JP2001253042A - Mask device for printing cream solder and method for printing cream solder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a printing deviation of a cream solder due to elongation and contraction of a base plate. SOLUTION: A mask device 40 comprises a mask plate 50, a frame 60 and a tensile force variably giving means 70. In this case, the means 70 couples the plate 50 to the frame 60 and gives a tensile force to the plate 50. The plate 50 is variably elongated or contracted by the means 70 to adapt itself to a deformation of the base plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called high-density mounting technique in which electronic components are mounted on a land of a printed wiring board (hereinafter, referred to as a substrate) by cream solder printing (also referred to as coating). In addition, the present invention relates to a technique for printing cream solder without causing a positional shift with respect to expansion and contraction of a substrate.

[0002]

2. Description of the Related Art As a process for mounting an electronic component on a substrate, a printing process for printing cream solder on the substrate, a component mounting process for mounting the electronic component on the printed cream solder, and a reflow device There is a reflow step in which the solder is melted and solidified by a (reflow furnace).

In the printing process of cream solder, generally,
Using a printing mask plate and a squeegee, cream solder is printed on a substrate. A large number of through holes are formed in the mask plate corresponding to each cream solder printing target portion (land or the like) on the substrate. The mask plate is placed on the substrate, the cream solder is filled in the through hole with a squeegee, and the mask plate is separated from the substrate, whereby the cream solder in the through hole is transferred onto the substrate, and the cream solder is printed.

[0004] A glass epoxy resin material is generally used for the substrate of the substrate, and other resin materials such as polyimide and polyamide are sometimes used.

[0005] Two to four target marks are formed on the surface of the substrate for positioning the mask plate.

[0006] Generally, stainless steel (S
A thin plate of US) material is used, and through holes are formed according to the design dimensions of the substrate to be printed.

The mask plate is overlaid on the substrate such that two to four target marks formed on the mask plate or two to four corners of the mask plate are aligned with target marks on the substrate.

[0008]

However, in an actual printing process, a "print shift" occurs in which the cream solder is printed while being shifted from a land on the board due to deformation of the board.

[0009] This is because the substrate is deformed due to the thermal history received before the printing process as exemplified below,
This is because the mask plate has a fixed size without deformation.
Even if the mask plate is aligned with one target mark on the deformed substrate, it will not be aligned with another target mark. In addition, the deformation of the substrate includes many elongations, but also includes shrinkage. (1) During the manufacturing process of the board, the board is heated by the press or the etching of the conductive foil. (2) When mounting electronic components on both sides of the board, cream solder printing, component mounting and reflow processing are performed on the first surface, and then cream solder is printed on the second surface.
The surface receives heat due to the reflow process, which causes further deformation.

[0010] If there is a misregistration of the cream solder, some electronic components may not be placed on the printed cream solder when the components are mounted, and the mounting accuracy of the components may be reduced.

[0011] When the component mounting accuracy is reduced, after reflow, the component is erected (only one end is soldered while the chip component is standing), the component is misaligned, or the component is missing (the component is not adhered to the cream solder, and Mounting failures, such as falling off from the solder), solder bridges, and floating feet.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cream solder printing mask device and a cream solder printing method capable of improving cream solder printing misalignment.

[0013]

The invention according to claim 1 is
A mask device for cream solder printing which solves the above-mentioned problem, comprising: a mask plate for cream solder printing corresponding to a substrate to be printed; a frame; connecting the mask plate and the frame, and pulling the mask plate. It is characterized by comprising a variable tension applying means for variably applying a force. The invention according to claim 2 is the mask device according to claim 1, wherein the mask plate is made of a metal material such as (1) a SUS (stainless steel) material, or (2) a polyvinyl chloride, polyethylene, polyimide, polyamide, or the like. Resin material, and
(3) It is characterized by being formed of any one of rubber-based elastic materials such as polyurethane.
According to a third aspect of the present invention, in the mask device of the first aspect, the mask plate is formed of the same material as a base material included in the substrate. According to a fourth aspect of the present invention, in the mask device according to the first aspect of the present invention, the mask plate is manufactured to be reduced with respect to a design dimension of the substrate, and a change rate of the mask plate is estimated in a shrinking direction expected for the substrate. Is larger than the maximum rate of change. According to a fifth aspect of the present invention, in the mask device of the first aspect of the present invention, the first and second side connecting the adjacent two sides of the mask plate and the adjacent two sides of the frame body as the tensile force variable applying means, respectively. A second connecting member, third and fourth connecting members having one ends fixed to the other two adjacent sides of the mask plate, and third and fourth connecting members provided at the other two adjacent sides of the frame, respectively. It is characterized by comprising first and second variable tension means for variably moving the other end of the fourth connecting member. Claim 6
In the mask device according to the fifth aspect of the present invention, the first variable tension means is rotatably provided on the frame, and the other end of the third connecting member is fixed.
A first winding roller for winding the connecting member, and a first actuator for driving the first winding roller to rotate. The second actuator is rotatably provided on the frame as second variable tension means. , The other end of the fourth connecting member is fixed,
And a second actuator that drives the second winding roller to rotate. The invention according to claim 7 is the mask device according to claim 5, wherein the first variable tension means is movably provided on the frame.
A first slider to which the other end of the third connecting member is fixed, and a first actuator for moving the first slider, wherein the first slider is movable to the frame as second variable tension means. It is provided with a second slider provided and the other end of the fourth connecting member is fixed, and a second actuator for moving the second slider.

