Preparation method of high-density interconnection HDI circuit board

Abstract

The invention relates to the technical field of circuit boards, in particular to a preparation method of a high-density interconnection (HDI) circuit board, which comprises the following steps of: testing the prepared circuit board, determining abnormal lines according to the connection condition of each contact, and preliminarily analyzing whether the preparation process of the circuit board is qualified or not according to the number of the abnormal lines. Classification is performed according to the communication condition of each abnormal line in the circuit board and the through hole, and then whether the preparation process of the circuit board is qualified or not is analyzed secondarily according to the number ratio of each type of abnormal lines, so that the control precision of the preparation process of the circuit board is improved. And when the preparation process is judged to be unqualified, the reason for the unqualified preparation process of the circuit board is analyzed according to the number of the abnormal lines, and then the parameters in the preparation process of the next batch of circuit boards are adjusted according to the analysis result, so that the quality of the circuit board is improved, and the preparation efficiency of the circuit board is improved while the quality of the prepared circuit board is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of circuit boards, and in particular to a method for preparing a high-density interconnection (HDI) circuit board. Background Art

[0002] The interconnection HDI circuit board is a circuit board with high-density interconnection technology. Its characteristics are high wiring density per unit area, which can realize smaller size and higher performance electronic equipment. The implementation of blind and buried hole technology in the preparation process requires high-precision equipment and is costly, which increases the complexity and cost of manufacturing. The interface activation and copper plating process after perforation have strict quality control requirements. Any deviation may affect the performance of the circuit board. As the lines become thinner and thinner, the control of position, thickness, bending angle, etc. is more stringent, which puts higher requirements on the manufacturing process. Due to the dense layout and the risk of damaging components near the rework area, the rework options of HDI circuit boards are very limited.

[0003] Chinese patent application number: CN202210141607.6 discloses a method for manufacturing an HDI circuit board and an HDI circuit board, the method for manufacturing the HDI circuit board comprising: obtaining an inner layer circuit board, the inner layer circuit board comprising at least one first metal layer and a second metal layer arranged at intervals; making an inner layer circuit on the inner layer circuit board through inner layer graphics and etching processing, and etching away the first metal layer at the blind hole position of the inner layer circuit board where the target multi-level blind hole needs to be opened to form a to-be-penetrated area; laminating a third metal layer on the first metal layer on the surface of the inner layer circuit board to form an HDI circuit board; opening a hole in the HDI circuit board to form the target multi-level blind hole, the target multi-level blind hole connects the third metal layer, and the target multi-level blind hole passes through the to-be-penetrated area and reaches the second metal layer. In the above manner, the present application can effectively guarantee the quality of the target multi-level blind hole, and can shorten the production process and reduce production costs.

[0004] However, the prior art still has the following problems: Due to the dense layout and the risk of damaging components near the rework area, the rework options for HDI circuit boards are very limited. The control accuracy of the circuit board preparation process is low. When the circuit board quality is insufficient, multiple reworks result in waste of resources and low preparation efficiency. Summary of the invention

[0005] To this end, the present invention provides a method for preparing a high-density interconnect HDI circuit board, which is used to overcome the problems in the prior art of low control accuracy of the circuit board preparation process, multiple reworks when the circuit board quality is insufficient, resulting in waste of resources and low preparation efficiency.

[0006] To achieve the above object, the present invention provides a method for preparing a high-density interconnect HDI circuit board. The method comprises: Step S1, cutting a double-sided copper clad laminate into working plates, mechanically drilling holes in the double-sided copper clad laminate, copper plating the holes, and then electroplating the holes to metallize the hole walls to form through holes; Step S2, laminating the materials to be laminated to obtain a circuit board, and browning the outer copper surface; Step S3, using resin to fill the holes, sending the laminated circuit boards into a vacuum hot press, using the heat energy of the vacuum hot press to melt the resin in the resin sheet to bond the substrates and fill the gaps; Step S4, testing whether the contacts of the circuit board are connected, recording the disconnected circuits as abnormal circuits and counting the number of abnormal circuits, performing electrical performance test on the circuit board, detecting the test voltage of the circuit board, analyzing whether the preparation process of the circuit board is qualified based on the number of abnormal circuits, classifying the abnormal circuits, performing a secondary determination on whether the preparation process of the circuit board is qualified based on the number of each type of abnormal circuits, and analyzing the reasons for the unqualified preparation process of the circuit board based on the proportion of abnormal circuits; Step S5, adjusting the parameters in the next batch of circuit board preparation process based on the analyzed reasons, including: When it is determined that the copper deposition of the through hole does not meet the standard, the concentration of the electrolyte in the copper deposition process is corrected based on the test voltage value; When determining the browning problem, adjust the concentration of the browning solution based on the thickness of the circuit board; When determining pressing problems, adjust the pressing temperature based on the circuit board top surface parameters; Step S6, preparing the next batch of circuit boards according to the adjusted parameters.

