A method for back-drilling and gold-plating leads to prevent wire flinging

Abstract

The present invention discloses a method for back-drilling and removing gold-plated leads to prevent wire flinging, which includes: S1: performing outer layer pattern transfer on a PCB board including a drilled hole, wherein the outer layer pattern transfer includes an etching process for the circuit pattern and an etching process for the gold-plated leads; one end of the gold-plated lead is connected to the back-drilled hole, and the other end is connected to the via hole of the ground layer; S2: performing solder mask on the PCB board and forming a solder mask opening at the drilled hole, wherein the solder mask layer covers the intersection of the annular gold-plated lead and the linear gold-plated lead; S3: plating fingers, plating the fingers through the gold-plated leads; S4: performing back-drilling on the back-drilled hole to ensure that the annular gold-plated lead in the back-drilled hole is completely removed. By designing the shape of the solder mask opening in combination with the radius of the back-drilled hole, the present invention ensures that the annular gold-plated lead in the back-drilled hole is completely removed, avoiding problems such as copper leakage or wire flinging short circuit.

Description

Technical Field

[0001] The present invention relates to the field of removing gold-plated leads, and particularly to a method for back-drilling to remove gold-plated leads to prevent wire flinging. Background Art

[0002] For gold plating of the gold fingers in a gold finger card board, there are mainly two gold plating methods. One is to pull a lead at the plug end of the gold finger, and remove the gold-plated lead by etching after gold plating. The second is to arrange one end of the gold-plated lead on a hole to be back-drilled, and the other end on a via short-circuited to the ground layer. The ground layer is short-circuited to the board edge when pulling the lead, and after gold plating, the gold-plated lead connected to the back-drilling can be disconnected by back-drilling, and the short circuit between the ground layer and the board edge can be disconnected by forming, thus realizing the gold plating of the gold fingers.

[0003] The second method for removing the lead is simple and fast, and has become a commonly used method in the field of removing gold-plated leads. In the customer's original data, a solder mask opening needs to be designed at the back-drilled hole. The size of the solder mask opening is usually larger than the diameter of the back-drilled hole. Therefore, when the gold-plated lead is designed on the back-drilled hole, when removing the gold-plated lead by back-drilling, there will be a problem of copper leakage for about 3 mil of the gold-plated lead. When the width of the gold-plated lead is designed to be too small, the cutting force when the back-drilling cuts the gold-plated lead is greater than the adhesion force of the lead, and the lead peeling problem will occur, resulting in a short circuit of the circuit. Summary of the Invention

[0004] The present invention aims to solve at least one of the problems in the related art to some extent. For this purpose, the object of the present invention is to provide a method for back-drilling to remove gold-plated leads to prevent wire flinging. By designing the shape of the solder mask opening in combination with the radius of the back-drilled hole, it is ensured that the annular gold-plated lead in the back-drilled hole is completely removed, avoiding the problems of copper leakage or short circuit caused by wire flinging.

[0005] To achieve the above object, the present application adopts the following technical solution: A method for back-drilling to remove gold-plated leads to prevent wire flinging, including:

[0006] S1: Perform outer layer pattern transfer on a PCB board including a drilling hole. Among them, the outer layer pattern transfer includes an etching process of the circuit pattern and an etching process of the gold-plated lead; one end of the gold-plated lead is connected to the back-drilled hole, and the other end is communicated with a via short-circuited to the ground layer; the back-drilled hole refers to a drilling hole to be back-drilled; the gold-plated lead includes an annular gold-plated lead located in the drilling hole and a linear gold-plated lead connected to the annular gold-plated lead;

[0007] S2: Apply a solder mask to the PCB board and form a solder mask opening at the drilling hole. Among them, the solder mask layer covers the intersection of the annular gold-plated lead and the linear gold-plated lead;

[0008] S3: Gold-plate the gold fingers, and gold-plate the gold fingers through the gold-plated leads;

[0009] S4: Back drill the back drill hole to ensure that the annular gold-plated lead in the back drill hole is completely removed.

