Lead frame manufacturing method and lead frame

Abstract

The present invention discloses a method for manufacturing a lead frame, which adopts a processing process of electroplating first and then etching. First, a plating layer is selectively electroplated on a copper substrate through the electroplating process, and then the surface of the copper substrate and the surface of the plating layer are simultaneously etched through the etching process. Since the etching speed of the etching solution on the copper substrate is greater than the etching speed on the plating layer, etching structures with different etching depths can be produced, thereby realizing the production of more complex circuit patterns, and no multiple etching processes are required, which is beneficial to improving the processing efficiency of the lead frame. In addition, the second etching structure can also be processed into a shallower groove to be used as a roughening structure, thereby improving the packaging reliability of the lead frame, and no additional roughening process is required, which is also beneficial to improving the processing efficiency of the lead frame. In addition, the present invention also discloses a lead frame manufactured using the above-mentioned lead frame manufacturing method.

Description

Technical Field

[0001] The present invention relates to the technical field of lead frames, and in particular to a lead frame manufacturing method and the lead frame. Background Art

[0002] Leadframes are essential components for manufacturing integrated circuit semiconductor elements, providing a carrier for the chips of integrated circuits. With the increasing application of leadframes in fields such as industrial and automotive electronics, the reliability requirements for leadframe packaging are becoming increasingly high. Currently, existing technologies typically require etching and electroplating to form a circuit pattern on the copper substrate of the leadframe, followed by surface treatment methods such as micro-etching roughening, rough copper plating, and brown oxidation to roughen the leadframe surface, thereby improving the bonding strength between the leadframe and the plastic encapsulation material and making the leadframe package more reliable. However, the above-mentioned method requires sequential etching, electroplating, and roughening processes, which are relatively cumbersome and have problems such as complex processes and high costs, seriously affecting the processing efficiency of the leadframe.

[0003] In addition, in the above-mentioned lead frame production method, the circuit pattern is usually produced by directly etching the surface of the copper substrate to form a full-etched structure or a half-etched structure. Therefore, it is generally only suitable for relatively simple circuit patterns. If a more complex circuit pattern is to be produced, multiple etchings are usually required. By adjusting the position and time of each etching, the etching amount of the copper substrate is adjusted to form the desired circuit pattern. However, this production method is relatively cumbersome and complicated, which seriously affects the processing efficiency of the lead frame. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a lead frame manufacturing method with high processing efficiency and capable of manufacturing relatively complex circuit patterns.

[0005] In addition, the present invention also provides a lead frame manufactured by the lead frame manufacturing method.

[0006] The lead frame manufacturing method according to an embodiment of the present invention includes the following steps:

[0007] S1: electroplating process, selective electroplating is performed on the copper substrate to form a plating layer;

[0008] S2: Etching process, etching the surface of the copper substrate to form a first etching structure, and etching the surface of the first plating layer to form a second etching structure, wherein the etching rate of the etching solution on the copper substrate is greater than the etching rate on the plating layer.

[0009] The lead frame manufacturing method according to the embodiment of the present invention has at least the following beneficial effects:

[0010] In the lead frame manufacturing method of the embodiment of the present invention, a processing step of electroplating first and then etching is adopted. First, a plating layer is selectively electroplated on the copper substrate through the electroplating step, and then the copper substrate surface and the plating layer surface are simultaneously etched through the etching step. Because the etching solution etches the copper substrate at a faster rate than the plating layer, the depth of the first etched structure is greater than the depth of the second etched structure. In addition, the depth of the second etched structure can also be flexibly adjusted by adjusting the thickness of the plating layer. Therefore, when manufacturing a circuit pattern, etched structures with different etching depths can be produced, thereby achieving the production of more complex circuit patterns without the need for multiple etching processes, which is beneficial to improving the processing efficiency of the lead frame. In addition, because the depth of the second etched structure can be adjusted as needed, the second etched structure can also be processed into a shallower groove to be used as a roughening structure while manufacturing the circuit. This can improve the bonding strength between the lead frame and the molding compound without the need for an additional roughening process, which is also beneficial to improving the processing efficiency of the lead frame.

[0011] According to some embodiments of the present invention, the copper substrate has a roughened area, the plating layer includes a first plating layer, and the second etching structure includes a first groove structure;

[0012] The step S1 comprises: forming the first plating layer by electroplating in the roughened area;

[0013] The step S1 includes: etching the surface of the first plating layer with the etching solution to form the first groove structure, wherein the first groove structure includes a plurality of first grooves arranged at intervals.

[0014] According to some embodiments of the present invention, the copper substrate has a pattern area, the pattern area has a full etching position, a half etching position and a shallow etching position, the plating layer includes a second plating layer located at the shallow etching position, the first etching structure includes a full etching structure and a half etching structure, and the second etching structure includes a shallow etching structure;

[0015] The step S1 comprises: forming the second plating layer by electroplating at the shallow etching position;

[0016] The step S2 includes: etching the full-etched position from the upper surface and the lower surface of the copper substrate simultaneously with the etching solution to form the full-etched structure, and the full-etched structure penetrates the copper substrate; etching the surface of the half-etched position with the etching solution to form the half-etched structure; etching the surface of the second plating layer with the etching solution to form the shallow-etched structure, and the shallow-etched structure extends to the interior of the copper substrate, and the full-etched structure, the half-etched structure, and the shallow-etched structure are combined to form a circuit pattern.

