JP2022047577A - Manufacturing method and manufacturing device for solder precoated board - Google Patents

Abstract

To provide a manufacturing method of a solder precoated substrate that can reduce the manufacturing cost.SOLUTION: A manufacturing method of a solder precoated substrate according to the present disclosure includes a supply step of supplying solder paste P to a plurality of lands 3, and a heating step of heating a substrate 1 such that the temperature of the plurality of lands 3 reaches the melting point of solder particles PL contained in the solder paste P faster than the surface temperature of the substrate 1 around the lands 3.SELECTED DRAWING: Figure 4

Description

The present disclosure relates to a method and an apparatus for manufacturing a solder precoated substrate.

Conventionally, a method of forming a solder precoat on a land of a substrate is known (for example, Patent Document 1). In the method of the same document, the opening of the mask is aligned with the land to cover the substrate, and then the solder paste is supplied to the opening to transfer the solder paste onto the land. A solder precoat is formed by melting the transferred solder paste.

Japanese Unexamined Patent Publication No. 7-302972

By the way, with the miniaturization of electronic components mounted on a substrate, the distance between adjacent lands tends to be shortened. When the distance between lands is short, by forming a solder precoat using a solder paste containing solder particles with a very small particle size, adjacent solder precoats can be connected to each other (hereinafter referred to as a bridge phenomenon). Can be prevented.

However, a solder paste containing solder particles having a small particle size is expensive, and its use leads to an increase in the manufacturing cost of a substrate on which a solder precoat is formed (hereinafter referred to as a solder precoated substrate). In such a situation, one of the purposes of the present disclosure is to provide a method for manufacturing a solder precoated substrate that can suppress the manufacturing cost.

One aspect of the present disclosure relates to a method of manufacturing a solder precoated substrate by forming a solder precoat on a plurality of lands provided on the surface of the substrate. The method for manufacturing the solder precoated substrate includes a supply step of supplying the solder paste to the plurality of lands, and the temperature of the plurality of lands is faster than the surface temperature of the substrate around the lands, and the solder paste contains the solder paste. The substrate is provided with a heating step of heating the substrate so as to reach the melting point of the solder particles.

Another aspect of the present disclosure relates to an apparatus for manufacturing a solder precoated substrate by forming a solder precoat on a plurality of lands provided on the surface of the substrate. In the solder precoat substrate manufacturing apparatus, the solder paste contains a supply unit that supplies the solder paste to the plurality of lands, and the temperature of the plurality of lands is faster than the surface temperature of the substrate around the lands. A heating unit for heating the substrate so as to reach the melting point of the solder particles is provided.

According to the present disclosure, a method and an apparatus for manufacturing a solder precoated substrate capable of suppressing the manufacturing cost can be obtained.

It is a front view which shows an example of the manufacturing apparatus of the solder precoated substrate of Embodiment 1. FIG. It is a side view which shows a part of the manufacturing apparatus of the solder precoated substrate of Embodiment 1. FIG. It is a side view which shows a part of the manufacturing apparatus of the solder precoated substrate of Embodiment 1. FIG. It is a schematic diagram for demonstrating the heating part and the heating process of Embodiment 1. FIG. It is a schematic diagram for demonstrating the heating part and the heating process of the modification of Embodiment 1. FIG. It is a perspective view which shows a part of the manufacturing apparatus of the solder precoated substrate of Embodiment 2. It is a schematic diagram for demonstrating the heating part and the heating process of Embodiment 2.

An example of a method for manufacturing a solder precoated substrate and an embodiment of a manufacturing apparatus according to the present disclosure will be described below. However, the present disclosure is not limited to the examples described below.

The method for manufacturing a solder precoated substrate according to the present disclosure is a method for manufacturing a solder precoated substrate by forming a solder precoat on a plurality of lands provided on the surface of the substrate, and the solder paste is supplied to the plurality of lands. A heating step of heating the substrate so that the temperature of the plurality of lands reaches the melting point of the solder particles contained in the solder paste, which is faster than the surface temperature of the substrate around the lands. To prepare for.

In the supply process, the solder paste is supplied to a plurality of lands provided on the surface of the substrate. Any method can be used as this supply method. For example, it is conceivable to supply the solder paste by a screen printing method, but the present invention is not limited to this.