[0007] Furthermore, in step S4, analyzing whether the preparation process of the circuit board is qualified based on the number of abnormal circuits includes: Determine the number of abnormal lines, Determine the total number of lines, Calculate the ratio of the number of abnormal lines to the total number of lines to get the abnormal line ratio. If the abnormal circuit ratio is less than or equal to the first preset abnormal circuit ratio standard threshold, it is determined that the preparation process of the circuit board is qualified; If the abnormal line ratio is greater than the first preset abnormal line ratio standard threshold and less than or equal to the second preset abnormal line ratio standard threshold, the determination is based on classifying the abnormal lines, and a secondary determination is made on whether the preparation process of the circuit board is qualified based on the number of each type of abnormal lines; If the abnormal line ratio is greater than the second preset abnormal line ratio standard threshold, it is determined that the manufacturing process of the circuit board is unqualified, and the reason why the manufacturing process of the circuit board is unqualified is analyzed based on the abnormal line ratio.

[0008] Furthermore, the abnormal circuits are classified, and a secondary determination is made on whether the manufacturing process of the circuit board is qualified based on the number of each type of abnormal circuits, including: Determine the abnormal line connected to the through hole and record it as the first-level abnormal line. Determine the abnormal lines that are not connected to the through-holes and record them as secondary abnormal lines. Count the number of first-level abnormal lines and second-level abnormal lines respectively. Calculate the ratio of the number of first-level abnormal lines to the total number of abnormal lines to obtain the proportion of first-level abnormal lines. Calculate the ratio of the number of secondary abnormal lines to the total number of abnormal lines to obtain the proportion of secondary abnormal lines. If the proportion of the first-level abnormal lines is greater than or equal to the preset proportion standard threshold, the preparation process of the circuit board is determined to be unqualified, the copper deposition of the through-holes does not meet the standards, and the concentration of the electrolyte in the copper deposition process of the next batch of circuit boards is corrected based on the test voltage value; If the proportion of the secondary abnormal lines is greater than or equal to the preset proportion standard threshold, it is determined that the preparation process of the circuit board is qualified.

[0009] Furthermore, the concentration of the electrolyte in the copper deposition process during the preparation of the next batch of circuit boards is corrected based on the test voltage, wherein the increase in the concentration of the electrolyte is positively correlated with the test voltage.

[0010] Further, when the concentration of the electrolyte in the copper deposition process in the preparation process of the next batch of circuit boards is adjusted, the steps S1-S4 are repeated, and whether the preparation process of the circuit boards is qualified is analyzed based on the number of abnormal circuits in the next batch of circuit boards. When it is determined that the copper deposition of the through holes does not meet the standards, the concentration of the electrolyte in the copper deposition process in the preparation process of the circuit boards is corrected based on the test voltage of the batch of circuit boards to obtain the required electrolyte concentration value. If the electrolyte concentration requirement value is less than the preset electrolyte concentration standard threshold value, the electrolyte concentration in the copper deposition process of the next batch of circuit boards after the current batch of circuit boards is corrected to the electrolyte concentration requirement value; If the electrolyte concentration requirement value is greater than or equal to the preset electrolyte concentration standard threshold value, adjusting the through hole size based on the difference between the electrolyte concentration requirement value and the preset electrolyte concentration standard threshold value; Among them, the increase in the through hole size is positively correlated with the demand difference.

