Calculation method of LTCC (Low Temperature Co-Fired Ceramic) substrate lamination alignment deviation value

Abstract

The invention relates to a method for calculating the lamination alignment deviation value of an LTCC (Low Temperature Co-Fired Ceramic) substrate. The method comprises the following steps of: punching a lamination alignment deviation value marking hole and a lamination alignment hole; the lamination alignment deviation value marking holes are filled with slurry; printing a cutting line on the uppermost layer of green ceramic chip; carrying out lamination, isostatic pressing and raw cutting treatment on the raw ceramic chips; and calculating the lamination alignment deviation value of each layer of green ceramic chip in the substrate. According to the invention, the alignment deviation value condition of the substrate lamination can be accurate to any specific layer, so that specific lamination deviation data can be provided for each substrate, screening data can be provided for some substrates with clear requirements on lamination precision, the substrates with deviation values not meeting the requirements can be eliminated, and the production quality can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of LTCC substrate manufacturing, and in particular to a method for calculating the alignment deviation of LTCC substrate stacking. Background Art

[0002] LTCC substrates are widely used in TR components and various passive chip components due to their excellent microwave dielectric properties. The processing and manufacturing method of the substrate is to fill the through holes of each layer of LTCC raw ceramic sheets and print metal paste on the surface to achieve metallization, and then stack different layers together according to the design sequence and sinter them into a dense multi-layer substrate. The main processing flow of LTCC substrates is: first, a circular through hole is punched out on the LTCC raw ceramic sheet by laser or mechanical means; then, the hole is filled with metal paste to interconnect different layers; then, the designed conductor wiring is printed on the surface of each layer of raw ceramic sheets, and all raw ceramic sheets are stacked layer by layer after the paste conductor is dried; then, co-firing, dicing, post-printing, post-firing and other processes are carried out; finally, it is processed into the required multi-layer substrate.

[0003] According to the design requirements, the number of layers of LTCC multilayer substrates usually ranges from 6 to 30. During the layer-by-layer lamination process, some layers will have different degrees of positional deviation in the horizontal direction, which will cause the through holes filled with metal paste between different layers to shift in the horizontal direction. For substrates with strict requirements for alignment accuracy, it is necessary to determine the final actual lamination offset of each substrate. At the same time, for production cost control, if there is a better method to screen and eliminate substrates whose lamination deviation does not meet the requirements after lamination, it can avoid flowing into the subsequent process and causing waste of material costs and human resources. However, in actual production, there is still a lack of quantitative calculation methods that can provide the offset between layers of each substrate.

[0004] Therefore, a method for calculating the LTCC substrate stacking deviation is needed. Summary of the invention

[0005] The object of the present invention is to provide a method for calculating the alignment deviation of LTCC substrate stacking, which can solve the deficiencies in the prior art and realize the calculation of the alignment deviation generated during the stacking process of LTCC green ceramic sheets.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for calculating the alignment deviation of LTCC substrate stacking, the method comprising the following steps:

[0008] S1. Punching of stacking alignment deviation marking holes and stacking alignment holes

[0009] A substrate is processed using raw ceramic sheets, and each layer of raw ceramic sheets is divided into a plurality of square areas of the same size; a group of marking holes is processed on the outside of each side length of each square area as stacking alignment deviation marking holes; each group of marking holes includes a plurality of circular marking holes with a diameter of D that are equidistantly distributed, and the centers of the circular marking holes in the same group of marking holes are located on the same straight line; a group of stacking alignment holes is processed on both sides of each layer of raw ceramic sheets along the X direction; each group of stacking alignment holes includes a plurality of circular alignment holes with equidistantly distributed and the same diameter, and the centers of the circular alignment holes in the same group of stacking alignment holes are located on the same straight line.

[0010] S2. Fill the holes for marking the stacking deviation with slurry

[0011] According to the positions of the stacking alignment deviation amount marking holes on each layer of raw porcelain sheet, a plurality of hole-filling screens corresponding to each layer of raw porcelain sheet are produced; at the corresponding positions of the hole-filling screen corresponding to each layer of raw porcelain sheet, a plurality of through holes having the same size and corresponding to each stacking alignment deviation amount marking holes on the layer of raw porcelain sheet are cut out; the slurry to be filled is spread on the hole-filling screen, the raw porcelain sheet corresponding to the hole-filling screen is placed on the vacuum adsorption table of the printing press, the hole-filling slurry on the hole-filling screen is pressed into each stacking alignment deviation amount marking hole by the printing press, the slurry is filled in the holes, and the raw porcelain sheet after the slurry filling is dried.

