Solder resist windowing structure

Abstract

The utility model relates to a kind of resistance welding window structure, involve impedance window field. Including substrate and covering the ink area and isolation area with the substrate outside side, ink area and isolation area are provided with window, the bottom of window is equipped with impedance line, the window still includes: the spacing of first window structure: impedance line outside side to the inside of isolation area is ≤n times of impedance line width, ink area window spacing is greater than or equal to the window spacing of isolation area;Second window structure: the spacing of impedance line outside side to the inside of isolation area is >n times of impedance line width, ink area window spacing is less than the window spacing of isolation area, n=2-6. The utility model is based on threshold design window mode, can reduce impedance value abnormal fluctuation, make actual production impedance line impedance value and design model's theoretical impedance value high degree of matching, significantly reduce the deviation of model and actual measurement value, solve the core problem of poor impedance simulation effect in prior art.

Description

Technical Field

[0001] This utility model relates to the field of impedance window opening, specifically, to a solder resist window opening structure. Background Technology

[0002] In modern electronic devices, printed circuit boards (PCBs) serve as the support for electronic components and the carrier of electrical connections, making their production and design crucial. As electronic products evolve towards miniaturization and high performance, the requirements for the design precision and performance of PCBs are also increasing. Among these requirements, ink windowing is a vital step in PCB production and design, determining whether specific areas can be soldered, connected, or subjected to other special treatments. For example, when soldering components, ink windowing is needed to expose the pads to ensure a good electrical connection; in some radio frequency circuit designs, special treatment of the windowed areas can reduce parasitic capacitance effects and improve signal transmission efficiency.

[0003] However, existing PCB ink windowing models often focus only on how to perform the windowing operation, such as defining the windowing area by drawing lines on the flux layer. After windowing, there is a lack of further optimization and adjustment measures for the windowed area and surrounding structures (such as copper foil); this limitation is particularly evident in impedance simulation. Because the impact of key factors such as ink windowing and copper foil spacing on impedance is not fully considered, the actual impedance simulation results are poor, failing to meet the requirements of current high-performance electronic products for precise impedance control of PCBs, thus affecting the signal transmission stability and performance of the entire electronic device.

[0004] Therefore, it is urgent to design a reasonable impedance line window structure to constrain the ink window position, improve the matching degree between production and processing and impedance model, and enhance the impedance design accuracy. Utility Model Content

[0005] To address the shortcomings of the existing technology, this utility model provides a weld-resistant window structure.

[0006] The technical solution of this utility model is as follows:

[0007] A solder resist window structure includes a substrate and an ink area and an isolation area covering the outside of the substrate. The ink area and the isolation area have windows, and an impedance line is provided at the bottom of the window. The window further includes:

[0008] First window structure: The distance from the outside of the impedance line to the inside of the isolation zone is ≤ n times the width of the impedance line, and the window spacing in the ink area is greater than or equal to the window spacing in the isolation zone, n = 2-6;

[0009] Second window structure: The distance from the outside of the impedance line to the inside of the isolation zone is greater than n times the width of the impedance line, and the window spacing in the ink area is less than the window spacing in the isolation zone, n = 2-6.

[0010] As a preferred technical measure, in the cross-section of the first window structure, the inner side of the ink area includes a first window edge, and the isolation area on one side of the window edge includes a second window edge. Along the length direction of the ink area, the distance between the first window edge and the second window edge is greater than or equal to 0.4-0.7 mil.

[0011] As a preferred technical measure, in the cross-section of the second window structure, the inner side of the ink area includes the first window edge, the isolation area on one side of the first window edge includes the second window edge, and the distance between the first window edge and the second window edge along the length direction of the ink area is less than 0.4-0.7 mil.

[0012] As a preferred technical measure, at least two impedance lines are provided at the bottom of the window, and the window opening structure includes:

[0013] First window structure: The distance from the outermost impedance line to the inner side of the isolation zone is ≤ n times the width of the impedance line, and the window spacing in the ink area is greater than or equal to that in the isolation zone, n = 2-6;

[0014] Second window structure: The distance from the outermost impedance line to the inner side of the isolation zone is greater than n times the width of the impedance line, and the window spacing in the ink area is less than that in the isolation zone, n = 2-6.

[0015] As a preferred technical measure, in the cross-section of the second window structure, the ink area includes a stepped portion that covers the isolation area from top to bottom and a window portion that covers the substrate.

[0016] As a preferred technical measure, the windowing includes a characteristic window and a differential window. The characteristic window has an impedance line, and the differential window has two symmetrically arranged impedance lines.

[0017] As a preferred technical measure, the multiple n = 5.

[0018] As a preferred technical measure, the isolation zone is made of copper foil.

