CN112487606B - Steel mesh opening design method for BGA package and computer readable storage medium - Google Patents
Steel mesh opening design method for BGA package and computer readable storage medium Download PDFInfo
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- CN112487606B CN112487606B CN202011181440.3A CN202011181440A CN112487606B CN 112487606 B CN112487606 B CN 112487606B CN 202011181440 A CN202011181440 A CN 202011181440A CN 112487606 B CN112487606 B CN 112487606B
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Abstract
The invention discloses a steel mesh opening design method for BGA encapsulation, which comprises the following steps: acquiring thermal deformation amount statistical data of a BGA solder ball area and original welding seam height, wherein the thermal deformation amount statistical data comprises a BGA solder ball position and thermal deformation amount in the solder ball area of the position; judging the relation between the thermal deformation amount in the solder ball area and the original welding seam height h to obtain a comparison result, and designing a steel mesh opening scheme according to the comparison result; and compensating the thermal deformation amount in the tin ball area at the local position according to the steel mesh opening scheme. The design method of the steel mesh opening for the BGA package obtains the corresponding reasonable size and thickness of the steel mesh opening by detecting the thermal deformation amount in the specific solder ball area of the BGA, so that the proper soldering tin amount can be obtained at each solder ball of the BGA, the open soldering caused by the deformation of the BGA is overcome to the maximum extent, and the soldering reliability of each solder ball of the BGA is ensured.
Description
Technical Field
The invention belongs to the field of printed circuit board assembly, and particularly relates to a steel mesh opening design method for BGA packaging and a computer readable storage medium.
Background
As electronic products become thinner, BGA (Ball Grid Array) ball grid array packages become thinner. Because different materials in the BGA are distributed in a layered manner, the BGA is inevitably deformed due to the different thermal expansion coefficients of the different materials when the reflow soldering process is heated. The need for lighter and thinner packages increases the amount of BGA deformation. Although the deformation amount of each solder ball of the BGA can be measured by the moire fringe method, the number of the solder balls of the BGA is large, and the thermal deformation amount of each solder ball is different, so that the thermal deformation of all the solder balls of the BGA is difficult to quickly and accurately compensate when the steel mesh is designed manually. For example, when compensation processing is performed, the operation amount is huge, time and labor are wasted, errors are easy to occur, so that the welding defects caused by thermal deformation of the BGA are difficult to overcome, and early recognition and early warning cannot be performed in advance.
Disclosure of Invention
In order to solve the above problems in the prior art, the present invention provides a method for designing a steel mesh opening for coping with BGA packages and a computer readable storage medium. The technical problems to be solved by the invention are realized by the following technical scheme:
a steel mesh opening design method for BGA package comprises the following steps:
acquiring thermal deformation amount statistical data of a BGA solder ball area and original welding seam height, wherein the thermal deformation amount statistical data comprises a BGA solder ball position and thermal deformation amount in the solder ball area of the position;
judging the relation between the thermal deformation Lx in the solder ball area and the original weld joint height h to obtain a comparison result, and designing a steel mesh opening scheme according to the comparison result;
and compensating the thermal deformation amount in the tin ball area at the local position according to the steel mesh opening scheme.
In one embodiment, obtaining the raw weld height comprises:
setting the opening area S of an original steel mesh 0 The thickness t of the original steel mesh;
according to the opening area S of the steel mesh 0 Calculating the original welding seam height h according to the thickness t of the steel mesh;
the original weld height h= (S 0 X t x alpha)/P, wherein S 0 The opening area of the original steel mesh is t is the thickness of the original basic steel mesh, alpha is the conversion rate of converting solder paste into soldering tin, and P is the area of a single PCB bonding pad.
In a specific embodiment, determining a relationship between the thermal deformation Lx in the solder ball area and the original weld height h to obtain a comparison result, so as to design a steel mesh opening scheme according to the comparison result, including:
if the thermal deformation Lx in the solder ball area is less than or equal to the original welding seam height h, the steel mesh opening scheme comprises: and designing a steel mesh opening scheme by adopting the opening area of the original steel mesh and the thickness of the original basic steel mesh.
In one specific embodiment, if it is determined that the thermal deformation Lx in the solder ball area is greater than the original weld height h, and when the maximum thermal deformation Lmax in the solder ball area is less than or equal to the original weld height h+β×the original base steel mesh thickness t, the steel mesh opening scheme includes:
for the thermal deformation Lx > the original weld height h in the solder ball regionThe steel mesh at the tin ball is automatically thickened locally, so that the total thickness of the thickened area steel mesh is the required tin paste quantity Vmax of the tin ball at the maximum deformation position/the opening area S of the original steel mesh 0 Wherein, beta is more than or equal to 0.2 and less than or equal to 0.4.
In one specific embodiment, the steel mesh opening scheme further comprises: if the thermal deformation amount in the solder ball area is h < Lx < Lmax, according to the theoretical solder amount V X0 Correspondingly reducing the opening at the solder ball; if the thermal deformation Lx in the solder ball area is less than or equal to h in the thickened area, the solder balls are thickened together, and the theoretical solder quantity V is calculated X0 Correspondingly shrinking the opening at the solder ball; if the solder ball is positioned at one solder ball position at the outer edge of the thickened area, calculating the thickness of the steel mesh at one solder ball position at the outer edge of the thickened area according to the thickness of the thickened position, and according to the theoretical soldering tin quantity V X0 Correspondingly shrinking the opening at the solder ball. For the position of a tin ball at the thickened outer edge, although the steel mesh is not thickened, the actual printing effect of the steel mesh is considered to be equal to the thickened position, the thickness of the steel mesh is calculated according to the thickness of the thickened position, and the theoretical tin soldering quantity V is calculated X0 Correspondingly shrinking the opening at the solder ball.