[0012] Specifically, the punched raw ceramic sheet is placed on the vacuum adsorption table of the printing press, the slurry to be filled is spread on the hole-filling screen, and the scraper pressure generated by the reciprocating movement of the printing press is used to press the hole-filling slurry into the holes marked with the stacking deviation amount of each layer of the raw ceramic sheet; after all the raw ceramic sheets have completed the slurry filling, they are uniformly placed in an oven to dry the slurry, and taken out after drying.

[0013] S3. Print cutting lines on the top raw ceramic sheet

[0014] A printing screen is made, and a plurality of cutting lines are designed on the printing screen; each cutting line is located directly above the straight line where the center of each marking hole on the same row or column is located; the top layer of raw porcelain sheet is placed on the vacuum adsorption table of the printing machine, and the cutting lines are printed on the top layer of raw porcelain sheet by using the printing machine and the printing screen, so that 8 cutting lines are formed directly above all the marking holes of the top layer of raw porcelain sheet; after the cutting lines are printed, a drying process is performed.

[0015] Specifically, the first layer of raw porcelain sheets (i.e. the top layer of raw porcelain sheets) is placed on the vacuum adsorption table of the printing machine, and cutting lines are printed on the first layer of raw porcelain sheets using a printing screen, forming 8 cutting lines directly above all the marking holes located on the same straight line in the raw porcelain sheets; after the raw porcelain sheets are printed, they are placed in an oven to dry the slurry, and taken out after drying.

[0016] S4. Lamination, isostatic pressing and raw cutting of raw ceramic pieces

[0017] All the raw ceramic sheets are stacked in sequence according to the design sequence, and then sealed in plastic and placed in an isostatic press to adhere all the layers of raw ceramic sheets together; the pressed whole-plate raw ceramic sheets are taken out and placed in a hot cutting machine, and the whole-plate raw ceramic sheets are cut along the X and Y directions along the centers of all the printed cutting lines to obtain multiple substrates; after the cutting is completed, the four groups of marking holes around each substrate are cut longitudinally to expose the filled slurry.

[0018] S5. Calculate the stacking deviation of each layer of raw ceramic sheets in the substrate

[0019] Obtain the horizontal length L of the slurry exposed by each marking hole around each layer of raw ceramic sheets on the substrate, and calculate the stacking alignment deviation along the X direction and the stacking alignment deviation along the Y direction of each layer of raw ceramic sheets according to the length L and the diameter D of the stacking alignment deviation marking hole, so as to determine the stacking alignment deviation of the layer of raw ceramic sheets.

[0020] Preferably, according to the present invention, in step S5, calculating the stacking alignment deviation of each layer of green ceramic sheets in the substrate specifically includes the following steps:

[0021] S51, obtaining the length L of the slurry exposed from each marking hole around each layer of the green ceramic sheet of the substrate in the horizontal direction;

[0022] S52, using formula (1) to calculate the stacking alignment deviation of each marking hole along the X direction and the stacking alignment deviation of each marking hole along the Y direction;

[0023]

[0024] S53, averaging the stacking alignment deviations of the marking holes along the X direction to obtain δ x , calculate the average value of the stacking deviation of each marked hole along the X direction δ y ;

[0025] S54, using formula (2), calculate the stacking deviation δ of each layer of raw ceramic sheets respectively w .

[0026]

[0027] Preferably, according to the present invention, in step S1, each group of marking holes includes 3 circular marking holes, and the vertical distance between the center of each circular marking hole and the side length of the corresponding square area is 3 mm; the diameter of the marking hole is 0.3 mm; and each group of overlapping alignment holes includes 5 circular alignment holes.

