JPH01199492A - Coating of hybrid integrated circuit - Google Patents

Abstract

PURPOSE:To control the thickness of a coating layer optionally without regulating a coating agent in viscosity with a thinner even if the coating agent high in viscosity and denseness is used by a method wherein the vibration speed of an integrated circuit at a pull-up process from the coating agent is made to vary optionally within the range of the vibration speed smaller than that at a dip process. CONSTITUTION:When a coating layer is formed on the surface of an integrated circuit 1 by dipping the circuit 1 into a liquid coating agent 3 of resin or the like, a dip process that the integrated circuit 1 is dipped into a coating agent 3 as it is kept vibrating and a pull-up process that the circuit 1 is pulled up from the coating agent 3 as being vibrated are provided. And, the vibration speed at the pull-up process is made to vary optionally to such a extent that it does not exceed that at the dip process. For instance, a vibration generating device 13 is driven by a DC motor 27, and a DC motor control section used for the control of the vibration speed of the hybrid IC 1, an up-down device, and others are controlled by regulating the number of revolution of the DC motor 27 with a control device 15.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is directed to forming a coating layer on the surface of a hybrid integrated circuit (hereinafter referred to as hybrid IC) by immersing the hybrid integrated circuit (hereinafter referred to as hybrid IC) in a liquid coating agent such as resin. Regarding how to.

(Prior Art) A coating layer is formed on the entire surface of a hybrid IC in order to improve reliability such as moisture resistance and impact resistance. The method for forming this coating layer is as follows:
There are dipping methods, botting methods, casting methods, etc., but the dipping method is usually used.

As shown in FIG. 9, in the dipping method, the hybrid ICI is immersed in the liquid coating agent 3 to adhere the coating agent to its surface, and after being pulled up, it is heated and cured to form a coating 1iI5. That is what it is.

In this case, since the thickness of the coating layer 5 depends on the viscosity of the coating agent 3, the thickness is adjusted by diluting the coating agent 3 with a suitable diluent such as a solvent to adjust its viscosity. It is.

Coating agents include acrylic, epoxy, silicone, phenol, polybutadiene,
Although urethane-based resins are known, silicone-based resins are generally used from the viewpoint of low stress, moisture resistance, and waterproofness.

As mentioned above, the thickness of the coating layer 5 depends on the viscosity of the liquid coating agent 3, so in order to increase the thickness, a coating agent 3 with a low viscosity is used. However, in the immersion method shown in Figure 9, the viscosity is high.
If the coating agent 3 is used, air is trapped in the coating agent 3 that adheres to the surface of the immersed hybrid I01, and a good quality coating layer 5 is not formed.

Therefore, as shown in FIG. 10, when the hybrid IC 1 is immersed in the coating agent 3, the hybrid I
A method was proposed in which C1 was vibrated up and down.

In addition, as prior art materials for this application, JP-A-57-
There are No. 133603 and Japanese Utility Model Application Publication No. 57-94903.

(Problems to be Solved by the Invention) A liquid coating agent containing a filler material such as silica may be used as a liquid coating agent for forming a coating layer on a hybrid IC. However, since such coating agents have high thixotropy, if a diluent is used to adjust the viscosity to adjust the film thickness, the diluent will be difficult to volatilize during heat curing, and the coating layer will be damaged during curing. Air bubbles will form inside. As a result, the quality of the coating layer deteriorates and the reliability of the hybrid IC is compromised. Therefore, viscosity adjustment by diluents is not desirable.

This invention provides a method for forming a coating layer without adjusting the viscosity with a diluent when using a coating agent with high viscosity and thixotropy. The object of the present invention is to provide a method that allows the thickness to be arbitrarily divided into vJ nodes.

(Means for Solving the Problems) The present invention is a method of forming a coating layer on the surface of a hybrid IC by immersing the hybrid IC in a liquid coating agent such as a resin, while shaking the hybrid IC. a dipping step of immersing the integrated circuit in the coating agent, and a pulling step of pulling the integrated circuit out of the coating agent while vibrating the integrated circuit,
The frequency in the pulling process is set to be arbitrarily changeable within a range smaller than the frequency in the dipping process.

(Example) Next, one embodiment of the present invention will be described based on the drawings.

As shown in FIG. 1, the immersion device mainly consists of an elevating device 10, a vibration generator 13, and a control device 15 for controlling the operation of these elevating devices @10 and the vibration generator 13. . A tank 17 is installed below the vibration generator 13 to store the coating agent 3 to be coated on the liquid hybrid IC 1.

As shown in FIGS. 2 and 3, the elevating device @10 mainly includes an elevating base 11, a rib motor 23, and a ball screw 19. The elevating base 11 is driven by a ball screw 19 rotated by a servo motor 23, and is guided by two guide bars 21 to be moved up and down. A counterbalance 25 is attached to the elevating base 11 to smoothly move it up and down. Note that an electromagnetic brake (not shown) is attached to the servo motor 23, so that the elevating base 11 can be stopped at a desired position.