[0010] Furthermore, the one drill hole is circular, the gold-plated leads around the one drill hole are annular, and the center of the annular gold-plated leads coincides with the center of the one drill hole.

[0011] Furthermore, the solder mask opening is circular, the center of the solder mask opening coincides with the center of the one drill hole, and the radius of the solder mask opening is smaller than the outer circle radius of the annular gold-plated leads.

[0012] Furthermore, the radius of the solder mask opening is 1 mil smaller than the outer circle radius of the annular gold-plated leads.

[0013] Furthermore, when back drilling the back drill hole in step S4, the radius of the back drill hole is larger than the outer circle radius of the annular gold-plated leads to ensure that the annular gold-plated lead in the back drill hole is completely removed.

[0014] Furthermore, the solder mask opening is bow-shaped, the solder mask opening is tangent to the annular gold-plated leads, and the tangent plane coincides with the intersection of the annular gold-plated leads and the linear gold-plated leads.

[0015] Furthermore, the radius of the solder mask opening is larger than the radius of the annular gold-plated leads.

[0016] Furthermore, when back drilling the back drill hole in step S4, the radius of the back drill hole is smaller than the radius of the solder mask opening and larger than the radius of the annular gold-plated leads; ensure that the annular gold-plated lead in the back drill hole is completely removed.

[0017] Furthermore, the width of the gold-plated lead is 8 mil.

[0018] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art: The present application designs that the solder mask layer completely covers the intersection of the annular gold-plated leads and the linear gold-plated leads. By controlling the shape and radius of the solder mask opening and combining with the back drill tool diameter, the annular gold-plated leads in the back drill hole are completely removed, avoiding the copper leakage phenomenon caused by the residual gold-plated leads in the back drill hole after back drilling. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present invention and used together with the specification to explain the principles of the present invention.

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] In the attached drawings:

[0022] Figure 1 is a schematic structural diagram of the gold-plated lead before back drilling in Example 1;

[0023] Figure 2 is a schematic structural diagram of the gold-plated lead after back drilling in Example 1;

[0024] Figure 3 is a schematic structural diagram of the gold-plated lead before back drilling in Example 2;

[0025] Figure 4 is a schematic structural diagram of the gold-plated lead after back drilling in Example 2;

[0026] Reference numerals in the attached drawings: 1. Gold-plated lead; 2. Solder mask opening; 3. Solder mask layer; 4. One drilling hole; 5. Back drilling hole. Detailed implementation manners

[0027] In order to have a clearer understanding of the technical features, objectives, and effects of the present invention, the detailed implementation manners of the present invention will now be described in detail with reference to the attached drawings. In the following description, it should be understood that the orientation or positional relationships indicated by "front", "rear", "upper", "lower", "left", "right", "longitudinal", "transverse", "vertical", "horizontal", "top", "bottom", "inner", "outer", "head", "tail", etc. are based on the orientation or positional relationships shown in the attached drawings, and are constructed and operated in a specific orientation, only for the convenience of describing the present technical solution, rather than indicating that the indicated mechanism or component must have a specific orientation, and thus should not be construed as a limitation to the present invention.

[0028] It should also be noted that unless otherwise clearly specified and defined, terms such as "installation", "connection", "connection", "fixation", "setting" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components. When an element is referred to as being "on" or "under" another element, the element can be "directly" or "indirectly" located above the other element, or there may also be one or more intermediate elements. The terms "first", "second", "third", etc. are only for the convenience of describing the present technical solution, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first", "second", "third", etc. can explicitly or implicitly include one or more of such features. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] In the following description, specific details such as specific system structures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present invention. However, those skilled in the art should clearly understand that the present invention can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, mechanisms, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present invention.

[0030] Please refer to the attached Figures 1-4 , a method for preventing wire flinging in backdrilling of gold-plated leads provided by the present application includes:

[0031] S1: Perform outer layer pattern transfer on a PCB board including a drill hole 4, where the outer layer pattern transfer includes an etching process for the circuit pattern and an etching process for the gold-plated lead 1; one end of the gold-plated lead 1 is connected to the backdrilled hole 5, and the other end is connected to a via for shorting to the ground layer; the backdrilled hole 5 refers to a drill hole 4 that needs to be backdrilled; the gold-plated lead includes a ring-shaped gold-plated lead located within a drill hole and a straight gold-plated lead connected to the ring-shaped gold-plated lead.