[0011] Furthermore, the analysis of reasons for failure in the preparation process of the circuit board based on the abnormal circuit proportion includes: Calculate the difference between the abnormal line proportion and the second preset abnormal line proportion standard threshold to obtain the proportion difference. If the ratio difference is less than or equal to a first preset ratio difference standard threshold, it is determined that the reason for the unqualified preparation of the circuit board is a browning problem, and the concentration of the browning liquid is adjusted based on the thickness of the circuit board; If the ratio difference is greater than the first preset ratio difference standard threshold and less than or equal to the second preset ratio difference standard threshold, a secondary determination is made as to whether the preparation of the circuit board is qualified based on the image information of the side surface of the circuit board; If the proportion difference is greater than the second preset proportion difference standard threshold, it is determined that the reason for the unqualified preparation of the circuit board is a pressing problem, and the pressing temperature in the preparation process of the next batch of circuit boards is adjusted based on the circuit board top surface parameters.

[0012] Further, the browning liquid concentration is adjusted based on the circuit board thickness, including: Calculate the difference between the circuit board thickness and the preset thickness standard threshold to obtain the required thickness deviation. The increase in the concentration of browning liquid is positively correlated with the required thickness deviation.

[0013] Furthermore, the secondary determination of whether the circuit board is qualified based on the side image information includes: Get image information of the side of the circuit board, Determine the outline of the circuit board in the image information, Compare the outline of the circuit board with the preset outline to determine the length of the outline of the overlapping part. Calculate the ratio of the length of the overlapping contour to the total length of the preset contour to get the overlap degree. If the overlap is less than or equal to a preset overlap standard threshold, it is determined that the reason for the unqualified preparation of the circuit board is a browning problem, and the concentration of the browning liquid is adjusted based on the thickness of the circuit board; If the overlap is greater than the preset overlap standard threshold, it is determined that the reason for the unqualified preparation of the circuit board is a pressing problem, and the pressing temperature in the preparation process of the next batch of circuit boards is adjusted based on the circuit board top surface parameters.

[0014] Further, the step of adjusting the pressing temperature in the next batch of circuit boards preparation process based on the circuit board top surface parameters includes: Determine the height of the highest point on the top of the circuit board. Determine the height of the lowest point on the top surface of the circuit board. Calculate the height difference between the highest point and the lowest point of the circuit board. The pressing temperature in the process of preparing the next batch of circuit boards is adjusted based on the height difference, wherein the increase in the pressing temperature is positively correlated with the height difference.

[0015] Compared with the prior art, the beneficial effect of the present invention lies in that, in the present invention, the prepared circuit board is tested, the abnormal circuit is determined according to the connectivity of each contact, and whether the preparation process of the circuit board is qualified is preliminarily analyzed according to the number of abnormal circuits. When the number of abnormal circuits is between a first preset abnormal circuit proportion standard threshold and a second preset abnormal circuit proportion standard threshold, the abnormal circuits in the circuit board are classified according to the connectivity between the abnormal circuits and the through holes, and then the preparation process of the circuit board is secondary analyzed according to the proportion of the number of abnormal circuits in each category, thereby improving the control accuracy of the circuit board preparation process, and when it is determined that the preparation process is unqualified, the reason for the unqualified preparation process of the circuit board is analyzed according to the number of abnormal circuits, and then the parameters in the preparation process of the next batch of circuit boards are adjusted according to the analysis results, thereby improving the quality of the circuit board, and improving the preparation efficiency of the circuit board while ensuring the quality of the prepared circuit board.

[0016] Furthermore, in the present invention, when determining that the copper deposition of the through hole does not meet the standard, taking into account that the copper ion concentration in the electrolyte directly affects the rate of chemical copper deposition, if the copper ion concentration is insufficient, it will cause the copper deposition layer to be uneven or of insufficient thickness, affecting the connectivity of the circuit board. The present invention adjusts the concentration of the electrolyte in the copper deposition process during the preparation of the next batch of circuit boards according to the test voltage value, thereby increasing the concentration of copper ions in the electrolyte, increasing the uniformity of the copper deposition layer, and further improving the quality of the circuit board, while ensuring the quality of the prepared circuit board, improving the preparation efficiency of the circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A flow chart of a method for preparing a high density interconnect HDI circuit board; Figure 2 A flow chart for analyzing whether the preparation process of a circuit board is qualified; Figure 3 A flow chart for secondary determination of whether the preparation process of the circuit board is qualified; Figure 4 A flow chart for analyzing the reasons why the circuit board preparation process is unqualified. DETAILED DESCRIPTION