[0017] In some embodiments, at least one of the half-etched structures and at least one of the shallow-etched structures are correspondingly arranged on two opposite surfaces of the copper substrate;

[0018] The method further includes step S3: injection molding, filling the full-etched structure, the half-etched structure and the shallow-etched structure with injection molding material to form an intermediate circuit layer located inside the injection molding material.

[0019] According to some embodiments of the present invention, the copper substrate has a mounting position for arranging a chip or a pin, the plating layer includes a third plating layer located at the mounting position, and the second etching structure includes a second groove structure;

[0020] The step S1 includes: forming the third plating layer by electroplating at the mounting position;

[0021] The step S2 includes: etching the surface of the third plating layer with the etching solution to form the second groove structure, wherein the second groove structure extends into the interior of the copper substrate.

[0022] According to some embodiments of the present invention, the second groove structure includes an annular groove, and the annular groove is arranged along the circumference of the mounting position;

[0023] And / or the mounting position has an annular area, the annular area is arranged along the circumference of the mounting position, the second groove structure includes a plurality of second grooves arranged at intervals, and all the second grooves are distributed in the annular area;

[0024] And / or the second groove structure includes a mounting groove corresponding to the mounting position, and the mounting position is located in the mounting groove.

[0025] According to some embodiments of the present invention, step S1 includes:

[0026] S1.1: First film application: applying a first dry film to the upper and lower surfaces of the copper substrate;

[0027] S1.2: first exposure and development to remove portions of the first dry film on the upper and lower surfaces of the copper substrate to expose locations corresponding to the second etched structures;

[0028] S1.3: electroplating, forming a coating on the surface of the copper substrate;

[0029] S1.4: stripping the film for the first time to remove the remaining first dry film on the upper and lower surfaces of the copper substrate.

[0030] According to some embodiments of the present invention, step S2 includes:

[0031] S2.1: Second film application, applying a second dry film to the upper and lower surfaces of the copper substrate;

[0032] S2.2: performing a second exposure and development to remove portions of the second dry film on the upper and lower surfaces of the copper substrate, exposing a portion of the surface of the copper substrate corresponding to the first etching structure and exposing the plating layer;

[0033] S2.3: etching, using the etching solution to etch the surface of the copper substrate to form the first etching structure, and etching the surface of the plating layer to form the second etching structure;

[0034] S2.4: stripping the film for the second time to remove the remaining second dry film on the upper and lower surfaces of the copper substrate;

[0035] S2.5: Clean and dry.

[0036] According to some embodiments of the present invention, the copper substrate has a welding area;

[0037] The step S1.2 further includes: removing a portion of the first dry film on the upper surface and the lower surface of the copper substrate to expose a position corresponding to the welding area;

[0038] The step S1.3 further includes: electroplating the surface of the welding area to form a welding pad;

[0039] In the step S2.2, the pad is covered by the second dry film.

[0040] The lead frame according to the embodiment of the present invention is manufactured by the lead frame manufacturing method of any of the above embodiments.

[0041] The lead frame according to the embodiment of the present invention has at least the following beneficial effects:

[0042] By adopting the leadframe fabrication method of any of the above-described embodiments, through a process of electroplating followed by etching, a first etched structure and a second etched structure with different etching depths can be obtained in the same etching process. Therefore, relatively complex circuit patterns can be produced on a copper substrate without requiring multiple etching steps, which is beneficial for improving the electrical performance of the leadframe and increasing its processing efficiency. Furthermore, the second etched structure can be used as a roughening structure to enhance the bonding strength between the leadframe and the molding compound, eliminating the need for an additional roughening process, thus also improving leadframe processing efficiency. This not only improves leadframe processing efficiency but also significantly enhances the electrical performance of the leadframe, thereby expanding the range of applications for the leadframe.

[0043] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0045] Figure 1 Schematic diagram of the completion of the electroplating process in step S1 of the lead frame manufacturing method according to an embodiment of the present invention;

[0046] Figure 2 Schematic diagram of the second exposure and development in step S2.2 of the lead frame manufacturing method according to an embodiment of the present invention;

[0047] Figure 3 Schematic diagram of etching in step S2.3 of the lead frame manufacturing method according to an embodiment of the present invention;

[0048] Figure 4 Schematic diagram of the second film stripping in step S2.4 of the lead frame manufacturing method according to an embodiment of the present invention;

[0049] Figure 5 This is a schematic diagram of the lead frame after injection molding packaging in the lead frame manufacturing method according to an embodiment of the present invention.

[0050] Reference numerals:

[0051] Copper substrate 100 , first plating layer 110 , first groove 111 , second plating layer 120 , shallow etching structure 121 , full etching structure 130 , half etching structure 140 , third plating layer 150 , annular groove 151 , second groove 152 , pad 160 , injection molding material 170 .