In one specific embodiment, the steel mesh opening scheme further comprises: the size of the opening is regulated so that the opening area ratio is larger than the preset area ratio, and the solder spreading area is smaller than or equal to the solder resisting windowing area of a single bonding pad; if the calculated opening area ratio of the final opening is smaller than or equal to the preset area ratio, the opening failure is early warned.
In one specific embodiment, if it is determined that the thermal deformation Lx in the solder ball area is greater than the original weld height h, and when the maximum thermal deformation Lmax in the solder ball area is greater than the original weld height h+β×the original base steel mesh thickness t, the steel mesh opening scheme includes:
the steel mesh at the solder ball position with the thermal deformation Lx larger than the original welding seam height in the solder ball area is automatically and locally thickened, so that the solder ball position with h being more than Lx and less than or equal to Lmax/2 is a first layer thickened position, and the thickness of the steel mesh = the required solder paste amount Vmax/2 of the solder ball at Lmax/2/the opening area S of the original steel mesh 0 So that the solder balls with Lmax/2 being less than Lx and less than or equal to Lmax are the thickened parts of the second layer, and the thickness of the steel mesh is equal to the solder balls at the maximum deformation partTin paste required amount Vmax/original steel mesh opening area S 0 The method comprises the steps of carrying out a first treatment on the surface of the If the thermal deformation Lx in a solder ball area is less than or equal to h in the middle of the local thickening area of the first layer, thickening the solder ball together, and if the solder ball area is positioned in the second layer, locally thickening the solder ball area to the thickness of the second layer; if the first layer local thickening area comprises a second layer local thickening opening, calculating the thickness of the opening at one solder ball around the second layer local thickening opening according to the thickness of the second layer local thickening; if the thermal deformation amount of a solder ball area in the middle of the second layer partial thickening area is smaller than h and smaller than Lx and smaller than Lmax/2, thickening the solder ball area together, wherein beta is larger than or equal to 0.2 and smaller than or equal to 0.4.
In one embodiment, the steel mesh opening scheme further comprises: for the solder balls with the thermal deformation amount in the solder ball area being h < Lx < Lmax/2 and Lmax/2 < Lx < Lmax, according to the theoretical solder amount V X0 Correspondingly reducing the opening at the solder ball; if the thermal deformation Lx in a solder ball area is less than or equal to h in the middle of the partial thickening area of the first layer, the solder balls are thickened together according to the theoretical solder quantity V X0 Correspondingly reducing the opening at the solder ball; the first layer partial thickening area comprises a second layer partial thickening opening, the thickness of the opening at one solder ball around the second layer partial thickening opening is calculated according to the thickness of the second layer partial thickening, and the theoretical solder quantity V is calculated X0 Correspondingly reducing the opening at the solder ball; if the thermal deformation amount of a solder ball area positioned in the middle of the second layer partial thickening area is smaller than h < Lx < Lmax/2, thickening the solder ball together according to the theoretical solder amount V X0 Correspondingly reducing the opening at the solder ball; if the solder ball is positioned at one solder ball position at the outer edge of the thickened area, calculating the thickness of the steel mesh at one solder ball position at the outer edge of the thickened area according to the thickness of the thickened position, and according to the theoretical soldering tin quantity V X0 Correspondingly shrinking the opening at the solder ball. For the position of a tin ball at the thickened outer edge, although the steel mesh is not thickened, the actual printing effect of the steel mesh is considered to be equal to the thickened position, the thickness of the steel mesh is calculated according to the thickness of the thickened position, and the theoretical tin soldering quantity V is calculated X0 Correspondingly shrinking the opening at the solder ball.
In one embodiment, the steel mesh opening scheme further comprises: and adjusting the size of the opening so that the opening area ratio is larger than the preset area ratio, and the solder spreading area is smaller than or equal to the solder resisting and windowing area of the single bonding pad, and if the calculated opening area ratio of the final opening is smaller than or equal to the preset area ratio, early warning of the opening failure.
The present invention also provides a computer readable storage medium having a computer program stored therein, which when executed by a processor, implements the steps of the above method.
The invention has the beneficial effects that:
1. according to the design method for the steel mesh opening for the BGA package, the corresponding reasonable size and thickness of the steel mesh opening are obtained by detecting the thermal deformation amount in the specific solder ball area of the BGA, so that the welding is carried out according to the parameter, the proper soldering tin amount can be obtained at each solder ball of the BGA, the open soldering caused by the deformation of the BGA is overcome to the maximum extent, and the welding reliability of each solder ball of the BGA is ensured.
2. The method for designing the steel mesh opening for dealing with BGA packaging solves the problem that manual steel mesh manufacturing can only carry out simple treatment on a few solder balls, and can automatically calculate and accurately reach each solder ball by an algorithm aiming at thousands of solder balls of a large-size BGA, thereby improving the product quality and reducing the loss of manpower, material resources and financial resources caused by welding defects;
3. according to the design method for the steel mesh opening for the BGA package, when the adjustment of the steel mesh opening cannot overcome the thermal deformation of the BGA due to overlarge heating, the position of the solder ball with risk is determined and reminded by calculating the opening area ratio to be smaller than or equal to the preset area ratio.
