CN112188761A - PCB processing method and PCB - Google Patents
PCB processing method and PCB Download PDFInfo
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- CN112188761A CN112188761A CN202011059584.1A CN202011059584A CN112188761A CN 112188761 A CN112188761 A CN 112188761A CN 202011059584 A CN202011059584 A CN 202011059584A CN 112188761 A CN112188761 A CN 112188761A
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/46—Manufacturing multilayer circuits
- H05K3/4611—Manufacturing multilayer circuits by laminating two or more circuit boards
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Abstract
The invention relates to the technical field of PCBs, and discloses a PCB and a processing method thereof. The processing method comprises the following steps: aiming at each medium in the M media, respectively obtaining the average pressing thickness X of the current ith medium after the ith medium is pressed with two core plates with the residual copper rate of 100%i(ii) a According to the formula (H ═ X)1+X2+…+XM)*c％‑h1*(1‑a1％)‑h2*(1‑b1%) determining a theoretical design value H of the pressing thickness of the M pieces of media; wherein h is1And h2Copper thickness of the inner layers of two core plates, respectively, a1% and b1% is the unit residual copper rate of the inner layers of the two core plates respectively, and c% is the thickness coefficient when the M pieces of media are laminated; and processing and designing the PCB. The embodiment of the invention can effectively improve the calculation precision of the medium pressing thickness, lays a reliable foundation for the subsequent PCB processing design, and further ensures the primary qualified rate and various process indexes of the PCB.
Description
Technical Field
The invention relates to the technical field of Printed Circuit Boards (PCBs), in particular to a PCB processing method and a PCB.
Background
In the manufacturing process of the PCB, the medium pressing thickness has important influences on the aspects of impedance design, back drilling depth control, signal loss control, installation and use of the PCB product at a terminal and the like, and is the basis for improving the impedance capability, the back drilling capability, the signal loss capability, the use qualification rate of the PCB product and the like.
With the rapid development of high-speed PCB products, the electronic products have higher and higher requirements for impedance control, back drilling capability control, and the like, and meanwhile, higher requirements are provided for the control capability of the dielectric lamination thickness.
In the current industry, theoretical design values of the dielectric lamination thickness of different laminated layers (namely formed by laminating media of different dielectric materials and/or different dielectric quantities) are determined according to empirical values, and the theoretical design value of the dielectric lamination thickness is greatly different from an actual thickness value due to the influence of various factors in the lamination process, so that the one-time qualification rate and various process indexes of the PCB are negatively influenced, and particularly, the influences on the impedance, the back drilling and the thickness of the finished PCB are greatly influenced.
Therefore, how to make the theoretical design value of the dielectric lamination thickness basically approach to the actual value is a great problem in the current PCB design and production process.
Disclosure of Invention
The invention aims to provide a PCB processing method and a PCB, and solves the defects of low PCB processing qualification rate and poor technological indexes caused by large difference between a theoretical design value and an actual value of medium lamination thickness in the prior art.
In order to achieve the purpose, the invention adopts the following technical scheme:
a processing method of a PCB comprises at least one unit and a technical edge arranged on the periphery of all the units, wherein each unit comprises a first core plate, M pieces of media and a second core plate which are sequentially laminated and pressed, and M is a natural number greater than 0; the processing method comprises the following steps:
aiming at each medium in the M media, respectively obtaining the average pressing thickness X of the current ith medium after the ith medium is pressed with two core plates with the residual copper rate of 100%i，1≦i≦M；
According to the formula (H ═ X)1+X2+...+XM)*c％-h1*(1-a1％)-h2*(1-b1%) determining a theoretical design value H of the pressing thickness of the M pieces of media;
wherein h is1Is the copper thickness of the inner layer of the first core plate adjacent to the medium, h2Is the copper thickness of the inner layer of the second core plate adjacent to the medium, the1% of the unit copper remaining rate of the inner layer of the first core sheet adjacent to the medium, b1% is the unit residual copper rate of the inner layer of the second core plate adjacent to the medium, c% is the thickness coefficient when the M pieces of medium are pressed, and the c% is in inverse proportion to the size of M;
and processing and designing the PCB based on the theoretical design value of the lamination thickness of the M pieces of media.