[0018] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0019] It should be pointed out that the data in this embodiment are obtained by comprehensive analysis and evaluation of the historical data of the system of the present invention in the six months before this determination and the corresponding historical determination results. It can be understood by those skilled in the art that the determination method of the system of the present invention for a single parameter mentioned above can be to select the value with the highest proportion as the preset standard parameter according to the data distribution, use weighted summation to use the obtained value as the preset standard parameter, substitute each historical data into a specific formula and use the value obtained by the formula as the preset standard parameter or other selection methods, as long as the system of the present invention can clearly define different specific situations in the single determination process through the obtained values.

[0020] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0021] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0022] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] See also Figure 1 As shown, it is a flow chart of a method for preparing a high-density interconnect HDI circuit board.

[0024] The method for preparing a high-density interconnect HDI circuit board provided by an embodiment of the present invention comprises: Step S1, cutting a double-sided copper clad laminate into working plates, mechanically drilling holes in the double-sided copper clad laminate, copper plating the holes, and then electroplating the holes to metallize the hole walls to form through holes; Step S2, laminating the materials to be laminated to obtain a circuit board, and browning the outer copper surface; Step S3, using resin to fill the holes, sending the laminated circuit boards into a vacuum hot press, using the heat energy of the vacuum hot press to melt the resin in the resin sheet to bond the substrates and fill the gaps; Step S4, testing whether the contacts of the circuit board are connected, recording the disconnected circuits as abnormal circuits and counting the number of abnormal circuits, performing electrical performance test on the circuit board, detecting the test voltage of the circuit board, analyzing whether the preparation process of the circuit board is qualified based on the number of abnormal circuits, classifying the abnormal circuits, performing a secondary determination on whether the preparation process of the circuit board is qualified based on the number of each type of abnormal circuits, and analyzing the reasons for the unqualified preparation process of the circuit board based on the proportion of abnormal circuits; Step S5, adjusting the parameters in the next batch of circuit board preparation process based on the analyzed reasons, including: When it is determined that the copper deposition of the through hole does not meet the standard, the concentration of the electrolyte in the copper deposition process is corrected based on the test voltage value; When determining the browning problem, adjust the concentration of the browning solution based on the thickness of the circuit board; When determining pressing problems, adjust the pressing temperature based on the circuit board top surface parameters; Step S6, preparing the next batch of circuit boards according to the adjusted parameters.

[0025] See also Figure 2 As shown, it is a flow chart for analyzing whether the preparation process of a circuit board is qualified.

[0026] Specifically, the step S4 of analyzing whether the preparation process of the circuit board is qualified based on the number of abnormal circuits includes: Determine the number of abnormal lines, Determine the total number of lines, Calculate the ratio of the number of abnormal lines to the total number of lines to get the abnormal line ratio. If the abnormal circuit ratio is less than or equal to the first preset abnormal circuit ratio standard threshold, it is determined that the preparation process of the circuit board is qualified; If the abnormal line ratio is greater than the first preset abnormal line ratio standard threshold and less than or equal to the second preset abnormal line ratio standard threshold, the determination is based on classifying the abnormal lines, and a secondary determination is made on whether the preparation process of the circuit board is qualified based on the number of each type of abnormal lines; If the abnormal line ratio is greater than the second preset abnormal line ratio standard threshold, it is determined that the manufacturing process of the circuit board is unqualified, and the reason why the manufacturing process of the circuit board is unqualified is analyzed based on the abnormal line ratio.

[0027] Specifically, in this embodiment, the first preset abnormal line proportion standard threshold and the second preset abnormal line proportion standard threshold are obtained in advance, and a number of qualified circuit boards are obtained, and the abnormal lines of each circuit board are respectively detected to see whether they are connected, and the abnormal lines are marked, and the proportion of abnormal lines in each circuit board is respectively calculated, and the average value of the proportion of abnormal lines is solved. The first preset abnormal line proportion standard threshold is 0.7~0.85 times the average value, and the second preset abnormal line proportion standard threshold is 0.95~1.15 times the average value.