The invention according to claim 8 is another mask device for cream solder printing which solves the above-mentioned problem, wherein the mask plate for cream solder printing corresponding to a substrate to be printed, a frame, and the mask plate are provided. It is characterized by comprising a compression force variable applying means for connecting the frame and the mask plate to variably apply a compression force to the mask plate. According to a ninth aspect of the present invention, in the mask apparatus according to the eighth aspect, the mask plate is made of a metal material such as (1) a SUS (stainless steel) material, or (2) a polyvinyl chloride, polyethylene, polyimide, polyamide, or the like. It is characterized by being formed of any one of a resin material and (3) a rubber-based elastic material such as polyurethane. According to a tenth aspect of the present invention, in the mask device of the eighth aspect, the mask plate is formed of the same material as a base material included in the substrate. According to an eleventh aspect of the present invention, in the mask apparatus according to the eighth aspect, the mask plate is formed so as to be enlarged with respect to a design dimension of the substrate, and a change rate of the mask plate is estimated in an elongation direction expected for the substrate. Is larger than the maximum rate of change. According to a twelfth aspect of the present invention, in the mask device according to the eighth aspect, the first and second sides of the mask plate connecting the two adjacent sides of the mask plate and the two adjacent sides of the frame body as the variable compressive force applying means. 2 connecting means;
Third and fourth connecting members, one ends of which are fixed to the other two adjacent sides of the mask plate, and the third and fourth connecting members provided on the other two adjacent sides of the frame, respectively. It is characterized by comprising first and second variable compression means for pressing the other end variably. According to a thirteenth aspect of the present invention, in the mask device of the twelfth aspect, the first variable compression means is movably provided on the frame, and the other end of the third connecting member is fixed. A first slider and a first actuator for moving the first slider are provided. The second slider is movably provided on the frame as second variable compression means. It is characterized by including a fixed second slider and a second actuator for moving the second slider.

According to a fourteenth aspect of the present invention, there is provided a cream solder printing method for solving the above-mentioned problems. In the method of printing cream solder on a substrate using a mask plate, the method is provided on the substrate for positioning the mask plate. The size between the target marks is measured, the mask plate is deformed so as to substantially match the measured size between the target marks, and cream solder is printed using the deformed mask plate.

According to a fifteenth aspect, in the cream solder printing method according to the fourteenth aspect, the mask device according to any one of the first to seventh aspects is used as the mask plate, and the tensile force of the mask device is used. The mask plate is deformed by the variable applying means. According to a sixteenth aspect of the present invention, in the cream solder printing method according to the fourteenth aspect, the mask device according to any one of the eighth to thirteenth aspects is used as the mask plate, and the compressive force variable imparting means of the mask device is provided. The mask plate is deformed by the method. The invention according to claim 17 is the cream solder printing method according to any one of claims 14 to 16,
The dimensions of the deformed mask plate are measured, and the mask plate is deformed so as to eliminate the difference between the measured dimension of the mask plate and the measured dimension between the target marks.

The invention according to claim 18 is the cream solder printing method according to claim 14, wherein the mask plate is deformed by heating according to the measured size between the target marks. According to a nineteenth aspect of the present invention, in the cream solder printing method according to the fourteenth aspect, the mask plate is deformed by cooling according to the measured size between the target marks. According to a twentieth aspect of the present invention, in the cream solder printing method according to the fourteenth aspect, the measurement between the target marks is performed by using a high-temperature heat storage tank having a higher temperature and a low-temperature heat storage tank having a lower temperature than the work environment of the cream solder printing. One of the heat storage tanks is selected based on the dimensions, and the mask plate is inserted into the selected heat storage tank to deform the mask plate. According to a twenty-first aspect of the present invention, in the cream solder printing method according to the twentieth aspect, a time for keeping the mask plate in the heat storage tank is set based on the measured dimension between the target marks. Things. The invention according to claim 22 is the cream solder printing method according to claim 20, wherein a plurality of heat storage tanks having different temperatures are used as the high-temperature heat storage tank and the low-temperature heat storage tank, respectively. .

According to a twenty-third aspect of the present invention, there is provided another cream solder printing method for solving the above-mentioned problems. In the method of printing cream solder on a substrate by using a mask plate, the base material contained in the substrate may be used as the mask plate. A mask plate made of the same material and given the same thermal history as the substrate is used.

According to a twenty-fourth aspect of the present invention, there is provided another cream solder printing method for solving the above-mentioned problems. In the method of printing cream solder on a substrate using a mask plate, the method is slightly shifted from a design dimension of the substrate. In addition, a plurality of mask plates prepared with different sizes from each other are prepared, and dimensions between target marks provided on the substrate for alignment of the mask plates are measured, and according to the measured dimensions between the target marks. One of the plurality of mask plates is selected, and cream solder is printed using the selected mask plate.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an outline of cream solder printing and an external view of a mask device. FIG. 2 is a plan view showing an example of the configuration of a mask device having a variable tensile force applying means.
FIG. 4 is a view for explaining an example of actual measurement of a dimension, FIG. 4 is a plan view showing another configuration example of a mask device having a variable tensile force applying means, and FIG.
Is a plan view showing a configuration example of a mask device having a variable compression force applying means, and FIG. 6 is a view showing an example in which a mask plate is deformed by temperature.

[First Embodiment] A first embodiment of the present invention will be described with reference to FIGS. In this example, as shown in FIG. 1, cream solder 20 is printed on a substrate 10 to be printed using a squeegee 30 and a mask device 40. The mask device 40 includes a mask plate 50, a frame body 60, and a variable tensile force applying means 70.

As shown in FIG. 3, four target marks 11, 12, 13, and 14 for positioning the mask plate 50 are formed on the component mounting surface of the substrate 10.

The mask plate 50 has a large number of through holes corresponding to the print target portions (lands) of the substrate 10. The outer shape of the mask plate 50 may be larger or smaller than the outer shape of the substrate 10, but in this example, it is made smaller and is formed in a rectangular shape (rectangle or square).

The mask plate 50 has a substrate 10
As shown in FIG. 2, four target marks 11, 12, 13, and 14 are used for alignment with the substrate 10.
One target mark 51, 52, 53, 54 is formed.