Optionally, when the M sheets of media are all epoxy glass cloth laminated board FR4 material types,
if M is 1, the thickness coefficient is 100-99%;
if M is 2, the thickness coefficient is 98-95%;
if the M is 3, the thickness coefficient is 96-93%;
if M is 4, the thickness coefficient is 92-89%.
Optionally, the M pieces of media are all high-speed materials, and the material types of the high-speed materials are: r _5775, R _5775G, R _5775N, R _5785, R _5785N, R-5785GE, R-5785GN, Metarwave 2000, Metarwave 3000, Metarwave 4000, Metarwave 6600, Metarwave 1000, TU-933+, TU-933V, DS7409DV, DS7409DVN, EM-891K, EM-890K, IT-988SE, IT-988GSE, IT-968, R-5725S, R-5725 or Synamic6,
if M is 1, the thickness coefficient is 100-99%;
if M is 2, the thickness coefficient is 98-96%;
if the M is 3, the thickness coefficient is 96-94%;
if M is 4, the thickness coefficient is 94-92%.
Optionally, the M pieces of media are all high-speed materials, and the material types of the high-speed materials are: in the case of other high-speed material models than the R _5775, R _5775G, R _5775N, R _5785, R _5785N, R-5785GE, R-5785GN, Metarwave 2000, Metarwave 3000, Metarwave 4000, Metarwave 6600, Metarwave 1000, TU-933+, TU-933V, DS7409DV, DS7409DVN, EM-891K, EM-890K, IT-988SE, IT-988GSE, IT-968, R-5725S, R-5725 and Synamic6,
if M is 1, the thickness coefficient is 100-99%;
if M is 2, the thickness coefficient is 99-97%;
if M is 3, the thickness coefficient is 97-95%;
if M is 4, the thickness coefficient is 95-93%.
Optionally, the machining design is an impedance design, a back-drilling depth design or a signal loss design.
A PCB manufactured by the PCB processing method.
Optionally, the PCB is a backplane or a single board.
Compared with the prior art, the invention has the beneficial effects that:
compared with the traditional method for determining the medium lamination thickness according to the empirical value, the method provided by the embodiment of the invention can effectively improve the calculation precision of the medium lamination thickness, lays a reliable foundation for subsequent PCB processing design, and further ensures the primary qualified rate and various technological indexes of the PCB.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a plan view and a cross-sectional view of a PCB according to an embodiment of the present invention.
Fig. 2 is a comparative analysis chart of the theoretical design value and the actual thickness value of the medium lamination thickness determined by different methods provided by the embodiment of the invention.
Detailed Description
In order to make the objects, features and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the embodiments described below are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
For ease of understanding, it is noted that on an insulating substrate, a conductive pattern providing electrical connection between elements and devices, referred to as a "printed circuit"; on an insulating substrate, a conductive pattern, called a "printed circuit", of a circuit, an element or a combination of both, is produced according to a predetermined design; the finished board of printed circuits or traces is called a PCB.
The PCB is an assembly basis for the joint of electronic elements and other parts, and is manufactured into an electronic product with specific functions. The PCB comprises a single-sided board, a double-sided board and a multi-layer board according to the classification of the number of the circuit layers. The basic manufacturing process flow of the multilayer board is as follows: cutting, manufacturing an inner layer circuit, laminating, drilling, copper deposition, hole masking and electroplating, optical imaging/etching, resistance welding, characters, tin spraying, appearance testing, final inspection and packaging and shipment.