[0019] As a preferred technical measure, the isolation zone is wrapped around the outer surface of the substrate, and ink is provided in a localized area. The overlapping part of the ink and the substrate has the window.

[0020] The advantages of this utility model based on the above solution are as follows:

[0021] In this invention, the threshold design based on the first and second openings effectively avoids the electromagnetic field disturbance around the impedance line caused by the difference between the dielectric constant of ink DK1 = 3.3-4.5 and the dielectric constant of air DK2 = 1, reducing abnormal fluctuations in impedance values ​​and ensuring a high degree of matching between the actual impedance value of the produced impedance line and the theoretical impedance value of the design model. This significantly reduces the deviation between the model and the actual measured value, solving the core problem of poor impedance simulation effect in the prior art. Furthermore, during PCB manufacturing, this structure provides clear parameter basis for the solder mask opening process, avoiding random deviations in the opening position and spacing, and ensuring the consistency of the impedance line opening structure for each batch of products. Attached Figure Description

[0022] Figure 1 This is a cross-sectional structural diagram of the first characteristic window opening method of this utility model;

[0023] Figure 2 This is a cross-sectional structural diagram of the second characteristic window opening method of this utility model;

[0024] Figure 3 This is a schematic diagram of the cross-sectional structure of the first differential windowing method of this utility model;

[0025] Figure 4 This is a schematic diagram of the cross-sectional structure of the second differential windowing method of this utility model;

[0026] In the diagram,

[0027] 100. Ink area; 110. First window edge; 120. Stepped section; 130. Window section

[0028] 200. Isolation zone; 210. Edge of the second window;

[0029] 300. Substrate;

[0030] 400, Impedance line. Detailed Implementation

[0031] To better understand the purpose, technical solution, and technical effects of this utility model, the following description, in conjunction with the accompanying drawings and embodiments, will provide further explanation. It should be noted that similar reference numerals and letters in the following drawings indicate similar items; therefore, once an item is defined in one drawing, it does not need further definition and explanation in subsequent drawings. It is also stated that the embodiments described below are only for explaining this utility model and are not intended to limit it.

[0032] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intermediate component. When a component is referred to as "connected to" another component, it can be directly connected to the other component or there may be an intermediate component.

[0033] The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product is usually placed when in use, or the orientation or positional relationship in which a person skilled in the art would normally understand it, or the orientation or positional relationship in which the product is usually placed when in use. It is only for the purpose of facilitating the description of this application and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0034] Example 1

[0035] The impedance window structure in this embodiment is applied to the impedance model design of a PCB board. The isolation area 200 is made of copper foil and wraps around the outer surface of the substrate 300. The isolation area 200 is partially covered with ink to form an ink area 100. A window is opened in the overlapping part of the ink area 100 and the substrate 300. An impedance line 400 is provided at the bottom of the window. Specifically, it includes two forms: characteristic window and differential window, as follows:

[0036] refer to Figure 1 The first window structure includes a first characteristic windowing method, namely a window structure with a single impedance line 400. The substrate 300 is made of FR-4 board with a dielectric constant Er = 4.2. The outer side of the substrate 300 is covered by an ink area 100 and a copper-clad isolation area 200. A rectangular window is opened in the overlapping area of ​​the ink area 100 and the isolation area 200. An impedance line 400 is fixed on the surface of the substrate 300 at the bottom of the window. The impedance line 400 has a width W = 3mil and a thickness T = 1.2mil. The horizontal distance H2 from the outer side of the impedance line 400 to the inner side of the isolation area 200 is measured to be 12mil. H2 is less than 5 times the width of the impedance line 400, 5 × 3mil = 15mil. Along the length direction of the ink area 100, the horizontal distance H1 between the first window edge 110 on the inner side of the ink area 100 and the second window edge 210 on the inner side of the isolation area 200 is set to 0.5mil.

[0037] Example 2: Compared with the first characteristic window opening method of the first window opening structure, this example further provides a second characteristic window opening method of the second window opening structure.

[0038] refer to Figure 2The second window structure also uses FR-4 as the base material 300 and copper foil as the isolation area 200. The isolation area 200 wraps the outer surface of the base material 300 and the upper part is partially covered with ink to form an ink area 100. A window is opened where the ink and the base material 300 overlap, and an impedance line 400 is set at the bottom of the window. It also includes two forms: characteristic window and differential window, as detailed below:

[0039] Along the length of the ink area 100, the ink area 100 includes a stepped portion 120 that covers the isolation area 200 from top to bottom and a windowed portion 130 that covers the substrate 300. The windowed portion 130 covers the surface of the substrate 300 and forms a first windowed edge 110. The stepped portion 120 achieves a stable fit between the ink area 100 and the isolation area 200. The distance H2 between the first windowed edge 110 on the inner side of the windowed portion 130 and the second windowed edge 210 on the inner side of the isolation area 200 is set to 0.35 mil.

