JPS6221245A - Sealing device - Google Patents

Abstract

PURPOSE:To facilitate the control of the temperature of a sealing device and to improve the throughput thereof by a method wherein the furnace is sectioned into plural partitions, and also, infrared heaters are arranged in every partition, and moreover, the heating temperature to semiconductor devices is controlled in partition unit. CONSTITUTION:Partitions D and E in a furnace 11 respectively set the temperature atmospheres thereof into such a temperature atmosphere as to be turned into that of a region A heating ICs to the heating temperatures thereof, a partition F set the temperature atmosphere thereof into such a temperature atmosphere as to be turned into that of a region B keeping the ICs at a constant temperature, and partitions G and H in the furnace 11 respectively set the temperature atmospheres thereof into such a temperature atmosphere as to be turned into that of a region C cooling the ICs at a constant cooling rate. Then, a conveyor 10 is actuated, and when the numerous ICs are carried in the furnace 11, the temperature of the partitions D and E show a dropping tendency. If so, in correspondence to that, the thermocouplers 16 of the regions D and E transfer the information 17 to a control part 4, the control part 4 compares the set temperature being memorized therein with the information 17, the temperature difference component is heated by infrared heaters 13a in the partitions D and E and the temperatures of the partitions D and E are both made to approach the setpoint. Similarly, the temperatures of the partitions F, G and H are also controlled respectively in such a way as to become equal to the setpoints of the regions B and C in the partitions F, G and H.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to a technique that is effective when applied to a technique of heating an object to be heated at a desired temperature globtail, for example, a semiconductor device using glass as a sealing material. The present invention relates to a technique that is particularly effective when used as a sealing technique.

[Background technology]

When a lead frame is interposed between ceramics or ceramics, low-melting glass is generally used as the sealing material. FIG. 3 shows an example of a temperature profile during sealing, and by performing glass melting, welding, and cooling according to this, a semiconductor device with high airtightness is obtained without cracking the glass. As a sealing device that can easily control the temperature according to this temperature profile, the electronic material 1983 special issue Super LS published by Kogyo Research Association
The conveyor furnace system disclosed in I Manufacturing and Testing Equipment Guidebook P, 154 is widely used. Fourth
The figure is a side sectional view of a conventional conveyor furnace type sealing device. , 1 is a substantially cylindrical sealed furnace, around which a plurality of heaters 2 each made of a magnetic tube piezoelectric heating wire are arranged, and furthermore, on the outside thereof, a heat insulating material is provided to prevent heat from dissipating to the outside. 3 are arranged surrounding the sealed furnace 1. 4 is a conveyor, and a semiconductor device (hereinafter referred to as an IC) 7, which is an encapsulated object, is transported to a conveyor port 5.
It is possible to move at a predetermined speed from to the exit 6.

By using such a sealing device, as shown in Fig. 3, a temperature profile is created such as region A exhibiting a constant heating rate, region B exhibiting a constant temperature T, and region C9 exhibiting a constant cooling rate. Even if the inside of the sealing furnace 1 is set to be empty, if a large number of ICs made of ceramics having a large heat capacity are carried into the sealing furnace 1, the temperature will drop rapidly. IC
Even if the temperature of heater 2 is increased to suppress the temperature drop that occurs when the water starts flowing into the furnace,
Since heat is transferred through each stage, such as radiation from to the sealing furnace 1, heat conduction from the outer wall of the sealing furnace 1 to the inner wall, and radiation from the inner wall of the sealing furnace 1 to the IC surface, the predetermined temperature is It took a long time to recover to the profile, and temperature control was difficult. Furthermore, at the end of the IC flow in the furnace, contrary to the above, the heat capacity 1 of the entire furnace decreases as the number of ICs flowing into the furnace decreases, but since the strength of the heater 2 does not change, the temperature is lower than the predetermined temperature profile. The temperature inside the furnace becomes high. Therefore, even if the heater 2 is turned off to stop heating, it takes a long time to recover to a predetermined temperature profile. In order to solve this problem, we have developed a furnace sink and a furnace sink.