[0028] Four groups of marking holes are punched out mechanically around the outline of each substrate in the raw porcelain sheet: the area of ​​each layer of raw porcelain sheet is divided into a corresponding number of regions according to the number of substrates distributed on it, and the area of ​​each region is larger than the outline area of ​​the substrate. A mechanical puncher is used to punch out three circular marking holes distributed at equal distances on each of the four sides of the raw porcelain sheet substrate outside the outline and 3 mm away from the outline. The centers of the three marking holes on each side are all located on the same straight line, totaling 12 holes, and the apertures of the 12 marking holes are the same, and the diameter is recorded as D. At the same time, a mechanical puncher is used to process the overlapping alignment holes on each layer of raw porcelain sheet, with a total of 10 holes distributed on the left and right sides of the raw porcelain sheet.

[0029] Preferably, according to the present invention, in step S2, the thickness of the hole-filling screen is 0.05 mm, and the material of the hole-filling screen is stainless steel; the temperature in the oven is 50° C., and the drying time is 30 minutes.

[0030] The relative positions of all punched through holes and marking holes are determined by making a corresponding stainless steel hole-filling screen with a thickness of 0.05mm. A laser cutting machine is used to cut circular holes on the stainless steel hole-filling screen with the same aperture and position as the alignment holes and marking holes on the raw ceramic sheet. The punched raw ceramic sheet is placed on the work surface of the printer for vacuum adsorption, and the slurry to be filled is spread on the stainless steel hole-filling screen. The scraper pressure of the printer's reciprocating motion is used to press the hole-filling slurry into all the through holes and marking holes in the raw ceramic sheet of this layer. After all the raw ceramic sheets are filled, they are uniformly placed in a 50°C oven to dry the slurry for 30 minutes and then taken out.

[0031] Preferably, according to the present invention, in step S3, the width of the cutting line is 0.3 mm; the temperature in the oven is 50° C., and the drying treatment time is 30 minutes.

[0032] According to the conductor design pattern of each layer of the substrate, the corresponding printing screen is made. At the same time, a cutting line with a width of 0.3mm is designed in each printing screen. The cutting line is located directly above the marking hole to ensure that the center of all marking holes is located at the center of the straight line after printing. Then the raw ceramic sheet is placed on the vacuum adsorption table of the printer to complete the printing of the substrate conductor pattern and cutting line of each layer of raw ceramic sheet. After all the raw ceramic sheets are printed, they are uniformly placed in a 50℃ oven to dry the slurry for 30 minutes and then taken out.

[0033] Preferably, according to the present invention, in step S4, the operating parameters of the isostatic press are: temperature of 75° C., pressure of 3000 psi, and time of 20 min.

[0034] Preferably, according to the present invention, in step S4, when the green ceramic sheets are stacked, positioning pins are inserted into corresponding stacking holes of each layer of green ceramic sheets to position each layer of green ceramic sheets.

[0035] Compared with the prior art, the advantages of the present invention are:

[0036] (1) The present invention performs punching of four groups of stacking alignment deviation marking holes at the same position of each layer of raw porcelain sheets before co-firing of the substrate, filling the holes with slurry, printing cutting lines, isostatic pressing and hot cutting, and compares the position change of the marking holes in any layer of raw porcelain relative to the marking holes on the surface layer, thereby obtaining the direction of the stacking alignment deviation of the raw porcelain sheet. In the LTCC production practice, usually only 2mm diameter alignment holes are punched out on the edge of the whole raw porcelain sheet for stacking alignment, and the edges of each substrate are all white porcelain after raw cutting, but the alignment deviation between the layers inside the substrate cannot be known due to the opacity of the porcelain body. In the present invention, smaller diameter marking holes are punched out around the edges of the contour of each substrate of the raw porcelain sheet, and then solidly filled with slurry. After cutting, the deviation of any layer of the substrate can be quantitatively calculated by the deviation of the slurry in the marking holes without destroying the internal structure of the substrate. Therefore, the present invention can accurately measure the substrate stacking alignment deviation to any specific layer, thereby providing specific stacking deviation data for each substrate and providing screening data for certain substrates that have clear requirements for stacking accuracy.