[0028] See also Figure 3 As shown, it is a flow chart for secondary determination of whether the preparation process of the circuit board is qualified.

[0029] Specifically, the abnormal circuits are classified, and a secondary determination is made on whether the manufacturing process of the circuit board is qualified based on the number of each type of abnormal circuits, including: Determine the abnormal line connected to the through hole and record it as the first-level abnormal line. Determine the abnormal lines that are not connected to the through-holes and record them as secondary abnormal lines. Count the number of first-level abnormal lines and second-level abnormal lines respectively. Calculate the ratio of the number of first-level abnormal lines to the total number of abnormal lines to obtain the proportion of first-level abnormal lines. Calculate the ratio of the number of secondary abnormal lines to the total number of abnormal lines to obtain the proportion of secondary abnormal lines. If the proportion of the first-level abnormal lines is greater than or equal to the preset proportion standard threshold, the preparation process of the circuit board is determined to be unqualified, the copper deposition of the through-holes does not meet the standards, and the concentration of the electrolyte in the copper deposition process of the next batch of circuit boards is corrected based on the test voltage value; If the proportion of the secondary abnormal lines is greater than or equal to the preset proportion standard threshold, it is determined that the preparation process of the circuit board is qualified.

[0030] Specifically, in this embodiment, the preset proportion standard threshold is selected in the interval [0.5, 0.6].

[0031] Specifically, the concentration of the electrolyte in the copper deposition process during the preparation of the next batch of circuit boards is corrected based on the test voltage, wherein the increase in the concentration of the electrolyte is positively correlated with the test voltage.

[0032] In this embodiment, optionally, The test voltage is compared with a first preset test voltage standard threshold and a second preset test voltage standard threshold, If the test voltage is less than or equal to the first preset test voltage standard threshold, it is determined to increase the first electrolyte concentration, and the first electrolyte concentration is 0.15 times the initial electrolyte concentration; If the test voltage is greater than the first preset test voltage standard threshold and less than or equal to the second preset test voltage standard threshold, it is determined to increase the second electrolyte concentration, and the second electrolyte concentration is 0.2 times the initial electrolyte concentration; If the test voltage is greater than the second preset test voltage standard threshold, it is determined to increase the third electrolyte concentration, and the third electrolyte concentration is 0.3 times the initial electrolyte concentration; Among them, based on the specifications of the current circuit board, its standard test voltage is determined from big data, the first preset test voltage standard threshold is 0.8~0.9 times the standard test voltage, and the second preset test voltage standard threshold is 0.9~1.1 times the standard test voltage.

[0033] Specifically, when the concentration of the electrolyte in the copper deposition process in the preparation process of the next batch of circuit boards is adjusted, the steps S1-S4 are repeated, and whether the preparation process of the circuit boards is qualified is analyzed based on the number of abnormal circuits in the next batch of circuit boards. When it is determined that the copper deposition of the through holes does not meet the standards, the concentration of the electrolyte in the copper deposition process in the preparation process of the circuit boards is corrected based on the test voltage of the batch of circuit boards to obtain the required electrolyte concentration value. If the electrolyte concentration requirement value is less than the preset electrolyte concentration standard threshold value, the electrolyte concentration in the copper deposition process of the next batch of circuit boards after the current batch of circuit boards is corrected to the electrolyte concentration requirement value; If the electrolyte concentration requirement value is greater than or equal to the preset electrolyte concentration standard threshold value, adjusting the through hole size based on the difference between the electrolyte concentration requirement value and the preset electrolyte concentration standard threshold value; Among them, the increase in the through hole size is positively correlated with the demand difference.

[0034] Specifically, in this embodiment, the preset electrolyte concentration standard threshold is obtained by pre-measurement, obtaining the preparation parameters of several qualified circuit board preparation processes, determining the electrolyte concentration in each circuit board preparation process, solving the electrolyte concentration mean, and obtaining the preset electrolyte concentration standard threshold.

[0035] See also Figure 4 As shown, it is a flow chart for analyzing the reasons why the preparation process of the circuit board is unqualified.

