Frame unit with wettable side wings, packaging structure and preparation method thereof
By employing partition etching and secondary grooving processes, the problems of cutting difficulties and tool wear caused by the width of the root of the wettable side wing connecting rib were solved, achieving high-quality welding and cutting performance.
Patent Information
- Application Number
- CN202511968384.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-24
- Publication Date
- 2026-02-13
AI Technical Summary
In the existing technology, the root of the connecting rib that can be wetted on the side is relatively wide, which makes it easy for the cutting edge to curl, the tool to wear, and the welding quality to be affected.
The process employs partitioned etching and secondary grooving. First, the all-metal structure is retained in the connecting rib area. After injection molding is completed, wettable side wings are etched on the connecting rib to form a gradient cross-section that is wider at the top and narrower at the bottom.
This reduces the width of the connecting rib root, avoids curling and burrs during cutting, reduces tool wear, and improves welding quality and product reliability.
Smart Images
Figure CN121532028A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to a frame unit with wettable flanks, a packaging structure and a preparation method thereof. BACKGROUND
[0002] In the manufacture of functional support, the packaging structure is usually formed by etching copper plate. In order to meet the requirements of performance testing, a groove for detecting the welding quality needs to be formed on the connecting rib of the packaging structure. The wettable flanks can provide a clear and reliable visual detection window for the tin paste climbing state after welding, facilitating the realization of automatic optical inspection. The depth of the wettable flanks needs to meet the contact requirements of the detection probe or detection clamp, while avoiding affecting the strength of the support.
[0003] As shown in Figure 12 The wettable flanks in the prior art are formed by one-time half-etching, that is, the wettable flanks are etched on the connecting rib at the same time when the pads and lines are formed. In order to ensure the stability and sufficient strength support of the packaging structure in the subsequent injection molding step, prevent the injection of the glue from leaking into the groove, a relatively wide root 20 needs to be formed on both sides of the wettable flanks, resulting in a typical "concave" structure of the cross section of the connecting rib. The bottom of the "concave" structure is thin, and the two side walls are thick. In the subsequent cutting step, this soft and hard uneven structure will cause the thin and weak groove bottom to break first, and the thick root on both sides to be pulled and even torn, forming metal curling or burrs. These burrs are extremely easy to cause short circuit, monument, etc. during the subsequent SMT mounting. More specifically, the monument phenomenon is that the element is abnormally raised at the end position or corner position due to uneven heating during welding, directly affecting the appearance and performance of the product, and may also cause short circuit, open circuit and other faults. In addition, the thick connecting rib root also aggravates the wear of the cutting tool.
[0004] Therefore, there is a need in the prior art for a functional support that is easier to cut, less likely to produce metal curling or wire drawing, and does not aggravate tool wear. SUMMARY
[0005] The purpose of the present application is to design a frame unit with wettable flanks, a packaging structure and a preparation method thereof, aiming to solve the problem of wide connecting rib root caused by the traditional one-time half-etching process forming wettable flanks, and the problem of curling and tool wear during cutting caused thereby.
[0006] The present application relates to a frame unit with wettable flanks, comprising a metal substrate, a pad area and a connecting rib are formed on the metal substrate, the connecting rib extends from the pad area, a wettable flank is formed on the connecting rib, and the root of the wettable flank is a tapered cross section that is wide at the top and narrow at the bottom.
[0007] The root of the wettable side wing can have a pointed end; the front surface of the frame unit can be provided with front surface pads, and the back surface of the frame unit can be provided with back surface pads; the area where the front surface pads and the back surface pads overlap can be a full metal area; and the area where the connecting rib overlaps with the pad area can be a full metal area.
[0008] The application also relates to a packaging structure, which can be arranged with a plurality of frame units, and the frame units are formed with packaging compounds by injection molding; the frame units can be the frame units described above. At least one pair of opposite sides of the frame units can be provided with the connecting ribs.