In the heating step, when the substrate is heated, the temperature of the plurality of lands reaches the melting point of the solder particles contained in the solder paste, which is faster than the surface temperature of the surrounding substrate. As a result, the solder particles melt and gather on the surface of the land. Such melted and collected solder particles are referred to as solder melt nuclei in this disclosure. The solder melt nuclei grow by attracting the surrounding solder particles contained in the solder paste as the substrate is heated. In this way, the solder particles contained in the solder paste gather on the land, and the solder precoat formed thereafter also stays on the land. As a result, even when a solder paste containing solder particles having a large particle diameter is used, the occurrence of the bridging phenomenon can be suppressed.

Here, in the heating step, any heating method can be used. For example, the substrate may be heated using a reflow oven, a heating plate, or an induction heating device, but the present invention is not limited thereto.

In the heating step, the substrate may be heated more strongly from the back surface side of the substrate than from the front surface side of the substrate. As a result, the temperature of the plurality of lands rises faster than the surface temperature of the substrate around them. This is because the land made of metal has a higher thermal conductivity than the surrounding substrate, and strong heat from the back surface side of the substrate is relatively easily transferred.

In the heating step, the substrate may be heated only from the back surface side of the substrate. As a result, the temperature of the plurality of lands rises faster than the surface temperature of the substrate around them. This is because the land made of metal has a higher thermal conductivity than the surrounding substrate, and heat from the back surface side of the substrate is relatively easily transferred.

In the heating step, the substrate may be heated so that the temperature of the surface of the substrate rises at an increase rate of 4 ° C./sec or more. By raising the surface temperature of the substrate at such an increase rate, the occurrence of the bridge phenomenon can be further suppressed.

In the heating step, the substrate may be heated using a heating plate that contacts the back surface of the substrate. The heat of the heating plate is easily transferred to the land having high thermal conductivity. Therefore, the temperature of the land rises faster than the surface temperature of the substrate around it.

In the heating step, the substrate may be heated with the sheet sandwiched between the substrate and the heating plate. By sandwiching the sheet, it is possible to prevent the substrate from being damaged or soiled due to contact with the heating plate.

The sheet may be made of a material (eg, silicon) that is softer than the substrate and the heating plate. By deforming the soft sheet according to the surface shape of the substrate or the heating plate, the heat transfer property from the heating plate to the substrate can be improved.

In the heating step, the substrate may be heated while pressing the substrate at a plurality of places. As a result, it is possible to prevent the substrate from warping due to heating.

The method for manufacturing a solder precoated substrate may further include, after the heating step, a cooling step of cooling the substrate while pressing the substrate at a plurality of places. As a result, it is possible to prevent the substrate from warping due to cooling.

The solder precoated substrate manufacturing apparatus according to the present disclosure is an apparatus for manufacturing a solder precoated substrate by forming a solder precoat on a plurality of lands provided on the surface of the substrate, and supplies a solder paste to the plurality of lands. A heating unit that heats the substrate so that the temperature of the plurality of lands reaches the melting point of the solder particles contained in the solder paste, which is faster than the surface temperature of the substrate around the lands. To prepare for.

The supply unit supplies the solder paste to a plurality of lands provided on the surface of the substrate. Any one can be used as this supply unit. For example, it is conceivable to use a squeegee for screen printing, but the present invention is not limited to this.

By heating the substrate, the heating unit causes the temperature of the plurality of lands to reach the melting point of the solder particles contained in the solder paste faster than the surface temperature of the surrounding substrate. As a result, the solder particles melt and gather on the surface of the land to form a solder melt nucleus. The solder melt nuclei grow by attracting the surrounding solder particles contained in the solder paste as the substrate is heated. In this way, the solder particles contained in the solder paste gather on the land, and the solder precoat formed thereafter also stays on the land. As a result, even when a solder paste containing solder particles having a large particle diameter is used, the occurrence of the bridging phenomenon can be suppressed.

Here, any heating unit can be used. For example, a reflow oven, a heating plate, or an induction heating device may be used, but is not limited to these.

