JP2009295746A - Transport cradle for substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transport cradle for a substrate capable of being repeatedly used in a solder printing and reflow process, and in a flow process, and even if component packaging is performed two times or more to the substrate already packaged with components by the flow process, heat stress to the already packaged components is largely reduced. <P>SOLUTION: The transport cradle includes a carrier on which an escape part for the mounted components on the substrate is disposed, and a frame capable of attaching the carrier , and the carrier can be changed according to the pattern of the substrate, wherein a distance from the mounted components to the wall face of the carrier is 5 mm or longer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a cradle that is used when a component is mounted on a substrate used in, for example, industrial equipment and household appliances.

Conventionally, there are two types of methods for mounting electronic components on a substrate, and a conductive paste typified by solder paste is applied to a conductive portion on the substrate by printing or a dispenser, and the electronic component is placed on the paste. A method of electrically joining the substrate and the electronic component (reflow method) by re-dissolving the paste by heat treatment, and an opening provided on the surface of the substrate with a conductive portion provided at the peripheral portion, There is a method (flow method) of electrically connecting a substrate and an electronic component by inserting a connection terminal of the electronic component into the opening and jetting molten solder into contact therewith or immersing it in the solder.

In recent years, a substrate has a structure in which a substrate on which components are mounted is formed in a multilayer structure, and the number of substrates on which double-sided components are mounted has increased accordingly. Therefore, it is necessary to repeat the steps of the mounting method a plurality of times. In addition, since the thickness of the substrate has been reduced and it is difficult for the substrate alone to flow through the mounting device, the substrate is mounted on a cradle for each process.
However, when mounting a component on a board, it is necessary to place the board on a cradle for each process in advance and transport it, but in the case of a board that needs to be mounted in multiple parts, for each process Since it is necessary to replace the substrate on a dedicated cradle, there is a problem that it takes time to replace the substrate.
In addition, since physical stress is applied to the mounted components and joints each time it is replaced, it is desirable that the number of replacement on the cradle is as small as possible.

Therefore, the carrier part on which the board is mounted and the pedestal part are structured independently, and when the paste printing is performed, the carrier part on which the board is mounted is attached to the pedestal part and transported. A cradle is disclosed in which the labor of replacing the substrate is omitted and the productivity is improved.
JP 2000-13011 A

However, if the component is mounted on the board on which the component is mounted on the cradle by the flow process for the second and subsequent times, the mounted component may be damaged by the heat of the second and subsequent mounting processes. There is also a problem such as the occurrence of connection failure due to remelting of the connection part of the component.
In addition, the normal flow process is performed while a carrier is placed on a conveyor and transported. At that time, the substrate is locally heated, so that the heated portion is deformed, thereby causing warpage of the substrate. As a result, physical stress is applied to the mounted component, causing the component to be damaged.

Substrate carrying cradle that can be used in the reflow process with less thermal stress on the mounted part even when the component is mounted on the substrate on which the component is mounted for the second time or later.

As a result of intensive studies, the present inventors have solved the above problems.
That is,
A cradle comprising a carrier part provided with a relief part for mounted parts on a board, and a frame part for mounting the carrier part, and the carrier part can be exchanged according to the type of board, and the frame part The pedestal characterized in that a holding part for fixing the carrier part is provided, and the carrier part is made of a laminate, and at least one layer of the laminate is made of a heat dissipation material. The cradle and any of the cradles described above, wherein the distance from the mounted component to the surface of the carrier part is 0.3 mm or more, and the holding part is pressed down to the substrate mounted on the carrier part. The cradle according to any one of the above, wherein the cradle has a length that is formed, and the cradle according to any one of the above, wherein a silicone resin layer is provided at a boundary between the frame part and the carrier part.

According to the cradle of the present invention, even when the component mounting is performed for the second and subsequent times on the substrate on which the component is mounted, the thermal stress on the mounted component is small.
Further, by incorporating a heat dissipation material in the cradle, heat applied to the substrate can be dispersed, and deformation of the substrate itself due to heat can be prevented.

The cradle of the present invention will be described in detail.
The cradle of the present invention comprises a carrier part and a frame part, and has a structure that can be mounted even on substrates of different sizes and patterns by exchanging the carrier part according to the shape of the substrate to be mounted.

As the material of the carrier portion, a material having low heat conductivity and being difficult to adhere to solder is desirable, and in consideration of processing accuracy and strength, a heat resistant resin typified by glass epoxy resin or the like is desirable.

The carrier part is provided with a relief part for mounted parts on the board, and it is desirable that the distance between the mounted part and the carrier part surface is 0.3 mm or more when the board is placed. It is more desirable that the distance is 0.5 to 5 mm in consideration of protecting the substrate more reliably and considering the size of the cradle.

By making the carrier part a laminated structure and embedding one or more heat dissipation materials, it is possible to disperse the heat when the carrier part is partially heated, thereby suppressing partial elongation of the carrier part. Physical stress on the board mounted on the carrier part and mounted parts can be reduced, and soaking heating of the soldered joint of the board, that is, preheating of the part to be soldered can be performed. Reliability can be improved.
In addition, heat can be more reliably dispersed by employing a structure in which a heat dissipation material is embedded in at least a part of the portion where the carrier portion is heated.
Furthermore, the strength of the carrier portion can be improved or the thermal conductivity can be changed by making the shape of the heat dissipation material planar or lattice, or by increasing the area of the heat dissipation material.