Since the deformation of the substrate 10 is usually in the elongation direction in many cases, if the mask plate 50 is manufactured according to the design dimensions of the substrate 10, the mask plate 5
0 can be extended to match the deformation of the substrate 10.

However, in the present embodiment, the mask plate 50 is made smaller than the design size of the substrate 10 in consideration of the deformation of the substrate 10 in the shrinking direction including the manufacturing error. At this time, the rate of change is greater than the maximum rate of change in the shrinkage direction expected for the substrate 10.

The mask plate 50 is thin, and its material is
A metal material such as SUS (stainless steel) that is usually used may be used, but since it is deformed by tension, the same material as the base material included in the substrate, or a resin material such as polyvinyl chloride, polyethylene, polyimide, polyamide, etc. ,
Alternatively, it can be formed of a rubber-based elastic material such as polyurethane.

The frame body 60 has an opening 61 larger than the outer shapes of the substrate 10 and the mask plate 50. In this example, both the inner shape and the outer shape of the frame body 60 are rectangular.

The variable tensile force applying means 70 connects the mask plate 50 and the frame 60, and
, And a structural example thereof will be described below with reference to FIG.

In FIG. 2, the variable pulling force applying means 70 includes four connecting members 71, 72, 73, 74, two winding rollers 75, 76, and two motors (for example, stepping motors) 77, 78. , Four gears 79 for reduction,
80, 81, and 82.

The four connecting members 71, 72, 73, 74 are respectively composed of connecting plates 71a, 72a, 73a, 74a and adhesives 71b, 72b, 73b, 74b. The two connecting plates 71a and 73a are arranged along the X direction in the figure, and the other two connecting plates 72a and 74a are arranged along the Y direction orthogonal to the two connecting plates.

The two connecting members 71 and 72 are connected to two adjacent orthogonal sides of the mask plate 50 and the adjacent orthogonal two sides of the frame 60.
Connect the sides. At this time, the connecting plate 71a is perpendicular to the mask plate 50 and the frame body 60, and both ends are adhered and fixed to them with an adhesive 71b. The connecting plate 72a is perpendicular to the connecting plate 71a, and both ends are fixed to the mask plate 50 and the frame 60 with an adhesive 72b.

The other two connecting members 73 and 74 connect the two adjacent orthogonal sides of the mask plate 50 and the two winding rollers 75 and 76, respectively. At this time, the two take-up rollers 75, 76 are rotatably mounted on other adjacent two orthogonal sides of the frame body 60 by appropriate bearing means, and are orthogonal to each other. Also, the connecting plate 73a is parallel to the connecting plate 71a, is perpendicular to the mask plate 50 and the take-up roller 75, and has both ends attached to the adhesive 73b.
It is pasted and fixed. The connecting plate 74a is connected to the connecting plate 73a.
, And both ends are adhered and fixed to the mask plate 50 and the take-up roller 76 with an adhesive 74b.

Gears 79, 8 are provided on each of the winding rollers 75, 76.
0 are attached, and gears 81 and 82 meshing with these are attached to the respective motors 77 and 78.

When the take-up roller 75 is rotated at a reduced speed in the take-up direction by the motor 77 via the gears 79 and 81, the take-up roller 75 takes up the connecting plate 73a and pulls the other end variably. Accordingly, the tensile force in the X direction applied to the mask plate 50 changes according to the rotation amount or the rotation angle of the motor 77, and the mask plate 50 is variably deformed (extended) in that direction. Therefore, the motor 77 and the gears 79, 8
Numeral 0 designates a rotary actuator for the take-up roller 75, and this actuator and the connecting members 71 and 73 constitute variable tension means for the mask plate 50 in the X direction.

When the take-up roller 76 is decelerated and rotated in the take-up direction by the motor 78 via the gears 80 and 82, the take-up roller 76 takes up the connecting plate 74a and pulls the other end variably. . Accordingly, the tensile force in the Y direction applied to the mask plate 50 changes according to the rotation amount or the rotation angle of the motor 78, and the mask plate 50 is variably deformed (extended) in that direction. Therefore, the motor 78 and the gear 8
Numerals 1 and 82 constitute a rotary actuator for the take-up roller 76, and this actuator and the connecting members 72 and 7
4 constitutes a variable tension means for the mask plate 50 in the Y direction.

When the above-described mask device 40 is used, the cream solder 20 is printed on the substrate 10 as follows. (1) First, the target marks 11, 12, 13, 13 on the substrate 10 are recognized by an appropriate recognition device used in the cream solder printing machine, for example, a recognition device 90 having a camera 91 and a control device 92 as shown in FIG. Fourteen pieces of position information are acquired, and at the same time, the size between target marks is actually measured. For example, a dimension between the target marks 11 and 12 (dimension in the X direction) and a dimension between the target marks 11 and 14 (dimension in the Y direction) are actually measured. The measured values at this time are Lp ₁₂ and Lp ₁₄ . The deformation of the substrate is usually about 0.2 mm per 100 mm. (2) Next, the rotation of the motors 77 and 78 is controlled by the control device 92 to change the tensile force in each of the X and Y directions with respect to the mask plate 50, and the actual measured value Lp ₁₂ between target marks is calculated.
Lp ₁₄ , target mark 5 of mask plate 50
The mask plate 50 is deformed so that the dimension between the target marks 1 and 52 and the dimension between the target marks 51 and 54 substantially match each other. (3) The position information of the target marks 51, 52, 53, 54 of the mask plate 50 thus deformed is acquired by the recognition device 90, and the target marks 11, 12, 13, 14 of the substrate 10 acquired earlier are acquired. Using the positional information, the mask plate 50 is positioned on the substrate 10 and the cream solder 20 is printed. The positioning means is an existing means, and the positioning is performed by the mask frame moving means and the substrate moving means. (4) As a result, since the mask plate 50 is also deformed in accordance with the deformation of the substrate 10, printing misregistration hardly occurs.