[0009] The application also relates to a preparation method of a packaging structure, which comprises the following steps: (1) providing a metal substrate for forming a packaging structure; (2) performing first selective etching, using a photoresist film to define an etching pattern, performing semi-etching on the areas where lines, pads and functional areas need to be formed, and completely protecting the areas planned as connecting ribs so that the connecting ribs remain in a full metal state during the whole process; (3) performing surface roughening on the substrate after the partition etching, and then injecting packaging compounds; (4) after the injection of the compounds is completed, performing back surface lithography on the metal substrate to form windows for opening wettable side wings at the predetermined positions of the connecting ribs in the full metal state; (5) performing second etching to form wettable side wings at the predetermined positions of the connecting ribs in the full metal state.
[0010] The application also relates to a preparation method of a packaging structure, which comprises the following steps: (1) providing a metal substrate for forming a packaging structure; (2) performing first selective etching, coating a photoresist film with a thickness of 5-20 μm on the surface of the metal substrate, forming a pattern after exposure and development; performing selective etching on the functional areas not protected by the photoresist film, and the etching depth is 0.1-0.3 mm to form a recess structure of the pads and lines while keeping the metal thickness of the connecting rib area unchanged; wherein the etching time during etching is 30-180 s, and the etching temperature is 20-80 °C; (3) performing surface roughening on the substrate after the partition etching, and the roughening depth is 0.3-3 μm; placing the treated substrate in a mold, and using epoxy packaging compounds to perform injection molding, completely filling the recess structure formed after etching and covering the connecting rib area; the injection molding temperature is 130-200 °C, the injection pressure is 30-150 MPa, the holding pressure time is 0.5-6 s, and the mold cavity vacuum degree is maintained at-60 kPa to-95 kPa; (4) After the injection of the glue, the back of the metal substrate is photoetched to form a window for opening the wettable side wing at the predetermined position of the connecting rib in the full metal state; (5) A photoresist film with a thickness of 5-20 μm is coated on the surface of the plastic package, and after exposure and development, an etching window is opened above the area corresponding to the connecting rib; the connecting rib metal under the window is removed by a second etching through the etching window, so as to separate the package units and expose the independent pads and lines, and the wettable side wing with a sharp end is formed on the connecting rib in the full metal state; wherein the width of the etching window is 0.1-0.3 mm, and is smaller than the width of the connecting rib; the etching time is 20-120 s, and the etching temperature is 20-80 °C.
[0011] According to the frame unit with the wettable side wing, the package structure and the preparation method thereof, the following beneficial technical effects are achieved: (1) The full metal pedestal is reserved at the connecting rib during the first etching, and the wettable side wing is formed by the second etching after the injection, so that the width of the root of the connecting rib can be minimized; by setting the root of the connecting rib as a shape with a wide upper part and a sharp lower part, the metal thickness on the cutting route is basically the same, and the shape is relatively smooth during cutting, and the phenomenon of edge curling and tearing basically does not occur, and the wear of the cutting tool can be greatly reduced; (2) The wettable side wing is formed by the second etching on the connecting rib after the injection, and the glue leakage during the injection and the support strength requirement of the root of the connecting rib do not need to be considered, so that the size of the root of the wettable side wing can be minimized according to the requirement, and the mechanical properties of the metal on the cutting route are as uniform as possible; the cutting quality of the support itself can be improved, and the detection function can be provided to improve the direct rate of the SMT mounting of the client and the reliability of the product; (3) The application also provides a preparation method of the package structure, which can prepare the package structure as described above, and solves the problem that only a wettable side wing with a wide thickness can be achieved in the prior art, and the package structure with the above excellent performance can be obtained. BRIEF DESCRIPTION OF DRAWINGS
[0012] Figure 1 is the overall schematic diagram of the package structure of the application.
[0013] Figure 2 is the front pad schematic diagram of the package structure of the application.
[0014] Figure 3 is the back pad schematic diagram of the package structure of the application.
[0015] Figure 4is a combined schematic view of the front and back pads of the package structure of the present application.
[0016] Figure 5 is Figure 4 is a B-B sectional view of the package structure of the present application.
[0017] Figure 6 is a sectional view of the package structure after the first etching and surface roughening.
