Method for roughening a packaging structure

Abstract

A roughening method of a packaging structure, the method comprising: providing a non-roughened lead frame; disposing a chip and leads on the non-roughened lead frame, the chip, the leads and the lead frame constituting a product to be roughened; obtaining a wiring pattern recognition model of the product to be roughened; identifying a prohibited roughening area of the lead frame based on the wiring pattern recognition model, the prohibited roughening area at least including a projection area of the chip on a surface of the lead frame and a projection area of the leads on the surface of the lead frame; and performing laser roughening treatment on a surface of the lead frame outside the prohibited roughening area to form a roughened lead frame. By performing laser roughening treatment on the surface of the lead frame outside the prohibited roughening area, the effective roughening area of the product to be roughened can be maximized, which is conducive to forming a lead frame with a micro-roughening structure (i.e., a lock glue structure), thereby significantly improving the delamination resistance and reliability of the packaging structure.

Description

Technical Field

[0001] This disclosure relates to the field of semiconductor manufacturing, and more particularly to a method for roughening a packaging structure. Background Technology

[0002] In the field of semiconductor packaging technology, the leadframe, as a key structural component that carries the chip, conducts electrical signals outward, and provides a heat dissipation path, is crucial for the reliability of its interface bonding with the molding compound. To enhance the adhesion between the molding compound and the metal leadframe and prevent interface delamination failure under environmental stresses such as temperature cycling and humidity, the industry commonly roughens the surface of the leadframe during the manufacturing stage before packaging. This roughening process aims to increase the microscopic roughness and effective contact area of ​​the leadframe surface, thereby creating a stronger mechanical interlocking effect with the molding compound in subsequent encapsulation processes. Traditional roughening techniques include chemical etching, sandblasting, and laser processing, and can be implemented as single-sided, double-sided, or locally in specific areas according to design requirements.

[0003] As semiconductor devices evolve towards miniaturization, high density, and high reliability, packaging structures are becoming increasingly complex, leading to higher requirements for the compatibility of leadframe surface conditions. While pursuing higher bonding strength, it is also necessary to consider the potential impact of roughened surfaces on subsequent precision assembly processes, such as chip mounting accuracy, wire bonding quality, and material coating controllability. To address this, a technique of selectively roughening the leadframe has emerged. This technique aims to retain the original flat surface in critical functional areas (such as chip mounting areas and bonding areas) while roughening other areas, seeking a balance between packaging reliability and front-end process feasibility. This localized roughening strategy has become a common technical choice for addressing complex packaging requirements.

[0004] Currently, the resistance to delamination and reliability of packaging structures still need to be improved. Summary of the Invention

[0005] The problem addressed by the embodiments of this disclosure is to provide a method for coarsening a packaging structure, thereby improving the packaging structure's resistance to delamination and its reliability.

[0006] To address the aforementioned problems, this disclosure provides a method for roughening a package structure, comprising: providing a non-roughened lead frame; setting a chip and leads on the non-roughened lead frame, wherein the chip, leads, and lead frame constitute a product to be roughened; obtaining a wiring pattern recognition model of the product to be roughened; identifying prohibited roughening regions of the lead frame based on the wiring pattern recognition model, wherein the prohibited roughening regions include at least the projection region of the chip on the surface of the lead frame and the projection region of the leads on the surface of the lead frame; and performing laser roughening treatment on the surface of the lead frame outside the prohibited roughening regions to form a roughened lead frame.

[0007] Optionally, the step of obtaining the wiring pattern recognition model of the product to be coarsened includes: acquiring images and processing data of the product to be coarsened using an automatic optical inspection device to generate the wiring pattern recognition model of the product to be coarsened.

[0008] Optionally, the step of identifying the prohibited coarsening region of the lead frame includes: extracting the geometric contour of the projection region of the chip on the surface of the lead frame and the geometric contour of the projection region of the lead on the surface of the lead frame based on the wiring pattern recognition model; and delineating the prohibited coarsening region on the surface of the lead frame based on the geometric contour.

[0009] Optionally, the step of laser roughening the surface outside the prohibited roughening region of the lead frame includes: selecting a laser processing light source; controlling the laser processing light source to scan the surface outside the prohibited roughening region, thereby forming a micro-roughening structure on the surface outside the prohibited roughening region.

[0010] Optionally, the laser processing light source selected for the laser roughening process includes one or both of nanosecond pulse lasers and femtosecond pulse lasers.