Actual measured value Lp between target marks₁₂, L
p₁₄The mask plate 50 so as to match
Can take any method, but here
The following four methods 1 to 4 will be exemplified. (i) Method 1: Rotation amount (or rotation angle) of motors 77 and 78
The relationship between the mask plate 50 and the dimensions of the mask plate 50 is determined in advance.
Because of this relationship, the target of the substrate 10 can be
Actual measured value between marks Lp₁₂, Lp₁₄Rotation equivalent to
Is obtained by the control device 92, and the motors 77 and 78 are
Control rolling. (ii) Method 2: Rotation amount (or rotation angle) of motors 77 and 78
And the relationship between the dimensional change amount of the mask plate 50 and
In advance, the design dimension Lpo between the target marks on the substrate 10
₁₂, Lpo₁₄And actual measured value Lp₁₂, Lp₁₄ΔL
p₁₂, ΔLp₁₄Is obtained by the control device 92, and whether
The dimensional change ΔLp of the substrate 10₁₂, ΔLp ₁₄Equivalent to
The amount of rotation is determined by the control device 92, and the motor 77,
78 is rotationally controlled. (iii) Method 3: The amount of rotation (or rotation) of the motors 77 and 78
Angle) and the dimensional change rate of the mask plate 50 in advance.
Determine the design dimensions between target marks on the substrate 10
Lpo₁₂, Lpo₁₄Actual measured value Lp for₁₂, Lp₁₄Strange
Conversion rate Lp₁₂/ Lpo₁₂, Lp₁₄/ Lpo₁₄With the control device 92
From the above relationship, the dimensional change rate Lp₁₂/
Lpo₁₂, Lp₁₄/ Lpo₁₄The amount of rotation corresponding to
2 and the rotation of the motors 77 and 78 is controlled accordingly.
In this method 3, the mask plate 50 is designed to have the design dimensions of the substrate 10.
It is effective when manufactured as follows. (iv) Method 4: Mask plate by any of the above methods 1 to 3
After deforming 50, the dimensions of the deformed mask plate 50
Method using target marks 51, 52, 53, 54
And measure it. Specifically, the target marks 51, 5
2 and the actual size between the target marks 51 and 54
Measure. Then, these mask plate dimension actual measurement values L
m₁₂, Lm₁₄Dimension between the target mark and the substrate 10
Lp₁₂, Lp₁₄Motors 77 and 7 until the difference with
The rotation of 8 is controlled to deform the mask plate 50.

[Second Embodiment] Next, a second embodiment of the present invention will be described with reference to FIG. In this example, a mask device 40A shown in FIG. 4 is used instead of the mask device 40 shown in FIG. The mask device 40A is different from the mask device 40 in that a variable pulling force applying unit 70A is configured using sliders 93 and 94 instead of the winding roller.

As shown in FIG. 4, the mask device 40A of this embodiment has a mask plate 50, a frame 60, and a variable tension applying means 70A. And the frame body 60, and a tensile force is variably applied to the mask plate 50.

The variable tensile force applying means 70A includes four connecting members 71, 72, 73, 74 and two sliders 93, 9
4 and two linearly driven actuators 95 and 96. The actuators 95 and 96 can be composed of, for example, a stepping motor and a feed screw mechanism.

The four connecting members 71, 72, 73, 74 are connected to connecting plates 71a, 72a, 73a,
74a and adhesives 71b, 72b, 73b, 74b. The two connecting plates 71a and 73a are arranged along the X direction in the figure, and the other two
Two connecting plates 72a and 74a are arranged.

The two connecting members 71 and 72 connect two adjacent orthogonal sides of the mask plate 50 and two adjacent orthogonal sides of the frame body 60 as in FIG. At this time, the connecting plate 71a is perpendicular to the mask plate 50 and the frame body 60, and both ends are adhered and fixed to them with an adhesive 71b. The connecting plate 72a is perpendicular to the connecting plate 71a, and both ends are fixed to the mask plate 50 and the frame 60 with an adhesive 72b.

The other two connecting members 73 and 74 are connected to the other adjacent two sides of the mask plate 50 and the two sliders 9.
3 and 94 are respectively connected. At this time, the two sliders 93 and 94 are slidable by appropriate guide means on the other adjacent two orthogonal sides of the frame body 60, respectively, and are installed orthogonal to each other. The connecting plate 73a is parallel to the connecting plate 71a, is perpendicular to the mask plate 50 and the slider 93, and is fixed to both ends thereof with an adhesive 73b. The connecting plate 74a is perpendicular to the connecting plate 73a, and both ends are fixed to the mask plate 50 and the slider 94 with an adhesive 74b.

Actuators 95 and 96 are connected to the sliders 93 and 94, respectively.

When the slider 93 is moved toward the mask plate 50 side by the actuator 95, the slider 93 is moved.
Pulls the connecting plate 73a variably. This allows
The tensile force applied to the mask plate 50 in the X direction changes according to the amount of driving of the actuator 95, and the mask plate 50 variably deforms (extends) in that direction. Therefore, the actuator 95 and the connecting members 71 and 73 constitute variable tension means in the X direction with respect to the mask plate 50.

Similarly, when the actuator 94 moves the slider 94 toward the mask plate 50 side, the slider 94 pulls the connecting plate 74a variably. Accordingly, the tensile force in the Y direction applied to the mask plate 50 changes according to the amount of movement of the actuator 96, and the mask plate 50 is variably deformed (extended) in that direction. Therefore, the actuator 96 and the connecting members 72 and 74 constitute a variable tension means for the mask plate 50 in the Y direction.