4. The steel mesh opening design method for coping with thermal deformation of the BGA package can calculate the required soldering tin amount of each tin ball of the BGA before welding, can identify the risk faced by the manufacturing process in advance, and inform how to process the tin balls, so that engineering personnel review the production process again, the problems of batch property, scrapping and the like are avoided, and the loss is reduced.
The present invention will be described in further detail with reference to the accompanying drawings and examples.
Drawings
Fig. 1 is a schematic flow chart of a method for designing a steel mesh opening corresponding to a BGA package according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of the positions of bonding pads and solder according to an embodiment of the present invention;
FIG. 3 is a flow chart of a specific steel mesh opening design provided by an embodiment of the present invention;
FIG. 4 is a schematic illustration of a partial thickening provided by an embodiment of the present invention;
fig. 5 is a schematic diagram of a computer device module according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to specific examples, but embodiments of the present invention are not limited thereto.
Example 1
Referring to fig. 1, fig. 1 is a flow chart of a method for designing a steel mesh opening for dealing with BGA packages according to an embodiment of the present invention, including:
acquiring thermal deformation amount statistical data of a BGA solder ball area and original welding seam height, wherein the thermal deformation amount statistical data comprises a BGA solder ball position and thermal deformation amount in the solder ball area of the position;
judging the relation between the thermal deformation Lx in the solder ball area and the original weld joint height h to obtain a comparison result, and designing a steel mesh opening scheme according to the comparison result;
and compensating the thermal deformation amount in the tin ball area at the local position according to the steel mesh opening scheme.
According to the design method for the steel mesh opening for the BGA package, the corresponding reasonable size and thickness of the steel mesh opening are obtained by detecting the thermal deformation amount in the specific solder ball area of the BGA, so that the welding is carried out according to the parameter, the proper soldering tin amount can be obtained at each solder ball of the BGA, the open soldering caused by the deformation of the BGA is overcome to the maximum extent, and the welding reliability of each solder ball of the BGA is ensured.
Specifically, referring to fig. 2, fig. 2 shows a schematic diagram of positions of a bonding pad and solder, each small circle represents a BGA solder ball, X represents a thermal deformation amount (unit: mm) in a solder ball area, and in order to achieve a better soldering effect, in this embodiment, first, statistical data of the thermal deformation amount in the BGA solder ball area, that is, thermal deformation amount in each solder ball area in fig. 2, needs to be obtained, so as to accurately determine and calculate the solder paste amount, and in general, the thermal deformation amount in the solder ball area can be measured by a moire fringe method, and the data can be measured by itself or can be obtained from a BGA manufacturer.
The statistics may be in the form of statistics tables, which may be stored in a data format for recall by the computing device, and corresponding statistics tables may be imported or exported prior to computation for different processes.
The original welding seam height h is obtained according to an original steel mesh opening scheme, and the original steel mesh opening scheme is built in steel mesh opening software according to the center distance of BGA solder balls and is directly read.
Setting the opening area S of the original steel mesh according to the center distance of the BGA solder balls 0 The thickness t of the original steel mesh;
according to the opening area S of the steel mesh 0 Calculating the original welding seam height h according to the thickness t of the steel mesh;
the original weld height h= (S 0 X t x alpha)/P, wherein S 0 The opening area of the original steel mesh is t is the thickness of the original basic steel mesh, alpha is the conversion rate of converting solder paste into soldering tin, and P is the area of a single PCB bonding pad.
It should be noted that, in this embodiment, the volume change of the solder paste converted after melting is considered, and when the height of the weld joint is calculated, the volume change is converted into the actual solder quantity, and in this embodiment, the applicant obtains that the volume change of the solder paste converted after melting is about 0.4 to 0.5 times of the original volume change of the solder paste, that is, the volume change is 2.5 times of the volume change of the solder paste, and α=0.4 to 0.5. Preferred α=0.4.
Then, in order to accurately design the steel mesh opening scheme, the implementation compares the original welding seam height h with the thermal deformation amount Lx in the tin ball area, selects different steel mesh opening schemes according to different conditions, and then welds BGA according to the obtained steel mesh opening scheme.
Example two
The present embodiment shows a steel mesh opening scheme under several condition choices, and it should be noted that, this embodiment is an exemplary example performed under the adjustment concept of identification, judgment, and calculation in the first embodiment, so that, in order to more clearly show the scheme process of the present application, the following conditions are merely exemplary, and in an actual production scenario, the following conditions may also be optimized or changed according to different conditions, so that the present application is more targeted. Such as ramp rate, preheat temperature, preheat time, solder temperature, solder time, solder paste selection, etc., may affect the details of the recipe.
In one embodiment, please refer to fig. 3, fig. 3 is a flowchart of a specific steel mesh opening design according to an embodiment of the present invention. And judging the relation between the thermal deformation Lx in the solder ball area and the original welding seam height h to obtain a comparison result, so as to design a steel mesh opening scheme according to the comparison result, and respectively carrying out the following two cases included in the judgment result.
In the first case, if it is determined that the thermal deformation Lx in the solder ball area is smaller than or equal to the original weld height h, the steel mesh opening scheme includes: and designing a steel mesh opening scheme by adopting the opening area of the original steel mesh and the thickness of the original basic steel mesh.