[0032] S2: Apply solder mask to the PCB board and form a solder mask opening 2 at the drill hole 4, and the solder mask layer 3 covers the intersection of the ring-shaped gold-plated lead and the straight gold-plated lead;

[0033] S3: Gold plating fingers, gold plating the fingers through the gold-plated lead 1;

[0034] S4: Backdrill the backdrilled hole 5 to ensure that the ring-shaped gold-plated lead within the backdrilled hole is completely removed.

[0035] The present application designs the solder mask layer to completely cover the intersection of the ring-shaped gold-plated lead and the straight gold-plated lead. By controlling the shape and radius of the solder mask opening and combining with the backdrill tool diameter, the ring-shaped gold-plated lead within the backdrilled hole is completely removed, avoiding copper leakage caused by the remaining gold-plated lead within the backdrilled hole after backdrilling.

[0036] Embodiment 1

[0037] Please refer to the attached Figures 1-2 , a method for preventing wire flinging in backdrilling of gold-plated leads provided by the present application includes:

[0038] S1: Perform outer layer pattern transfer on a PCB board including a drill hole 4, where the outer layer pattern transfer includes an etching process for the circuit pattern and an etching process for the gold-plated lead 1; the circuit pattern refers to the circuits on the PCB board normally used for lead-out and functional areas, and its etching process adopts the etching process in the prior art.

[0039] One end of the gold-plated lead 1 is connected to the back drill hole 5, and the other end is communicated with the via hole shorted to the ground layer; the back drill hole 5 refers to a drill hole 4 that needs to be back drilled. In this application, the width of the gold-plated lead 1 is set to 7-9 mil, preferably 8 mil, to ensure that the gold-plated lead 1 has a sufficient large adhesion to the PCB board and prevent the problem of wire throwing short circuit caused by insufficient adhesion in the subsequent back drilling process. In this application, the gold-plated lead 1 includes an annular gold-plated lead located in the drill hole 4 and a linear gold-plated lead connected to the annular gold-plated lead.

[0040] S2: Apply solder mask to the PCB board and form a solder mask opening 2 at the drill hole 4. The solder mask layer 3 covers the intersection of the annular gold-plated lead and the linear gold-plated lead.

[0041] In this step, the solder mask process is to coat the ink on the PCB board. The part of the ink coated on the PCB board forms the solder mask layer 3, and the part where the ink is not coated forms the solder mask opening 2. In this application, the solder mask layer 3 needs to cover the intersection of the linear gold-plated lead and the annular gold-plated lead.

[0042] Specifically, the drill hole 4 is circular. The gold-plated lead 1 around the drill hole 4 is annular, and the center of the annular gold-plated lead coincides with the center of the drill hole 4. The annular gold-plated lead is connected to the linear gold-plated lead. The width of the above gold-plated lead 1 refers to the width of the linear gold-plated lead, and the diameter of the annular gold-plated lead is greater than the width of the linear gold-plated lead.

[0043] The solder mask opening 2 is circular, and the center of the solder mask opening 2 coincides with the center of the drill hole 4. The radius of the solder mask opening 2 is greater than the radius of the drill hole 4 and less than the outer circle radius of the annular gold-plated lead. Note: The radius of the solder mask opening 2 is less than the outer circle radius of the annular gold-plated lead, which means that the solder mask layer 3 covers the outside of the annular gold-plated lead. The centers of the drill hole 4, the solder mask opening 2, the back drill hole 5 and the annular gold-plated lead coincide, and their radii are arranged from small to large as: the drill hole 4, the solder mask opening 2, the outer circle radius of the annular gold-plated lead, the radius of the back drill hole 5. The radius of the back drill hole 5 refers to the back drill tool diameter. It can be seen that: in the solder mask process, the solder mask layer 3 covers the edge of the annular gold-plated lead, that is, the solder mask layer 3 covers the part where the annular gold-plated lead intersects with the linear gold-plated lead. Since in the subsequent back drilling process, the annular gold-plated lead needs to be completely removed, that is, the solder mask layer 3 covering the edge of the annular gold-plated lead needs to be removed. In order to ensure the smooth progress of the back drilling process and avoid the solder mask layer 3 being unfavorable for back drilling, in this embodiment, the radius of the solder mask opening 2 is designed to be 1 mil smaller than the outer circle radius of the annular gold-plated lead.