[0011] Optionally, the step of controlling the laser processing light source to scan the surface outside the prohibited roughening area includes: controlling the laser processing light source to scan a single side of the lead frame; or, controlling the laser processing light source to scan multiple sides of the lead frame.

[0012] Optionally, the step of controlling the laser processing light source to scan multiple surfaces of the lead frame includes: using multiple beams of the laser processing light source to scan multiple surfaces of the lead frame.

[0013] Optionally, the step of controlling the laser processing light source to scan the surface outside the prohibited roughening area includes: driving the laser processing light source to scan the surface outside the prohibited roughening area according to a predetermined scanning path and scanning parameters.

[0014] Optionally, the scanning parameters include one or more of the following: wavelength, output power, pulse energy, repetition frequency, and scanning speed of the laser processing light source.

[0015] Optionally, the predetermined scan path includes: a scan path predetermined based on the surface shape outside the prohibited roughening region of the lead frame.

[0016] Optionally, the micro-coarsening structure includes one or more of circular grooves, honeycomb grooves, and rectangular grooves.

[0017] Optionally, the micro-coarsening structures are arranged in a uniform array on the surface outside the prohibited coarsening region of the lead frame.

[0018] Optionally, after setting the chip and leads on the uncoarsened lead frame, and before obtaining the wiring pattern recognition model of the product to be coarsened, the coarsening method further includes: placing the product to be coarsened on a support pad.

[0019] Optionally, the bearing pad includes a liquid-cooled pad.

[0020] Optionally, the liquid cooling pad has a coolant circulation channel inside.

[0021] Optionally, after the step of laser roughening the surface outside the prohibited roughening area of ​​the lead frame, the roughening method further includes: using the wiring pattern recognition model to perform optical inspection on the roughened lead frame.

[0022] Optionally, the steps of acquiring the wiring pattern recognition model, identifying the prohibited roughening region, and performing laser roughening treatment on the surface outside the prohibited roughening region of the lead frame are all completed on the same automated optical inspection equipment integrated with a laser roughening module.

[0023] Optionally, the step of setting the chip on the non-coarsened lead frame includes: setting the chip on the lead frame by means of an adhesive layer.

[0024] Optionally, the process of setting leads on the uncoarsened lead frame includes a wire bonding process.

[0025] Optionally, in the step of providing a non-coarsened lead frame, the lead frame includes a base and pins; in the step of setting a chip and a lead on the non-coarsened lead frame, the chip is set on the base, one end of the lead is electrically connected to the chip, and the other end of the lead is electrically connected to the pin.

[0026] Optionally, after laser roughening, the method may further include forming a molding compound layer that covers the substrate and the chip.

[0027] Optionally, the material of the encapsulation layer includes epoxy resin.

[0028] Compared with the prior art, the technical solution of the present disclosure has the following advantages: The roughening method for the packaging structure provided in this disclosure involves setting a chip and leads on a non-roughened lead frame, wherein the chip, leads, and lead frame constitute a product to be roughened. A wiring pattern recognition model of the product to be roughened is obtained. Based on the wiring pattern recognition model, prohibited roughening regions of the lead frame are identified. These prohibited roughening regions include at least the projection areas of the chip and the leads on the surface of the lead frame. In other words, by first setting the chip and leads on the non-roughened lead frame to form the product to be roughened, subsequent laser roughening processing will not interfere with the preceding assembly process, thereby avoiding… To address the difficulties in subsequent die bonding identification and energy dissipation issues caused by pre-roughening of the leadframe, this method acquires a wiring pattern recognition model of the product to be roughened and accurately identifies prohibited roughening areas. This ensures that laser roughening strictly avoids the projection areas of the chip and leads on the leadframe surface, thus achieving precise roughening. Furthermore, by performing laser roughening on the surface outside the prohibited roughening areas on the leadframe, the effective roughening area can be maximized on the product to be roughened, facilitating the formation of a leadframe with a micro-roughened structure (i.e., a glue-locking structure). This significantly improves the package structure's resistance to delamination and reliability. Attached Figure Description

[0029] Figure 1 This is a flowchart of the steps corresponding to the coarsening method of the packaging structure implemented in this disclosure; Figures 2 to 5 This is a schematic diagram of the structure corresponding to each step of an embodiment of the roughening method for the packaging structure of this disclosure. Detailed Implementation

[0030] Currently, the resistance to delamination and reliability of packaging structures still need to be improved.