The heating unit may heat the substrate more strongly from the back surface side of the substrate than from the front surface side of the substrate. As a result, the temperature of the plurality of lands rises faster than the surface temperature of the substrate around them. This is because the land made of metal has a higher thermal conductivity than the surrounding substrate, and strong heat from the back surface side of the substrate is relatively easily transferred.

The heating unit may heat the substrate only from the back surface side of the substrate. As a result, the temperature of the plurality of lands rises faster than the surface temperature of the substrate around them. This is because the land made of metal has a higher thermal conductivity than the surrounding substrate, and heat from the back surface side of the substrate is relatively easily transferred.

The heating unit may heat the substrate so that the temperature of the surface of the substrate rises at a rate of increase of 4 ° C./sec or more. By raising the surface temperature of the substrate at such an increase rate, the occurrence of the bridge phenomenon can be further suppressed.

The heating unit may have a heating plate that comes into contact with the back surface of the substrate to heat the substrate. The heat of the heating plate is easily transferred to the land having high thermal conductivity. Therefore, the temperature of the land rises faster than the surface temperature of the substrate around it.

The solder precoated substrate manufacturing apparatus may further include a sheet sandwiched between the substrate and the heating plate when the substrate is heated. By sandwiching the sheet, it is possible to prevent the substrate from being damaged or soiled due to contact with the heating plate.

The solder precoated substrate manufacturing apparatus may further include a heating presser portion that presses the substrate at a plurality of locations when the substrate is heated. Such a presser foot during heating can prevent the substrate from warping due to heating.

The solder precoated substrate manufacturing apparatus may further include a cooling unit for cooling the heated substrate and a cooling pressing unit for pressing the substrate at a plurality of places when the substrate is cooled. With such a cooling presser portion, it is possible to prevent the substrate from warping due to cooling.

Hereinafter, an example of a method for manufacturing a solder precoated substrate and a manufacturing apparatus according to the present disclosure will be specifically described with reference to the drawings. The above-mentioned steps and components can be applied to the steps and components of the manufacturing apparatus of the method for manufacturing a solder precoated substrate described below. The process of the method for manufacturing the solder precoated substrate and the components of the manufacturing apparatus described below can be changed based on the above description. Further, the matters described below may be applied to the above-described embodiment. Among the steps of the method for manufacturing a solder precoated substrate and the components of the manufacturing apparatus described below, the steps and components that are not essential for the manufacturing method and manufacturing apparatus of the solder precoated substrate according to the present disclosure may be omitted.

<Embodiment 1>
The first embodiment of the present disclosure will be described. First, the configuration of the solder precoated substrate manufacturing apparatus 10 (hereinafter, also simply referred to as “manufacturing apparatus 10”) will be described, and then the solder precoated substrate manufacturing method (hereinafter, also simply referred to as “manufacturing method”) will be described. do.

-Solder pre-coated board manufacturing equipment-
The manufacturing apparatus 10 shown in FIGS. 1 to 3 is an apparatus for manufacturing a solder precoated substrate by forming a solder precoat on a plurality of lands 3 (see FIG. 4) provided on the surface of the substrate 1. In the present specification, the direction in which the substrate 1 is conveyed is the X direction, the vertical direction is the Z direction, and the direction perpendicular to the X direction and the Z direction is the Y direction. Further, the axes along the respective directions are defined as the X-axis, the Y-axis, and the Z-axis.

As shown in FIG. 1, the manufacturing apparatus 10 includes a supply unit 100, a heating unit 210, a cooling unit 220, and a control unit 20. The supply unit 100, the heating unit 210, and the cooling unit 220 are arranged side by side in a row in the X direction on the base 101. For ease of understanding, FIG. 1 shows an example in which the substrate 1 is arranged in each of the supply unit 100, the heating unit 210, and the cooling unit 220.

(Supply section)
The supply unit 100 supplies the solder paste P to the plurality of lands 3 of the substrate 1 by screen printing. The supply unit 100 may supply the solder paste P to the land 3 by a method other than screen printing.

The supply unit 100 includes a moving table 102, an elevating mechanism 103, a printing stage 104, a printing head 113, a mask plate 116, a printing stage conveyor 231, a substrate carrying conveyor 234, and a substrate relay conveyor 232.