[0037] (2) Since the processing flow of LTCC multi-layer substrates is relatively complicated, it usually involves punching, filling holes, printing, lamination, isostatic pressing, co-firing, slicing, post-printing, post-firing, etc. Therefore, the present invention can remove substrates that do not meet the lamination alignment deviation amount early before co-firing, and unqualified substrates do not need to flow into the remaining processes for unnecessary production and processing, which can save human resources on the one hand. At the same time, since the post-printing of the substrate will use metal slurries such as gold, palladium and silver, the early removal of unqualified substrates can also reduce the waste of slurry and save material costs. For LTCC substrates in certain specific application scenarios, such as RF terminal substrates, the lamination alignment accuracy of the microwave signal transmission layer in the substrate is extremely high, and the conventional substrate production process cannot provide the lamination alignment deviation amount of this layer in each substrate. However, in the present invention, by calculating the lamination deviation amount of this layer, a basis can be provided for screening the lamination deviation amount of the substrate, and substrates with deviation amounts that do not meet the requirements can be eliminated, thereby improving production quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A flow chart of the method for monitoring and calculating the LTCC substrate stacking deviation calculation in the present invention;

[0039] Figure 2 This is a schematic diagram of the distribution of the marked holes in the green ceramic sheet in step S1 of the method of the present invention;

[0040] Figure 3 A schematic diagram of the distribution of cutting lines of the marked holes in step S3 of the method of the present invention;

[0041] Figure 4 It is a schematic diagram of the front and partial enlargement of the marking hole after cutting in step S4 of the method of the present invention;

[0042] Figure 5 It is a schematic cross-sectional view of the marking hole after raw cutting in step S4 of the method of the present invention;

[0043] Figure 6 This is the schematic diagram for calculating the stack alignment deviation.

[0044] in:

[0045] 1. Raw ceramic sheet, 2. Overlay alignment hole, 3. Outline of substrate, 4. Overlay alignment deviation marking hole, 5. Marking hole cutting line. DETAILED DESCRIPTION

[0046] The present invention will be further described below in conjunction with the accompanying drawings:

[0047] The present invention includes a Figure 1 The method for calculating the stacking deviation of the LTCC substrate shown in the figure mainly includes punching the marking holes, filling the marking holes with slurry, printing the cutting lines, stacking, isostatic pressing, raw cutting and calculation of the stacking deviation.

[0048] The following is a specific example of a method for monitoring and calculating the LTCC substrate stacking alignment deviation. The method includes the following steps:

[0049] S1. Select raw ceramic sheets to make substrates, mechanically punch out 4 groups of stacking alignment deviation marking holes around the outline of each substrate in the raw ceramic sheets, and punch out 2 groups of stacking alignment holes on the left and right sides of the raw ceramic sheets.

[0050] S11, select 6 green ceramic sheets 1 with a size of 170×170×0.127 mm, and the substrate to be processed is a square of 60×60 mm. A total of 4 substrates can be divided within the effective area of ​​each green ceramic sheet.

[0051] S12. According to the number of substrates, each layer of raw ceramic sheets is divided into four square areas of equal size, each of which corresponds to a substrate outline 3. At the same time, it is necessary to ensure that the area of ​​each area is larger than the outline area of ​​the substrate, so as to reserve a stacking alignment deviation mark hole area at the edge of the substrate outline.

[0052] S13, mechanically punch out four groups of stacking alignment deviation marking holes 4 around each square area, that is, around the outline 3 of each substrate in the raw ceramic sheet 1. A group of stacking alignment holes 2 is processed on both sides of each layer of the raw ceramic sheet 1 along the X direction; each group of stacking alignment holes 2 includes a plurality of circular alignment holes with equal distances and the same diameter, and the centers of the circular alignment holes in the same group of stacking alignment holes 2 are located on the same straight line;

[0053] Specifically, a mechanical punching machine is used to punch the stacking alignment holes and stacking alignment deviation marking holes for each layer of raw porcelain sheet. All holes are vertically penetrated from the upper surface of the raw porcelain sheet through the lower surface. The diameter of the stacking alignment holes 2 is 5mm, distributed on the left and right sides of the raw porcelain sheet 1, with a total of 10 holes. The stacking alignment holes 2 are used to insert into the positioning pins at the corresponding positions of the stacking plate in the subsequent stacking steps to achieve the alignment of all layers. The diameter of the stacking deviation identification marking holes is 0.3mm, and they are evenly distributed outside the outline of the substrate and 3mm away from the outline. There are 3 holes on each side, and the centers of the marking holes are all on the same straight line. There are a total of 12 holes, such as Figure 2 shown.