[0031] In traditional semiconductor packaging processes, lead frame roughening is a separate step after manufacturing and before assembly.

[0032] The specific process is as follows: First, the leadframe, after being stamped or etched, is sent to a roughening process. Using methods such as chemical etching, sandblasting, or laser processing, the entire surface of the leadframe (double-sided roughening), a single surface (single-sided roughening), or a specific area outside the predetermined functional region (local roughening) is modified to create a microscopically rough morphology. This roughening process aims to increase the adhesion to the molding compound during subsequent molding. The roughened leadframe, as raw material, enters a standard packaging assembly line for subsequent processes such as die attach, wire bonding, and molding.

[0033] Although the aforementioned traditional roughening process aims to improve the reliability of the final package, the process sequence of roughening followed by assembly in semiconductor packaging has itself caused the following technical problems, the specific manifestations of which and their root causes are as follows: Firstly, after the lead frame surface is roughened, it changes from a smooth surface to a diffuse reflective surface, and the incident light is strongly scattered, making it difficult for the vision system to capture clear, high-contrast image features. After roughening, the color of the lead frame surface becomes darker and the reflective properties change, resulting in a serious decrease in the contrast of the automatic optical alignment system, causing positioning deviations when picking up and placing the chip. At the same time, the rough surface exacerbates the uncontrolled lateral diffusion of the bottom filler or silver paste.

[0034] Secondly, the roughening process is completed before assembly. Its pattern design must be based on the prediction of the subsequent chip size and lead layout, leaving sufficient process margin and space. In order to avoid the roughened area from interfering with chip mounting and lead bonding, the local roughening scheme must reserve a large flat safety area around the chip and bonding wire. This results in a significant reduction in the effective roughening area used to enhance bonding, which affects the anti-delamination ability of the packaging structure and thus affects the reliability of the packaging structure.

[0035] To address the aforementioned technical problems, this disclosure provides a method for coarsening a packaging structure. Specifically, Figure 1 A flowchart of the steps corresponding to the roughening method of the packaging structure according to the present disclosure is shown.

[0036] Step S1: Provide a non-coarsened lead frame; Step S2: A chip and a lead are disposed on the uncoarsened lead frame, wherein the chip, the lead, and the lead frame constitute the product to be coarsened; Step S3: Obtain the wiring pattern recognition model of the product to be coarsened; Step S4: Based on the wiring pattern recognition model, identify the prohibited coarsening region of the lead frame. The prohibited coarsening region includes at least the projection region of the chip on the surface of the lead frame and the projection region of the lead on the surface of the lead frame. Step S5: Perform laser roughening treatment on the surface outside the prohibited roughening area of ​​the lead frame to form a roughened lead frame.

[0037] The roughening method for the packaging structure provided in this disclosure involves setting a chip and leads on a non-roughened lead frame, wherein the chip, leads, and lead frame constitute a product to be roughened. A wiring pattern recognition model of the product to be roughened is obtained. Based on the wiring pattern recognition model, prohibited roughening regions of the lead frame are identified. These prohibited roughening regions include at least the projection areas of the chip and the leads on the surface of the lead frame. In other words, by first setting the chip and leads on the non-roughened lead frame to form the product to be roughened, subsequent laser roughening processing will not interfere with the preceding assembly process, thereby avoiding… To address the difficulties in subsequent die bonding identification and energy dissipation issues caused by pre-roughening of the leadframe, this method acquires a wiring pattern recognition model of the product to be roughened and accurately identifies prohibited roughening areas. This ensures that laser roughening strictly avoids the projection areas of the chip and leads on the leadframe surface, thus achieving precise roughening. Furthermore, by performing laser roughening on the surface outside the prohibited roughening areas on the leadframe, the effective roughening area can be maximized on the product to be roughened. This facilitates the formation of a leadframe with a micro-roughened structure (i.e., a glue-locking structure), thereby significantly improving the package structure's resistance to delamination and reliability.

[0038] To make the above-mentioned objects, features and advantages of the embodiments of this disclosure more apparent and understandable, the specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings.

[0039] in, Figures 2 to 5 This is a schematic diagram of the structure corresponding to each step of an embodiment of the roughening method for the packaging structure of this disclosure.

[0040] refer to Figure 2 Provides a non-coarsened lead frame 102.