In this embodiment, since the thermal deformation Lx.ltoreq.h in the solder ball region is obtained, that is, the current thickness of the steel mesh satisfies the requirement, there is no need to adjust the opening area S 0 . Therefore, the default original steel mesh opening scheme is adopted directly.
In a second embodiment, please refer to fig. 3, fig. 3 is a flowchart of a specific steel mesh opening design provided in an embodiment of the present invention. In this embodiment, β=0.3 is taken as an example, and β can be determined according to the element size and the center distance, and a larger β value can be selected when the element is larger or the center distance is larger. If the thermal deformation Lx in the solder ball area is judged to be larger than the original welding seam height h and the maximum thermal deformation Lmax in the solder ball area is less than or equal to h+0.3t, the steel mesh opening scheme is that Lx is larger than hThe mesh is automatically thickened locally by software so that the total thickness of the thickened area steel mesh = the amount of solder paste required for the solder balls at the maximum deformation/the area of the openings of the original steel mesh. If the middle of the thickening area contains the thermal deformation Lx less than or equal to h in a solder ball area, thickening is carried out together, and software is based on the theoretical solder amount Vx 0 Automatically adjusting the pad opening (shrink); all solder balls with thermal deformation amount of h < Lx < Lmax in the solder ball area and one solder ball at the thickened outer edge, the steel mesh is calculated according to the thickness of local thickening, and the software is based on theoretical soldering tin amount Vx 0 Calculating the opening area (reducing), if the opening area ratio is not satisfied, adjusting the opening size until the opening area ratio is satisfied and the solder spreading area is smaller than or equal to the single solder pad solder mask window area M, so as to avoid the occurrence of tin connection.
In the second case, please refer to fig. 3, in one embodiment, the determining the relationship between the thermal deformation Lx in the solder ball area and the original weld height h to obtain a comparison result, so as to design a steel mesh opening scheme according to the comparison result includes:
if the thermal deformation Lx in the solder ball area is judged to be greater than the original welding seam height h, and the maximum thermal deformation Lmax in the solder ball area is more than h+0.3t, the steel mesh opening scheme is that h is less than Lx and less than or equal to Lmax/2, the steel mesh at the solder ball is uniformly and locally thickened (the first layer is locally thickened), and the total steel mesh thickness = the thermal deformation in the solder ball area is equal to the solder paste amount required by the solder ball at Lmax/2/the opening area of the original steel mesh. And the steel mesh at the solder balls with Lmax/2 being more than Lx and less than or equal to Lmax is uniformly and locally thickened (the second layer is locally thickened), and the total thickness of the steel mesh is equal to the required solder paste quantity of the solder balls at the maximum deformation position/the opening area of the original steel mesh. If the thermal deformation Lx of the solder ball area with a bonding pad in the middle of the thickening area is less than or equal to h, the solder is thickened together (the layer is thickened to the thickness of the layer when the layer is locally thickened), and the software is based on the theoretical soldering tin amount Vx 0 Adjusting the opening (shrinking) of this pad; if the first layer partial thickening area contains the second layer partial thickening opening, the opening thickness of one solder ball around the second layer partial thickening opening is calculated according to the second layer partial thickening thickness, and the software calculates the theoretical solder amount Vx 0 Adjusting openings (shrinking) of the plurality of bonding pads; the thermal deformation amount in the solder ball area is h < Lx <All solder balls of Lmax/2 and a solder pad at one solder ball at the outer edge of the first layer which is locally thickened, the steel mesh is calculated according to the thickness of the first layer which is locally thickened, and the software is used for carrying out the calculation according to the theoretical soldering tin quantity Vx 0 And (3) adjusting the opening area (reducing), and if the opening area ratio is not satisfied, adjusting the opening size until the opening area ratio is satisfied and the welding area is smaller than or equal to the single welding pad welding-resisting window area M. The thermal deformation amount of the solder balls in the solder ball area is between Lmax/2 < Lx < Lmax and the solder pad at one solder ball at the outer edge of the second layer which is locally thickened, the steel mesh is calculated according to the thickness of the second layer which is locally thickened, and the software is used for controlling the theoretical solder amount Vx 0 Calculating the opening area (reducing), if the opening area ratio is not satisfied, adjusting the opening size until the opening area ratio is satisfied and the solder spreading area is less than or equal to the single solder pad solder mask window area M; if the thermal deformation amount of a solder ball area covered in the second layer local thickening area is smaller than h < Lx < Lmax/2, thickening the solder ball area according to the second layer local thickening and the theoretical solder amount Vx by software 0 And calculating the opening area (reducing), and if the opening area ratio is not satisfied, adjusting the opening size until the opening area ratio is satisfied and the solder spreading area is smaller than or equal to the single solder pad solder mask window area M. The opening area ratio can be determined according to the steel mesh opening standard IPC-7525, for example, set to 0.66.
When the thermal deformation amount of the BGA heated too much cannot be overcome due to the adjustment of the steel mesh openings, the method for designing the steel mesh openings for coping with the thermal deformation determines the position of the solder ball with risk and reminds by calculating the opening area ratio to be smaller than or equal to the preset area ratio.