[0052] The second dry film 200 . DETAILED DESCRIPTION

[0053] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0054] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0055] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0056] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0057] Reference Figures 1 to 5 An embodiment of the present invention provides a lead frame manufacturing method, comprising the following steps:

[0058] S1: electroplating process, performing selective electroplating on the copper substrate 100 to form a plating layer;

[0059] S2: Etching process, etching the surface of the copper substrate 100 to form a first etching structure, and etching the surface of the first plating layer 110 to form a second etching structure, wherein the etching solution etches the copper substrate 100 at a higher rate than the plating layer.

[0060] In the lead frame manufacturing method of the embodiment of the present invention, a processing step of electroplating followed by etching is adopted. First, a plating layer is selectively electroplated on the copper substrate 100 through the electroplating step, and then the surface of the copper substrate 100 and the surface of the plating layer are simultaneously etched through the etching step. Since the etching speed of the etching solution on the copper substrate 100 is greater than the etching speed on the plating layer, the depth of the first etched structure is greater than the depth of the second etched structure. In addition, etching starting from the surface of the copper substrate 100 can obtain two etched structures with different etching depths through full etching and half etching. The depth of the second etched structure can also be flexibly adjusted by adjusting the thickness of the plating layer. Therefore, in the process of manufacturing a circuit pattern, etching structures with different etching depths can be manufactured in the same time, thereby realizing the production of more complex circuit patterns without the need for multiple etchings, which is beneficial to improving the processing efficiency of the lead frame. In addition, since the plating layer etches more slowly than the copper substrate 100, and the depth of the second etching structure can be adjusted as needed, the second etching structure can also be processed into a shallower groove to be used as a roughening structure while making the circuit. This can improve the bonding force between the lead frame and the plastic packaging material, thereby improving the reliability of the lead frame package. Since this method can complete the processing of the roughening structure simultaneously during the etching process, there is no need for an additional roughening process, which is conducive to further improving the processing efficiency of the lead frame.

[0061] Reference Figures 1 to 5 In some embodiments, the copper substrate 100 has a roughened area, the plating layer includes a first plating layer 110, and the second etching structure includes a first groove structure;

[0062] Step S1 includes: forming a first plating layer 110 by electroplating in the roughened area;

[0063] Step S1 includes: etching the surface of the first plating layer 110 with an etching solution to form a first groove structure, wherein the first groove structure includes a plurality of first grooves 111 arranged at intervals.

[0064] In order to facilitate the packaging of the lead frame, after the circuit pattern is completed, a plurality of shallow grooves are usually processed in the roughened area of the surface of the copper substrate 100 through a roughening process to improve the bonding strength between the lead frame and the plastic packaging material. However, the additional roughening process will also reduce the processing efficiency of the lead frame. To this end, by adopting the lead frame manufacturing method of the embodiment of the present invention, the difference in etching speed of the same etching solution on different metals can be utilized to first electroplate and form a first plating layer 110 in the roughened area, and then etch a plurality of first grooves 111 in the first plating layer 110. Since the etching speed of the etching solution on the copper substrate 100 is greater than the etching speed on the first plating layer 110, the depth of the first groove 111 can be made smaller than the depth of the first etching structure, that is, the shallower first groove 111 can be processed. Therefore, the first groove structure can be used as a roughening structure to improve the bonding strength between the lead frame and the plastic packaging material, thereby facilitating the improvement of the reliability of the lead frame packaging. In addition, the first groove structure can be processed simultaneously with the first etching structure, that is, there is no need to add an additional roughening process, and the roughening structure can be processed in a normal etching process, which is beneficial to improving the processing efficiency of the lead frame.

[0065] It is understandable that when etching is used to form the groove of the roughened structure, if etching is started directly from the surface of the copper substrate 100, it is easy to form a deep groove on the surface of the copper substrate 100 due to the high etching speed, and it is also easy to cause the groove opening formed on the surface of the copper substrate 100 to be too large due to the occurrence of side etching. Therefore, in the embodiment of the present invention, by adopting the method of electroplating first and then etching, although the first etching structure and the first groove structure are formed at the same time, the etching speed of the etching solution on the first plating layer 110 is lower than the etching speed on the copper substrate 100, that is, the etching speed of the first plating layer 110 is slower, so a first groove 111 with a smaller depth can be formed, and side etching is not likely to occur, that is, the influence of side etching on the size of the groove opening can be reduced, which is conducive to forming a first groove 111 with a smaller opening, and then the number of first grooves 111 per unit area in the first groove structure can be increased, thereby further improving the bonding strength between the lead frame and the molding compound, and further improving the stability of the lead frame package.

[0066] It can be understood that when the distance between two adjacent first grooves 111 is relatively close, a convex point will be formed between the two adjacent first grooves 111, thereby allowing the first groove structure to form a dense concave-convex structure, thereby further improving the roughness of the roughened area, enhancing the bonding force between the lead frame and the plastic packaging material, and helping to further improve the stability of the lead frame package.