[0041] Specifically, the surface of the lead frame 102 is not roughened, and its surface remains smooth with consistent optical reflection characteristics. This creates superior process conditions for the subsequent placement of the chip 111 and the lead 110 on its surface. During the placement of the chip 111, the smooth surface enables the automatic optical inspection system to obtain high-contrast, clear images, thereby achieving accurate identification and alignment of the chip 111 position. This effectively avoids problems such as identification difficulties, chip 111 misalignment, and poor application of bottom filler or silver paste caused by surface roughness or uneven color. At the same time, during the wire bonding process, the smooth surface of the lead frame 102 is more efficient in energy transfer, reducing energy scattering and loss at rough interfaces, which is conducive to the formation of firmly bonded solder joints. It also reduces the wear caused by friction of the wire bonding cutter on the rough surface and extends the service life of the cutter.

[0042] In some embodiments, the material of the lead frame 102 includes one or more of copper, copper alloys, and iron-nickel alloys.

[0043] Specifically, copper, copper alloys, and iron-nickel alloys are all metallic materials with good electrical conductivity, high thermal conductivity, and high mechanical strength.

[0044] In some embodiments, during the step of providing a non-coarsened lead frame 102, the lead frame 102 includes a base 100 and pins 101.

[0045] Specifically, the base 100 is used to fix and support the chip for subsequent installation, and provides mechanical support and heat dissipation path for the chip.

[0046] It should be noted that pin 101 is used to bring out the electrical signals of the packaged chip to an external circuit board or other devices to achieve electrical interconnection.

[0047] In some embodiments, the pins 101 typically extend outward from the side of the base 100, and the pins 101 and the base 100 constitute the lead frame 102. The pins 101 are arranged around the base 100, and their specific number and layout depend on the input / output requirements of the chip 111.

[0048] Continue to refer to Figure 2 A chip 111 and a lead 110 are disposed on the uncoarsened lead frame 102, and the chip 111, the lead 110 and the lead frame 102 constitute the product 120 to be coarsened.

[0049] Specifically, before subsequent laser roughening, chips 111 and leads 110 are set on the unroughened lead frame 102. This creates superior process conditions for the subsequent setting of chips 111 and leads 110 on its surface, completely eliminating the negative impact on the identification accuracy of the die (i.e., setting of chips 111) and the energy transfer of the bonding wires (i.e. leads 110) caused by the pre-roughening of the lead frame 102, thereby improving the reliability of the packaging structure.

[0050] In some embodiments, the step of setting the chip 111 on the uncoarsened lead frame 102 includes setting the chip 111 on the lead frame 102 via an adhesive layer 112.

[0051] In some embodiments, the process of setting the leads 110 on the uncoarsened lead frame 102 includes a wire bonding process.

[0052] Specifically, the wire bonding process is performed on the non-roughened lead frame 102. Since the surface of the pin 101 is smooth, the ultrasonic energy can be effectively concentrated on the interface of the lead frame 102, which is conducive to forming a strong solder joint and thus obtaining a reliable electrical connection.

[0053] In some embodiments, in the step of setting the chip 111 and the lead 110 on the non-coarsened lead frame 102, the chip 111 is set on the base 100, one end of the lead 110 is electrically connected to the chip 111, and the other end of the lead 110 is electrically connected to the pin 101.

[0054] It should be noted that one end of the lead 110 is electrically connected to the chip 111, and the other end of the lead 110 is electrically connected to the pin 101, which can establish an electrical path from the internal circuit of the chip 111 to the external package pin 101. This allows the electrical signals generated by the chip 111 or the required external power supply to be transmitted to the pin 101 through the lead 110, and then to communicate and supply power to the external system through the pin 101.

[0055] In some embodiments, the specific type of chip 111 can be selected according to actual needs. For example, chip 111 may include one or more of the following: ASIC (Application-Specific Integrated Circuit) chip, HBM (High Bandwidth Memory) chip, CPU (Central Processing Unit) chip, GPU (Graphics Processing Unit) chip, and FPGA (Field-Programmable Gate Array) chip.

[0056] Continue to refer to Figure 2 Obtain the wiring pattern recognition model of the product 120 to be coarsened.

[0057] Specifically, by acquiring the wiring pattern recognition model of the product 120 to be roughened, it is beneficial to accurately identify the prohibited roughening area in the future, and to ensure that the laser roughening process can strictly avoid the projection area of ​​the chip 111 and the lead wire 110 on the surface of the lead frame 102, thereby achieving the accuracy of the roughening area.

[0058] In some embodiments, the step of obtaining the wiring pattern recognition model of the product 120 to be coarsened includes: performing image acquisition and data processing on the product 120 to be coarsened using an automatic optical inspection device to generate the wiring pattern recognition model of the product 120 to be coarsened.