And the lamination process is a process for bonding the core plates into a whole through a medium. The medium, specifically a prepreg, also called "PP sheet", is one of the main materials in the production of multilayer boards. The prepreg mainly comprises resin and a reinforcing material, the reinforcing material is divided into several types such as glass fiber cloth, paper base, composite materials and the like, and most prepregs used for manufacturing the multilayer board adopt the glass fiber cloth as the reinforcing material. The treated glass fiber cloth is impregnated with a resin solution, and then the resin is pre-cured by heat treatment (pre-baking) to form a sheet material called a prepreg, which is softened under heat and pressure and reacts and cures after cooling.
For the media between two adjacent core plates of the laminated plate, regardless of whether the number of the part of the media is one, two or more, the sum of the thicknesses of the part of the media before stitching is always larger than the sum of the thicknesses after stitching. For convenience of description, the subsequent part refers to the sum of the thicknesses of all the mediums between two adjacent core plates after lamination, which is called the medium lamination thickness. According to research, the size of the medium pressing thickness is mainly determined by the ideal pressing thickness of the medium under a proper pressing condition and inner layer patterns of two adjacent core plates, wherein the ideal pressing thickness of the medium refers to the average pressing thickness of a single medium after being pressed with two core plates with 100% or 0% residual copper rate, and the inner layer patterns of the core plates mainly refer to the residual copper rate and the copper thickness of inner layers of the core plates adjacent to the medium.
On the one hand, because the main component of prepreg is glass fiber and resin, under the pressfitting environment of high temperature high pressure, thereby the resin can take place to melt under the high temperature high pressure environment and produce the mobility of certain degree, and glass fiber does not possess the flow nature because of unable melting, consequently under the pressfitting environment of high temperature high pressure, the resin that flows can fill glass fiber for the actual thickness before the pressfitting of prepreg is compared and is reduced. It should be noted that, for prepregs of different materials, the reduction degree of the lamination thickness may be different due to the different resin flowability.
On the other hand, usually, the inner layer of the core board, which is adjacent to the medium, is patterned, so that a gap is formed between the inner layer and the prepreg before lamination; when a plurality of prepregs are continuously used between two adjacent core plates, a certain gap is formed between the prepregs. Therefore, under the high-temperature and high-pressure laminating environment, the resins flowing among the prepregs react with each other and fill the gaps, so that the laminating thickness of the prepregs is further reduced compared with the actual thickness before lamination.
Based on this, if various influence factors are not considered, the theoretical design value of the medium pressing thickness is directly determined according to the conventional empirical value, and then subsequent processing design is carried out according to the theoretical design value, which inevitably causes adverse effects.
Therefore, an embodiment of the present invention provides a method for processing a PCB, where the PCB includes at least one unit and a processing edge disposed on the periphery of all the units, each unit includes a first core board, M pieces of media, and a second core board, which are sequentially stacked and laminated, where M is a natural number greater than 0.
Specifically, the method for processing the PCB of the present embodiment includes the steps of:
aiming at each medium in the M media, respectively obtaining the average pressing thickness X of the current ith medium after the ith medium is pressed with two core plates with 100 percent or 0 percent of residual copperi，1≦i≦M；
According to the formula (H ═ X)1+X2+...+XM)*c％-h1*(1-a1％)-h2*(1-b1%) determining a theoretical design value H of the pressing thickness of the M pieces of media;
wherein h is1Is the copper thickness of the inner layer of the first core plate adjacent to the medium, h2Is the copper thickness of the inner layer of the second core plate adjacent to the medium, a1% of the residual copper content of the cells of the inner layer of the first core web adjacent to the medium, b1% is the residual copper rate of the unit of the inner layer of the second core plate adjacent to the medium, c% is the thickness coefficient when the M pieces of medium are pressed, and the c% is in inverse proportion to the size of M;
and performing subsequent processing design on the PCB based on the theoretical design value of the lamination thickness of the M pieces of media.