[0067] It is understandable that the first groove 111 can extend from the first plating layer 110 to the inside of the copper substrate 100. In this case, the depth of the first groove 111 can be set to 6μm-200μm, depending on the thickness of the first plating layer 110 and the thickness of the copper substrate 100. In addition, the first groove 111 can also be set on the first plating layer 110 and does not extend to the copper substrate 100. In this case, the depth of the first groove 111 can be set to 2μm-5μm, and the present invention does not make specific limitations on this. In addition, the minimum size of the opening of the first groove 111 can be processed to 10μm by the above method. Specifically, the diameter or width of the opening of the first groove 111 can be designed to be between 10μm-100μm, wherein the diameter or width of the opening of the first groove 111 is preferably designed to be 15μm-60μm. The present invention does not make specific limitations on this.

[0068] Reference Figures 1 to 5 In some embodiments, the copper substrate 100 has a pattern area, the pattern area has a full etching position, a half etching position, and a shallow etching position, the plating layer includes a second plating layer 120 located at the shallow etching position, the first etching structure includes a full etching structure 130 and a half etching structure 140, and the second etching structure includes a shallow etching structure 121;

[0069] Step S1 includes: forming a second plating layer 120 by electroplating at the shallow etching position;

[0070] Step S2 includes: etching the full-etched position from the upper surface and the lower surface of the copper substrate 100 simultaneously with an etching solution to form a full-etched structure 130, and the full-etched structure 130 penetrates the copper substrate 100; etching the surface of the half-etched position with an etching solution to form a half-etched structure 140; etching the surface of the second plating layer 120 with an etching solution to form a shallow-etched structure 121, and the shallow-etched structure 121 extends to the interior of the copper substrate 100. The full-etched structure 130, the half-etched structure 140, and the shallow-etched structure 121 are combined to form a circuit pattern.

[0071] By adopting the above method, the pattern of the copper substrate 100 is divided into a full etching position, a half etching position and a shallow etching position, and a second plating layer 120 is electroplated in the shallow etching position by electroplating, and then the full etching position, the half etching position and the shallow etching position are etched at the same time. During the etching process, since the etching of the full etching position and the half etching position is started from the surface of the copper substrate 100, the etching speed of the full etching position is the same as the etching speed of the half etching position. The surface of the half etching position is etched by the etching solution to form a half etching structure 140, that is, the etching depth is one-tenth of the copper substrate 100. The half-etched structure 140 can extend from the surface of the copper substrate 100 to the middle of the copper substrate 100. Therefore, when etching the full-etched position, since the etching time for the full-etched position is the same as the etching time for the half-etched position, by etching the full-etched position from the upper surface and the lower surface of the copper substrate 100 at the same time, half etching can be performed from the upper surface and the lower surface of the copper substrate 100 at the same time and etched to the middle of the copper substrate 100, thereby etching through the copper substrate 100 to form the full-etched structure 130, that is, a full-etched structure 130 that penetrates the copper substrate 100 can be formed. Furthermore, since the half-etched portion is electroplated with the first plating layer 110, etching the shallow etched structure 121 requires starting from the second plating layer 120. The etching rate of the etching solution on the second plating layer 120 is lower than the etching rate on the copper substrate 100. The etching time for the shallow etched portion is the same as the etching time for the half-etched portion and the full-etched portion. Consequently, within the same etching time, the etching depth of the shallow etched structure 121 is less than the etching depth of the half-etched structure 140. This allows etching of a shallow etched structure 121 having a depth different from that of the half-etched structure 140 and the full-etched structure 130, thereby enabling the production of more complex circuit patterns. Furthermore, the half-etched structure 140, the shallow etched structure 121, and the shallow etched structure 121 can be simultaneously etched and formed in the same etching process, eliminating the need for multiple etching steps. This also helps improve leadframe processing efficiency. Furthermore, the depth of the shallow etched structure 121 can be adjusted by adjusting the thickness of the second plating layer 120, thereby making the leadframe circuit pattern configuration more flexible, allowing operators to produce circuit patterns of varying depths as needed.

[0072] It can be understood that when the half-etched structure 140 and the first groove structure are simultaneously etched in the etching process, since the half-etched structure 140 is formed by etching the surface of the copper substrate 100 and extends from the surface of the copper substrate 100 to the middle of the copper substrate 100, and the first groove 111 is formed by etching starting from the first plating layer 110, the etching solution needs to etch the first plating layer 110 first during etching, so that the first groove 111 cannot extend to the middle of the copper substrate 100 within the same etching time. Therefore, when the roughening area and the half-etched position are correspondingly arranged on the opposite sides of the copper substrate 100, the first groove 111 and the half-etched structure 140 do not affect each other and interfere with each other or directly etch through the copper substrate 100. Therefore, the roughening area and the half-etched position can be correspondingly arranged on the opposite sides of the copper substrate 100, that is, the layout of the first groove structure and the half-etched structure 140 is more convenient and flexible, which not only helps to better improve the bonding strength between the lead frame and the molding compound and improve the reliability of the lead frame package, but also facilitates the design and layout of the lead frame circuit pattern.

[0073] Reference Figures 1 to 5 In some embodiments, at least one half-etched structure 140 and at least one shallow-etched structure 121 are correspondingly arranged on two opposite surfaces of the copper substrate 100 ;

[0074] The process further includes step S3 : injection molding, filling the injection molding material 170 into the full-etched structure 130 , the half-etched structure 140 and the shallow-etched structure 121 to form an intermediate circuit layer inside the injection molding material 170 .