[0040] Example 3: Compared to Example 1, the first window structure further includes:

[0041] refer to Figure 3 The first differential windowing method features a symmetrical structure with two impedance lines 400. The substrate 300 also uses FR-4 board. A rectangular window is formed between the ink area 100 and the copper isolation area 200 on the outer side of the substrate 300. Two impedance lines 400 are symmetrically arranged on the surface of the substrate 300 at the bottom of the window. Each impedance line 400 has a width W = 3mil and a thickness T = 1.2mil. The center-to-center distance between the two impedance lines 400 is 4mil. Measurements show that the horizontal distance H4 from the outermost impedance line 400 (the one closest to the isolation area 200) to the inner side of the isolation area 200 is 13mil. H4 is less than 5 times the width of the impedance line 400 (15mil). Along the length of the ink area 100, the horizontal distance H3 between the first window edge 110 on the inner side of the ink area 100 and the second window edge 210 on the inner side of the isolation area 200 is set to 0.5mil.

[0042] Example 4: Compared to Example 3, the second window structure also includes a second differential windowing method.

[0043] refer to Figure 4 Two impedance lines 400 are symmetrically arranged at the bottom of the window. Each line has a width W = 3 mil, a thickness T = 1.2 mil, and a center-to-center distance of 8 mil. Measurements show that the horizontal distance H4 from the outermost impedance line 400 to the inner side of the isolation zone 200 is 18 mil. H4 is greater than 5 times the width of impedance line 400, which is 15 mil.

[0044] Along the length of the ink area 100, the distance H3 between the first window edge 110 and the second window edge 210 is 0.35 mil; the ink area 100 is also provided with a stepped part 120 and a window part 130, the window part 130 forms the window edge, and the two impedance lines 400 are symmetrical about the center line of the window to ensure the symmetry of the differential impedance, and the distance H4 between the outermost impedance line 400 and the isolation area 200 is 18 mil.

[0045] In Examples 1 to 4, the spacing H1 to H4 is set as a horizontal spacing relative to the substrate plane, or it can be set circumferentially on a curve or as a distance of curve parallel to the surface.

[0046] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0047] The above embodiments only illustrate several implementation methods of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A weld-resistant window structure, characterized in that, It includes a substrate and an ink area and a barrier area covering the outside of the substrate. The ink area and the barrier area have windows, and an impedance line is provided at the bottom of the window. The window also includes: First window structure: The distance from the outside of the impedance line to the inside of the isolation zone is ≤ n times the width of the impedance line, and the window spacing in the ink area is greater than or equal to the window spacing in the isolation zone, n=2-6; Second window structure: The distance from the outside of the impedance line to the inside of the isolation zone is greater than n times the width of the impedance line, and the window spacing in the ink area is less than the window spacing in the isolation zone, n=2-6.

2. The weld resistance window structure according to claim 1, characterized in that, In the cross-section of the first window structure, the inner side of the ink area includes the first window edge, and the isolation area on one side of the window edge includes the second window edge. The distance between the first window edge and the second window edge is greater than or equal to 0.4-0.7 mil.

3. The weld resistance window structure according to claim 1, characterized in that, In the cross-section of the second window structure, the inner side of the ink area includes the first window edge, the isolation area on one side of the first window edge includes the second window edge, and the distance between the first window edge and the second window edge is less than 0.4-0.7 mil.

4. The weld resistance window structure according to claim 3, characterized in that, The window has at least two impedance lines at its bottom, and the window opening structure includes: First window structure: The distance from the outermost impedance line to the inner side of the isolation zone is ≤ n times the width of the impedance line, and the window spacing in the ink area is greater than or equal to that in the isolation zone, n=2-6; Second window structure: The distance from the outermost impedance line to the inner side of the isolation zone is greater than n times the width of the impedance line, and the distance between the windows in the ink area is less than that in the isolation zone, n=2-6.

5. The weld resistance window structure according to claim 1, characterized in that, In the cross-section of the second window structure, the ink area includes a stepped portion that covers the isolation area from top to bottom and a window portion that covers the substrate.

6. A weld-resistant window structure according to any one of claims 1-5, characterized in that, The window includes a characteristic window and a differential window. The characteristic window has an impedance line, and the differential window has two symmetrically arranged impedance lines.

7. A weld-resistant window structure according to any one of claims 1-5, characterized in that, The multiple n=5.

8. A weld-resistant window structure according to any one of claims 1-5, characterized in that, The isolation zone is made of copper sheet.

9. A weld-resistant window structure according to any one of claims 1-5, characterized in that, The isolation zone is wrapped around the outer surface of the substrate and is partially covered with ink. The window is located where the ink overlaps with the substrate.

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