Firstly, in the method for determining the theoretical design value of the lamination thickness of M sheets of media, in this embodiment, the factors of mutual reaction between resins of the media and the factors of a certain gap between adjacent media when a plurality of prepregs are continuously used are considered, and the degree of adverse effect of the two factors on the design value of the lamination thickness of the media is reduced through the design of the thickness coefficient;
secondly, the present embodiment applies the unit residual copper rate a in the determination method1% and b1% rather than the residual copper rate of the whole PCB. In the actual production process, in order to improve the production efficiency, the whole board is often manufactured, the whole board comprises a plurality of units and process edges, the process edges are used for testing, positioning and other auxiliary functions of the units, and the process edges are removed before leaving a factory; therefore, according to the unit residual copper rate a1% and b1The% can eliminate the influence factors of the process edge which are not actually related to the processing and application of the unit, and further improve the calculation precision of the medium pressing thickness.
Therefore, compared with the traditional method for determining the theoretical design value of the medium pressing thickness according to the empirical value, the method provided by the embodiment of the invention can effectively improve the calculation precision of the value, lays a reliable foundation for subsequent processing design, and further ensures the primary qualified rate and various technological indexes of the PCB.
For example, the present embodiment further provides a relatively preferable thickness coefficient for media of different materials and numbers of stacked layers, which is shown in the following table:
for comparative analysis, the following will be expressed as H ═ X1+X2+...+XM-h1*(1-a％)-h2The calculated dielectric lamination thickness value is called the original set theoretical dielectric thickness value (where a% and b% are the residual copper rate of the whole plate of two adjacent core plates respectively), and the value according to the embodiment is expressed as H ═ X (X)1+X2+...+XM)*c％-h1*(1-a1％)-h2*(1-b1%) is called theoretical medium thickness value designed by the patent, and the calculated medium lamination thickness value isAnd the medium lamination thickness value obtained by the lamination actual test is called as the medium thickness value of the actual product. Referring to fig. 2, it can be clearly seen that, compared to the original set theoretical medium thickness value obtained by non-optimized design, the theoretical medium thickness value obtained by the optimized design of the present application is closer to the actual medium thickness value of the product, and the accuracy is higher.
It can be understood that, based on the theoretical design value of the lamination thickness of the M sheets of media, the subsequent processing and designing of the PCB may include: impedance design, back-drilling depth design and/or signal loss design; of course, it is not limited thereto, and any other design that requires the thickness based on the pressed media is within the scope of the present invention.
When the number of the core plates pressed by the laminated plate is larger than two, the medium pressing thickness values H of a plurality of media between two adjacent core plates can be respectively calculated according to the same method, and the subsequent processing design is carried out on the PCB based on the sum of the medium pressing thickness values H.
Because the optimization algorithm design is adopted for the medium pressing thickness, a good foundation is laid for the subsequent processing design of the PCB, the subsequent processing design can be reliably carried out, various process indexes of the product are finally guaranteed to meet the manufacturing requirements, and the one-time qualification rate of the product is improved.
The embodiment of the invention also provides a PCB which is manufactured by the PCB processing method. Specifically, the PCB may be a backplane or a single board, and the present invention is not limited thereto.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (7)
1. A processing method of a PCB (printed Circuit Board), wherein the PCB comprises at least one unit and a technical edge arranged on the periphery of all the units, each unit comprises a first core plate, M pieces of media and a second core plate which are sequentially laminated and pressed, and M is a natural number greater than 0, and the processing method is characterized by comprising the following steps:
aiming at each medium in the M media, respectively obtaining the average pressing thickness X of the current ith medium after the ith medium is pressed with two core plates with 100 percent or 0 percent of residual copperi，1≦i≦M；
According to the formula (H ═ X)1+X2+...+XM)*c％-h1*(1-a1％)-h2*(1-b1%) determining a theoretical design value H of the pressing thickness of the M pieces of media;
wherein h is1Is the copper thickness of the inner layer of the first core plate adjacent to the medium, h2Is the copper thickness of the inner layer of the second core plate adjacent to the medium, the1% of the unit copper remaining rate of the inner layer of the first core sheet adjacent to the medium, b1% is the unit residual copper rate of the inner layer of the second core plate adjacent to the medium, c% is the thickness coefficient when the M pieces of medium are pressed, and the c% is in inverse proportion to the size of M;
and processing and designing the PCB based on the theoretical design value of the lamination thickness of the M pieces of media.
