solutions in a single vertical continuous electroplating process. At the same time, by increasing the achievable height of the target copper pillars, it is beneficial to improve the maturity of double-sided packaging technology and expand the application range of double-sided packaging technology. In addition, by setting redundant copper pillars in the pattern setting in the large board before the cutting process, the residual copper rate of the whole board when setting the target copper pillars is improved, thereby reducing the risk of board burning and board leakage, and further improving the uniformity of the target copper pillars. Finally, by setting an area in the electroplating tank with current density distributed according to a preset ratio, the uniformity of high copper pillars can be improved without increasing the risk of process defects.

[0120] Therefore, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0121] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for fabricating copper pillars using a substrate, characterized in that, The method includes: A packaging substrate for electroplating copper pillars is provided, wherein a patterned solder resist layer is provided on the outer patterned surface of the packaging substrate; A copper plating layer is compliantly coated onto the surface of the packaging substrate using vertical chemical copper plating. A patterned dry film is formed on the surface of the copper plating layer; The outer patterned surface exposed in the grooves between the patterned dry films is formed by a vertical continuous electroplating process on two surfaces or one surface parallel to the side wall of the electroplating tank, forming n first copper pillar groups with an arithmetic sequence of height from top to bottom, where n is an integer greater than or equal to 2. The encapsulation carrier plate in the electroplating tank is rotated 180° about the central axis in the direction perpendicular to the side wall of the electroplating tank. Using the same process parameters, n second copper pillar groups are formed on two surfaces or one surface parallel to the side wall of the electroplating tank through a vertical continuous electroplating process. The height of each second copper pillar group is the same as that of the first copper pillar group. Each copper pillar in the second copper pillar group and the copper pillar of the first copper pillar group at the corresponding position constitute a target copper pillar. The height of each target copper pillar is the same. The surface of the encapsulation substrate with the target copper pillar after electroplating is ground until smooth; Remove the dry film; Remove the exposed copper plating layer.

2. The method for fabricating copper pillars using a packaging carrier plate according to claim 1, characterized in that, Before the cutting process, the packaging carrier board of the copper pillar to be electroplated is a large board. The preset area of ​​the large board is designed with redundant copper pillars that are prepared at the same time as the target copper pillar. When performing the milling process after setting the target copper pillar, the redundant copper pillars are removed simultaneously.

3. The method for fabricating copper pillars using a packaging carrier plate according to claim 1, characterized in that, By setting the electroplating plates on the sidewall of the electroplating tank in the vertical continuous electroplating process into n regions with current densities distributed in a preset ratio, a first group of copper pillars and a second group of copper pillars with heights arranged in an arithmetic sequence can be obtained.

4. The method for fabricating copper pillars using a packaging substrate according to claim 1, characterized in that, n is 3.

5. The method for fabricating copper pillars using a packaging carrier plate according to claim 1, characterized in that, The resulting target copper pillar is higher than the patterned dry film set before the vertical continuous electroplating process.

6. The method for fabricating copper pillars using a packaging carrier plate according to claim 1, characterized in that, Each of the target copper pillars has a height greater than 100 micrometers.

7. The method for fabricating copper pillars using a packaging carrier plate according to claim 1, characterized in that, The copper plating layer is removed by a flash etching process.

8. The method for fabricating copper pillars using a packaging substrate according to claim 1, characterized in that, After removing the copper plating layer, an automated optical inspection is performed, using a high-resolution camera to scan the surface of the packaging substrate to detect any defects.

9. The method for fabricating copper pillars using a packaging substrate according to claim 8, characterized in that, After automatic optical inspection, if the inspection is qualified, surface treatment, milling, electrical testing, and appearance inspection are carried out to obtain the final packaging substrate.

10. A packaging carrier board, characterized in that, The encapsulation carrier is obtained by the method for fabricating copper pillars using the encapsulation carrier as described in any one of claims 1-9, and the encapsulation carrier comprises: The target copper pillars are located on the bottom and / or top surfaces of the encapsulation carrier, corresponding to a preset outer layer pattern surface, and all the target copper pillars have the same height. The pads are located on the top and / or bottom surfaces of the packaging substrate, corresponding to a preset outer layer pattern surface.

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