[0075] In the above method, since the half-etched structure 140 is formed by etching the surface of the copper substrate 100 and extends from the surface of the copper substrate 100 to the middle of the copper substrate 100, and the shallow-etched structure 121 is formed by etching starting from the second plating layer 120, the etching solution needs to etch the second plating layer 120 first during etching, so that the shallow-etched structure 121 cannot extend to the middle of the copper substrate 100 within the same etching time. Therefore, the half-etched structure 140 and the shallow-etched structure 121 can be arranged correspondingly on the opposite sides of the copper substrate 100. The shallow-etched structure 121 and the half-etched structure 140 will not affect each other and interfere with each other or directly etch through the copper substrate 100, thereby facilitating the design of more complex circuit patterns. Specifically, in an embodiment of the present invention, by arranging at least one half-etched structure 140 and at least one shallow-etched structure 121 on opposite sides of the copper substrate 100, a relatively complex circuit pattern can be formed on the copper substrate 100, and the circuit pattern can extend into the interior of the copper substrate, so that when the copper substrate 100 is injection-molded in the subsequent step S3, the injection molding material 170 can be filled into the full-etched structure 130, the half-etched structure 140 and the shallow-etched structure 121, so that the circuit pattern can be embedded in the interior of the injection molding material 170, thereby forming an intermediate circuit layer located inside the injection molding material 170.

[0076] Reference Figures 1 to 5 In some embodiments, the copper substrate 100 has a mounting position for arranging a chip or a pin, the plating layer includes a third plating layer 150 located at the mounting position, and the second etching structure includes a second groove structure;

[0077] Step S1 includes: forming a third plating layer 150 at the mounting position by electroplating;

[0078] Step S2 includes: etching the surface of the third plating layer 150 with an etching solution to form a second groove structure, wherein the second groove structure extends into the interior of the copper substrate 100 .

[0079] In the above method, a second groove structure can be formed at the mounting position by electroplating first and then etching. Specifically, the third plating layer 150 is first electroplated on the mounting position through the electroplating process of step S1, and then the etching process of step S2 is performed from the third plating layer 150 to the inside of the copper substrate 100 to form a second groove structure. The formation of the second groove structure not only facilitates the setting of the chip or pin, but also, since the second groove structure is formed by etching from the second plating layer 120 and has a shallow depth, it can also facilitate the subsequent packaging of the lead frame, improve the bonding strength between the lead frame and the plastic packaging material, and improve the reliability of the packaging.

[0080] In some embodiments, the second groove structure includes an annular groove 151 , and the annular groove 151 is arranged along the circumference of the mounting position.

[0081] By employing the aforementioned method, the second groove structure is formed into an annular groove 151, allowing a chip or pin to be positioned within the annular groove 151. The presence of the annular groove 151 can enhance the bonding strength between the mounting area and the molding compound, thereby improving package reliability. When the mounting area is used to mount a chip, the annular groove 151 surrounds the chip, further enhancing the bond between the mounting area and the black plastic. It also limits the diffusion of silver or non-conductive adhesive when the chip is affixed, thereby improving chip mounting reliability.

[0082] It is understandable that the above-mentioned second groove structure includes an annular groove 151. Specifically, the shape of the annular groove 151 can be set to a circular ring, a square ring, etc. according to the shape of the corresponding chip or pin, and the present invention does not make specific restrictions on this. In addition, the number of annular grooves 151 can be one, or two, three or more, and the present invention does not make specific restrictions on this. When the number of annular grooves 151 is two or more, each annular groove 151 is arranged in sequence from the inside to the outside, and the chip or pin can be set inside the innermost annular groove 151. It is understandable that, referring to Figures 1 to 5 When there are two or more annular grooves 151, the etching process can start from the surface of the third plating layer 150 and the surface of part of the copper substrate 100 on both sides of the third plating layer 150, thereby simultaneously etching two annular grooves 151, and the etching position of the third plating layer 150 is located at the upper end between the two annular grooves 151.

[0083] In some embodiments, the mounting position has an annular area, which is arranged along the circumference of the mounting position. The second groove structure includes a plurality of second grooves 152 arranged at intervals, and all second grooves 152 are distributed in the annular area.

[0084] By adopting the above method, the second groove structure is set to a plurality of second grooves 152 arranged at intervals, and all the second grooves 152 are distributed in the annular area so that the second groove structure is arranged along the circumference of the mounting position, thereby allowing the chip or pin to be set inside the annular area. The second groove 152 can also serve as a roughened structure of the lead frame to improve the bonding force between the mounting position and the plastic packaging material, thereby helping to improve the reliability of the package.

[0085] It is understandable that the shape of the annular area can be set to a circular ring, a square ring, etc. according to the shape of the corresponding chip or pin, and the present invention does not make any specific limitation on this.

[0086] In some embodiments, the second groove structure includes a mounting slot corresponding to the mounting position, and the mounting position is located in the mounting slot.

[0087] By adopting the above method, the second groove structure is directly set as a mounting groove structure, so that the chip or the pin can be directly set in the mounting groove.