It should be noted that, referring to fig. 4, in which the area in the black wire frame is thickened, the thermal deformation amount in the black filled solder ball area is greater than h, the thermal deformation amount in the solder ball area without filling is less than h, and there may be thermal deformation amount Lx in one solder ball area at the middle of the thickened area or Lx in one solder ball area at the outer edge of the thickened area or h, for both cases, the solder pad openings are adjusted according to the above-mentioned idea, and the openings of the solder pads are reduced according to the theoretical solder amount.
The steel mesh opening scheme further includes: the size of the opening is adjusted so that the opening area ratio is larger than the preset area ratio, and the solder spreading area is smaller than or equal to the solder mask windowing area of the single bonding pad.
When the opening is adjusted, the opening is too small, so that the opening area ratio is possibly not met, and the opening area ratio is adjusted until the solder spreading area S is less than or equal to the single solder pad solder mask windowing area M.
Specifically, the solder spreading area s=the open area of the steel mesh×the thickness of the steel mesh×α (α=0.4 as an example)/Lx.
That is, the solder amount Vx theoretically required at the pad at the middle of the thickened area and the pad at one solder ball at the outer edge of the thickened area 0 P×lx, P is the single PCB pad area, thus calculated opening area=vx 0 X 1/α (α=0.4 for example)/the thickness of the locally thickened portion, where this area is the opening area after the adjustment of the portion, if the opening area ratio is not satisfied, the opening size needs to be adjusted to satisfy the area ratio and the solder spreading area S is not more than the single solder pad solder mask window area M.
The method for designing the steel mesh opening for the BGA package can calculate the soldering tin amount required by each tin ball of the BGA before welding, can identify the risk faced by the process in advance, inform how to process the process, and enable engineering personnel to review the production process again, thereby avoiding the problems of batch property, scrapping and the like and reducing the loss.
In another specific embodiment, if it is determined that the thermal deformation Lx in the solder ball area is greater than the original weld height h, and when the maximum thermal deformation Lmax in the solder ball area is > the original weld height h+0.3×the original base steel mesh thickness t, the steel mesh opening scheme includes:
two to three layers can be thickened according to actual conditions (the embodiment takes two thickened layers as an example for illustration), so that the tin ball position with h < Lx less than or equal to Lmax/2 is the thickened position of the first layer, and the thickness of the steel mesh=Lmax/2 tin ball required tin paste amount Vmax/2/original steel mesh opening area S 0 So that the solder ball position with Lmax/2 being less than Lx and less than or equal to Lmax is the thickened position of the second layer, and the thickness of the steel mesh=the solder paste quantity Vmax required by the solder ball at the maximum deformation position/the opening area S of the original steel mesh 0 . If the thermal deformation Lx in the solder ball area is less than or equal to h in the middle of the thickening area, the solder ball area is thickened together, and the thickness of the layer is thickened to the thickness of the layer. If the first layer partial thickening area comprises a second layer partial thickening opening, the thickness of the opening at one solder ball around the second layer partial thickening opening is calculated according to the thickness of the second layer partial thickening. If the thermal deformation amount in the solder ball area contained in the second layer local thickening area is smaller than h < Lx < Lmax/2, the second layer local thickening area is thickened together.
Where the required solder paste amount vmax= (p×lmax)/α at the solder ball of the maximum thermal deformation amount Lmax in the solder ball region, P is a single PCB pad area.
The amount of solder paste Vmax/2= (p×lmax/2)/α required at solder balls with thermal deformation amount Lmax/2 in the solder ball area, P being the single PCB pad area.
In this embodiment, when Lx > h is first determined, lmax > h+0.3t is then determined, and at this time, it is known that the steel mesh needs to be locally thickened and the deformation amount is large, so that two layers need to be thickened.
In one embodiment, the steel mesh opening scheme further comprises: for the solder balls with the thermal deformation amount in the solder ball area being h < Lx < Lmax/2 and Lmax/2 < Lx < Lmax, according to the theoretical solder amount Vx 0 Correspondingly shrinking the opening at the solder ball.
The calculation is performed by using the solder paste amount required by the maximum thermal deformation amount Lmax/2 in the solder ball area for the solder ball position where h < Lx is less than or equal to Lmax/2, that is, the steel mesh needs to be thickened to the thickness Vmax/2 satisfying the solder paste amount required by Lmax/2, and since the thermal deformation amount in all the solder ball areas is not the maximum thermal deformation amount Lmax/2 in the solder ball area, the thermal deformation amount in the solder ball area is less than h < Lx < Lmax/2, under the condition that the thickness of the steel mesh is unchanged, if the solder paste amount Vmax/2 is still used, the solder paste is possibly excessive, the welding effect is affected, so in order to prevent the problem, the opening needs to be correspondingly reduced on the basis of the current opening, thereby indirectly reducing the solder paste amount to prevent the occurrence of the phenomenon of multiple tin.
Similarly, the calculation is performed for the solder paste amount required for the maximum thermal deformation amount Lmax in the solder ball area for the solder ball position of Lmax/2 < Lx < Lmax, that is, the steel mesh needs to be thickened to a thickness Vmax which satisfies the solder paste amount required for Lmax, and since the thermal deformation amount in all the solder ball areas is not the maximum thermal deformation amount Lmax in the solder ball area, for the position where the thermal deformation amount in the solder ball area is between Lmax/2 < Lx < Lmax, in the case that the steel mesh thickness is unchanged, if the solder paste amount Vmax is still adopted, the solder is possibly excessively large, and the soldering effect is affected, so in order to prevent the problem, the opening needs to be correspondingly reduced on the basis of the current opening, thereby indirectly reducing the solder paste amount to prevent the occurrence of the phenomenon of multiple tin.