When using the mask device 40A described above,
The cream solder 20 is printed on the substrate 10 as follows. (1) First, the target marks 11, 12, 13, 13 on the substrate 10 are recognized by an appropriate recognition device used in the cream solder printing machine, for example, a recognition device 90 having a camera 91 and a control device 92 as shown in FIG. Fourteen pieces of position information are acquired, and at the same time, the size between target marks is actually measured. For example, a dimension between the target marks 11 and 12 (dimension in the X direction) and a dimension between the target marks 11 and 14 (dimension in the Y direction) are actually measured. The measured values at this time are Lp ₁₂ and Lp ₁₄ . The deformation of the substrate is usually about 0.2 mm per 100 mm. (2) Next, the actuators 95 and 9 are
6 is changed to change the tensile force in each of the X and Y directions with respect to the mask plate 50, and the actual measured value L between the target marks is changed.
The dimensions between the target marks 51 and 52 of the mask plate 50 and the target marks 51 and 54 are added to p ₁₂ and Lp _14.
The mask plate 50 is deformed such that the dimensions therebetween substantially match. (3) The position information of the target marks 51, 52, 53, 54 of the mask plate 50 thus deformed is acquired by the recognition device 90, and the target marks 11, 12, 13, 14 of the substrate 10 acquired earlier are acquired. Using the positional information, the mask plate 50 is positioned on the substrate 10 and the cream solder 20 is printed. The positioning means is an existing means, and the positioning is performed by the mask frame moving means and the substrate moving means. (4) As a result, since the mask plate 50 is also deformed in accordance with the deformation of the substrate 10, printing misregistration hardly occurs.

Actual measured values between target marks Lp ₁₂ , Lp
To deform the mask plate 50 to match the p _14, including four methods 1 to 4 described in the first embodiment, it is possible to employ any method.

[Third Embodiment] Next, a third embodiment of the present invention will be described with reference to FIG. In this example, a mask device 40B shown in FIG. 5 is used instead of the mask device 40A shown in FIG. The mask device 40B has a structure in which the variable tension applying means 70A pulls the sliders 93 and 94, whereas the variable masking device 40A uses the variable compressing force applying means 70B for pressing the sliders 93 and 94. different.

As shown in FIG. 5, the mask device 40B of this embodiment includes a mask plate 50, a frame body 60, and a variable compression force applying means 70B. And the frame body 60 and variably apply a compressive force to the mask plate 50.

The variable compression force applying means 70B has the same configuration as the variable tension force applying means 70A shown in FIG. 4, and includes four connecting members 71, 72, 73, 74, two sliders 93, 94, Two linear drive actuators 9
5, 96 are provided. Actuators 95, 9
6 can be composed of, for example, a stepping motor and a feed screw mechanism.

The four connecting members 71, 72, 73, 74 are connected to connecting plates 71a, 72a, 7
3a, 74a and adhesives 71b, 72b, 73b, 74
b. The two connecting plates 71a and 73a are arranged along the X direction in the figure, and along the Y direction
The other two connecting plates 72a and 74a are arranged.

The two connecting members 71 and 72 are adjacent to each other at the right angle of the mask plate 50 as in FIGS.
The side and two adjacent orthogonal sides of the frame body 60 are connected.
At this time, the connecting plate 71a is perpendicular to the mask plate 50 and the frame body 60, and both ends are adhered and fixed to them with an adhesive 71b. The connecting plate 72a is perpendicular to the connecting plate 71a, and both ends are fixed to the mask plate 50 and the frame 60 with an adhesive 72b.

The other two connecting members 73 and 74 are connected to the other two adjacent orthogonal sides of the mask plate 50 as in FIG.
The two sliders 93 and 94 are respectively connected. At this time, the two sliders 93 and 94 are slidable by appropriate guide means on the other adjacent two orthogonal sides of the frame body 60, respectively, and are installed orthogonal to each other. The connecting plate 73a is parallel to the connecting plate 71a, is perpendicular to the mask plate 50 and the slider 93, and is fixed to both ends thereof with an adhesive 73b. Connecting plate 74a
Are perpendicular to the connecting plate 73a, and are fixed at both ends to the mask plate 50 and the slider 94 with an adhesive 74b.

Actuators 95 and 96 are connected to the sliders 93 and 94, respectively.

When the slider 93 is moved toward the mask plate 50 by the actuator 95, the slider 93 urges the connecting plate 73a variably. This allows the mask plate 5 to be driven in accordance with the driving amount of the actuator 95.
0, the compressive force in the X direction changes, and the mask plate 5
0 variably deforms (shrinks) in that direction. Therefore, the actuator 95 and the connecting members 71 and 73 constitute variable compression means in the X direction with respect to the mask plate 50.

Similarly, when the slider 94 is moved by the actuator 96, the slider 94 urges the connecting plate 74a variably. Thereby, the actuator 9
The compressive force in the Y direction applied to the mask plate 50 changes according to the drive amount of 6, and the mask plate 50 variably deforms (shrinks) in that direction. Therefore, the actuator 96 and the connecting members 72 and 74 constitute variable compression means for the mask plate 50 in the Y direction.

When using the above-described mask device 40B,
The cream solder 20 is printed on the substrate 10 as follows. (1) First, the target marks 11, 12, 13, 13 on the substrate 10 are recognized by an appropriate recognition device used in the cream solder printing machine, for example, a recognition device 90 having a camera 91 and a control device 92 as shown in FIG. Fourteen pieces of position information are acquired, and at the same time, the size between target marks is actually measured. For example, a dimension between the target marks 11 and 12 (dimension in the X direction) and a dimension between the target marks 11 and 14 (dimension in the Y direction) are actually measured. The measured values at this time are Lp ₁₂ and Lp ₁₄ . The amount of deformation of the substrate is, for example, about 0.2 mm per 100 mm. (2) Next, the actuators 95 and 9 are
6 to change the compressive force in each of the X and Y directions on the mask plate 50 to obtain the actual measured value L between the target marks.
The dimensions between the target marks 51 and 52 of the mask plate 50 and the target marks 51 and 54 are added to p ₁₂ and Lp _14.
The mask plate 50 is deformed such that the dimensions therebetween substantially match. (3) The position information of the target marks 51, 52, 53, 54 of the mask plate 50 thus deformed is acquired by the recognition device 90, and the target marks 11, 12, 13, 14 of the substrate 10 acquired earlier are acquired. Using the positional information, the mask plate 50 is positioned on the substrate 10 and the cream solder 20 is printed. The positioning means is an existing means, and the positioning is performed by the mask frame moving means and the substrate moving means. (4) As a result, since the mask plate 50 is also deformed in accordance with the deformation of the substrate 10, printing misregistration hardly occurs.