The moving table 102 is arranged on the base 101 between a pair of support frames 11 erected at intervals in the X direction. An elevating mechanism 103 for elevating and lowering the printing stage 104 is arranged on the moving table 102.

The print stage 104 has a base 104a coupled to the elevating mechanism 103. A support column 104b is provided on the upper surface of the base portion 104a. A substrate guide 104c extending along the X axis is coupled to the upper end of the support column 104b. Inside the board guide 104c, a printing stage conveyor 231 including a belt for transporting the board 1 is arranged.

The moving table 102 horizontally moves the elevating mechanism 103, that is, by moving the elevating mechanism 103 along the X-axis and the Y-axis. The moving table 102 rotates the printing stage 104 around the Z axis by rotating the elevating mechanism 103 around the Z axis. The elevating mechanism 103 moves, that is, elevates the printing stage 104 along the Z axis.

The printing stage conveyor 231 includes a substrate carry-in conveyor 234 disposed through the opening of one support frame 11 and a substrate relay conveyor 232 disposed through the opening of the other support frame 11. It is configured to pass the substrate 1 between them. The substrate 1 carried in by the substrate carry-in conveyor 234 is delivered to the printing stage conveyor 231 and conveyed to the solder paste supply area PA, and is held by the printing stage 104. The substrate 1 to which the solder paste P is supplied in the printing stage 104 is carried out from the solder paste supply area PA of the printing stage conveyor 231 and delivered to the substrate relay conveyor 232.

A backup elevating mechanism 104e is arranged on the upper surface of the base portion 104a. The backup elevating mechanism 104e elevates and elevates the backup unit 104f that supports the substrate 1 from below. The backup unit 104f supports the lower surface of the substrate 1 by being raised while the substrate 1 is carried into the solder paste supply region PA of the printing stage conveyor 231.

A side clamper 104d extending along the X axis is provided on the upper surface of each of the pair of substrate guides 104c. The side clamper 104d is opened and closed by a drive mechanism (not shown). The backup unit 104f raises the substrate 1 to a height at which the upper surface of the substrate 1 and the upper surface of the side clamper 104d are substantially flush with each other while supporting the lower surface of the substrate 1. By closing the side clamper 104d with the heights of the substrate 1 and the side clamper 104d aligned, both side surfaces of the substrate 1 are sandwiched between the side clampers 104d, and the substrate 1 is fixed. In this way, the print stage 104 holds the substrate 1.

A support beam 113a that supports the print head 113 is arranged at the upper ends of the pair of support frames 11 so as to be movable along the Y axis via the linear motion guide mechanism 11a. One end of the support beam 113a is coupled to a well-known print head moving mechanism 11b composed of a feed screw and a motor for rotating the feed screw. By driving the print head moving mechanism 11b, the print head 113 reciprocates (squeezing operation) along the Y axis.

As shown in FIG. 2, the print head 113 has a rear squeegee 113b and a front squeegee 113c extending downward from the support beam 113a. By driving the squeegee drive unit 113d provided on the upper surface of the support beam 113a, either the rear squeegee 113b or the front squeegee 113c descends according to the direction of the squeezing operation.

Below the print head 113, the mask plate 116 is arranged in a horizontal state. The mask plate 116 is formed with a pattern hole (not shown) penetrating in the thickness direction. The pattern holes are formed corresponding to the arrangement and shape of the plurality of lands 3 on the substrate 1. The supply unit 100 moves the solder paste P (see FIG. 3) supplied to the upper surface of the mask plate 116 by the rear squeegee 113b or the front squeegee 113c, so that the solder paste P is transferred onto the substrate 1 in a predetermined printing pattern. Perform screen printing to supply.

(Heating part)
The heating unit 210 heats the solder paste P supplied to the land 3 to melt the solder particles PL contained in the solder paste P. The heating unit 210 has a housing 213 that covers the downstream side of the substrate relay conveyor 232 extending from the supply unit 100, and a first heater 211 and a second heater 212 arranged inside the housing 213. The housing 213 is formed with ventilation holes 215 for exhausting volatile components from the solder paste P generated by heating.

