KR102065094B1 - Reflow method and apparatus for LED or lead frame - Google Patents

Abstract

The present invention relates to a method and apparatus for reflowing an LED or lead frame capable of reflowing solder after mounting the LED or lead frame on a mounting substrate, comprising: at least one substrate having a first material capable of induction heating; Preparing an LED or lead frame; Preparing a mounting substrate made of a second material capable of induction heating; Applying a conductive bonding medium on the mounting substrate; Mounting the LED or lead frame on the conductive bonding medium; Inductively heating the substrate made of the first material and the mounting substrate made of the second material; Reflowing as the conductive bonding medium is melted; And curing the reflowed conductive bonding medium.

Description

Reflow method and apparatus for LED or lead frame

The present invention relates to a method and apparatus for reflowing an LED or lead frame, and more particularly, to reflow of an LED or lead frame capable of reflowing a conductive bonding medium such as solder after mounting the LED or lead frame on a mounting substrate. A method and apparatus are disclosed.

The process of packaging a semiconductor includes an assembly process of providing a solder ball that functions as a terminal for electrical connection with the outside to the semiconductor chip, and a mounting process of mounting the semiconductor chip provided with the solder ball on a printed circuit board. Both the assembly and mounting processes require the solder balls to be heated to reflow the solder balls.

A general reflow apparatus heats an object using a heater that directly heats the object. The object here is a semiconductor chip to which solder balls are attached or a printed circuit board on which the semiconductor chip is mounted. The reflow apparatus that is generally used heats the object to a high temperature for a long time, so that the entire object is exposed to thermal stress, which causes deformation such as warpage of the object. In recent years, as the pattern in the semiconductor is miniaturized and the semiconductor component is thinned, the allowable range of deformation is gradually reduced, and thus the above-mentioned problem becomes larger in the future.

On the other hand, LED (LED) is a kind of light emitting device package using a semiconductor process, and these conventional light emitting device packages, like the semiconductor devices, by directly applying the reflow device as described above to apply heat directly to the LED thermal stress is Of course, since the deformation occurs, as the size of the LED is gradually miniaturized, there is a problem that these problems are gradually increased due to the decrease in the deformation allowance range.

The present invention is to solve a number of problems including the above problems, the heat is not penetrated from the outside using an induction heating method, the metal material forming the lead frame and the substrate internally by using an induced electromotive force itself heating By reducing the heat penetration time, the process time can be greatly shortened. By using the characteristics of the small induction coil, the space utilization of the equipment can be greatly improved, and other components that do not respond to induced electromotive force are not heated. It is an object of the present invention to provide a method and apparatus for reflowing an LED or a lead frame which can minimize thermal stress between them and partially shield the induced electromotive force, thereby enabling precise temperature control. However, these problems are exemplary, and the scope of the present invention is not limited thereby.

According to an aspect of the present invention, there is provided a method of reflowing an LED or lead frame, the method comprising: preparing at least one LED or lead frame having a substrate made of a first material; Preparing a mounting substrate made of a second material; Applying a conductive bonding medium on the mounting substrate; Mounting the LED or lead frame on the conductive bonding medium; Induction heating the substrate or the mounting substrate; Reflowing as the conductive bonding medium is melted; And curing the reflowed conductive bonding medium.

According to the present invention, the step of reflowing while the conductive bonding medium is melted may include: heating to a first temperature; And heating to a second temperature higher than the first temperature.

According to the present invention, the first material or the second material may include a copper or aluminum component, and the conductive bonding medium may include a solder component.

On the other hand, the reflow apparatus of the LED or lead frame according to the idea of the present invention for solving the above problems, the reflow oven is formed to accommodate the LED or lead frame therein; At least one induction heating coil installed in the reflow oven, the induction electromotive force being formed to induce heating of the inductive heating material of the LED or the lead frame to reflow the conductive bonding medium by receiving AC power; And a transfer device for loading or unloading the LED or the lead frame into the reflow oven.

In addition, according to the present invention, the reflow oven, the first heat treatment module for heating the LED or the lead frame to a first temperature; And a second heat treatment module for heating the LED or lead frame to a second temperature higher than the first temperature.

In addition, according to the present invention, the induction heating coil may include a first induction coil installed in the first heat treatment module; And a second induction coil installed in the second heat treatment module.

Further, according to the present invention, at least one of the first induction coil and the second induction coil is at least a rod shape, a U shape, a circle disposed long in a direction orthogonal to a conveying direction in which the LED or lead frame is conveyed. The coil may include any one or more of a shape, an arc shape, a spiral shape, a square coil, a polygonal coil, a wave shape, and a combination thereof.