[0018] Figure 7 is a sectional view of the package structure after the injection of the plastic material.
[0019] Figure 8 is a sectional view of the package structure after the second etching.
[0020] Figure 9 is a plan view of the finished functional support.
[0021] Figure 10 is a plan view of the finished support unit.
[0022] Figure 11 is a sectional view of the finished support unit.
[0023] Figure 12 is a sectional view of the existing package structure. DETAILED DESCRIPTION
[0024] In order to make the purpose, technical scheme and advantages of the present application more clear, the embodiments of the present application will be described in detail below with reference to the drawings. It should be noted that the embodiments and features in the embodiments can be combined with each other as long as they do not conflict. Those skilled in the art can understand that the technical term "full metal" in the present application is relative to "half etching", which means that the thickness of the full metal area is greater than the thickness of the half etching area, and does not represent the half relationship in the thickness value. In the description of the present application, it should be understood that the orientation words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" and the like indicate the orientation or position relationship shown in the drawings, and are only used for the convenience of describing the present application and simplifying the description. Without the opposite description, these orientation words do not indicate and imply that the indicated device or element must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the scope of protection of the present application.
[0025] According to the frame unit with wettable side wings, the package structure and the preparation method thereof of the present application, the core lies in the process strategy of "partition etching" and "second slotting": (1) Zoning etching: in the first etching, the metal substrate is selectively regionally etched: the functional area where the circuit and pad are to be formed is semi-etched, while the connecting rib area which is the structural support and cutting path is protected to keep the original full metal thickness; (2) Second slotting: after the injection of the plastic material fixes the overall structure, a groove for welding detection is processed on the complete connecting rib through high-precision etching.
[0026] In the first etching according to the present application, the full metal structure is reserved in the connecting rib area, and the wettable flanks are etched on the connecting rib after the injection is completed. At this time, since the injection process has been completed, there is no need to consider the strength requirement of the connecting rib and the influence of preventing the leakage of the plastic material, so that the root width of the wettable flanks etched in the second time can be reduced as much as possible according to the requirement, and is formed in the structure form of wide at the top and sharp at the bottom. In this way, the cutting is relatively smooth when the cutter cuts from top to bottom, and stress concentration is not formed at the root or bottom of the wettable flanks, which can avoid the phenomenon of curling or burr of the metal connecting rib during cutting, and can also reduce the wear of the cutter, and the cutting performance is basically equivalent to that of the metal connecting rib with uniform thickness.
[0027] According to the preparation method of the packaging structure, the following steps are specifically included: (1) providing a metal substrate for forming a packaging structure; (2) performing the first selective etching, which can use a photoresist film to accurately define the pattern, and semi-etch the area where the circuit, pad and functional area are to be formed, and completely protect the area planned as the connecting rib, so that it remains in the complete full metal state without being etched during the whole process; more specifically, a photoresist film with a thickness of 5-20 μm can be coated on the surface of the metal substrate, and a pattern is formed after exposure and development; the functional area not protected by the photoresist film is selectively etched to a depth of 0.1-0.3 mm to form a recess structure of the pad and circuit, while the metal thickness of the connecting rib area remains unchanged; wherein the process parameters of the etching process meet: etching time is 30-180 s, etching temperature is 20-80 °C; (3) roughening the surface of the substrate after zoning etching, and then injecting the encapsulating material 7; more specifically, the roughening depth is 0.3-3 μm, which can be performed by sandblasting to enhance the adhesion of the metal surface to the epoxy encapsulating material; the treated substrate is placed in a mold, and the epoxy encapsulating material is used for injection molding to completely fill the recess structure formed after etching and cover the connecting rib area; the injection molding process parameters are: injection molding temperature 130-200 °C, injection pressure 30-150 MPa, holding pressure time 0.5-6 s, and mold cavity vacuum degree is maintained at-60 kPa to-95 kPa; (4) After the injection molding of the encapsulation material 7 is completed, the back of the metal substrate is photoetched to form a window for opening the wettable side wing at the predetermined position of the connecting rib in the full metal state; (5) A second etching is performed, and the purpose of this etching is to form the wettable side wing at the predetermined position of the connecting rib in the full metal state. The wettable side wing with a pointed root can be formed on the connecting rib. Specifically, the two side roots of the connecting rib in the present application form a structure with a wide upper part and a narrow lower part, which can be in the shape as shown in Figure 8 As shown in Figure 8 , the width of the lowermost side of the root of the connecting rib is almost negligible, and when cutting along the cutting line 30 as shown in Figure 9 , the resistance of the cutter from top to bottom becomes smaller and smaller, so that stress concentration on the connecting rib can be avoided, the phenomenon of curling and burr can be avoided, and the wear of the cutter can be reduced. As shown in Figures 9-11 , the finished frame unit of the present application includes an injection molded cup mouth 9 and a cup bottom 10, and the front pad 5 is encapsulated in the encapsulation glue 7.