The first heater 211 is arranged below the substrate relay conveyor 232. The first heater 211 covers the entire substrate 1 located in the heating region HA when viewed from below. The first heater 211 heats the entire substrate 1 located in the heating region HA from below (that is, from the back surface side of the substrate 1).

The substrate relay conveyor 232 of the present embodiment is composed of a metal chain extending along the transport direction of the substrate 1 (see FIG. 4), but is not limited thereto.

The second heater 212 is arranged above the substrate relay conveyor 232. The second heater 212 covers the entire substrate 1 located in the heating region HA when viewed from above. The second heater 212 heats the entire substrate 1 located in the heating region HA from above (that is, from the surface side of the substrate 1). Alternatively, the second heater 212 does not have to heat the substrate 1 located in the heating region HA (that is, it may be turned off).

The first heater 211 and the second heater 212 preferably heat the substrate 1 so that the temperature of the surface of the substrate 1 rises at an increase rate of 4 ° C./sec or more. By heating the substrate 1 at such an increase rate, the occurrence of the bridge phenomenon can be further suppressed. The rate of increase is a value of (200-100) / Δt (unit: ° C./sec), where Δt (unit: seconds) is the time required for the surface temperature of the substrate 1 to rise from 100 ° C. to 200 ° C. Is conceivable, but is not limited to this.

(Cooling unit)
The cooling unit 220 cools and solidifies the molten solder particles PL (hereinafter, also referred to as “molten solder”). The cooling unit 220 has a housing 224 that covers the substrate unloading conveyor 233, and a cooling fan 221 arranged inside the housing 224. Vent holes 220a and 220b for introducing and discharging cooling air are formed in the housing 224. The cooling fan 221 cools the substrate 1 on the substrate unloading conveyor 233. This cools and solidifies the molten solder.

(Control unit)
The control unit 20 controls the supply unit 100, the heating unit 210, the cooling unit 220, and the conveyors 231 to 234 to cause the manufacturing apparatus 10 to perform the work of forming the solder precoat on the substrate 1. The control unit 20 is provided inside the base 101. The control unit 20 is composed of an arithmetic processing unit (CPU), a storage device (memory) for storing a program that can be executed by the arithmetic processing unit, and the like.

-Board configuration-
Next, the configuration of the substrate 1 will be described. As shown in FIG. 4, the substrate 1 of the present embodiment is connected to the substrate main body 2, a plurality of lands 3 provided on the front surface (upper surface) of the substrate main body 2, and each land 3 and is connected to the back surface of the substrate main body 2. It has a plurality of wiring patterns 4 exposed on the (lower surface). The substrate body 2 is composed of an insulator, while the plurality of lands 3 and the wiring pattern 4 are composed of conductors.

As described above, the substrate 1 of the present embodiment is a double-sided printed circuit board, but the type of the substrate 1 is not limited to this. For example, the substrate 1 may be a single-sided printed circuit board or a multilayer printed circuit board. The manufacturing apparatus and manufacturing method of the present disclosure can be applied to any type of substrate 1.

-Manufacturing method of solder precoated board-
Next, the manufacturing method of this embodiment will be described. The manufacturing method includes a supply step, a heating step, and a cooling step.

(Supply process)
In the supply step, the solder paste P is supplied to a plurality of lands 3 provided on the surface of the substrate 1. Specifically, the control unit 20 operates the substrate carry-in conveyor 234 and the printing stage conveyor 231 to convey the substrate 1 on which the solder precoat is not formed to the solder paste supply region PA. Subsequently, the control unit 20 operates the backup elevating mechanism 104e to support the substrate 1 on the backup unit 104f, and clamps the substrate 1 by the side clamper 104d. As a result, the print stage 104 holds the substrate 1.

Next, the control unit 20 aligns the horizontal position of the substrate 1 with respect to the mask plate 116, and then drives the elevating mechanism 103 to raise the substrate 1 and bring it into contact with the lower surface of the mask plate 116. .. Then, the control unit 20 operates the print head 113 to screen-print the solder paste P on the substrate 1.