[0054] S2. Fill the marked holes around the outline of the substrate in the green ceramic sheet with slurry.

[0055] S21, record the 6 raw porcelain sheets 1 as 1-6 layers in order from top to bottom after lamination, wherein the 1st layer of raw porcelain sheets is located at the top and the 6th layer of raw porcelain sheets is located at the bottom. According to the relative positions of the punched marking holes in the 1-6 layers of raw porcelain sheets, 6 stainless steel hole-filling screens with a thickness of 0.05 mm are respectively made. The 6 stainless steel hole-filling screens are divided into No. 1 stainless steel hole-filling screen, No. 2 stainless steel hole-filling screen, No. 3 stainless steel hole-filling screen, No. 4 stainless steel hole-filling screen, No. 5 stainless steel hole-filling screen and No. 6 stainless steel hole-filling screen, which are distributed corresponding to the 1-6 layers of raw porcelain sheets. A laser cutting machine is used to cut circular holes on the stainless steel hole-filling screen with the same aperture and position as the raw porcelain sheet marking holes.

[0056] S22, place the punched first layer of raw porcelain sheet on the work surface of the semi-automatic printing machine for vacuum adsorption, spread the Ag slurry to be filled on the corresponding No. 1 stainless steel hole-filling screen, set the printing parameters, that is, the distance between the stainless steel hole-filling screen and the raw porcelain sheet: 0mm, the printing machine scraper hole-filling speed: 10mm / s, and the scraper hole-filling pressure: 100N. Under this parameter, the scraper pressure of the printing machine is used to press the hole-filling slurry into all the marked holes of the raw porcelain sheet of this layer. At this time, all the marked holes in each raw porcelain sheet have been filled with Ag slurry, and the slurry in each hole is a solid cylinder with a height of 0.127mm and a diameter of 0.3mm. The above method is used to perform the hole-filling treatment of the 2nd to 6th layers of raw porcelain sheets in turn. After all the raw porcelain sheets of 1-6 layers have completed the hole-filling, they are uniformly placed in a 50°C oven to dry the raw porcelain sheets filled with slurry for 30 minutes and then taken out.

[0057] S3. Print cutting lines above all the marking holes in the first layer of green ceramic sheets.

[0058] S31, make a printing screen, design 8 straight lines with a width of 0.3 mm and a length of 150 mm in the printing screen as cutting lines 5 for the subsequent raw cutting process. A cutting line 5 is provided directly above each marking hole on the same straight line.

[0059] S32, placing the green ceramic sheet on the vacuum adsorption table of the printing machine, and setting the printing parameters after spreading the Ag slurry to be printed on the printing screen, that is, the distance between the printing screen and the green ceramic sheet: 1mm; the printing speed of the printing machine scraper: 30mm / s, the scraper printing pressure: 70N.

[0060] S33, start the printer to print the cutting line of the first layer of raw ceramic sheets. After printing, the centers of all the marking holes are located at the center of the cutting line. After printing, the surface of the first layer of raw ceramic sheets is as follows: Figure 3 After printing is completed, the first layer of green ceramic sheets is placed in a 50°C oven for drying for 30 minutes and then taken out.

[0061] S4, stacking, isostatic pressing and raw cutting the 1-6 layers of raw ceramic sheets after the hole filling and printing.

[0062] S41, stack all the dried green ceramic sheets in order: set a stacking cover plate with positioning pins, put the stacking alignment holes of the 6th layer of green ceramic sheets on the stacking cover plate through the positioning pins of the stacking cover plate, and then stack the 5-1 layers one by one and place them on the 6th layer of green ceramic sheets. During the stacking process of each green ceramic sheet, the positioning pins are inserted into the corresponding stacking holes 2 of each layer of green ceramic sheets to position each layer of green ceramic sheets.