[0028] More specifically, in the second etching, a photoresist film with a thickness of 5-20 μm can be coated on the surface of the plastic package, and after exposure and development, an etching window is opened above the area corresponding to the connecting rib; etching is performed through the etching window to remove the encapsulation material 7 in the window and etch through the underlying connecting rib metal, thereby separating the encapsulation units and exposing the independent pads and lines; wherein the width of the etching window can be 0.1-0.3 mm, and less than the width of the connecting rib; the etching time is 20-120 s, and the etching temperature is 20-80°C.
[0029] The encapsulation structure and the preparation method thereof of the present application make the metal on the cutting path be a relatively uniform full-thickness metal material when cutting along the cutting path. As shown in Figure 8 , the encapsulation structure of the present application forms a root 20 on both sides of the wettable side wing 8, the root 20 is a tapered cross section with a wide upper part and a narrow lower part, and the lowermost end of the root 20 is preferably in the shape of a sharp angle. With this structure, when cutting along the cross section, since the root 20 is a tapered cross section with a wide upper part and a narrow lower part, the thickness difference of the root 20 is almost negligible during cutting from top to bottom, the cutting of the cutter is relatively smooth, and stress concentration on the metal connecting rib is avoided, the mechanical properties are basically consistent, and neat brittle fracture can be achieved, thereby reducing the occurrence of curling or burr. Figure 8
[0030] As Figures 1-12 As shown, the packaging structure of this application has multiple frame units arranged on it, and adjacent frame units are connected by connecting ribs. The packaging structure has a fully etched area 4 and a half-etched area 3, and the half-etched area 3 can be used as the pad area of the frame unit. A first connecting rib 1 is provided between adjacent frame units in a first direction, and a second connecting rib 2 is provided in a second direction. The first connecting rib 1 and the second connecting rib 2 are both all-metal connecting ribs before the second etching. After the second etching, at least one of the first connecting rib 1 and the second connecting rib 2 has a wettable wing formed on it. The wettable wing is formed on the all-metal base by a secondary etching.
[0031] like Figures 2-3 As shown, the frame unit has a front pad 5 on the front and a back pad 6 on the back. In use, the front pad 5 and the back pad 6 need to be connected by wires to form a path. For example... Figure 4 As shown, the overlapping area of the front pad 5 and the back pad 6 is an all-metal area. In addition, the areas where the connecting ribs overlap with the pad areas are also all-metal connecting ribs. Through the aforementioned all-metal area structure design of the frame unit, this application allows for complete isolation between the all-metal bonding area between the metal connecting ribs and the front half-etched area and the all-metal area of the pads after injection molding by filling the semi-etched area of the pads with injection molding compound. This ensures that the connection areas between the metal connecting ribs and the pads are embedded within the injection molding compound, and also avoids test failures caused by dye directly penetrating into the functional area pads through the connection between the connecting ribs and the pads during red ink testing.