Next, the control unit 20 pulls the substrate 1 away from the mask plate 116 by driving the elevating mechanism 103 (plate release). Subsequently, the control unit 20 operates the side clamper 104d and the backup elevating mechanism 104e to release the fixing of the substrate 1 by the side clamper 104d, and lowers the backup unit 104f to place the substrate 1 on the printing stage conveyor 231. Place it. Then, the control unit 20 operates the printing stage conveyor 231 and the substrate relay conveyor 232 to convey the substrate 1 to the heating region HA in the heating unit 210.

(Heating process)
In the heating step, the substrate 1 to which the solder paste P is supplied on the land 3 is heated by the first heater 211 and the second heater 212, or only by the first heater 211. Specifically, as shown in FIG. 4, the control unit 20 operates the first heater 211 at a high temperature to heat the substrate 1 from the back surface side (bottom surface side). The control unit 20 operates the second heater 212 at a low temperature to heat the substrate 1 from the front surface side (upper surface side), or does not operate the second heater 212.

When the first heater 211 and the second heater 212 are controlled in this way, the first heater 211 having a relatively high output becomes the main heat source, and the substrate 1 is stronger from the back surface side than from the front surface side in the heating region HA. Be heated. The heat of the first heater 211 as the main heat source is transferred to the land 3 via the wiring pattern 4. As a result, the temperature of each land 3 reaches the melting point of the solder particles PL contained in the solder paste P, which is faster than the surface temperature of the substrate 1 around the land 3.

When the temperature of the land 3 reaches the melting point of the solder particles PL, solder melt nuclei C are generated on the surface of the land 3 as shown in the middle part of FIG. After that, the solder melt nucleus C grows while attracting the surrounding solder particles PL. At this time, the solder melt nucleus C on the right side of FIG. 4 also attracts the solder particles PL between the adjacent lands 3. Finally, as shown in the lower part of FIG. 4, substantially all the solder particles PL including the solder particles PL around the land 3 are melted and gathered on the land 3. Then, the control unit 20 operates the substrate relay conveyor 232 and the substrate unloading conveyor 233 to convey the substrate 1 to the cooling unit 220.

(Cooling process)
In the cooling step, the cooling fan 221 cools the substrate 1 in which the molten solder is present on the land 3. Specifically, the control unit 20 operates the cooling fan 221 to cool the substrate 1 by the air flow through the ventilation holes 220a and 220b, thereby solidifying the molten solder. In this way, a solder precoat is formed on the land 3 of the substrate 1, and the solder precoat substrate is completed. Then, the control unit 20 operates the substrate unloading conveyor 233 to unload the cooled substrate 1 (solder precoated substrate) from the cooling unit 220.

<Modification Example 1>
A modified example of the first embodiment of the present disclosure will be described. In this modification, the configuration of the heating unit 210 is different from that of the first embodiment. Hereinafter, the differences from the first embodiment will be mainly described.

As shown in FIG. 5, the heating unit 210 of this modification does not include the second heater 212. Therefore, in the heating step of this modification, the substrate 1 is heated only by the first heater 211. In other words, in the heating step of this modification, the substrate 1 is heated only from the back surface side (lower surface side) of the substrate 1. Also in this modification, it is preferable to heat the substrate 1 so that the temperature of the surface of the substrate 1 rises at an increase rate of 4 ° C./sec or more.

As described above, by not providing the second heater 212, in other words, by providing only the first heater 211 as a heat source, it is possible to reduce the cost of the manufacturing apparatus 10 and simplify the structure.

<Embodiment 2>
The second embodiment of the present disclosure will be described. In this embodiment, the configurations of the heating unit 210 and the cooling unit 220 are different from those of the first embodiment. Hereinafter, the differences from the first embodiment will be mainly described.

(Heating part)
As shown in FIGS. 6 and 7, the heating unit 210 of the present embodiment includes a heating plate 214, a sheet 216, and a pressing unit 217 during heating.

The heating plate 214 contacts the back surface (lower surface) of the substrate 1 located in the heating region HA to heat the substrate 1. More specifically, the heating plate 214 heats the substrate 1 only from the back surface side by generating heat while contacting the wiring pattern 4 of the substrate 1. As a result, as shown in FIG. 7, as in the first embodiment, the molten solder nuclei grow on the land 3 of the substrate 1 by heating, and finally, the molten solder is gathered on the land 3. To.