[0044] S3: Gold plating fingers, gold plate the fingers through the gold-plated lead 1;

[0045] S4: Back drill the back drill hole 5 to ensure that the annular gold-plated lead in the back drill hole is completely removed. In this embodiment, since the solder mask layer 3 covers the intersection of the annular gold-plated lead and the linear gold-plated lead, and the radius of the back drill hole 5 is greater than the outer circle radius of the annular gold-plated lead, it is ensured that the annular gold-plated lead in the back drill hole is completely removed. Since the radius of the solder mask opening 2 is 1 mil smaller than the outer circle radius of the annular gold-plated lead, in the back drilling process, a part of the solder mask layer 3 at the edge of the solder mask opening 2 needs to be removed. Since the removed solder mask layer 3 is less, it will not affect the smooth progress of the back drilling process.

[0046] Embodiment 2

[0047] Please refer to the attached Figures 3-4 , a method for preventing wire flinging and removing gold-plated leads by back drilling provided by the present application includes:

[0048] S1: Perform outer layer pattern transfer on a PCB board including a drill hole 4, where the outer layer pattern transfer includes an etching process for the circuit pattern and an etching process for the gold-plated lead 1; the circuit pattern refers to the circuits normally used for lead-out and functional areas on the PCB board, and its etching process adopts the etching process in the prior art.

[0049] One end of the gold-plated lead 1 is connected to the back drill hole 5, and the other end is connected to the ground via hole in a short circuit; the back drill hole 5 refers to a drill hole 4 that needs to be back drilled. In the present application, the width of the gold-plated lead 1 is set to 7 - 9 mil, preferably 8 mil, to ensure that the gold-plated lead 1 has sufficient adhesion to the PCB board and prevent the wire flinging and short circuit problems caused by insufficient adhesion in the subsequent back drilling process. In the present application, the gold-plated lead 1 includes an annular gold-plated lead located in the drill hole 4 and a linear gold-plated lead connected to the annular gold-plated lead.

[0050] S2: Apply solder mask to the PCB board and form a solder mask opening 2 at the drill hole 4, and the solder mask layer 3 covers the intersection of the annular gold-plated lead and the linear gold-plated lead.

[0051] In this step, the solder mask process is to coat the PCB board with ink. The part of the ink coated on the PCB board forms the solder mask layer 3, and the part where the ink is not coated forms the solder mask opening 2. In the present application, the solder mask layer 3 needs to cover the intersection of the linear gold-plated lead and the annular gold-plated lead.

[0052] Specifically, the drill hole 4 is circular, the gold-plated lead 1 around the drill hole 4 is annular, and the center of the annular gold-plated lead coincides with the center of the drill hole 4. The annular gold-plated lead is connected to the linear gold-plated lead. The width of the above-mentioned gold-plated lead 1 refers to the width of the linear gold-plated lead, and the diameter of the annular gold-plated lead is greater than the width of the linear gold-plated lead.

[0053] As shown in the attached Figure 3As shown, the solder resist window 2 is arched, and the tangent of the arched solder resist window 2 is tangent to the annular gold-plated lead, and the tangent coincides with the intersection of the annular gold-plated lead and the straight gold-plated lead, that is, the solder resist layer 3 covers the straight gold-plated lead, and just covers the position where the annular gold-plated lead and the straight gold-plated lead intersect.