[0088] When the mounting position is used to mount a chip, the chip can be directly installed in the mounting groove via a soldering structure. This not only limits the diffusion range of silver glue or non-conductive glue when the chip is affixed, but also facilitates heat dissipation from the chip due to the chip's contact with the inner surface of the mounting groove, protecting the chip and dissipating stress on the chip. Furthermore, since the second groove structure is etched from the third plating layer 150, the thickness of the third plating layer 150 can be controlled during the electroplating process to control the depth of the second groove structure, thereby matching the thickness of the mounting groove to the thickness of the chip. This allows the entire chip to be embedded in the mounting groove, which not only helps reduce the thickness of the lead frame but also better disperses the internal stress on the chip, making it less susceptible to warping.

[0089] When the mounting position is used to set the pin, the second groove structure is directly set as the mounting groove, so that the mounting groove can be directly used as the pin of the lead frame. Specifically, since the mounting groove is formed by etching the third plating layer 150 into the interior of the copper substrate 100, the obtained mounting groove depth is less than half the thickness of the copper substrate 100, and the depth of the mounting groove can be adjusted by controlling the thickness of the third plating layer 150. Therefore, when setting the pin, it is not necessary to consider the half-etched structure 140 on the bottom surface of the pin, that is, the setting of the pin is not easily affected by the bottom surface half-etched structure 140, thereby making the pin setting of the lead frame more convenient.

[0090] It is understandable that the shape of the mounting groove can be set to be circular or square according to the shape of the corresponding chip or pin, and the present invention does not make any specific limitation on this.

[0091] It can be understood that the above-mentioned second groove structure may include only the annular groove 151, or only include multiple second grooves 152 located in the annular area, or only include mounting grooves. In addition, the second groove structure may also include a combination of any two of the aforementioned three structures, or may directly include the aforementioned three structures. The present invention does not make specific limitations on this.

[0092] It is understood that the copper substrate 100 may be provided with one mounting position, or may be provided with two, three, or more mounting positions, which is not specifically limited in the present invention. Furthermore, when there are two or more mounting positions, different mounting positions may be used to provide the same or different structures, and the second groove structures formed in different mounting positions may also be the same or different, which is not specifically limited in the present invention.

[0093] Reference Figure 1 In some embodiments, step S1 includes:

[0094] S1.1: First film lamination: Laminating the first dry film on the upper and lower surfaces of the copper substrate 100;

[0095] S1.2: First exposure and development to remove portions of the first dry film on the upper and lower surfaces of the copper substrate 100 to expose locations corresponding to the second etching structure;

[0096] S1.3: Electroplating: forming a coating on the surface of the copper substrate 100;

[0097] S1.4: stripping the film for the first time to remove the remaining first dry film on the upper and lower surfaces of the copper substrate 100.

[0098] By adopting the above method, the surface of the copper substrate 100 can be selectively electroplated, that is, electroplating is performed only in the locations where the second etching structure is required. Specifically, step S1.1 applies a first dry film to the upper and lower surfaces of the copper substrate 100 to protect the areas of the copper substrate 100 that do not require electroplating. Step S1.2, through a first exposure and development process, reveals the locations where the second etching structure is required, thereby facilitating the subsequent step S1.3 of electroplating a coating on the surface of the copper substrate 100, thereby facilitating the etching of the second etching structure in the subsequent etching process.

[0099] Reference Figures 1 to 5 In some embodiments, step S2 includes:

[0100] S2.1: Second film lamination: Laminating the second dry film 200 on the upper and lower surfaces of the copper substrate 100;

[0101] S2.2: A second exposure and development step is performed to remove a portion of the second dry film 200 on the upper and lower surfaces of the copper substrate 100, exposing the portion of the surface of the copper substrate 100 corresponding to the first etching structure and the plating layer.

[0102] S2.3: Etching: etching the surface of the copper substrate 100 with an etching solution to form a first etching structure, and etching the surface of the plating layer to form a second etching structure;

[0103] S2.4: stripping the film for the second time to remove the remaining second dry film 200 on the upper and lower surfaces of the copper substrate 100;

[0104] S2.5: Clean and dry.

[0105] By adopting the above method, the surface of the copper substrate 100 can be selectively etched, that is, etching is performed only at the locations where the first etching structure and the second etching structure are required. Figure 2In step S2.1, a second dry film 200 is applied to the upper and lower surfaces of the copper substrate 100 to protect the areas on the copper substrate 100 that do not need to be etched. Then, in step S2.2, the areas that need to be etched are exposed by a second exposure and development. In this step, the surface of the copper substrate 100 that needs to be set with the first etching structure can be exposed to facilitate subsequent etching on the surface of the copper substrate 100. At the same time, the plating layer that needs to be set with the second etching structure can be exposed to facilitate subsequent etching on the plating layer surface. After the etching is completed, the remaining second dry film 200 can be removed in step S2.4, so that Figure 4 The lead frame structure. After the film is removed, the lead frame can be encapsulated with plastic. Figure 5 lead frame structure.