The reflow apparatus of the LED or the lead frame according to the present invention may further include a magnetic body that is open to surround the coil and concentrate the magnetic flux in the direction of the LED or the lead frame.

In addition, the reflow apparatus of the LED or lead frame according to the present invention, the magnetic flux shielding plate which is installed between the coil and the LED or the lead frame, and is installed to shield the induction heating of the unnecessary portion; may further include a have.

In addition, according to the present invention, a cooling device may be installed in the magnetic flux shielding plate.

According to some embodiments of the present invention made as described above, the heat is not penetrated from the outside by using the induction heating method, the metal material constituting the lead frame and the substrate internally by the induction electromotive force itself is heated to penetrate the heat By reducing the time, the process time can be greatly shortened, and the characteristics of the bulky induction coil can greatly improve the space utilization of the equipment, and other parts that do not respond to the induced electromotive force are not heated so that the thermal The stress can be minimized, and the induced electromotive force can be partially shielded to have an effect of enabling precise temperature control. Of course, the scope of the present invention is not limited by these effects.

1 is a conceptual diagram illustrating a reflow apparatus of an LED or lead frame according to some embodiments of the present invention.
2 is a conceptual diagram illustrating a reflow apparatus of an LED or lead frame according to some other embodiments of the present invention.
3 is a flowchart illustrating a reflow method of an LED or lead frame according to some embodiments of the present invention.

Hereinafter, various exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art, and the following examples can be modified in various other forms, and the scope of the present invention is It is not limited to an Example. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In addition, the thickness or size of each layer in the drawings is exaggerated for convenience and clarity of description.

1 is a conceptual diagram illustrating a reflow apparatus of an LED or lead frame according to some embodiments of the present invention.

First, as shown in FIG. 1, the reflow apparatus of an LED or lead frame according to some embodiments of the present invention includes a reflow in which an accommodation space is formed to accommodate the LED or lead frame 3 therein. Installed in the oven (1) and the reflow oven (1), the induction heating material of the LED or the lead frame (3) is inductively heated by applying alternating current power (solder ball, solder bumps, solder pads) Yeast, solder cream, etc.) and at least one induction heating coil 8 to form an induction electromotive force and a transfer device 2 for loading or unloading the LED or lead frame into the reflow oven. can do.

Here, for example, the reflow oven 1, the first heat treatment module for heating the LED or lead frame to a first temperature and the second for heating the LED or lead frame to a second temperature higher than the first temperature. Heat treatment modules and the like.

However, the reflow oven 1 is not necessarily limited thereto, and further includes, for example, a third heat treatment module for post-heating to a third temperature lower than the second temperature in order to prevent a sudden drop in temperature, or in addition, heating to a single temperature. It can be applied in a wide variety of shapes, such as only a single module is applied.

Also, for example, the induction heating coil may include a first induction coil installed in the first heat treatment module and a second induction coil installed in the second heat treatment module.

However, the induction heating coil is also not limited thereto, and may further include, for example, a third induction coil installed in the third heat treatment module, or in addition to a single induction coil installed in the single module. Can be.

Further, for example, at least one of the first induction coil and the second induction coil may be at least a rod shape, a U shape, a circular shape, and an arc arranged long in a direction orthogonal to a conveying direction in which the LED or lead frame is conveyed. Coils may be any one or more of a shape, a spiral shape, a square coil, a polygonal coil, a wave shape, and combinations thereof. The coil may receive the high frequency power source 11 to generate induced electromotive force.

Here, the induced electromotive force is heated by converting electrical energy into thermal energy by electromagnetic induction, and generates heat inside the object by converting the induced current generated by the magnetic field into heat inside the object, which is a material capable of induction heating described above. Refers to electromotive force.

2 is a conceptual diagram illustrating a reflow apparatus of an LED or lead frame according to some other embodiments of the present invention.

On the other hand, as shown in Figure 2, the reflow apparatus of the LED or lead frame according to some embodiments of the present invention, the shape that is open so as to surround the coil and to concentrate the magnetic flux in the direction of the LED or the lead frame The magnetic body 9 may further include a magnetic flux shielding plate 10 installed between the coil and the LED or the lead frame and installed to shield induction heating of unnecessary portions.

Here, a cooling device may be installed in the magnetic flux shielding plate 10. The cooling device may be connected to the cooler 12 to receive coolant or coolant to cool the temperature.

3 is a flowchart illustrating a reflow method of an LED or lead frame according to some embodiments of the present invention.