[0036] Specifically, the reasons for analyzing the failure of the circuit board preparation process based on the abnormal circuit proportion include: Calculate the difference between the abnormal line proportion and the second preset abnormal line proportion standard threshold to obtain the proportion difference. If the ratio difference is less than or equal to a first preset ratio difference standard threshold, it is determined that the reason for the unqualified preparation of the circuit board is a browning problem, and the concentration of the browning liquid is adjusted based on the thickness of the circuit board; If the ratio difference is greater than the first preset ratio difference standard threshold and less than or equal to the second preset ratio difference standard threshold, a secondary determination is made as to whether the preparation of the circuit board is qualified based on the image information of the side surface of the circuit board; If the proportion difference is greater than the second preset proportion difference standard threshold, it is determined that the reason for the unqualified preparation of the circuit board is a pressing problem, and the pressing temperature in the preparation process of the next batch of circuit boards is adjusted based on the circuit board top surface parameters.

[0037] Specifically, in this embodiment, the first preset proportion difference standard threshold is 0.05-0.08 times the second preset abnormal line proportion standard threshold, and the second preset proportion difference standard threshold is 0.1-0.13 times the second preset abnormal line proportion standard threshold.

[0038] Specifically, the method of adjusting the concentration of the browning liquid based on the thickness of the circuit board includes: Calculate the difference between the circuit board thickness and the preset thickness standard threshold to obtain the required thickness deviation. The increase in the concentration of browning liquid is positively correlated with the required thickness deviation.

[0039] In this embodiment, optionally, The required thickness deviation is compared with the first preset required thickness deviation standard threshold and the second preset required thickness deviation standard threshold, If the required thickness deviation is less than or equal to the first preset required thickness deviation standard threshold, the concentration of the first browning liquid is increased, and the concentration of the first browning liquid is 0.15 times the initial concentration of the browning liquid; If the required thickness deviation is greater than the first preset required thickness deviation standard threshold and less than or equal to the second preset required thickness deviation standard threshold, then the concentration of the second browning liquid is increased, and the concentration of the second browning liquid is 0.2 times the initial concentration of the browning liquid; If the required thickness deviation is greater than the second preset required thickness deviation standard threshold, the concentration of the third browning liquid is increased, and the concentration of the third browning liquid is 0.3 times the concentration of the initial browning liquid; Among them, the first preset required thickness deviation standard threshold is 0.05~0.08 times the preset thickness standard threshold, and the second preset required thickness deviation standard threshold is 0.09~0.12 times the preset thickness standard threshold.

[0040] Specifically, the secondary determination of whether the circuit board is qualified based on the side image information includes: Get image information of the side of the circuit board, Determine the outline of the circuit board in the image information, Compare the outline of the circuit board with the preset outline to determine the length of the outline of the overlapping part. Calculate the ratio of the length of the overlapping contour to the total length of the preset contour to get the overlap degree. If the overlap is less than or equal to a preset overlap standard threshold, it is determined that the reason for the unqualified preparation of the circuit board is a browning problem, and the concentration of the browning liquid is adjusted based on the thickness of the circuit board; If the overlap is greater than the preset overlap standard threshold, it is determined that the reason for the unqualified preparation of the circuit board is a pressing problem, and the pressing temperature in the preparation process of the next batch of circuit boards is adjusted based on the circuit board top surface parameters.

[0041] Specifically, in this embodiment, the preset overlap standard threshold is selected in the interval [0.75, 0.9].

[0042] Specifically, the method of adjusting the pressing temperature in the process of preparing the next batch of circuit boards based on the circuit board top surface parameters includes: Determine the height of the highest point on the top of the circuit board. Determine the height of the lowest point on the top surface of the circuit board. Calculate the height difference between the highest point and the lowest point of the circuit board. The pressing temperature in the process of preparing the next batch of circuit boards is adjusted based on the height difference, wherein the increase in the pressing temperature is positively correlated with the height difference.