[0059] It should be noted that the image acquisition uses an optical imaging system to obtain a high-definition digital image of the product 120 to be coarsened, converting the physical spatial layout of the chip 111, lead wire 110, solder joints and lead frame 102 into image information that can be processed by a computer, providing the raw data foundation for subsequent analysis. The data processing is used to perform a series of algorithmic processing on the acquired image, namely filtering and noise reduction to improve the signal-to-noise ratio, image enhancement to improve feature visibility, edge detection and contour extraction to identify the precise boundaries of the chip 111 and lead wire 110, and finally integrating this information to generate a digital model that can accurately describe the geometric features of the product wiring, namely the wiring pattern recognition model.

[0060] refer to Figure 3 Based on the wiring pattern recognition model, the prohibited coarsening region 100A of the lead frame 102 is identified. The prohibited coarsening region 100A includes at least the projection region of the chip 111 on the surface of the lead frame 102 and the projection region of the lead 110 on the surface of the lead frame 102.

[0061] It should be noted that by identifying the prohibited roughening area 100A, the laser roughening process can strictly avoid the projection areas of the chip 111 and the lead wire 110 on the surface of the lead frame 102, thereby achieving precision in the roughening area. Furthermore, this facilitates subsequent laser roughening of the surface outside the prohibited roughening area 100A on the lead frame 102, maximizing the effective roughening area on the product 120 to be roughened. This is beneficial for forming a lead frame 102 with a micro-roughening structure (i.e., a glue-locking structure), thereby significantly improving the packaging structure's resistance to delamination and reliability.

[0062] In some embodiments, the step of identifying the prohibited roughening region 100A of the lead frame 102 includes: extracting the geometric contour of the projection region of the chip 111 on the surface of the lead frame 102 and the geometric contour of the projection region of the lead 110 on the surface of the lead frame 102 based on the wiring pattern recognition model; and delineating the prohibited roughening region 100A on the surface of the lead frame 102 based on the geometric contours.

[0063] Specifically, by extracting the geometric contour based on the wiring pattern recognition model, the actual space occupied by components such as chip 111 and lead wire 110 on the lead frame 102 can be accurately obtained with an accuracy of micrometer level. Then, based on the geometric contour, the prohibited roughening region 100A is delineated on the surface of the lead frame 102. This can directly convert the geometric contour into a no-go zone instruction in the subsequent laser roughening process, ensuring that the laser beam is less likely to be mistakenly scanned to key components such as chip 111 and lead wire 110, and reducing the risk of damage to chip 111 and lead wire 110.

[0064] Continue to refer to Figure 3 After setting the chip 111 and the lead 110 on the uncoarsened lead frame 102, before obtaining the wiring pattern recognition model of the product to be coarsened 120, the coarsening method further includes: placing the product to be coarsened 120 on the support pad 140.

[0065] It should be noted that the bearing pad 140 is used to stabilize and position the product 120 to be roughened during subsequent optical inspection and laser roughening processes, ensuring its fixed position to guarantee the stability of image acquisition and the positioning accuracy of laser scanning.

[0066] In some embodiments, the support pad 140 includes a liquid-cooled pad.

[0067] Specifically, during the subsequent laser roughening process, the laser energy acting on the surface of the lead frame 102 will generate heat. The liquid cooling pad can effectively absorb and remove this heat, preventing the heat from accumulating on the product 120 to be roughened and causing local overheating. This avoids problems such as chip 111 damage, decreased reliability of lead wire 110 connection, or product deformation caused by local overheating, and further improves the reliability of the packaging structure.

[0068] In some embodiments, the liquid cooling pad has a coolant circulation channel inside.

[0069] It should be noted that the liquid-cooled pad has a coolant circulation channel inside to form a cooling circulation system. The coolant flows through the channel and exchanges heat with the heat-absorbing bearing pad 140 body, thereby reducing the surface temperature of the product 120 to be roughened.

[0070] refer to Figures 4 to 5 Laser roughening is performed on the surface outside the prohibited roughening region 100A of the lead frame 102 to form a roughened lead frame 130.

[0071] Specifically, the laser roughening process uses a laser to create a micro-roughened structure 180 on a specific area of ​​the lead frame 102 surface (i.e., the surface outside the prohibited roughening area 100A of the lead frame 102). The micro-roughened structure 180 can form a strong mechanical interlocking effect with the injected molding compound in the subsequent molding process, which greatly enhances the bonding force between the molding compound and the roughened lead frame 130, thereby reducing the probability of delamination failure in the packaging structure and improving the reliability of the packaging structure.