The material of the heat radiating material is not limited as long as it is a heat radiating material capable of dispersing heat during the flow, and copper or aluminum is preferable in consideration of heat radiating property and workability.

By providing a silicone resin layer at the boundary between the carrier part and the frame part, around the opening part of the carrier part, especially at the contact part between the carrier part and the board, the upper part of the board and the components mounted on the board can escape during the flow process. It is possible to prevent the problem that the molten solder wraps around the part. Moreover, the boundary in this case refers to the place which contacts when a carrier part is mounted in a frame part.
By making the silicone resin layer heat-resistant and adhesive, it is possible to prevent a problem that the substrate is warped during heating, thereby causing the substrate to float from the carrier portion.

The frame portion is provided with a pressing portion so that the carrier portion can be held.
The shape of the presser is a shape that holds the carrier portion from the frame portion side, and has a structure that rotates around a shaft provided in the frame portion. By setting the length of the pressing tool to a length that can be pressed to the substrate, the effects of both the adhesiveness of the silicone resin layer and the pressing portion can be obtained, and the substrate can be held more firmly.

Examples of the present invention will be described below. FIG. 1 shows a bird's-eye view of the structure of a cradle and a substrate mounting method according to the present invention, and FIG. 2 shows a cross-sectional view when a substrate on which primary components are mounted is conveyed in a flow process.
The cradle of the present invention comprises a carrier portion 1 on which a substrate 3 is mounted and a frame portion 2 in which the carrier portion 1 is incorporated.

The carrier portion 1 is made of glass epoxy resin, and is provided with a through hole 8 through which the lead electrode 13 of the insertion mounting component 12 passes and a relief portion 9 of the surface mounting component 11, and a contact portion with the substrate 3 and the frame portion 2. A heat-resistant adhesive silicone resin layer 5 is provided at the boundary.

The frame part 2 is made of glass epoxy resin, and is provided with a through hole 10 for mounting the carrier part and a pressing part 7. The holding part 7 has a length that can be pressed down to the substrate 3 mounted on the carrier part 1.

The substrate 3 is mounted on the carrier portion 1 of the cradle of the first embodiment, and the carrier portion 1 is separated from the frame portion 2, that is, the solder paste is printed and the surface mount component 11 is placed in a state where the substrate 3 is mounted on the carrier portion 1. When the reflow process was performed, the surface mount component 11 was successfully mounted.

The mounted carrier part 1 was mounted on the frame part 2, the substrate 3 was inverted, and the mounted surface-mounted part 11 was stored in the escape part 9. At that time, the distance between the mounted surface mount component 11 and the carrier portion 1 was 0.5 mm apart.

When the insertion component 12 was placed on the substrate 3 mounted on the cradle and the flow process was performed, the lead portion 13 of the insertion component 12 and the substrate 3 could be electrically connected, and could be mounted with almost no problem. The back periphery of the molten solder to other parts was not seen, and the substrate 3 was not lifted from the carrier part 1 during the flow process.

FIG. 3 shows a sectional view of the second embodiment of the present invention. The cradle has the same structure as the cradle of Example 1 except that the carrier portion 1 has a laminated structure of glass epoxy resin and copper.

As in Example 1, the substrate 3 was mounted on the carrier portion 1 of the cradle, and when the substrate 3 was mounted on the carrier portion 1, the solder paste printing, the mounting of the surface mount component 11, and the reflow process were performed. The surface mount component 11 could be mounted on.

As in Example 1, the carrier portion 1 on which the component-mounted substrate 3 was placed was mounted on the frame portion 2, the substrate 3 was inverted, and the mounted surface-mounted component 11 was stored in the escape portion 9. At that time, the distance between the mounted surface-mounted component 11 and the carrier portion 1 was 8 mm apart.

When the insertion mounting component 12 was placed on the substrate 3 in the same manner as in Example 1 and the flow process was performed, the lead portion 13 of the insertion mounting component 12 and the substrate 3 could be electrically connected and more preferably mounted. The back periphery of the molten solder to other parts was not seen, and the substrate 3 was not lifted from the carrier part 1 during the flow process.

The cradle of the present invention can mount a component without applying thermal stress to the mounted component even when the component is mounted on the mounted substrate by a flow process.
Moreover, since the board | substrate of a different specification can also be conveyed by replacing | exchanging a carrier part, it is excellent in economical efficiency.

One use example (1) of the cradle of the present invention Example of use of the cradle of the present invention (2) An embodiment of the cradle of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Carrier part 2 Frame part 3 Board | substrate 5 Silicone resin layer 7 Holding | suppressing part 8 Through-hole 9 Escape part 10 Through-hole 11 for carrier part mounting Surface mount component 12 Insertion mount component 13 Lead electrode 14 Copper plate

Claims (5)

A board cradle comprising a carrier part provided with a relief part for mounted parts on a board, and a frame part for mounting the carrier part, the carrier part being exchangeable depending on the type of board. The cradle is provided with a pressing part for fixing the carrier part to the frame part. 2. The cradle according to claim 1, wherein the carrier part is made of a laminate, and at least one layer of the laminate is made of a heat dissipation material. The cradle according to claim 1 or 2, wherein a distance from the mounted component to the surface of the carrier part is 0.3 mm or more. The cradle according to any one of claims 1 to 3, wherein the holding part has a length capable of being pressed down to a substrate mounted on the carrier part. The cradle according to claim 1, wherein a silicone resin layer is provided at a boundary between the frame portion and the carrier portion.

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