In one embodiment, the steel mesh opening scheme further comprises: the size of the opening is adjusted so that the opening area ratio is larger than the preset area ratio, and the solder spreading area is smaller than or equal to the solder mask windowing area of the single bonding pad.
When the opening is adjusted, the opening is too small, so that the opening area ratio requirement of the steel mesh is not met, the opening area ratio is adjusted until the opening area ratio is met, and the solder spreading area S is less than or equal to the single solder pad solder mask windowing area M.
Specifically, the solder spreading area s= (steel mesh opening area×steel mesh thickness×α (0.4))/Lx.
That is, the solder amount Vx theoretically required at the pad at the middle of the thickened area and the pad at one solder ball at the outer edge of the thickened area 0 P×lx, P is the single PCB pad area, thus calculated opening area=vx 0 *2.5 (α=0.4 for example)/the thickness of the locally thickened portion, where the area is the adjusted opening area, if the opening area ratio is not satisfied, the opening size is adjusted to satisfy the area ratio, and the solder spreading area S is not greater than the single solder pad solder mask opening area M.
In the embodiment, the thermal deformation amount in the specific solder ball area of the BGA is automatically identified through the steel mesh opening software, the actually required soldering tin amount is automatically calculated according to the thermal deformation amount in the solder ball area, the required soldering tin amount is calculated according to the required soldering tin amount, and finally the reasonable steel mesh opening size and thickness are calculated according to the required soldering tin amount. The whole process is orderly and precisely calculated, so that necessary soldering tin amount can be obtained at each solder ball of the BGA, and the soldering reliability of each solder ball of the BGA is ensured. The scheme can overcome the open welding caused by BGA deformation to the maximum extent; the welding reliability of the BGA solder balls is improved, the product quality is improved, and the loss of manpower, material resources and financial resources caused by welding defects is reduced. The number of large-size BGA tin balls is thousands, manual layer-by-layer calculation is labor-consuming and is easy to make mistakes, and the large-size BGA tin balls cannot be realized at all (the current manual steel mesh manufacturing can only perform simple treatment on a few tin balls).
When the thermal deformation amount of the BGA, which is excessively heated, cannot be overcome through the steel mesh opening adjustment, the software can automatically judge and identify the position of the tin ball at risk (judged through the steel mesh opening area ratio, scientific and reliable), prompt that the scheme of tin printing through the steel mesh is not feasible (the upper limit of the capability of the steel mesh tin printing process is exceeded), recommend that a steel mesh designer adopt other recommended schemes aiming at the identified tin ball position, and inform the current foundation of the additional tin ball supplementing amount. Therefore, the risk can be identified and effectively managed and controlled before batch generation, and the phenomena of batch reworking, scrapping and the like are avoided. The method can identify the risk of the process in advance, inform how to process the risk, and enable engineering personnel to review the production process again, so that the effect of preventing the occurrence of the accident is achieved.
Example III
The present invention also provides a computer-readable storage medium having a computer program stored therein, which when executed by a processor, implements the steps of the first and second embodiments described above.
In general, the computer readable storage medium may be disposed in a computer device, referring to fig. 5, which may include a processor, a communication interface, a computer readable storage medium, and a communication bus or other units or modules, where the processor, the communication interface, and the memory perform communication with each other via the communication bus,
a computer readable storage medium storing a computer program;
a processor for executing the program stored on the computer readable storage medium, implementing the steps of:
acquiring thermal deformation amount statistical data of a BGA solder ball area and original welding seam height, wherein the thermal deformation amount statistical data comprises a BGA solder ball position and thermal deformation amount in the solder ball area of the position;
judging the relation between the thermal deformation amount in the solder ball area and the original welding seam height h to obtain a comparison result, and designing a steel mesh opening scheme according to the comparison result;
and compensating the thermal deformation amount in the tin ball area at the local position according to the steel mesh opening scheme.
The communication bus mentioned above for the computer device may be a peripheral component interconnect standard (Peripheral Component Interconnect, PCI) bus or an extended industry standard architecture (Extended Industry Standard Architecture, EISA) bus, etc. The communication bus may be classified as an address bus, a data bus, a control bus, or the like.
The communication interface is used for communication between the electronic device and other devices.
The processor may be a general-purpose processor, including a central processing unit (Central Processing Unit, CPU), a network processor (Network Processor, NP), etc.; but also digital signal processors (Digital Signal Processing, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), field programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.
The computer device may be: desktop computers, portable computers, intelligent mobile terminals, servers, etc. Any electronic device capable of implementing the present invention is not limited herein, and falls within the scope of the present invention.
For a computer device/storage medium embodiment, the description is relatively simple as it is substantially similar to the method embodiment, and reference is made to the description of the first and second method embodiments for relevant points.
The computer equipment provided by the embodiment of the invention obtains the corresponding reasonable size and thickness of the steel mesh opening by detecting the thermal deformation amount in the specific solder ball area of the BGA, so that the welding is carried out according to the parameter, the proper soldering tin amount can be obtained at each solder ball of the BGA, the open soldering caused by the deformation of the BGA is overcome to the maximum extent, and the welding reliability of each solder ball of the BGA is ensured.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Further, one skilled in the art can engage and combine the different embodiments or examples described in this specification.