[0072] In some embodiments, the step of performing laser roughening treatment on the surface outside the prohibited roughening region 100A of the lead frame 102 includes: selecting a laser processing light source; controlling the laser processing light source to scan the surface outside the prohibited roughening region 100A, and forming a micro-roughening structure 180 on the surface outside the prohibited roughening region 100A.

[0073] Specifically, by selecting a laser processing light source, the most suitable laser type can be selected based on the material of the lead frame 102 and the morphology of the required roughening structure. The laser processing light source is controlled to scan to form a micro-roughening structure 180, which enables patterning and customization of the surface of the lead frame 102 outside the prohibited roughening area 100A.

[0074] In some embodiments, the laser processing light source selected for the laser roughening process includes one or both of nanosecond pulse lasers and femtosecond pulse lasers.

[0075] It should be noted that both nanosecond pulsed lasers and femtosecond pulsed lasers are suitable for precision micromachining. Nanosecond pulsed lasers have mature technology, relatively low cost, and high processing efficiency, making them suitable for applications where heat-affected zones are not particularly stringent. In contrast, femtosecond pulsed lasers have extremely short pulse durations and minimal heat diffusion effects, enabling submicron-level processing accuracy with almost no heat-affected zone, thus avoiding the risk of thermal damage.

[0076] In some embodiments, the step of controlling the laser processing light source to scan the surface outside the prohibited roughening region 100A includes: controlling the laser processing light source to scan a single side of the lead frame 102; or, controlling the laser processing light source to scan multiple sides of the lead frame 102.

[0077] Specifically, controlling the laser processing light source to scan one side of the lead frame 102 is relatively simple in terms of process control and is suitable for situations where only one side needs roughening. However, controlling the laser processing light source to scan multiple sides of the lead frame 102 can complete the roughening process of multiple surfaces (such as the front and side) of the lead frame 102 at one time, which greatly improves production efficiency and process consistency.

[0078] In some embodiments, the step of controlling the laser processing light source to scan multiple surfaces of the lead frame 102 includes: using multiple beams of the laser processing light source to scan multiple surfaces of the lead frame 102.

[0079] It should be noted that by using a multi-beam laser processing light source to scan multiple surfaces, different surfaces of the lead frame 102 can be processed in parallel at the same time. Compared with sequential scanning with a single laser beam, the speed of laser roughening is increased many times, making it suitable for large-scale mass production.

[0080] In some embodiments, the step of controlling the laser processing light source to scan the surface outside the prohibited roughening region 100A includes: driving the laser processing light source to scan the surface outside the prohibited roughening region 100A according to a predetermined scanning path and scanning parameters.

[0081] Specifically, the predetermined scanning path ensures accurate reproduction of the roughened structure, and the predetermined scanning parameters ensure the consistency of the roughened structure's depth and morphology, thereby guaranteeing the reliability of the encapsulation structure's sealing effect.

[0082] In some embodiments, the scanning parameters include one or more of the following: wavelength, output power, pulse energy, repetition frequency, and scanning speed of the laser processing light source.

[0083] It should be noted that the wavelength parameter affects the interaction mechanism and absorption rate between the laser processing source and the lead frame 102 material. The output power and pulse energy together determine the amount of energy that a single pulse acts on the lead frame 102 material, directly affecting the depth and size of the roughened structure. The repetition frequency determines the number of laser processing source pulses per unit time, affecting the processing efficiency. The scanning speed determines the time that the laser processing source acts on a unit area, affecting the heat accumulation of the lead frame 102 and the morphology of the roughened structure. By comprehensively controlling these scanning parameters, the laser roughening process can be precisely controlled, thereby obtaining a micro-roughened structure 180 that meets the requirements and has stable quality.

[0084] In some embodiments, the predetermined scan path includes: a scan path predetermined based on the surface shape outside the prohibited roughening region 100A of the lead frame 102.

[0085] Specifically, a scanning path is predetermined based on the surface shape outside the prohibited roughening area 100A of the lead frame 102, so that the laser scanning trajectory can closely fit and completely cover all effective areas that need to be roughened, avoiding missed processing or path overlap, and improving processing efficiency while ensuring the quality of roughening processing.