[0032] The "partition etching" and "secondary grooving" methods proposed in this invention form a unique structure of "connecting ribs with an all-metal base and post-formed wettable side wings," and employ a unique manufacturing method that involves "first performing all-metal protection on the connecting ribs and completing injection molding, then performing secondary etching and grooving." This application changes the structure of the connecting ribs, especially the structure of its root, through the above process flow, solving a long-standing technological problem. This approach of separating "functional area etching" from "structural component reinforcement" and then "functionalizing" the reinforced structure after injection molding is not obvious to those skilled in the art. This application enables secondary etching at specific locations of the all-metal connecting ribs to form wettable side wings, reducing the area ratio of the all-metal connecting ribs and lowering tool wear.
[0033] Although the embodiments disclosed in this application are as described above, the content is merely for the purpose of facilitating understanding of this application and is not intended to limit this application. Any person skilled in the art to which this application pertains may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in this application; however, the scope of patent protection of this application shall still be determined by the scope defined in the appended claims.
Claims
1. A frame unit with wettable side wings comprising a metal substrate, on which a land area and a connecting rib are formed, the connecting rib extending from the land area, a wettable side wing being formed on the connecting rib, characterized in that, The root of the wettable side wing is tapered from wide to narrow.
2. The frame unit according to claim 1, characterized in that The root of the wettable side wing has a pointed end.
3. The frame unit of claim 1, wherein, The front surface of the frame unit is provided with front surface pads, the back surface of the frame unit is provided with back surface pads, and the area where the front surface pads and the back surface pads overlap is a full metal area.
4. Frame unit according to any of claims 1-3, characterized in that, The area where the connecting rib overlaps with the pad area is a full metal area.
5. A packaging structure, a plurality of frame units being arranged on the packaging structure, a packaging compound being injection molded on the frame units, characterized in that, The frame unit is the frame unit according to any one of claims 1-4.
6. A method for manufacturing a package structure, characterized by, The method comprises the following steps: (1) providing a metal substrate for forming a packaging structure; (2) performing a first selective etching, using a photoresist film to define an etching pattern, performing a semi-etching on the area where the circuit, the pad and the functional area are to be formed, and completely protecting the area planned to be the connecting rib so that it remains in a full metal state throughout the process; (3) performing surface roughening on the substrate after the partition etching, and then injecting a packaging adhesive; (4) after the completion of the adhesive injection, performing back surface lithography on the metal substrate to form a window for opening the wettable side wing at the predetermined position of the connecting rib in the full metal state; (5) performing a second etching to form the wettable side wing at the predetermined position of the connecting rib in the full metal state.
7. A method for manufacturing a package structure, characterized by, The method comprises the following steps: (1) providing a metal substrate for forming a packaging structure; (2) performing a first selective etching, applying a photoresist film with a thickness of 5-20 μm on the surface of the metal substrate, and forming a pattern after exposure and development; performing a selective etching on the functional area not protected by the photoresist film, with an etching depth of 0.1-0.3 mm, to form a recessed structure of the pad and the circuit, while keeping the metal thickness of the connecting rib area unchanged; wherein the etching time during etching is 30-180 s, and the etching temperature is 20-80 °C; (3) performing surface roughening on the substrate after the partition etching, with a roughening depth of 0.3-3 μm; placing the treated substrate in a mold, and using an epoxy packaging adhesive to perform injection molding, completely filling the recessed structure formed after etching and covering the connecting rib area; the injection molding temperature is 130-200 °C, the injection pressure is 30-150 MPa, the holding pressure time is 0.5-6 s, and the mold cavity vacuum degree is maintained at -60 kPa to -95 kPa; (4) after the completion of the adhesive injection, performing back surface lithography on the metal substrate to form a window for opening the wettable side wing at the predetermined position of the connecting rib in the full metal state; (5) applying a photoresist film with a thickness of 5-20 μm on the surface of the plastic package, and forming an etching window above the area corresponding to the connecting rib after exposure and development; performing a second etching through the etching window to remove the packaging adhesive within the window and etch through the underlying connecting rib metal, separating the packaging units and exposing the independent pads and circuits, and forming the wettable side wing with a pointed root on the connecting rib in the full metal state; wherein the width of the etching window is 0.1-0.3 mm, which is smaller than the width of the connecting rib; the etching time is 20-120 s, and the etching temperature is 20-80 °C.