Although the present application has been described herein in connection with various embodiments, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed application, from a review of the figures, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.
It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, apparatus, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects all generally referred to herein as a "module" or "system. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein. A computer program may be stored/distributed on a suitable medium supplied together with or as part of other hardware, but may also take other forms, such as via the Internet or other wired or wireless telecommunication systems.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The foregoing is a further detailed description of the invention in connection with the preferred embodiments, and it is not intended that the invention be limited to the specific embodiments described. It will be apparent to those skilled in the art that several simple deductions or substitutions may be made without departing from the spirit of the invention, and these should be considered to be within the scope of the invention.
Claims (9)
1. A steel mesh opening design method for handling BGA packages, comprising:
acquiring thermal deformation amount statistical data of a BGA solder ball area and original welding seam height, wherein the thermal deformation amount statistical data comprises a BGA solder ball position and thermal deformation amount in the solder ball area of the position;
judging the relation between the thermal deformation Lx in the solder ball area and the original welding seam height h to obtain a comparison result, and designing a steel mesh opening scheme according to the comparison result, wherein the method specifically comprises the following steps of:
if the thermal deformation Lx in the solder ball area is less than or equal to the original welding seam height h, the steel mesh opening scheme comprises: adopting the opening area of an original steel mesh and the thickness of the original basic steel mesh to design a steel mesh opening scheme;
if the thermal deformation Lx in the tin ball area is larger than the original welding seam height h, when the maximum thermal deformation Lmax in the tin ball area is smaller than or equal to the original welding seam height h+beta multiplied by the original basic steel mesh thickness t or when the maximum thermal deformation Lmax in the tin ball area is larger than the original welding seam height h+beta multiplied by the original basic steel mesh thickness t, the steel mesh at the tin ball with the thermal deformation Lx larger than the original welding seam height is automatically thickened locally, wherein beta is larger than or equal to 0.2 and smaller than or equal to 0.4;
if the thermal deformation amount in the solder ball region is h < Lx < Lmax, or if the thermal deformation amount in the solder ball region is h < Lx < Lmax/2 and Lmax/2 < Lx < Lmax, the theoretical solder amount V X0 Correspondingly reducing the opening at the solder ball;
and compensating the thermal deformation amount in the tin ball area at the local position according to the steel mesh opening scheme.
2. The method of designing a steel mesh opening for a BGA package according to claim 1, wherein obtaining the original bead height comprises:
setting the opening area S of an original steel mesh 0 The thickness t of the original steel mesh;
according to the opening area S of the steel mesh 0 Calculating the original welding seam height h according to the thickness t of the steel mesh;
the original weld height h= (S 0 X t x alpha)/P, wherein S 0 The opening area of the original steel mesh is t is the thickness of the original basic steel mesh, alpha is the conversion rate of converting solder paste into soldering tin, and P is the area of a single PCB bonding pad.
3. The steel mesh opening design method for coping with BGA packages according to claim 2, wherein if it is judged that the thermal deformation amount Lx in the solder ball area > the original bead height h, and when the maximum thermal deformation amount Lmax in the solder ball area is less than or equal to the original bead height h+β x the original base steel mesh thickness t, the steel mesh opening scheme comprises:
the steel mesh at the solder ball position where the thermal deformation Lx in the solder ball area is larger than the original welding seam height h is automatically and locally thickened, so that the total thickness of the steel mesh at the thickened area is the solder paste amount Vmax required by the solder ball at the maximum deformation position/the opening area S of the original steel mesh 0 Wherein, beta is more than or equal to 0.2 and less than or equal to 0.4.
4. The steel mesh opening design method for coping with BGA packages according to claim 2, wherein the steel mesh opening scheme further comprises:
if the thermal deformation amount in the solder ball area is smaller than h < Lx < Lmax, according to the theoretical solder amount V X0 Correspondingly reducing the opening at the solder ball; if the thermal deformation Lx in the solder ball area is less than or equal to h in the middle of the thickening area, the solder balls are thickened together, and the theoretical solder amount V is calculated X0 Correspondingly reducing the opening at the solder ball; if the solder ball is positioned at one solder ball position at the outer edge of the thickened area, calculating the thickness of the steel mesh at one solder ball position at the outer edge of the thickened area according to the thickness of the thickened position, and according to the theoretical soldering tin quantity V X0 Correspondingly shrinking the opening at the solder ball.
5. The steel mesh opening design method for coping with BGA packages of claim 4, further comprising: the size of the opening is regulated so that the opening area ratio is larger than a preset ratio, and the solder spreading area is smaller than or equal to the solder resisting and windowing area of a single bonding pad; if the calculated opening area ratio of the final opening is smaller than or equal to the preset area ratio, the opening failure is early warned.