2. The PCB processing method of claim 1, wherein when the M pieces of media are all of the type of epoxy glass cloth laminated board FR4 material,
if M is 1, the thickness coefficient is 100-99%;
if M is 2, the thickness coefficient is 98-95%;
if the M is 3, the thickness coefficient is 96-93%;
if M is 4, the thickness coefficient is 92-89%.
3. The processing method of the PCB of claim 1, wherein the M pieces of media are all high-speed materials, and the types of the high-speed materials are as follows: r _5775, R _5775G, R _5775N, R _5785, R _5785N, R-5785GE, R-5785GN, Metarwave 2000, Metarwave 3000, Metarwave 4000, Metarwave 6600, Metarwave 1000, TU-933+, TU-933V, DS7409DV, DS7409DVN, EM-891K, EM-890K, IT-988SE, IT-988GSE, IT-968, R-5725S, R-5725 or Synamic6,
if M is 1, the thickness coefficient is 100-99%;
if M is 2, the thickness coefficient is 98-96%;
if the M is 3, the thickness coefficient is 96-94%;
if M is 4, the thickness coefficient is 94-92%.
4. The PCB processing method of claim 4, wherein the M pieces of media are all high-speed materials, and the types of the high-speed materials are as follows: in the case of other high-speed material models than the R _5775, R _5775G, R _5775N, R _5785, R _5785N, R-5785GE, R-5785GN, Metarwave 2000, Metarwave 3000, Metarwave 4000, Metarwave 6600, Metarwave 1000, TU-933+, TU-933V, DS7409DV, DS7409DVN, EM-891K, EM-890K, IT-988SE, IT-988GSE, IT-968, R-5725S, R-5725 and Synamic6,
if M is 1, the thickness coefficient is 100-99%;
if M is 2, the thickness coefficient is 99-97%;
if M is 3, the thickness coefficient is 97-95%;
if M is 4, the thickness coefficient is 95-93%.
5. The method of processing a PCB of claim 1, wherein the processing design is an impedance design, a back-drilling depth design or a signal loss design.
6. A PCB manufactured by the method of manufacturing a PCB according to any of claims 1 to 7.
7. The PCB of claim 6, wherein the PCB is a backplane or a single board.
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| CN202011059584.1A CN112188761A (en) | 2020-09-30 | 2020-09-30 | PCB processing method and PCB |
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| CN202011059584.1A CN112188761A (en) | 2020-09-30 | 2020-09-30 | PCB processing method and PCB |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103188892A (en) * | 2011-12-30 | 2013-07-03 | 北大方正集团有限公司 | Method and device for manufacturing multi-layer PCB (Printed Circuit Board) and thickness estimating method and thickness estimating device |
| CN109548279A (en) * | 2018-12-29 | 2019-03-29 | 广州兴森快捷电路科技有限公司 | Prepreg lamination design method |
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2020
- 2020-09-30 CN CN202011059584.1A patent/CN112188761A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103188892A (en) * | 2011-12-30 | 2013-07-03 | 北大方正集团有限公司 | Method and device for manufacturing multi-layer PCB (Printed Circuit Board) and thickness estimating method and thickness estimating device |
| CN109548279A (en) * | 2018-12-29 | 2019-03-29 | 广州兴森快捷电路科技有限公司 | Prepreg lamination design method |
Non-Patent Citations (2)
| Title |
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| 刘冬: "PCB层间介质层厚度探讨", 《印制电路信息》 * |
| 李志东: "层间介质层厚度研究", 《2006春季国际PCB技术/信息论坛论文集》 * |
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