Actual measured value Lp between target marks₁₂, L
p₁₄The mask plate 50 so as to match
Can take any method, but here
The four methods 1 to 4 are exemplified. (i) Method 1: Driving amount and mass of actuators 95 and 96
It is necessary to determine the relationship with the dimensions of the plate 50 in advance.
From this relationship, the target marker of the substrate 10 can be obtained.
Actual dimension Lp₁₂, Lp₁₄Drive amount equivalent to
With the device 92, the actuators 95 and 96 are
Control. (ii) Method 2: Driving amount and mass of actuators 95 and 96
The relationship with the dimensional change of the plate 50 is determined in advance.
The design dimension Lpo between the target marks on the substrate 10 ₁₂,
Lpo₁₄And actual measured value Lp₁₂, Lp₁₄ΔL
p₁₂, ΔLp₁₄Is obtained by the control device 92, and whether
The dimensional change ΔLp of the substrate 10₁₂, ΔLp₁₄Equivalent to
Controller 92 determines the amount of drive to be performed, and the actuator
Control the data 95 and 96. (iii) Method 3: Driving amounts of actuators 95 and 96 and
The relationship with the dimensional change rate of the plate 50 is determined in advance.
The design dimension Lpo between the target marks on the substrate 10₁₂,
Lpo₁₄Actual measured value Lp for₁₂, Lp₁₄Of change Lp
₁₂/ Lpo₁₂, Lp ₁₄/ Lpo₁₄Is obtained by the controller 92, and
From the above relationship, the dimensional change rate Lp of the substrate 10 ₁₂/ Lpo₁₂,
Lp₁₄/ Lpo₁₄Is calculated by the control device 92.
Therefore, the actuators 95 and 96 are controlled accordingly. This
Method 3 is to pass the mask plate 50 through the design dimensions of the substrate 10.
It is effective when it is manufactured in advance. (iv) Method 4: Mask plate by any of the above methods 1 to 3
After deforming 50, the dimensions of the deformed mask plate 50
Method using target marks 51, 52, 53, 54
And measure it. Specifically, the target marks 51, 5
2 and the actual size between the target marks 51 and 54
Measure. Then, these mask plate dimension actual measurement values L
m₁₂, Lm₁₄Dimension between the target mark and the substrate 10
Lp₁₂, Lp₁₄Until the difference with
By controlling 95 and 96, the mask plate 50 is deformed.
You.

Since the deformation of the substrate 10 is usually in the elongation direction, the mask plate 50 is made larger than the design size of the substrate 10 in this embodiment, including the manufacturing error of the substrate 10. At this time, the change rate is larger than the maximum change rate in the elongation direction expected for the substrate 10.

Since the material of the mask plate 50 is deformed by compression, any material may be used as long as it does not buckle under compression even if it is a thin plate, and a metal material such as a commonly used SUS (stainless) material, or , The same material as the substrate that the substrate contains, or polyvinyl chloride or polyethylene,
It can be formed of a resin material such as polyimide or polyamide, or a rubber-based elastic material such as polyurethane. A mask plate 50 formed using a polyimide resin material or a polyamide resin material can be applied to a cream solder printing method when a substrate including the same material as the mask plate 50 (polyimide resin material or polyamide resin material) as a base material is used. Particularly suitable.

[Fourth Embodiment] Next, a fourth embodiment of the present invention will be described with reference to FIG. In this example, when cream solder is printed on the substrate by the mask plate 50, target marks provided on the substrate for positioning the mask plate 50 (see 11 to 14 in FIG. 3 and the like)
The dimension between the target marks is measured, the mask plate 50 is deformed by heating or cooling so as to substantially match the measured dimension between the target marks, and cream solder is printed using the deformed mask plate. As a result, since the mask plate 50 is also deformed in accordance with the deformation of the substrate, printing misregistration hardly occurs.

If necessary, the dimensions of the deformed mask plate are measured, and the mask plate is deformed by heating or cooling so that there is no difference between the measured dimensions of the mask plate and the measured dimensions between the target marks.

A large number of through holes are formed in the mask plate 50 so as to correspond to portions (lands) to be printed on the substrate. In addition, a plurality of target marks (see 51 to 54 in FIG. 2 and the like) are formed on the mask plate 50 so as to correspond to the plurality of target marks on the substrate.

Usually, the deformation of the substrate is often in the elongation direction, but the mask plate 50 is manufactured according to the design dimensions of the substrate in consideration of the deformation in the contraction direction including the manufacturing error.

The mask plate 50 is thin, and its material is
A metal material such as SUS (stainless steel) which is usually used may be used, but the same material as the base material such as glass epoxy resin, polyimide resin, polyamide resin or the like contained in the substrate, or a resin material such as polyvinyl chloride or polyethylene is used. It is possible to form.

In the example shown in FIG.
20 ° C considering that it is about 0.2mm per 0mm
It is assumed that cream solder printing is performed at a room temperature of 22.5 ° C. using a mask plate 50 that expands and contracts by about 0.4% between the temperature and 25 ° C. Therefore, using a high-temperature heat storage tank 100A at 25 ° C. higher than the working environment temperature and a low-temperature heat storage tank 100B at 20 ° C. lower than the working environment temperature, the target of the substrate is recognized by the recognition device 90 (camera 91 and control device 92) shown in FIG. The position information of the mark is acquired, and at the same time, the dimension between the target marks is actually measured. For example, a dimension (dimension in the X direction) between a pair of target marks is actually measured. The measured value at this time is Lp _12.