6. The steel mesh opening design method for coping with BGA packages according to claim 2, wherein if it is judged that the thermal deformation amount Lx in the solder ball area is larger than the original bead height h, and when the maximum thermal deformation amount Lmax in the solder ball area > the original bead height h+β x the original base steel mesh thickness t, the steel mesh opening scheme comprises:
the steel mesh at the solder ball position with the thermal deformation Lx larger than the original welding seam height in the solder ball area is automatically and locally thickened, so that the solder ball position with h being more than Lx and less than or equal to Lmax/2 is a first layer thickened position, and the thickness of the steel mesh = the required solder paste amount Vmax/2 of the solder ball at Lmax/2/the opening area S of the original steel mesh 0 So that the solder ball position with Lmax/2 being less than Lx and less than or equal to Lmax is the thickened position of the second layer, and the thickness of the steel mesh is equal to the required solder paste amount Vmax of the solder ball at the maximum deformation position/the opening area S of the original steel mesh 0 The method comprises the steps of carrying out a first treatment on the surface of the If the thermal deformation Lx in a solder ball area is less than or equal to h in the middle of the local thickening area of the first layer, thickening the solder ball together, and if the solder ball is positioned in the second layer, locally thickening the solder ball to the thickness of the second layer; if the first layer local thickening area comprises a second layer local thickening opening, calculating the thickness of the opening at one solder ball around the second layer local thickening opening according to the thickness of the second layer local thickening; if the thermal deformation amount of a solder ball area in the middle of the second layer partial thickening area is smaller than h and smaller than Lx and smaller than Lmax/2, thickening the solder ball area together, wherein beta is larger than or equal to 0.2 and smaller than or equal to 0.4.
7. The steel mesh opening design method for coping with BGA packages of claim 6, further comprising: for the solder balls with the thermal deformation amount in the solder ball area being h < Lx < Lmax/2 and Lmax/2 < Lx < Lmax, according to the theoretical solder amount V X0 Correspondingly reducing the opening at the solder ball; if there is a solder ball area in the middle of the first layer local thickening areaThe thermal deformation Lx is less than or equal to h, the solder balls are thickened together, and the theoretical solder quantity V is used X0 Correspondingly reducing the opening at the solder ball; the first layer partial thickening area comprises a second layer partial thickening opening, the thickness of the opening at one solder ball around the second layer partial thickening opening is calculated according to the thickness of the second layer partial thickening, and the theoretical solder quantity V is calculated X0 Correspondingly reducing the opening at the solder ball; if the thermal deformation amount in a solder ball area in the middle of the second layer partial thickening area is smaller than h < Lx < Lmax/2, the solder balls are thickened together, and the theoretical solder amount V is calculated X0 Correspondingly reducing the opening at the solder ball; if the solder ball is positioned at one solder ball position at the outer edge of the thickened area, calculating the thickness of the steel mesh at one solder ball position at the outer edge of the thickened area according to the thickness of the thickened position, and according to the theoretical soldering tin quantity V X0 Correspondingly shrinking the opening at the solder ball.
8. The steel mesh opening design method for coping with BGA packages of claim 7, further comprising: and adjusting the size of the opening so that the opening area ratio is larger than the preset area ratio, and the solder spreading area is smaller than or equal to the solder resisting and windowing area of the single bonding pad, and if the calculated opening area ratio of the final opening is smaller than or equal to the preset area ratio, early warning of the opening failure.
9. A computer readable storage medium, characterized in that the computer readable storage medium has stored therein a computer program which, when executed by a processor, implements the steps of the method of any of claims 1-8.
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| CN202011181440.3A CN112487606B (en) | 2020-10-29 | 2020-10-29 | Steel mesh opening design method for BGA package and computer readable storage medium |
| PCT/CN2021/109984 WO2022088817A1 (en) | 2020-10-29 | 2021-08-02 | Steel mesh opening design method for bga packaging, and computer-readable storage medium |
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| CN114880853B (en) * | 2022-05-09 | 2024-05-28 | 江西兆驰半导体有限公司 | Method and system for determining thickness of steel mesh in tin brushing process |
| CN115458420B (en) * | 2022-09-16 | 2024-04-02 | 惠州市则成技术有限公司 | Ball mounting process of IC carrier plate |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6352153B1 (en) * | 1999-03-24 | 2002-03-05 | Senju Metal Industry Co., Ltd. | Solder ball container |
| CN1540749A (en) * | 2003-04-25 | 2004-10-27 | ͬ�Ϳ�ҵ��ʽ���� | Thin flm bearing belt of mounting electronic parts, its prodn. method and printing screen for coating welding resistance agent |
| CN111274697A (en) * | 2020-01-19 | 2020-06-12 | 上海望友信息科技有限公司 | Simulation method and device for welding tension, electronic equipment and storage medium |
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| KR100192766B1 (en) * | 1995-07-05 | 1999-06-15 | 황인길 | Solder ball planarization method of ball grid array semiconductor package using solder ball as an input/output electrode and its circuit structure |
| CN100539058C (en) * | 2007-06-21 | 2009-09-09 | 华为技术有限公司 | Plant the ball-planting device and the method for ball frock, BGA Package chip |
| CN110600402B (en) * | 2019-08-27 | 2022-05-13 | 上海望友信息科技有限公司 | Design method of steel mesh opening, design device of steel mesh opening and electronic equipment |
| CN112487606B (en) * | 2020-10-29 | 2023-07-04 | 上海望友信息科技有限公司 | Steel mesh opening design method for BGA package and computer readable storage medium |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6352153B1 (en) * | 1999-03-24 | 2002-03-05 | Senju Metal Industry Co., Ltd. | Solder ball container |
| CN1540749A (en) * | 2003-04-25 | 2004-10-27 | ͬ�Ϳ�ҵ��ʽ���� | Thin flm bearing belt of mounting electronic parts, its prodn. method and printing screen for coating welding resistance agent |
| CN111274697A (en) * | 2020-01-19 | 2020-06-12 | 上海望友信息科技有限公司 | Simulation method and device for welding tension, electronic equipment and storage medium |
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