The sheet 216 is sandwiched between the substrate 1 and the heating plate 214 when the substrate 1 is heated by the heating plate 214. The sheet 216 is made of a material (eg, silicon) that is softer than the substrate 1 and the heating plate 214. It is preferable that the sheet 216 is replaced every time the substrate 1 is replaced by a predetermined number (for example, one) by the supply roller 216a that feeds out the sheet 216 and the recovery roller 216b that winds up the sheet 216. In the heating step of the present embodiment, the substrate 1 is heated by the heating plate 214 with the sheet 216 sandwiched between the substrate 1 and the heating plate 214.

The heating presser portion 217 presses the substrate 1 at a plurality of locations (in this example, the four corner portions of the substrate 1) when the substrate 1 is heated by the heating plate 214. Each of the heating pressing portions 217 has a plurality of legs 217a that press the substrate 1 and a frame body 217b that connects the plurality of legs 217a. The plurality of legs 217a and the frame body 217b are made of a highly heat insulating material. In the heating step of the present embodiment, the substrate 1 is heated by the heating plate 214 in a state where the substrate 1 is pressed at a plurality of locations by the pressing portions 217 during heating.

(Cooling unit)
As shown in FIG. 6, the cooling unit 220 of the present embodiment has a cooling pressing unit 222. The cooling presser portion 222 presses the substrate 1 at a plurality of locations (in this example, six locations along the opposite sides of the substrate 1) when the substrate 1 is cooled by the cooling fan 221. The cooling pressing portion 222 has a plurality of lower rollers 222a that abut on the back surface of the substrate 1, and a plurality of upper rollers 222b that sandwich the substrate 1 together with the plurality of lower rollers 222a. Each lower roller 222a and each upper roller 222b are made of a highly insulating material. In the cooling step of the present embodiment, the substrate 1 is cooled by the cooling fan 221 in a state where the substrate 1 is pressed at a plurality of locations by the cooling presser portions 222.

Hereinafter, embodiments will be described in more detail based on Examples and Comparative Examples. The scope of the present disclosure is not construed as limiting by the examples.

Probability that a bridge will occur for 200 chips for each measurement condition (Comparative Examples 1 and 2 and Examples 1 to 3) using the heating unit 210, the substrate 1, and the solder paste P having the following configurations. (Hereinafter, referred to as "bridge occurrence rate") was measured. In this case, the bridge occurrence rate is a value represented by (number of bridge occurrences / 200) × 100 (unit:%).

Specifically, a reflow oven UNI-6116 manufactured by Antomu Co., Ltd. was used as the heating unit 210. In the heating step, only the first heater 211 was operated, and the second heater 212 was turned off. The set temperatures of the first heater 211 are 230 ° C. (Comparative Example 1), 260 ° C. (Comparative Example 2), 300 ° C. (Example 1), 330 ° C. (Example 2), and 360 ° C. (Example 3). did.

Further, as the substrate 1, a rectangular substrate having a size of 150 mm × 100 mm and a thickness of 0.8 mm was used. The arrangement of the lands 3 on the substrate 1 is based on the assumption that the 0201 chip components are mounted at a distance of 70 μm between the components.

Further, as the solder paste P, solder paste type 5 (particle size: 15 to 25 μm) made of Senju Metal was used.

The measurement results of Comparative Examples 1 and 2 and Examples 1 to 3 are shown in Table 1. Here, the rate of increase is (200-100) / Δt (unit: ° C./sec), where Δt (unit: second) is the time required for the surface temperature of the substrate 1 to rise from 100 ° C. to 200 ° C. The value represented.

As can be seen from Table 1, the bridge occurrence rate was 0% under the condition that the rate of increase was 4.00 ° C./sec or more. On the other hand, under the condition that the rate of increase was less than 4.00 ° C./sec, the bridge occurrence rate was not 0%, and the occurrence of the bridge phenomenon was confirmed.

The present disclosure can be used in a method and an apparatus for manufacturing a solder precoated substrate.