[0043] In this embodiment, optionally, The height difference is compared with the first preset height difference and the second preset height difference, If the height difference is less than or equal to the first preset height difference, the first pressing temperature is increased, and the first pressing temperature is 0.1 times the initial pressing temperature; If the height difference is greater than the first preset height difference and less than or equal to the second preset height difference, then increase the second pressing temperature, the second pressing temperature being 0.15 times the initial pressing temperature; If the height difference is greater than the second preset height difference, the third pressing temperature is increased, and the third pressing temperature is 0.2 times the initial pressing temperature; The first preset height difference is 0.2% to 0.5% of the thickness of the circuit board, and the second preset height difference is 0.55% to 0.75% of the thickness of the circuit board.

[0044] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a high density interconnect HDI circuit board, characterized in that: include: Step S1, cutting a double-sided copper clad laminate into working plates, mechanically drilling holes in the double-sided copper clad laminate, performing copper deposition treatment on the holes, and then electroplating to metalize the hole walls to form through holes; Step S2, laminating the materials to be laminated to obtain a circuit board, and browning the outer copper surface; Step S3, using resin to fill the holes, sending the laminated circuit boards into a vacuum hot press, using the heat energy of the vacuum hot press to melt the resin in the resin sheet to bond the substrates and fill the gaps; Step S4, testing whether the contacts of the circuit board are connected, recording the disconnected circuits as abnormal circuits and counting the number of abnormal circuits, performing electrical performance test on the circuit board, detecting the test voltage of the circuit board, analyzing whether the preparation process of the circuit board is qualified based on the number of abnormal circuits, classifying the abnormal circuits, performing a secondary determination on whether the preparation process of the circuit board is qualified based on the number of each type of abnormal circuits, and analyzing the reasons for the unqualified preparation process of the circuit board based on the proportion of abnormal circuits; Step S5, adjusting the parameters in the next batch of circuit board preparation process based on the analyzed reasons, including: When it is determined that the copper deposition of the through hole does not meet the standard, the concentration of the electrolyte in the copper deposition process is corrected based on the test voltage value; When determining the browning problem, adjust the concentration of the browning solution based on the thickness of the circuit board; When determining pressing problems, adjust the pressing temperature based on the circuit board top surface parameters; Step S6, preparing the next batch of circuit boards according to the adjusted parameters.

2. The method for preparing a high density interconnect HDI circuit board according to claim 1, characterized in that: The step S4 of analyzing whether the preparation process of the circuit board is qualified based on the number of abnormal circuits includes: Determine the number of abnormal lines, Determine the total number of lines, Calculate the ratio of the number of abnormal lines to the total number of lines to get the abnormal line ratio. If the abnormal circuit ratio is less than or equal to the first preset abnormal circuit ratio standard threshold, it is determined that the preparation process of the circuit board is qualified; If the abnormal line ratio is greater than the first preset abnormal line ratio standard threshold and less than or equal to the second preset abnormal line ratio standard threshold, the determination is based on classifying the abnormal lines, and a secondary determination is made on whether the preparation process of the circuit board is qualified based on the number of each type of abnormal lines; If the abnormal line ratio is greater than the second preset abnormal line ratio standard threshold, it is determined that the manufacturing process of the circuit board is unqualified, and the reason why the manufacturing process of the circuit board is unqualified is analyzed based on the abnormal line ratio.

3. The method for preparing a high density interconnect HDI circuit board according to claim 1, characterized in that: The abnormal circuits are classified, and a secondary determination is made on whether the preparation process of the circuit board is qualified based on the number of each type of abnormal circuits, including: Determine the abnormal line connected to the through hole and record it as the first-level abnormal line. Determine the abnormal lines that are not connected to the through-holes and record them as secondary abnormal lines. Count the number of first-level abnormal lines and second-level abnormal lines respectively. Calculate the ratio of the number of first-level abnormal lines to the total number of abnormal lines to obtain the proportion of first-level abnormal lines. Calculate the ratio of the number of secondary abnormal lines to the total number of abnormal lines to obtain the proportion of secondary abnormal lines. If the proportion of the first-level abnormal lines is greater than or equal to the preset proportion standard threshold, the preparation process of the circuit board is determined to be unqualified, the copper deposition of the through-holes does not meet the standards, and the concentration of the electrolyte in the copper deposition process of the next batch of circuit boards is corrected based on the test voltage value; If the proportion of the secondary abnormal lines is greater than or equal to the preset proportion standard threshold, it is determined that the preparation process of the circuit board is qualified.