[0086] In some embodiments, the micro-coarsening structure 180 includes one or more of circular grooves, honeycomb grooves, and rectangular grooves.

[0087] It should be noted that circular grooves, honeycomb grooves, and rectangular grooves can provide uniform stress distribution and effective mechanical anchoring points, improving the bonding force between the molding compound formed in subsequent packaging processes and the lead frame 102.

[0088] In some embodiments, the micro-coarsening structures 180 are arranged in a uniform array on the surface outside the prohibited coarsening region 100A of the lead frame 102.

[0089] Specifically, the micro-coarsened structures 180 are arranged in a uniform array, which can provide a high degree of consistent adhesive retention in the areas where coarsening is required, avoiding the risk of weak local bonding due to uneven structure distribution, thereby ensuring the reliability of the packaging structure.

[0090] In some embodiments, the steps of acquiring the wiring pattern recognition model, identifying the prohibited roughening region 100A, and performing laser roughening treatment on the surface of the lead frame 102 outside the prohibited roughening region 100A are all completed on the same automatic optical inspection equipment integrated with a laser roughening module. This realizes the integration of inspection and laser roughening functions. After the product to be roughened 120 is positioned and clamped once, multiple steps such as establishing the wiring pattern recognition model, identifying the prohibited roughening region 100A, and laser roughening treatment can be completed sequentially on the same equipment. This greatly reduces the positioning error and handling damage introduced by the transfer of products between different equipment, and improves process efficiency and consistency.

[0091] It should be noted that after the step of laser roughening the surface outside the prohibited roughening region 100A of the lead frame 102, the roughening method further includes: using the wiring pattern recognition model to perform optical inspection on the roughened lead frame 130.

[0092] By using the wiring pattern recognition model to perform optical inspection on the roughened lead frame 130, it is possible to verify whether the laser roughening process is strictly performed according to the area defined by the model, check the formation quality of the micro-roughened structure 180 (such as the integrity and uniformity of the micro-roughened structure 180), and re-examine whether the laser roughening process has caused damage or contamination to structures such as the chip 111 and the lead 110.

[0093] In some embodiments, the step of performing optical inspection using the wiring pattern recognition model includes: activating the image acquisition module of an automatic optical inspection device, acquiring an image of the coarsened lead frame 130, and comparing and analyzing it with the wiring pattern recognition model to identify defects or anomalies.

[0094] In some embodiments, the optical inspection items for the roughened lead frame 130 include: whether the roughened area completely covers the surface outside the prohibited roughening area 100A of the lead frame 102, whether the morphology and distribution of the micro-roughened structure 180 are uniform, and whether the position and state of the chip 111 and the lead 110 have changed due to the roughening process. Thus, through this inspection, unqualified roughened products can be screened out in a timely manner.

[0095] After the laser roughening process is performed, the method further includes: forming a molding compound (not shown) covering the substrate 100, chip 111 and lead 110.

[0096] Specifically, the molding layer protects the chip 111, prevents the leads 110 from cross-connecting, and reduces the probability of damage to the chip 111 and air pollution. At the same time, the molding layer also makes the chip 111 easier to install and transport.

[0097] In some embodiments, the material of the molding layer includes molding compound.

[0098] Specifically, the molding compound material includes epoxy resin, which has advantages such as low shrinkage, good adhesion, good corrosion resistance, excellent electrical properties, and low cost.

[0099] It should be noted that the molding compound may also include one or more of the following: hardener, catalyst, and filler.

[0100] It should also be noted that the molding compound needs to be cured and baked to allow the molecular chains in the molding compound to cross-react more fully, so as to give it more stable physical and chemical properties and release the internal stress in the molding compound.

[0101] While the above disclosure is provided, it is not limited thereto. Any person skilled in the art may make various alterations and modifications without departing from the spirit and scope of this disclosure; therefore, the scope of protection of this disclosure shall be determined by the scope defined in the claims.

Claims

1. A method of roughening a package structure, comprising: include: Provides a non-coarsened lead frame; A chip and leads are disposed on the uncoarsened lead frame, and the chip, leads, and lead frame constitute the product to be coarsened. Obtain the wiring pattern recognition model of the product to be coarsened; Based on the wiring pattern recognition model, the prohibited coarsening region of the lead frame is identified. The prohibited coarsening region includes at least the projection region of the chip on the surface of the lead frame and the projection region of the lead on the surface of the lead frame. Laser roughening is performed on the surface outside the prohibited roughening area of ​​the lead frame to form a roughened lead frame.