[0054] The center of the arcuate solder resist window 2 coincides with the center of the drill hole 4, the radius of the back drill hole 5 is larger than the outer radius of the annular gold-plated lead, and the radius of the solder resist window 2 is larger than the radius of the back drill hole 5. Note: Although the radius of the solder resist window 2 is larger than the radius of the annular gold-plated lead, the solder resist window 2 is arcuate, and the solder resist layer 3 covers the straight gold-plated lead, and just covers the intersection of the annular gold-plated lead and the straight gold-plated lead, ensuring that all the annular gold-plated leads are not covered by the solder resist layer 3 and are exposed in the solder resist window 2. The centers of the drill hole 4, the solder resist window 2, the back drill hole 5 and the annular gold-plated lead all coincide, and their radii are arranged from small to large as follows: a drill hole 4, the outer radius of the annular gold-plated lead, the radius of the back drill hole 5, the solder resist window 2, and the radius of the back drill hole 5 refers to the back drill tool diameter. It can be seen that: in the solder resist process, the solder resist layer 3 covers the part where the annular gold-plated lead and the straight gold-plated lead intersect, but there is still a distance from the other edges of the annular gold-plated lead; since the back-drilled hole 5 formed in the subsequent back-drilling process is circular, it is necessary to remove the part of the solder resist layer 3 that overlaps with the back-drilled hole 5. The overlapping part is only a smaller arched notch in the solder resist layer 3, which will not affect the back-drilling process and can avoid the problem of solder resist cracking caused by too much cutting of the solder resist layer 3 by the surface back-drilling knife.

[0055] S3: Gold-plated finger, gold-plated finger through gold-plated lead 1;

[0056] S4: Back-drill the back-drilled hole 5 to ensure that the annular gold-plated lead in the back-drilled hole is completely removed. In this embodiment, since the solder resist layer 3 covers the part where the annular gold-plated lead and the straight gold-plated lead intersect, and the radius of the back-drilled hole 5 is larger than the outer radius of the annular gold-plated lead, part of the straight gold-plated lead connected to the annular gold-plated lead is also removed, achieving the purpose of completely removing the gold-plated lead 1 in the back-drilled hole 5. Since the removed straight gold-plated lead is covered by the solder resist layer 3, the adhesion between the straight gold-plated lead and the PCB board is increased, ensuring that there will be no problem of copper leakage and short circuit after back drilling.

[0057] It can be understood that the above embodiments only represent the preferred embodiments of the present invention, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the patent of the present invention; it should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, the above technical features can be freely combined, and several deformations and improvements can also be made, and these all belong to the protection scope of the present invention; therefore, all equivalent transformations and modifications made to the scope of the claims of the present invention shall fall within the scope covered by the claims of the present invention.

Claims

1. A method for back-drilling and gold-plating leads to prevent wire flinging, characterized in that, Including: S1: Perform outer layer pattern transfer on a PCB board with a drilled hole. Among them, the outer layer pattern transfer includes an etching process for the circuit pattern and an etching process for the gold-plated lead. One end of the gold-plated lead is connected to the back-drilled hole, and the other end is connected to the via hole of the ground layer. The back-drilled hole refers to a drilled hole that needs to be back-drilled. The gold-plated lead includes a circular gold-plated lead located outside the drilled hole and a linear gold-plated lead connected to the circular gold-plated lead. The drilled hole is circular, the gold-plated lead around the drilled hole is circular, and the center of the circular gold-plated lead coincides with the center of the drilled hole. S2: Apply solder mask to the PCB board and form a solder mask opening at the drilled hole. Among them, the solder mask layer covers the intersection of the circular gold-plated lead and the linear gold-plated lead. The solder mask opening is bow-shaped, tangent to the circular gold-plated lead, and the tangent plane coincides with the intersection of the circular gold-plated lead and the linear gold-plated lead. The radius of the solder mask opening is greater than the radius of the circular gold-plated lead. S3: Gold fingers, gold-plate the gold fingers through the gold-plated leads. S4: Back-drill the back-drilled hole. The radius of the back-drilled hole is less than the radius of the solder mask opening and greater than the radius of the circular gold-plated lead. Ensure that the circular gold-plated lead inside the back-drilled hole is completely removed.

2. A method for preventing wire flinging in back-drilled and gold-plated leads according to claim 1, characterized in that, The width of the gold-plated lead is 8 mil.

Images