[0106] In addition, when the second etching structure is etched into the first groove structure for use as a roughening structure, since the above method can perform selective etching, only the roughening area that needs to be roughened on the lead frame can be roughened, thereby reducing the risk of serious injection molding flash due to overall roughening resulting in roughening in places that do not need to be roughened, avoiding the problem of difficulty in removing injection molding flash, thereby greatly reducing the processing difficulty of the lead frame and improving the processing efficiency of the lead frame.

[0107] Reference Figures 1 to 5 In some embodiments, the copper substrate 100 has a welding area; step S1.2 further includes: removing part of the first dry film on the upper surface and the lower surface of the copper substrate 100 to expose the position corresponding to the welding area; step S1.3 further includes: electroplating to form a welding pad 160 on the surface of the welding area; in step S2.2, the welding pad 160 is covered by the second dry film 200.

[0108] By employing the above method, solder pads 160 can be electroplated on the soldering area of the copper substrate 100. During the etching process, solder pads 160 can be protected by the second dry film 200, thereby preventing the solder pads 160 from being affected by the etching solution. The provision of solder pads 160 facilitates soldering between the lead frame and the chip and other external components, thereby improving the reliability of the electrical connection between the lead frame and the external components.

[0109] In some embodiments, the etching solution is an acidic cupric chloride etching solution or an acidic ferric chloride etching solution; the pad 160 and the plating layer are both silver-plated layers, and the thickness of the silver-plated layer is 0.1 μm-6 μm.

[0110] In the above method, etching is performed using an acidic cupric chloride etching solution or an acidic iron oxide etching solution, and both the pad 160 and the plating layer are set as a silver plating layer. The acidic cupric chloride etching solution and the acidic iron oxide etching solution have a higher etching rate for copper than for silver. Therefore, the difference in etching rate of different metals by the same etching solution can be utilized to enable etching from the surface of the copper substrate 100 and the surface of the plating layer respectively within the same etching time, thereby obtaining a first etching structure and a second etching structure with different etching depths. This can achieve the production of more complex circuit patterns without the need for multiple etchings, which is beneficial to improving the processing efficiency of the lead frame. In addition, since silver etches more slowly than copper, the depth of the second etched structure is less than that of the first etched structure, and the depth of the second etched structure can be adjusted by adjusting the thickness of the plating. Therefore, while making the circuit, the second etched structure can also be processed into a shallower groove to be used as a roughening structure, thereby improving the bonding force between the lead frame and the plastic packaging material, thereby improving the reliability of the lead frame package. Moreover, since this method can complete the processing of the roughening structure simultaneously during the etching process, there is no need for an additional roughening process, which is conducive to further improving the processing efficiency of the lead frame.

[0111] In addition, by setting the thickness of the silver plating layer to 0.1 μm-6 μm, the connection between the pad 160 and the external components can be facilitated, and the plating layer can also be easily etched to obtain a second etching structure with a better size.

[0112] It can be understood that in addition to being set as a silver-plated layer, in some embodiments, the pad 160 and the plating layer can also be a nickel-palladium-gold plating layer, wherein the nickel-palladium-gold plating layer includes a nickel-plated layer, a palladium-plated layer, and a gold-plated layer from the inside to the outside, wherein the thickness of the nickel-plated layer is 0.5μm-2μm, the thickness of the palladium-plated layer is 0.020μm-0.150μm, and the thickness of the gold-plated layer is 0.005μm-0.030μm.

[0113] By adopting the above method, the nickel-palladium-gold plating layer has good solderability and high temperature and humidity resistance, and has good air tightness and high reliability, thereby facilitating reliable connection between the pad 160 and external components.

[0114] In one specific embodiment, the copper substrate 100 has a copper layer thickness of 0.203 mm. In step S1, the copper substrate 100 is electroplated using a silver plating solution, resulting in both the pad 160 and the plated layer being silver-plated. The thickness of the silver-plated layer is 3 μm. In step S2, an etching process is performed using an acidic cupric chloride etchant at a temperature of 45°C, a specific gravity of 1.32, and 1.5 mol / L of HCl. Under these conditions, the acidic cupric chloride etchant etches copper at a rate of 40 μm / min and silver at a rate of 0.6 μm / min. The etching time is 5 minutes, and the silver-plated layer is ultimately etched down 15 μm, removing 3 μm of the silver-plated layer itself, resulting in a second etched structure with a depth of 12 μm.

[0115] An embodiment of the present invention further provides a lead frame, which is manufactured by the lead frame manufacturing method of any of the above embodiments.

[0116] By adopting the leadframe manufacturing method of any of the above-described embodiments, through a process of electroplating followed by etching, a first etched structure and a second etched structure with different etching depths can be obtained in the same etching process. Therefore, a relatively complex circuit pattern can be produced on the copper substrate 100 without requiring multiple etching steps, which is beneficial for improving the electrical performance of the leadframe and increasing the processing efficiency of the leadframe. In addition, the second etched structure can be used as a roughening structure to improve the bonding strength between the leadframe and the molding compound, without requiring an additional roughening process, thus also improving the processing efficiency of the leadframe. Not only can the processing efficiency of the leadframe be improved, but the electrical performance of the leadframe can also be greatly improved, thereby increasing the scope of use of the leadframe.

[0117] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the scope of the present invention.