2. The roughening method according to claim 1, wherein The steps for obtaining the wiring pattern recognition model of the product to be coarsened include: acquiring images and processing data of the product to be coarsened using an automatic optical inspection device to generate the wiring pattern recognition model of the product to be coarsened.

3. The coarsening method as described in claim 1, characterized in that, The steps for identifying the prohibited coarsening regions of the lead frame include: Based on the wiring pattern recognition model, the geometric contour of the projection area of ​​the chip on the lead frame surface and the geometric contour of the projection area of ​​the lead on the lead frame surface are extracted. Based on the geometric profile, the prohibited coarsening region is defined on the surface of the lead frame.

4. The coarsening method as described in claim 1, characterized in that, The step of laser roughening the surface outside the prohibited roughening region of the lead frame includes: Select a laser processing light source; The laser processing light source is controlled to scan the surface outside the prohibited roughening region, forming a micro-roughening structure on the surface outside the prohibited roughening region.

5. The coarsening method as described in claim 1 or 4, characterized in that, The laser processing light source selected for the laser roughening process includes one or both of nanosecond pulse lasers and femtosecond pulse lasers.

6. The coarsening method as described in claim 4, characterized in that, The step of controlling the laser processing light source to scan the surface outside the prohibited roughening area includes: controlling the laser processing light source to scan one side of the lead frame; or, The laser processing light source is controlled to scan multiple surfaces of the lead frame.

7. The coarsening method as described in claim 6, characterized in that, The step of controlling the laser processing light source to scan multiple surfaces of the lead frame includes: using multiple beams of the laser processing light source to scan multiple surfaces of the lead frame.

8. The coarsening method as described in claim 4, characterized in that, The step of controlling the laser processing light source to scan the surface outside the prohibited roughening area includes: driving the laser processing light source to scan the surface outside the prohibited roughening area according to a predetermined scanning path and scanning parameters.

9. The coarsening method as described in claim 8, characterized in that, The scanning parameters include one or more of the following: wavelength, output power, pulse energy, repetition frequency, and scanning speed of the laser processing light source.

10. The coarsening method as described in claim 8, characterized in that, The predetermined scan path includes: a scan path predetermined based on the surface shape outside the prohibited roughening region of the lead frame.

11. The coarsening method as described in claim 4, characterized in that, The micro-coarsening structure includes one or more of the following: circular grooves, honeycomb grooves, and rectangular grooves.

12. The coarsening method as described in claim 4, characterized in that, The micro-coarsening structures are arranged in a uniform array on the surface outside the prohibited coarsening region of the lead frame.

13. The coarsening method as described in claim 1, characterized in that, After setting the chip and leads on the uncoarsened lead frame, before obtaining the wiring pattern recognition model of the product to be coarsened, the coarsening method further includes: placing the product to be coarsened on a support pad.

14. The coarsening method as described in claim 13, characterized in that, The bearing pad includes a liquid-cooled pad.

15. The coarsening method as described in claim 14, characterized in that, The liquid cooling pad has a coolant circulation channel inside.

16. The coarsening method as described in claim 1, characterized in that, After the step of laser roughening the surface outside the prohibited roughening region of the lead frame, the roughening method further includes: using the wiring pattern recognition model to perform optical inspection on the roughened lead frame.

17. The coarsening method as described in claim 1, characterized in that, The steps of acquiring the wiring pattern recognition model, identifying the prohibited roughening region, and performing laser roughening treatment on the surface outside the prohibited roughening region of the lead frame are all completed on the same automated optical inspection equipment integrated with a laser roughening module.

18. The coarsening method as described in claim 1, characterized in that, The step of setting the chip on the uncoarsened lead frame includes: setting the chip on the lead frame by means of an adhesive layer.

19. The coarsening method as described in claim 1, characterized in that, The process of setting leads on the uncoarsened lead frame includes a wire bonding process.

20. The coarsening method as described in claim 1, characterized in that, In the step of providing a non-coarsened lead frame, the lead frame includes a base and pins; In the step of setting the chip and leads on the non-coarsened lead frame, the chip is set on the base, one end of the lead is electrically connected to the chip, and the other end of the lead is electrically connected to the pin.

21. The coarsening method as described in claim 20, characterized in that, After performing the laser roughening process, the method further includes forming a molding compound covering the substrate and the chip.

22. The coarsening method as described in claim 21, characterized in that, The material of the molding layer includes epoxy resin.

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