JPH084933B2 - Substrate heating device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate heating device used for soldering an electronic component onto a printed circuit board.

2. Description of the Related Art In the technological trend of mounting electronic components on a printed circuit board (hereinafter abbreviated as a board) at high density, a soldering method for elements using a reflow furnace is being adopted. The reflow method is different from the flow method of dipping the board on which the element is placed in the molten solder bath so far, cream-like solder made of fine solder particles and paste, and the element is placed after being applied at a predetermined position on the board, It is a method of heating and melting by infrared rays and soldering.

A general reflow furnace is shown in FIG. On the conveyor 1 which moves at a constant speed ν, the substrate 2 on which the elements are mounted is heated by the heating element 3 which continues to generate a constant amount of heat. The first half A of the furnace is a normal heating part, and usually heats the substrate 2 around 150 ° C. Next, at the portion B, a temperature of about 250 ° C. is generated and soldering is performed, and then the product is cooled by fan blowing and taken out.

Problems to be Solved by the Invention The conventional reflow method described above is not necessarily good in terms of the efficiency of heating the substrate, and it is possible to simultaneously heat a large amount of the substrate with a single or a very small amount of heating section. is necessary. Further, due to the difference in heat capacity between the elements on the board and the non-uniformity of the arrangement, a temperature distribution is generated on the board 2, and in some cases, the temperature of the elements does not rise completely, so that there are places where soldering cannot be performed. On the other hand, some elements, such as resin-molded parts, may melt, deform, or cause thermal damage when the temperature is raised too high for soldering. There are elements that require different heating and elements that do not prefer heating, and it is necessary to solder these elements at the same time.

The present invention is to solve the above problems, by heating the substrate with a heating element with high efficiency, and by significantly improving the temperature controllability, improve productivity, reduce soldering defects, An object of the present invention is to provide a substrate heating device capable of stably protecting the quality of elements.

Means for Solving the Problems In order to solve the above problems, the substrate heating apparatus of the present invention is a heating apparatus main body, and the surface of the heating apparatus main body on the side of the center of curvature is a semi-cylindrical shape and is a mirror surface. A pair of reflecting mirror bodies, which are provided so as to face each other on the mirror surface side with a predetermined distance therebetween, and a columnar heating element that is disposed near the focal point of the reflecting mirror body,
A substrate holding unit that holds a substrate between the pair of reflecting mirror bodies and near the heating element, and a substrate transporting unit that moves the substrate holding unit along the reflecting mirror body, and further if necessary. In the space between the substrate holder and the reflecting mirror body in close proximity to the substrate held by the holder,
A mask made of a heat ray impermeable material having at least one hole is provided.

Action With the above-described configuration, the radiant heat from the heating element at the focal position by the reflecting mirror body is reflected with high efficiency as parallel heat rays to irradiate the substrate on the substrate holding portion, and at the same time, the substrate heating of a plurality of chambers is made highly efficient. By doing and applying a mask,
It is possible to perform substrate heating that effectively equalizes the temperature distribution on the substrate.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially cutaway perspective view showing a substrate heating apparatus according to a first embodiment of the present invention. 11 is the heating device body,
Reference numeral 12 is a substrate, 13 is a reflecting mirror body, 14 is a heating element, 15 is a substrate holding portion, 16 is a substrate transporting portion, 17 is an entrance / exit of a heating device main body, and 18 is a shutter. Inside the heating device main body 11, a pair of reflecting mirror bodies 13 having a substantially semi-cylindrical curvature and having a mirror-like surface on the center side of the curvature (hereinafter, this surface is referred to as a mirror surface) are
a-arranged in parallel with each other at a predetermined interval so as to face each other, and at a substantially focal position of the reflecting mirror body 13, a cylindrical heating element.
Reference numeral 14 is provided parallel to the longitudinal direction of the reflecting mirror body 13. In the space between the pair of reflecting mirror bodies 13 and the heat generating body 14, there is installed a substrate holding part 15 for holding a plurality of substrates 12 in two stages at regular intervals. It is connected to the transfer unit 16 and transferred in the longitudinal direction of the heating device main body 11. The heating device main body 11 is provided with a heat insulating function, one entrance 17 is provided at each of front and rear ends in the carrying direction of the substrate carrying section 16, and a shutter 18 is attached to the entrance 17.