The actual measured value Lp _{12 of the} dimension between target marks
, One of the heat storage tanks is selected, the mask plate 50 is put in the selected heat storage tank, deformed by heating or cooling, and then taken out and used for cream solder printing.

For example, the actual measured value L between the target marks L
p₁₂Is the design dimension Lpo between the target marks on the substrate.₁₂And ratio
Compare, Lp₁₂-Lpo₁₂If> δ, mask plate 50
Into a high-temperature heat storage tank 100A for a predetermined period of time
To extend the Lpo₁₂-Lp ₁₂If δ, low temperature heat storage tank
100B for a predetermined period of time, cool and shrink
Then remove it and use this deformed mask plate.
And print cream solder. Here, δ is set in advance
-Δ <Lp₁₂-Lpo₁₂<Δ
No heating or cooling is required.

[0071] Alternatively, depending on the target mark dimension between measured values Lp _12, for example, the difference between the target mark dimension between the measured value Lp ₁₂ and its design dimensions Lpo ₁₂ | Lp ₁₂ -Lpo ₁₂
| Or high-temperature storage tank 100A or low-temperature storage tank 10
By adjusting or controlling the time for which the mask plate 5 is kept in the mask plate 5B, the mask plate 5 can be adjusted so as to conform to the deformation of the substrate.
0 can be finely transformed.

[0072] Alternatively, different temperatures of the hot thermal storage tank together preparing a plurality also prepared a plurality cold heat storage tank of different temperatures, depending on the target mark dimension between measured values Lp _12, or the dimension measured between the target mark Depending on the difference Lp ₁₂ −Lpo ₁₂ between the value Lp ₁₂ and its design dimension Lpo ₁₂ , one of the heat storage tanks is selected and inserted for a predetermined period of time to expand and contract by heating or cooling, thereby deforming the substrate. The mask plate 50 can be finely deformed so as to more closely match.

The temperatures of the high-temperature heat storage tank and the low-temperature heat storage tank are not particularly limited as long as extremely high or low temperatures that adversely affect the properties of the cream solder are avoided.

[Other Embodiment: Part 1] Although not shown, a mask plate made of the same material as the base material included in the substrate and further given the same heat history as the substrate is used for cream soldering. Print. For example, in the case of a double-sided mounting substrate, the same heat history as the substrate is received in the manufacturing stage, such as hot pressing or etching, is given to the first surface mask plate on which the component mounting and reflow processing are performed first.
A mask plate for the second surface on which cream solder printing is performed after the reflow process on the first surface is given the same heat history as the reflow process on the first surface, such as through a reflow furnace, in addition to the heat history in the substrate manufacturing stage. Keep it. In this case, it is sufficient if both the mask plate for the first surface and the mask plate for the second surface are manufactured according to the design dimensions of the substrate.

By using the mask plate having the same material and the same thermal history as the substrate as described above, the change in the dimension between the target marks on the substrate and the variation in the dimension between the target marks on the mask plate always substantially match. Little deviation occurs. In this case, it is sufficient if both the mask plate for the first surface and the mask plate for the second surface are manufactured according to the design dimensions of the substrate.

[Other Embodiments: Part 2] Although not shown, the mask plate is slightly reduced or enlarged relative to the design dimension of the substrate within the expected maximum deformation range in the direction of extension and contraction of the substrate. A plurality of mask plates having different dimensions are prepared. The dimensions between the target marks provided on the substrate for mask plate alignment are measured, and one of the plurality of mask plates having the dimension closest to the measured dimension between the target marks is selected. Print cream solder using plate.

In this case, since the dimension between target marks on the substrate to be printed and the dimension between target marks on the selected mask plate always substantially coincide with each other, printing deviation hardly occurs.

[0078]

As described above, according to the present invention,
Since the size of the mask plate substantially matches the size of the deformed substrate, printing displacement of the cream solder hardly occurs. Therefore, it is possible to prevent a decrease in mounting accuracy at the time of mounting components after printing the cream solder. Further, mounting defects after reflow (part standing, part displacement, missing parts, solder bridges, foot lifting, etc.) can be avoided.

[Brief description of the drawings]

FIG. 1 is a diagram showing an outline of cream solder printing and an appearance of a mask device as a first embodiment of the present invention.

FIG. 2 is a plan view showing a configuration example of a mask device having a variable tensile force applying means.

FIG. 3 is a view for explaining an example of actual measurement of dimensions.

FIG. 4 is a plan view showing another configuration example of a mask device having a variable tensile force applying means as a second embodiment of the present invention.

FIG. 5 is a plan view showing a configuration example of a mask device having a variable compression force applying means as a third embodiment of the present invention.

FIG. 6 is a view showing an example in which a mask plate is deformed at a temperature as a fourth embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 substrate 11 to 14 target mark 20 cream solder 30 squeegee 40, 40A mask device (with variable tensile force applying means) 40B mask device (with variable compressive force applying device) 50 mask plate 51 to 54 target mark 60 frame 61 opening 70, 70A Variable tensile force applying means 70B Variable compressive force applying means 71-74 Connecting member 71a-74a Connecting plate 71b-74b Adhesive 75, 76 Take-up roller 77, 78 Motor 79-82 Gear 90 Recognition device 91 Camera 92 Control Apparatus 93, 94 Slider 95, 96 Actuator 100A High-temperature heat storage tank 100B Low-temperature heat storage tank

Claims (24)