At the end, it is conceivable to run a dummy jig (with the same heat capacity as the IC) so that the overall heat capacity in the furnace does not fluctuate and maintain a predetermined temperature profile. There were problems in that the efficiency of the division work was poor and the throughput was also poor.

[Purpose of the invention]

It is an object of the present invention to provide a sealing technique that can improve sulpunto.

An object of the present invention is to provide a technique for easily controlling the temperature of a sealing device.

The above and other objects and novel features of the present invention include:
It will become clear from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

That is, by dividing the sealing furnace into a plurality of sections, arranging an infrared heater in each valley section, and providing means for controlling the temperature of the IC in each section, it is possible to set a desired temperature profile. Furthermore, since radiant heating is performed in each section using an infrared heater, even if the temperature fluctuates, it is possible to restore the predetermined temperature profile in a short time.

〔Example〕

Fig. 1 is a side schematic sectional view of a sealing device which is an embodiment of the present invention, and Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1. A sealing device which is one embodiment will be described. The restraint furnace 11 is made of a heat insulating material such as brick, and is partitioned in the longitudinal direction by a partition wall 12 into at least three parts: a furnace inlet, a furnace center, and a furnace outlet. In this embodiment, it is divided into five sections, E, F, G, and H, as an example. 13 is a plurality of infrared heaters arranged in each section in a direction perpendicular to the longitudinal direction of the sealed furnace 11;
Their intensities are determined by the control signal 15 from the temperature control section 14, respectively.
It is designed to be independently controlled. 16 is each section D-
At least one heat detection device, for example a thermocouple, is disposed in each of the thermocouples H, and temperature information (hereinafter simply referred to as information) 17 of each thermocouple is transmitted to the temperature control section 14. The temperature control section 14 includes a storage section that stores temperature profile data for sealing in advance, a comparison section that compares the data with information 17 from the thermocouple 16, and a comparison section that compares the data with information 17 from the thermocouple 16. It has a control signal sending section for adjusting the intensity of the infrared heater 15. Note that each thermocouple 16 is arranged near the ICl 3 so that the IC surface temperature and the temperature of the thermocouple almost match. 1
Reference numeral 9 denotes a wire mesh conveyor, which is capable of conveying a plurality of ICl3 at a predetermined speed from the furnace inlet 20 to the furnace outlet 21 through openings 22 provided in each partition wall 12.

23 is a support member for the conveyor 19.

Next, the operation will be explained. First, while the sealed furnace 1 is empty, the information 17 from the thermocouples 16 arranged in each compartment D-H and the data of the temperature pr:I file stored in the storage section of the temperature control section 14 are While comparing, the control signal 15 is sent out and the intensity of each infrared heater 13 is adjusted while heating.
The inside of the sealed furnace 1 is set to a temperature profile shown in FIG. 3, for example.

At this time, for example, section E is the temperature atmosphere of the AS region that heats the IC to a constant heating rate, section F is the temperature atmosphere of the B region that maintains the IC at a constant temperature, and section 0.1 (is the temperature atmosphere of the IC The temperature and surrounding atmosphere of zone C are set to be the same as that of zone C, which is cooled at a constant cooling rate.Then, the conveyor 19 is moved to carry a large number of aligned ICl3 into the furnace.In section A, ICl3 at room temperature is poured one after another. Because it is brought in, the heat is
The thermocouple 16a of the compartment A transmits this state as information 17a to the temperature control unit 4.The temperature control unit 81514 transmits the information 1 as information 17a.
7a and the temperature profile stored in the storage section in the comparing section, and the intensity of the infrared heater 13a is increased as necessary to correct the temperature difference. Such adjustment is made for each section E-H. The inside of the furnace is set to have a predetermined temperature profile. In addition, if the supply of ICs onto the conveyor is stopped when the ICs are finished flowing through the furnace, the I
As C moves, the number of ICs in each section changes. That is, as the ICs move, the number of ICs with large heat capacities decreases, so the temperature of each section becomes higher than the predetermined temperature profile. However, the thermocouple 16 constantly measures the temperature within each compartment, and the information 17 is sent to the temperature controller 14.
- Since the temperature is transmitted and fed back, it is now possible to weaken the intensity of the infrared heater as necessary and immediately restore the predetermined temperature profile in order to correct the difference between the temperature profile and the same temperature in each section. There is.