4. The method for preparing a high density interconnect HDI circuit board according to claim 3, characterized in that: The concentration of the electrolyte in the copper deposition process during the preparation of the next batch of circuit boards is corrected based on the test voltage, wherein the increase in the concentration of the electrolyte is positively correlated with the test voltage.

5. The method for preparing a high density interconnect HDI circuit board according to claim 4, characterized in that: When the concentration of the electrolyte in the copper deposition process in the preparation process of the next batch of circuit boards is adjusted, the steps S1-S4 are repeated, and whether the preparation process of the circuit boards is qualified is analyzed based on the number of abnormal circuits in the next batch of circuit boards. When it is determined that the copper deposition of the through holes does not meet the standards, the concentration of the electrolyte in the copper deposition process in the preparation process of the circuit boards is corrected based on the test voltage of the batch of circuit boards to obtain the required electrolyte concentration value. If the electrolyte concentration requirement value is less than the preset electrolyte concentration standard threshold value, the electrolyte concentration in the copper deposition process of the next batch of circuit boards after the current batch of circuit boards is corrected to the electrolyte concentration requirement value; If the electrolyte concentration requirement value is greater than or equal to the preset electrolyte concentration standard threshold value, adjusting the through hole size based on the difference between the electrolyte concentration requirement value and the preset electrolyte concentration standard threshold value; Among them, the increase in the through hole size is positively correlated with the demand difference.

6. The method for preparing a high density interconnect HDI circuit board according to claim 1, characterized in that: The reasons for analyzing the failure of the circuit board preparation process based on the abnormal circuit proportion include: Calculate the difference between the abnormal line proportion and the second preset abnormal line proportion standard threshold to obtain the proportion difference. If the ratio difference is less than or equal to a first preset ratio difference standard threshold, it is determined that the reason for the unqualified preparation of the circuit board is a browning problem, and the concentration of the browning liquid is adjusted based on the thickness of the circuit board; If the ratio difference is greater than the first preset ratio difference standard threshold and less than or equal to the second preset ratio difference standard threshold, a secondary determination is made as to whether the preparation of the circuit board is qualified based on the image information of the side surface of the circuit board; If the proportion difference is greater than the second preset proportion difference standard threshold, it is determined that the reason for the unqualified preparation of the circuit board is a pressing problem, and the pressing temperature in the preparation process of the next batch of circuit boards is adjusted based on the circuit board top surface parameters.

7. The method for preparing a high density interconnect HDI circuit board according to claim 6, characterized in that: The method of adjusting the concentration of the browning liquid based on the thickness of the circuit board comprises: Calculate the difference between the circuit board thickness and the preset thickness standard threshold to obtain the required thickness deviation. The increase in the concentration of browning liquid is positively correlated with the required thickness deviation.

8. The method for preparing a high density interconnect HDI circuit board according to claim 6, characterized in that: The second step of determining whether the circuit board is qualified based on the side image information includes: Get image information of the side of the circuit board, Determine the outline of the circuit board in the image information, Compare the outline of the circuit board with the preset outline to determine the length of the outline of the overlapping part. Calculate the ratio of the length of the overlapping contour to the total length of the preset contour to get the overlap degree. If the overlap is less than or equal to a preset overlap standard threshold, it is determined that the reason for the unqualified preparation of the circuit board is a browning problem, and the concentration of the browning liquid is adjusted based on the thickness of the circuit board; If the overlap is greater than the preset overlap standard threshold, it is determined that the reason for the unqualified preparation of the circuit board is a pressing problem, and the pressing temperature in the preparation process of the next batch of circuit boards is adjusted based on the circuit board top surface parameters.

9. The method for preparing a high density interconnect HDI circuit board according to claim 6, characterized in that: The method of adjusting the pressing temperature in the process of preparing the next batch of circuit boards based on the circuit board top surface parameters includes: Determine the height of the highest point on the top of the circuit board. Determine the height of the lowest point on the top surface of the circuit board. Calculate the height difference between the highest point and the lowest point of the circuit board. The pressing temperature in the process of preparing the next batch of circuit boards is adjusted based on the height difference, wherein the increase in the pressing temperature is positively correlated with the height difference.

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