[0063] S42, after the layers of green ceramic sheets are laminated, they are sealed and placed in an isostatic press, and the isostatic press parameters of the isostatic press are set as follows: temperature: 75°C; pressure: 3000psi; time: 20min. Since the green ceramic sheets contain organic colloids, this process aims to use temperature and pressure to adhere all layers of green ceramic sheets together. After isostatic pressing, the six layers of green ceramic sheets are pressed together to form a whole.

[0064] S43, take out the pressed whole-plate raw ceramic sheet and put it into the hot cutting machine, put it into the center along all the printed cutting lines, cut the whole-plate raw ceramic sheet vertically downward along the X direction and the Y direction respectively, after cutting 8 times in total, 4 green pieces with an area larger than the outer contour of the substrate are formed as the substrate.

[0065] S44, after the green cutting, the slurry filled in the stacking deviation mark hole at the edge of each green blank is divided into two, and only half of the hole slurry remains around the substrate contour, such as Figure 4 As shown, a longitudinal cross section is exposed on the side wall.

[0066] S5. Calculate the stacking deviation of each layer of raw ceramic sheets in the substrate.

[0067] Obtain the horizontal length L of the slurry exposed by each marking hole around each layer of raw ceramic sheets on the substrate, and calculate the stacking alignment deviation along the X direction and the stacking alignment deviation along the Y direction of each layer of raw ceramic sheets according to the length L and the diameter D of the stacking alignment deviation marking hole, so as to determine the stacking alignment deviation of the layer of raw ceramic sheets.

[0068] Preferably, according to the present invention, in step S5, calculating the stacking alignment deviation of each layer of green ceramic sheets in the substrate specifically includes the following steps:

[0069] S51, obtaining the length L of the slurry exposed from each marking hole around each layer of the green ceramic sheet of the substrate in the horizontal direction;

[0070] S52, using formula (1) to calculate the stacking alignment deviation of each marking hole along the X direction and the stacking alignment deviation of each marking hole along the Y direction;

[0071]

[0072] S53, averaging the stacking alignment deviations of the marking holes along the X direction to obtain δ x , calculate the average value of the stacking deviation of each marked hole along the X direction δ y ;

[0073] S54, using formula (2), calculate the stacking deviation δ of each layer of raw ceramic sheets respectively w .

[0074]

[0075] Specifically, the stacking alignment deviation of each layer of raw ceramic sheets in the substrate is calculated based on the horizontal length of the slurry exposed by the marking holes around the substrate and the diameter of the stacking alignment deviation marking holes. The four groups of marking holes around each substrate are cut longitudinally to expose the filled cylindrical slurry; the marking holes on the topmost raw ceramic sheet in the substrate are evenly cut into two pieces of equal area along the hole diameter, and the horizontal length of the exposed slurry is the diameter length of the marking hole.

[0076] Taking the topmost raw ceramic sheet in the substrate as a reference, the lengths of the exposed slurry in the horizontal direction of the remaining raw ceramic sheets may be different due to possible stacking deviations. The length of the slurry exposed in the marked holes of the raw ceramic sheets other than the topmost raw ceramic sheet in the horizontal direction is recorded as L. The shorter the length L, the greater the alignment deviation of the raw ceramic sheet in this layer. The specific deviation is D is the diameter of the marking hole; for any layer of raw ceramic sheets, the stacking deviation of the raw ceramic sheets can be decomposed into the horizontal X-direction component and the vertical Y-direction component. There are a total of 6 marking holes in the horizontal X direction. According to formula 1, the deviation of the 6 holes is calculated and the average value is taken, which is the deviation component of the raw ceramic sheet in the vertical Y direction, recorded as δ y There are also 6 marking holes in the vertical Y direction. The deviation of the 6 holes is calculated according to formula 1 and the average value is taken, which is the deviation component of the raw ceramic piece along the horizontal X direction, recorded as δ x The two deviation components in the horizontal X direction and the vertical Y direction can be obtained by Finally, the stacking alignment deviation of the layer of raw ceramic sheets is calculated.

[0077] After each substrate is cut, the four groups of marking holes around it are cut longitudinally to expose the filled semi-cylindrical slurry. The marking holes on the topmost layer of raw porcelain (i.e. the first layer of raw porcelain) are evenly cut into two pieces of equal area along the diameter of the marking holes by the cutting line. The exposed slurry in the horizontal direction is exactly 0.3mm, the diameter of the marking holes.