With respect to the above-described substrate heating device, the operation principle regarding heating will be described with reference to FIG. When the center of the heating element 14 is installed and heated at the focal position of the semi-cylindrical reflecting mirror body 13, the heat ray component given in the form of radiant heat is generated on the surface of the reflecting mirror body 13 in the same manner as light. It is reflected with high efficiency, and thereafter is emitted as parallel light (heat) rays. Therefore, it is placed between the reflector 13 and the heating element 14, and each heating surface is a reflecting mirror body.
A plurality of substrates 12 are arranged so as to face the mirror surface 13a of 13
Will be heated almost in the normal direction, and the plurality of substrates 12 can be heated at the same time and the number of heating elements 14 can be minimized. Further, the reflecting mirror body 13
After being reflected by, the heat rays that have not been applied to the substrate 12 hit the reflecting mirror body 13 on the opposite side and are reflected again to irradiate the substrate 13. Therefore, energy loss can be minimized. From the above points, the diffuse reflection heat rays that have been absorbed to the outside of the furnace wall in the conventional furnace, resulting in unnecessary heating of the furnace wall, are effectively reused. The so-called substrate transfer system including the substrate holding unit 15 and the substrate transfer unit 16 intermittently carries out a group of heated substrates 12 to the outside of the heating apparatus main body 11, while a group of new unprocessed substrates 12 is carried out. Is operated so as to be loaded into the heating device 11, and the group of substrates 12 can be heated with high efficiency. The shutter 18 provided in the entrance / exit 17 can be opened only when the group of these substrates 12 is carried in / out, and the atmosphere temperature of the heating device main body 11 is lowered and the atmosphere temperature near the entrance 17 is lowered as much as possible. Can be suppressed. Further, in order to positively preheat the substrate 12, by providing a heater or the like for appropriately setting the ambient temperature of the heating device body 11, the efficiency thereof can be further greatly improved.

FIG. 3 is a schematic cross-sectional view of the substrate heating apparatus according to the second embodiment of the present invention. The same reference numerals as those in FIGS. 1 and 2 denote the same members. This second embodiment corresponds to the substrate holder 15 of the substrate heating apparatus of the embodiment shown in FIGS. 1 and 2.
Between the substrate 12 and the reflecting mirror body 13 held on the substrate 12,
A mask 19 is installed almost parallel to and close to. The mask 19 is a substrate 12 among the heat rays emitted from the heating element 14.
It has a function of appropriately adjusting the radiant heat component radiated to the window, and selects a heat ray non-transmissive material such as a metal plate having a high reflectance, and as shown in FIG. The hole 20 is provided. The position, size, number, etc. of the holes 20 provided in the mask 19 may be determined by appropriately adjusting the amount of radiant heat in accordance with the heat capacity, thermal characteristics, distribution density, etc. of the elements on the substrate 12 immediately below. By providing the mask 19, the substrate 12 having a heat capacity distribution can be uniformly heated, for example, soldering failure can be significantly reduced, and heat-sensitive parts can be protected and damage to the parts is small.

EFFECTS OF THE INVENTION As described above, the substrate heating apparatus of the present invention can simultaneously heat a large number of substrates with a minimum number of heating elements and with high efficiency. It can be adjusted and heated accurately, and it is possible to greatly reduce the occurrence of soldering defects and damage to parts,
It is also possible to simultaneously heat different types of substrates.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a substrate heating apparatus according to a first embodiment of the present invention, FIG. 2 is a schematic cross-sectional view of the substrate heating apparatus, and FIG. 3 is a second embodiment of the present invention. 4 is a schematic cross-sectional view of the substrate heating apparatus in FIG. 4, FIG. 4 is a perspective view of a mask of the substrate heating apparatus, and FIG. 5 is a schematic cross-sectional view of the substrate heating apparatus in the conventional example. 11 …… Heating device main body, 12 …… Substrate, 13 …… Reflecting mirror body, 14
...... Heating element, 15 …… Substrate holding unit, 16 …… Substrate transfer unit, 17
…… Doorway, 18 …… Shutter, 19 …… Mask.

Claims (2)

[Claims] 1. A heating device main body, and a pair of reflecting mirrors provided in the heating device main body, the surfaces having a substantially semi-cylindrical shape and having a center of curvature being mirror surfaces, and the mirror surface sides facing each other with a predetermined distance therebetween. Body and
A columnar heating element arranged near the focal point of the reflecting mirror body; a substrate holding section for holding a substrate between a pair of facing reflecting mirror bodies and in the vicinity of the heating element; and a substrate holding section. A substrate heating device comprising a substrate transfer unit that moves along the reflecting mirror body. 2. A space between the substrate holder and the reflecting mirror body,
2. The substrate heating apparatus according to claim 1, wherein a mask made of a heat ray non-transmissive material having at least one hole is provided in the vicinity of the substrate held by the holding portion substantially in parallel.