[Claims] 1. A mask plate for cream solder printing corresponding to a substrate to be printed, a frame, and a variable pulling force for connecting the mask plate and the frame and variably applying a pulling force to the mask plate. A mask device comprising an application means. 2. The mask device according to claim 1, wherein
The mask plate may be made of any one of (1) a metal material such as SUS (stainless steel), (2) a resin material such as polyvinyl chloride, polyethylene, polyimide, and polyamide, and (3) a rubber-based elastic material such as polyurethane. A mask device characterized by being formed of a material. 3. The mask apparatus according to claim 1, wherein
The mask device, wherein the mask plate is formed of the same material as a base material included in the substrate. 4. The mask device according to claim 1, wherein
The mask apparatus according to claim 1, wherein the mask plate is manufactured to be smaller than a design dimension of the substrate, and a rate of change thereof is larger than a maximum rate of change in a shrinking direction expected for the substrate. 5. The mask device according to claim 1, wherein
First and second connecting members for connecting the adjacent two sides of the mask plate and the adjacent two sides of the frame body respectively as the tensile force variable applying means, and one end portions on the other adjacent two sides of the mask plate, respectively. Are fixed to the third and fourth connecting members, respectively, and the first and second connecting members are provided on the other two adjacent sides of the frame, respectively, and the other ends of the third and fourth connecting members are movably pulled. A mask device comprising: two variable tension means. 6. The mask device according to claim 5, wherein
A first take-up roller that is rotatably provided on the frame body, the other end of the third connection member is fixed, and takes up the third connection member, as first variable tension means; A first actuator that rotationally drives one take-up roller;
As a second variable tension means, a second winding roller rotatably provided on the frame body, the other end of the fourth connecting member being fixed, and winding the fourth connecting member; A mask device comprising: a second actuator that rotationally drives the second winding roller. 7. The mask device according to claim 5, wherein
As a first variable tension means, a first slider movably provided on the frame body and having the other end of the third connecting member fixed thereto, and a first actuator for moving the first slider A second slider provided movably on the frame as a second variable tension means, the other end of the fourth connecting member being fixed, and a second slider for moving the second slider. A mask device comprising the above-mentioned actuator. 8. A mask plate for cream solder printing corresponding to a substrate to be printed, a frame, and a variable compression force for connecting the mask plate and the frame and variably applying a compression force to the mask plate. A mask device comprising an application means. 9. The mask device according to claim 8, wherein
The mask plate may be made of any one of (1) a metal material such as SUS (stainless steel), (2) a resin material such as polyvinyl chloride, polyethylene, polyimide, and polyamide, and (3) a rubber-based elastic material such as polyurethane. A mask device characterized by being formed of a material. 10. The mask apparatus according to claim 8, wherein the mask plate is formed of the same material as a base material included in the substrate. 11. The mask apparatus according to claim 8, wherein the mask plate is manufactured by enlarging with respect to a design dimension of the substrate, and a change rate of the mask plate is a maximum change rate in an elongation direction expected for the substrate. A mask device characterized by being larger than the mask device. 12. The mask device according to claim 8, wherein the first and second connecting means connect the adjacent two sides of the mask plate and the adjacent two sides of the frame, respectively, as the compressive force variable applying means. And third and fourth connecting members having one ends fixed to the other two adjacent sides of the mask plate, respectively, and provided on the other two adjacent sides of the frame,
A mask apparatus comprising first and second variable compression means for variably moving the other end of the third and fourth connecting members. 13. The mask device according to claim 12, wherein the first variable compression means is provided movably on the frame, and the other end of the third connecting member is fixed to the first slider. A first actuator for moving the first slider, a second variable compression means movably provided on the frame, and a fourth connecting member to which the other end is fixed. A mask apparatus comprising: a second slider; and a second actuator that moves the second slider. 14. A method of printing cream solder on a substrate using a mask plate, wherein dimensions between target marks provided on the substrate for alignment of the mask plate are measured, and the measured dimensions between the target marks are substantially measured. A cream solder printing method, wherein the mask plate is deformed so as to conform to the above, and cream solder is printed using the deformed mask plate. 15. The cream solder printing method according to claim 14, wherein the mask plate according to any one of claims 1 to 7 is used as the mask plate, and the mask plate is deformed by a variable tensioning means of the mask device. A cream solder printing method characterized by being performed. 16. The cream solder printing method according to claim 14, wherein the mask device according to any one of claims 8 to 13 is used as the mask plate, and the mask plate is deformed by a compression force variably applying means of the mask device. A cream solder printing method characterized by being performed. 17. The cream solder printing method according to claim 14, wherein the dimension of the deformed mask plate is measured, and the difference between the measured dimension of the mask plate and the measured dimension between the target marks is eliminated. And a mask solder printing method, wherein the mask plate is deformed. 18. The cream solder printing method according to claim 14, wherein the mask plate is deformed by heating according to the measured size between the target marks. 19. The cream solder printing method according to claim 14, wherein the mask plate is deformed by cooling according to the measured size between the target marks. 20. The cream solder printing method according to claim 14, wherein a high-temperature heat storage tank having a higher temperature and a low-temperature heat storage tank having a lower temperature than the working environment of the cream solder printing are used.
Any one based on the measured dimension between the target marks
A cream solder printing method, wherein one of the heat storage tanks is selected, and the mask plate is deformed by placing the mask plate in the selected heat storage tank. 21. The cream solder printing method according to claim 20, wherein a time for keeping the mask plate in the heat storage tank is set based on the actually measured dimension between the target marks. . 22. The cream solder printing method according to claim 20, wherein a plurality of heat storage tanks having different temperatures are used as the high-temperature heat storage tank and the low-temperature heat storage tank, respectively. 23. A method of printing cream solder on a substrate by using a mask plate, wherein the mask plate is made of the same material as a base material included in the substrate and has the same thermal history as the substrate. A cream solder printing method characterized by using: 24. A method of printing cream solder on a substrate by using a mask plate, wherein a plurality of mask plates are prepared which are slightly shifted from a design size of the substrate and have different sizes from each other. The dimensions between target marks provided on the substrate for alignment of the target marks are measured, one of the plurality of mask plates is selected according to the measured dimensions between the target marks, and the cream is selected using the selected mask plate. A cream solder printing method characterized by printing solder.