Claims

1. A lead frame manufacturing method, characterized in that: The following steps are involved: S1: an electroplating process, performing selective electroplating on a copper substrate (100) to form a plating layer; S2: an etching process, wherein the surface of the copper substrate (100) is etched by an etching solution to form a first etching structure, and the surface of the plated layer is etched to form a second etching structure, wherein the etching speed of the etching solution on the copper substrate (100) is greater than the etching speed on the plated layer; The copper substrate (100) has a roughened area, the plating layer includes a first plating layer (110), and the second etching structure includes a first groove structure; The step S1 comprises: forming the first plating layer (110) by electroplating in the roughened area; The step S1 comprises: etching the surface of the first plating layer (110) with the etching solution to form the first groove structure, wherein the first groove structure comprises a plurality of first grooves (111) arranged at intervals; The copper substrate (100) has a pattern area, the pattern area has a full etching position, a half etching position, and a shallow etching position, the plating layer includes a second plating layer (120) located at the shallow etching position, the first etching structure includes a full etching structure (130) and a half etching structure (140), and the second etching structure includes a shallow etching structure (121); The step S1 comprises: forming the second plating layer (120) by electroplating at the shallow etching position; The step S2 comprises: etching the full etching position from the upper surface and the lower surface of the copper substrate (100) simultaneously with the etching solution to form the full etching structure (130), wherein the full etching structure (130) penetrates the copper substrate (100); etching the surface of the half etching position with the etching solution to form the half etching structure (140); etching the surface of the second plating layer (120) with the etching solution to form the shallow etching structure (121), wherein the shallow etching structure (121) extends to the interior of the copper substrate (100), and the full etching structure (130), the half etching structure (140), and the shallow etching structure (121) are combined to form a circuit pattern; A processing step of electroplating followed by etching is adopted, wherein a plated layer is selectively plated on a copper substrate (100) through an electroplating step, and then the surface of the copper substrate (100) and the surface of the plated layer are simultaneously etched through an etching step. Since the etching speed of the etching solution on the copper substrate (100) is greater than the etching speed on the plated layer, the depth of the first etching structure is greater than the depth of the second etching structure. At least one of the half-etched structures (140) and at least one of the shallow-etched structures (121) are correspondingly arranged on two opposite surfaces of the copper substrate (100); The method further comprises step S3: injection molding, filling the injection molding material (170) into the full-etched structure (130), the half-etched structure (140) and the shallow-etched structure (121), to form an intermediate circuit layer located inside the injection molding material (170).

2. The lead frame manufacturing method according to claim 1, wherein: The copper substrate (100) has a mounting position for arranging a chip or a pin, the plating layer comprises a third plating layer (150) located at the mounting position, and the second etching structure comprises a second groove structure; The step S1 comprises: forming the third plating layer (150) by electroplating at the mounting position; The step S2 comprises: etching the surface of the third plating layer (150) with the etching solution to form the second groove structure, wherein the second groove structure extends into the interior of the copper substrate (100).

3. The lead frame manufacturing method according to claim 2, characterized in that: The second groove structure comprises an annular groove (151), and the annular groove (151) is arranged along the circumference of the installation position; And / or the mounting position has an annular area, the annular area is arranged along the circumference of the mounting position, the second groove structure includes a plurality of second grooves (152) arranged at intervals, and all the second grooves (152) are distributed in the annular area; And / or the second groove structure includes a mounting groove corresponding to the mounting position, and the mounting position is located in the mounting groove.

4. The lead frame manufacturing method according to any one of claims 1 to 3, characterized in that: The step S1 comprises: S1.1: first film lamination, laminating a first dry film on the upper surface and the lower surface of the copper substrate (100); S1.2: first exposure and development, removing a portion of the first dry film on the upper surface and the lower surface of the copper substrate (100), exposing a position corresponding to the second etching structure; S1.3: electroplating, forming a coating on the surface of the copper substrate (100); S1.4: stripping the film for the first time, removing the first dry film remaining on the upper surface and the lower surface of the copper substrate (100).

5. The lead frame manufacturing method according to claim 4, characterized in that: Step S2 includes: S2.1: laminating the second film, laminating the second dry film (200) on the upper surface and the lower surface of the copper substrate (100); S2.2: performing a second exposure and development to remove a portion of the second dry film (200) on the upper and lower surfaces of the copper substrate (100), exposing a position on the surface of the copper substrate (100) corresponding to the first etching structure, and exposing the plating layer; S2.3: etching, etching the surface of the copper substrate (100) with the etching solution to form the first etching structure, and etching the surface of the plating layer to form the second etching structure; S2.4: stripping the film for the second time, removing the second dry film (200) remaining on the upper surface and the lower surface of the copper substrate (100); S2.5: Clean and dry.

6. The lead frame manufacturing method according to claim 5, characterized in that: The copper substrate (100) has a welding area; The step S1.2 further comprises: removing a portion of the first dry film on the upper surface and the lower surface of the copper substrate (100) to expose a position corresponding to the welding area; The step S1.3 further comprises: forming a pad (160) by electroplating on the surface of the welding area; In the step S2.2, the solder pad (160) is covered by the second dry film (200).

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