[0078] The calculation process of the stacking alignment deviation in this embodiment is described below:

[0079] First, determine the deviation calculation formula. Taking the first layer of green porcelain as a reference, the marking holes on the remaining layers of green porcelain may have different lengths of exposed slurry along the horizontal direction from the first layer of green porcelain due to stacking deviation. The shorter the length, the greater the alignment deviation of the layer. Figure 5 As shown, Lμ is the length of the slurry exposed after the marking holes in different layers are cut, where μ=2, 3, 4, 5, 6, representing different layers. Figure 6This is a schematic diagram of any marked hole with deviation after cutting. Figure 6 The deviation calculation formula (1) can be obtained: Wherein, D is the diameter of the marking hole, and in this embodiment, the value is 0.3 mm.

[0080] Secondly, the stacking deviation components of each layer of green ceramic sheets on the substrate along the X direction and the Y direction are obtained respectively.

[0081] Depend on Figure 4 It can be seen that the stacking deviation of the substrate along the Y direction is reflected in the length of the slurry exposed after cutting each mark distributed in the X direction; similarly, the stacking deviation of the substrate along the X direction is reflected in the length of the slurry exposed after cutting each mark distributed in the Y direction. By averaging the alignment deviation values ​​of the 6 mark holes in the X direction of the substrate (calculated by formula 1), the value obtained is the deviation of the substrate along the Y direction, recorded as δ y The value obtained by averaging the alignment deviation values ​​of the six marking holes in the Y direction of the substrate (calculated by formula 1) is the deviation of the substrate in the X direction, denoted as δ x .

[0082] Finally, the stacking alignment deviation of any layer of raw ceramic sheets on the substrate.

[0083] Since the deviation value can be decomposed into components along the X and Y directions, when the stacking deviation components of any layer of green ceramic sheets on the substrate in the X and Y directions are obtained in step S52, the stacking deviation of the green ceramic sheets can be calculated by formula (2): Calculated.

[0084] In the actual production of LTCC substrates, for the layer in the design where the alignment deviation of the raw ceramic tape is required, the alignment deviation of each layer of the substrate is calculated. If the deviation is within the required range, the next process is continued. If the deviation exceeds the required range, the substrate is discarded to avoid the waste of labor and material costs caused by flowing into the next process. The present invention can accurately determine the alignment deviation of the substrate stacking to a specific arbitrary layer, thereby providing each substrate with its specific stacking deviation data, and providing screening data for certain substrates with clear requirements for stacking accuracy. In the present invention, by calculating the stacking deviation of the layer, a basis can be provided for screening the stacking deviation of the substrate, and substrates with deviations that do not meet the requirements can be eliminated, thereby improving production quality.

[0085] The above-described embodiments are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the scope of protection determined by the claims of the present invention.