In the embodiment described above, the temperature of each compartment of the sealing furnace 11 is set in advance to the temperature profile necessary for sealing, and when the temperature of each compartment deviates from the temperature profile, the temperature of each compartment is set in advance. A temperature control method is used to compensate by changing the intensity of each independently controlled infrared heater. However, the temperature inside the sealing furnace changes rapidly when ICs begin to flow into the furnace and when ICs finish flowing into the furnace, that is, when the number of ICs in the furnace changes. Focusing on one thing, it is also possible to set the intensity of each infrared heater in advance so as to suppress the fluctuation in temperature of each section between the time when the IC starts to flow and the end of the furnace. It is preferable that the heater emits far-infrared light that is not easily affected by the material, color, etc. of the sealed object. [Effects] (1) The sealed furnace is divided into multiple sections using partition walls, and each section is By arranging an infrared heater and a thermocouple and adjusting the intensity of the infrared heater based on the information from the thermocouple, the temperature can be controlled independently for each section, so the desired temperature profile can be achieved. The advantage is that even if the temperature within the compartment deviates from the predetermined temperature profile, it can be quickly recovered.

(2) Divide the sealed furnace into multiple sections using partition walls, and install an infrared heater and thermocouple in each section, and
By adjusting the intensity of the infrared heater based on the pair of information, the temperature can be controlled independently for each section, so there is no need to use a dummy jig at the beginning and end of the furnace flow. The effect is that the work efficiency and sealing throughput can be dramatically improved.

(3) Since the temperature can be controlled independently for each section, the optimal temperature profile can be set depending on the glass material, package size, heat capacity of the object to be sealed, etc., making it possible to seal a wide variety of ICs in small quantities. Effects can be obtained in certain cases.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the above Examples and can be modified in various ways without departing from the gist thereof. Nor. For example, multiple thermocouples may be placed longitudinally within each compartment to more accurately detect longitudinal temperature, or the intensity of each infrared heater can be adjusted by simply increasing or decreasing the intensity. Alternatively, the temperature within the compartment may be controlled by turning on and off the infrared heater.

[Application field]

In the above explanation, the invention made by the present inventor was mainly applied to the application field of IC sealing technology, which is the background of the invention, but it is not limited to this, for example, glazing of low melting point glass. The present invention can be applied to encapsulation of ICs using low-melting brazing materials, and can be applied to various bake ovens that require temperature control.

[Brief explanation of the drawing]

FIG. 1 is a side schematic sectional view of a sealing device which is an embodiment of the present invention, FIG. 2 is a sectional view taken along the line ■-n in FIG. 1, and FIG. 3 is an explanatory diagram of a temperature profile. FIG. 4 is a schematic side sectional view of a conventional sealing device. DESCRIPTION OF SYMBOLS 11... Sealed furnace, 12... Compartment wall, 13... Infrared heater, 14... Temperature control section, 15... Control@signal, 16... Thermocouple, 17... Information , 18...IC
, 19... Conveyor, 20... Furnace inlet, 21...
Furnace outlet, 22... opening, 23... support member. Figure 1 Figure 2E Figure 3 Figure 4

Claims (1)

[Claims] 1. A sealing device having a sealing furnace for sealing a semiconductor device using glass as a sealing material, and a conveyor on which a plurality of semiconductor devices can be placed and moved within the sealing furnace. In the apparatus, the sealing furnace is divided into a plurality of sections, an infrared heater is provided in each section, and a control means is provided for controlling the heating temperature of the semiconductor device in each section. Sealing device. 2. The control means includes a thermocouple arranged in each section;
2. The sealing device according to claim 1, further comprising an intensity adjusting means for adjusting the intensity of each infrared heater based on information from the thermocouple.