Reflow method of the LED or lead frame according to some embodiments of the present invention, comprising the steps of preparing at least one LED or lead frame having a substrate made of a first material capable of induction heating (S1); Preparing a mounting substrate made of a second material capable of induction heating (S2); Applying a conductive bonding medium on the mounting substrate (S3); Mounting the LED or lead frame on the conductive bonding medium (S4); Inductively heating the substrate made of the first material and the mounting substrate made of the second material (S5); Reflowing as the conductive bonding medium is melted (S6); And curing the reflowed conductive bonding medium (S7).

Further, for example, step S6 of reflowing while the conductive bonding medium is melted may include heating to a first temperature; And heating to a second temperature higher than the first temperature. In addition, the method may further include a step of post-heating to a third temperature lower than the second temperature in order to prevent a sudden temperature drop.

For example, the first material or the second material may include a copper or aluminum component, and the conductive bonding medium may include a solder component.

The materials include components capable of induction heating, and may be included in any one of the substrate, the mounting substrate, the LED, the lead frame, or in the form of granules in the conductive bonding medium.

Therefore, the induction heating method does not allow heat to penetrate from the outside, but rather, the metal materials constituting the lead frame and the substrate are internally heated by using induction electromotive force, which shortens the process time by reducing heat penetration time. The small volume of induction coils can be used to significantly improve the space utilization of the equipment.

For example, the LED or lead frame reflow apparatus according to the technical idea of the present invention can be replaced with a space of 1/10 of the size of the existing reflow apparatus, as well as greatly reduce the reflow process time, thereby increasing production yield. This can be improved 2 to 10 times. This significantly reduces equipment and maintenance costs and product costs.

In addition, other components that do not respond to induced electromotive force may not be heated to produce high quality products by minimizing thermal stress between the components, and may partially shield the induced electromotive force to enable precise temperature control.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

1: reflow oven
2: conveying device (conveyor)
3: LED or lead frame
4: loading device
5: unloading device
6: exhaust
7: induction heating module
8: induction coil
9: magnetic material
10: magnetic flux shielding plate
11: high frequency power
12: cooler

Claims (10)

Applying a conductive bonding medium to the mounting substrate;
Mounting an LED or lead frame on the conductive bonding medium;
Inductively heating the inductive heating material of the LED or the lead frame or the mounting substrate;
Reflowing as the conductive bonding medium is melted; And
Curing the reflowed conductive bonding medium;
In the induction heating step,
Magnetic flux is concentrated in the direction of the LED or the lead frame by a magnetic body having an open shape surrounding the induction heating coil, and induction heating of an unnecessary portion by a magnetic flux shielding plate installed between the induction heating coil and the LED or the lead frame. Reflow method of an LED or lead frame, which is shielded. The method of claim 1,
The conductive bonding medium is reflowed while melting,
Heating to a first temperature; And
Heating to a second temperature higher than the first temperature;
Including, Reflow method of the LED or lead frame. The method of claim 1,
The inductive heating material of the LED or the lead frame, or the mounting substrate comprises a copper or aluminum component, and the conductive bonding medium comprises a solder component. A reflow oven in which an accommodating space is formed to accommodate the LED or the lead frame therein;
At least one induction apparatus installed in the reflow oven and configured to generate induction electromotive force so as to reflow the conductive bonding medium by induction heating of the inductive heating material of the LED or the lead frame or the mounting substrate by receiving AC power. Heating coil; And
A transfer device for loading or unloading the LED or the lead frame into the reflow oven;
A magnetic body that is shaped to surround the induction heating coil and to concentrate magnetic flux in the direction of the LED or the lead frame; And
A magnetic flux shielding plate disposed between the induction heating coil and the LED or the lead frame and installed to shield induction heating of an unnecessary portion;
Reflow apparatus for an LED or lead frame comprising a. The method of claim 4, wherein
The reflow oven,
A first heat treatment module for heating the LED or lead frame to a first temperature; And
A second heat treatment module for heating the LED or lead frame to a second temperature higher than the first temperature;
Reflow apparatus for an LED or lead frame comprising a. The method of claim 5,
The induction heating coil,
A first induction coil installed in the first heat treatment module; And
A second induction coil installed in the second heat treatment module;
Reflow apparatus for an LED or lead frame comprising a. The method of claim 6,
At least one of the first induction coil and the second induction coil has at least a rod shape, a U shape, a circular shape, an arc shape, and a spiral shape which are long and disposed in a direction orthogonal to a conveying direction in which the LED or lead frame is conveyed. And a coil in the shape of at least one of a square coil, a polygonal coil, a wavy shape, and combinations thereof. delete delete The method of claim 4, wherein
A reflow device for an LED or lead frame, wherein a cooling device is installed inside the magnetic flux shielding plate.

Images