Claims

1. A method for calculating the deviation of LTCC substrate stacking, characterized in that: The method comprises the following steps: S1. Punching of stacking alignment deviation marking holes and stacking alignment holes A substrate is processed using raw ceramic sheets, and each layer of raw ceramic sheets is divided into a plurality of square areas of the same size; a group of marking holes is processed on the outside of each side length of each square area as stacking alignment deviation marking holes; each group of marking holes includes a plurality of circular marking holes with a diameter of D and distributed at equal distances, and the centers of the circular marking holes in the same group of marking holes are located on the same straight line; a group of stacking alignment holes is processed on both sides of each layer of raw ceramic sheets along the X direction; each group of stacking alignment holes includes a plurality of circular alignment holes with equal distances and the same diameters, and the centers of the circular alignment holes in the same group of stacking alignment holes are located on the same straight line; S2. Fill the holes for marking the stacking deviation with slurry According to the positions of the stacking alignment deviation amount marking holes on each layer of raw porcelain sheet, a plurality of hole-filling screens corresponding to each layer of raw porcelain sheet are produced; at the corresponding positions of the hole-filling screens corresponding to each layer of raw porcelain sheet, a plurality of through holes having the same size and corresponding to each stacking alignment deviation amount marking hole on the layer of raw porcelain sheet are cut; the hole-filling slurry to be filled is spread on the hole-filling screen, the raw porcelain sheet corresponding to the hole-filling screen is placed on the vacuum adsorption table of the printing press, the hole-filling slurry on the hole-filling screen is pressed into each stacking alignment deviation amount marking hole by the printing press, the slurry is filled in the holes, and the raw porcelain sheet after the slurry filling is dried; S3. Print cutting lines on the top raw ceramic sheet A printing screen is made, and a plurality of cutting lines are designed on the printing screen; each cutting line is located directly above the straight line where the center of each marking hole on the same row or column is located; the top layer of raw porcelain sheet is placed on the vacuum adsorption table of the printing machine, and the cutting lines are printed on the top layer of raw porcelain sheet by using the printing machine and the printing screen, so that 8 cutting lines are formed directly above all the marking holes of the top layer of raw porcelain sheet; after the cutting lines are printed, a drying process is performed; S4. Lamination, isostatic pressing and raw cutting of raw ceramic pieces All the green ceramic sheets are stacked in order according to the design sequence, and then sealed in plastic and placed in an isostatic press to adhere all the layers of green ceramic sheets together; the pressed whole-plate green ceramic sheets are taken out and placed in a hot cutting machine, and the whole-plate green ceramic sheets are cut along the centers of all the printed cutting lines along the X and Y directions to obtain multiple substrates; after the cutting is completed, the four groups of marking holes around each substrate are cut longitudinally to expose the filling slurry; S5. Calculate the stacking deviation of each layer of raw ceramic sheets in the substrate Obtain the horizontal length L of the slurry exposed by each marking hole around each layer of raw ceramic sheets on the substrate, and calculate the stacking alignment deviation along the X direction and the stacking alignment deviation along the Y direction of each layer of raw ceramic sheets according to the length L and the diameter D of the stacking alignment deviation marking hole, so as to determine the stacking alignment deviation of the layer of raw ceramic sheets.

2. The method for calculating the LTCC substrate stacking deviation according to claim 1, characterized in that: In the step S5, calculating the stacking alignment deviation of each layer of green ceramic sheets in the substrate specifically includes the following steps: S51, obtaining the length L of the slurry exposed from each marking hole around each layer of the green ceramic sheet of the substrate in the horizontal direction; S52, using formula (1) to calculate the stacking alignment deviation of each marking hole along the X direction and the stacking alignment deviation of each marking hole along the Y direction; S53, averaging the stacking alignment deviations of the marking holes along the X direction to obtain δ x , calculate the average value of the stacking deviation of each marked hole along the X direction δ y ; S54, using formula (2), calculate the stacking deviation δ of each layer of raw ceramic sheets respectively w .

3. The method for calculating the LTCC substrate stacking deviation according to claim 1, characterized in that: In step S1, each group of marking holes includes three circular marking holes, and the vertical distance between the center of each circular marking hole and the side length of the corresponding square area is 3 mm; the diameter of the marking hole is 0.3 mm.

4. The method for calculating the LTCC substrate stacking deviation according to claim 1, characterized in that: In the step S1, each group of overlapping alignment holes includes 5 circular alignment holes.

5. The method for calculating the LTCC substrate stacking deviation according to claim 1, characterized in that: In the step S2, the thickness of the hole-filling screen is 0.05 mm, and the material of the hole-filling screen is stainless steel; the temperature in the oven is 50° C., and the drying time is 30 minutes.

6. The method for calculating the LTCC substrate stacking deviation according to claim 1, characterized in that: In the step S3, the width of the cutting line is 0.3 mm; the temperature in the oven is 50° C., and the drying time is 30 minutes.

7. The method for calculating the LTCC substrate stacking deviation according to claim 1, characterized in that: In step S4, the operating parameters of the isostatic press are: temperature of 75° C., pressure of 3000 psi, and time of 20 min.

8. The method for calculating the LTCC substrate stacking deviation according to claim 1, characterized in that: In step S4, during the green ceramic sheets stacking process, positioning pins are inserted into the corresponding stacking holes of each layer of green ceramic sheets to position each layer of green ceramic sheets.

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