1: Board 2: Board body 3: Land 4: Wiring pattern 10: Solder precoated board manufacturing equipment 11: Support frame 11a: Linear guide mechanism 11b: Print head movement mechanism 20: Control unit 100: Supply unit 101: Base 102: Moving table 103: Elevating mechanism 104: Printing stage 104a: Base 104b: Strut 104c: Board guide 104d: Side clamper 104e: Backup elevating mechanism 104f: Backup unit 113: Print head 113a: Support beam 113b: Rear squeegee 113c: Front Solder 113d: Solder drive part 116: Mask plate 210: Heating part 211: First heater 212: Second heater 213: Housing 214: Heating plate 215: Vent hole 216: Sheet 216a: Supply roller 216b: Recovery roller 217: Heating Time presser 217a: Leg 217b: Frame 220: Cooling part 220a: Vent hole 220b: Vent hole 221: Cooling fan 222: Cooling presser 222a: Lower roller 222b: Upper roller 224: Housing 231: Printing stage conveyor 232 : Substrate relay conveyor 233: Substrate carry-out conveyor 234: Board carry-in conveyor C: Solder melt core HA: Heating region P: Solder paste PA: Solder paste supply region PL: Solder particles

Claims (16)

It is a method of manufacturing a solder precoated substrate by forming a solder precoat on a plurality of lands provided on the surface of the substrate.
A supply process for supplying solder paste to a plurality of the above lands, and
A heating step of heating the substrate so that the temperature of the plurality of lands reaches the melting point of the solder particles contained in the solder paste at a temperature higher than the surface temperature of the substrate around the lands.
A method for manufacturing a solder precoated substrate. The method for manufacturing a solder precoated substrate according to claim 1, wherein in the heating step, the substrate is heated more strongly from the back surface side of the substrate than from the front surface side of the substrate. The method for manufacturing a solder precoated substrate according to claim 2, wherein in the heating step, the substrate is heated only from the back surface side of the substrate. The method for manufacturing a solder precoated substrate according to any one of claims 1 to 3, wherein in the heating step, the substrate is heated so that the temperature of the surface of the substrate rises at an increase rate of 4 ° C./sec or more. .. The method for manufacturing a solder precoated substrate according to any one of claims 1 to 4, wherein in the heating step, the substrate is heated by using a heating plate that contacts the back surface of the substrate. The method for manufacturing a solder precoated substrate according to claim 5, wherein in the heating step, the substrate is heated with a sheet sandwiched between the substrate and the heating plate. The method for manufacturing a solder precoated substrate according to any one of claims 1 to 6, wherein in the heating step, the substrate is heated while pressing the substrate at a plurality of places. The method for manufacturing a solder precoated substrate according to any one of claims 1 to 7, further comprising a cooling step of cooling the substrate while pressing the substrate at a plurality of places after the heating step. A device for manufacturing a solder precoated substrate by forming a solder precoat on a plurality of lands provided on the surface of the substrate.
A supply unit that supplies solder paste to the plurality of lands,
A heating unit that heats the substrate so that the temperature of the plurality of lands reaches the melting point of the solder particles contained in the solder paste at a temperature higher than the surface temperature of the substrate around the lands.
A solder pre-coated substrate manufacturing device. The solder precoated substrate manufacturing apparatus according to claim 9, wherein the heating unit heats the substrate more strongly from the back surface side of the substrate than from the front surface side of the substrate. The solder precoated substrate manufacturing apparatus according to claim 10, wherein the heating unit heats the substrate only from the back surface side of the substrate. The solder precoated substrate manufacturing apparatus according to any one of claims 9 to 11, wherein the heating unit heats the substrate so that the temperature of the surface of the substrate rises at an increase rate of 4 ° C./sec or more. .. The solder precoated substrate manufacturing apparatus according to any one of claims 9 to 12, wherein the heating unit has a heating plate that comes into contact with the back surface of the substrate to heat the substrate. The solder precoated substrate manufacturing apparatus according to claim 13, further comprising a sheet sandwiched between the substrate and the heating plate when the substrate is heated. The solder precoated substrate manufacturing apparatus according to any one of claims 9 to 14, further comprising a heating presser portion that presses the substrate at a plurality of locations when the substrate is heated. A cooling unit that cools the heated substrate, and
The solder precoated substrate manufacturing apparatus according to any one of claims 9 to 15, further comprising a cooling presser portion that presses the substrate at a plurality of locations when the substrate is cooled.

Images