The vibration generator 13, as shown in FIGS. 4 and 5,
It consists of a DC motor 27, a rotating disk 31 attached to a motor shaft 29 of the DC motor 27, and a shaft 35 attached to the rotating disk 31 via a pin 33. And this vibration generator 13
is attached to the elevating base 11 by fixing the DC motor 27 on the elevating base 11.

At the free end of the shaft 35 of the vibration generator 13, a bottle 3 is provided.
A support shaft 39 is attached via 7. A holder 41 for holding the hybrid IC 1 is attached to this support shaft 39, as shown in FIGS. 6 and 7.

The hybrid 101 is held in this holder 41 with the lead terminal facing upward.

Since the vibration generator 13 is configured as described above,
By rotating the DC motor 27, the shaft 3
5 is reciprocated up and down, and as a result, the hybrid I
CI is vibrated up and down.

Note that if the distance between the center of the motor shaft 29 and the center of the bottle 33 is 1, the amplitude of vibration is 2×1, so
By changing the value of the distance 11g, the amplitude can be changed arbitrarily. Also, the number of shots is 27 DC motors.
The armature voltage of the DC motor 27 is equal to the rotation speed of ! I
I I'll or motor shaft 29
By providing a speed change gear between the rotary disk 31 and the rotary disk 31, it can be changed as desired.

The control device 15 controls the rotation speed of the DC motor 27 by controlling the DC motor & IJ In section (not shown) and the servo motor 23 for adjusting the frequency of the hybrid IC 1, thereby controlling the lifting base. 11
It has a servo motor control section 42 for determining the direction of elevation of the base 11 and for stopping the elevation base 11. As shown in FIG. 8, the servo motor control section 42 includes a memory 43, an encoder 45, a deviation counter 47, a digital/analog converter 49, and ir! l1lIifS51 and H Frequency/I Pressure Change Jl [537] It consists of 16, basically memory 43
Control is performed by comparing the position data of the elevating base 11 stored in the position data and the position signal obtained from the encoder 45.

Next, the ω) operation of the dipping device configured as above 2 will be explained. Note that as the coating agent 3, a coating agent with a high degree of oxidation is used.

First of all, control! By the action of the DC motor control section of the Il device 15, the DC motor 27 is rotated at a preset rotation speed, and the hybrid IC is accordingly rotated at a predetermined frequency fi.
It is vibrated at o. At the same time, servo motor 1aJJ 11
The servo motor 23 is rotated by the action of the first part 42, and the elevating base 11 is lowered. Then, the hybrid ICI has a frequency f1. The coating agent 3 is immersed in the coating agent 3 in the tank 17 while being vibrated. Then, when the hybrid ICI is immersed to a desired depth, both the DC motor 27 and the servo motor 23 are stopped and held stationary for several seconds to several tens of seconds.

Next, in the same manner, the DC motor 27 is rotated at a predetermined rotation speed, and the hybrid ICI is rotated at a frequency fio.
is vibrated at a preset frequency fout smaller than . At the same time, the elevating base 11 is raised and the hybrid J
The CI is pulled up from the coating agent 3 while being shaken at a frequency f.

Note that the value of fout is preferably set between 20% and 80% of the value of fin.

Through the series of operations described above, a coating layer 5 is formed on the surface of the hybrid ICI. In this case, since the coating agent 3 has thixotropy, the viscosity of the coating agent 3 around the hybrid IC 1 during dipping and pulling changes depending on the respective vibration frequencies. Therefore, during immersion, the viscosity becomes sufficiently small according to the vibration frequency fio, and the inclusion of air bubbles is effectively prevented. On the other hand, during pulling, the viscosity changes according to the frequency f, and this viscosity u
A coating layer 5 having a thickness corresponding to the degree t is formed.

Next, Tables 1 and 2 show the results of an experiment conducted using a two-component thermosetting high viscosity silicone resin with a thixotropy index of 6. Tables 1 and 2 show the results when the amplitudes are 111II and 5jll+, respectively.

Table 1 Table 2 In the above experiment, after forming the coating layer, it was left at room temperature for 1 hour, dried at 70° C. for 1 hour, and then heated at 120° C. to harden it. Then, by measuring the film thickness and observing the cross section, we checked the
Expressed in OJ.

(Effect of the invention) In a method of forming a coating layer on a hybrid IC by dipping, vibration is applied to the hybrid IC in both the dipping step and the pulling step, and the frequency in the pulling step is set within a range smaller than the frequency in the dipping step. Since this method can be changed arbitrarily, when this method is applied to a coating agent with high viscosity and thixotropy, it can be arbitrarily set within a range where the viscosity at the time of pulling around the hybrid IC is higher than the viscosity at the time of dipping. Therefore,
The thickness of the coating layer b can be adjusted as desired without using a diluent to adjust the viscosity.

[Brief explanation of the drawing]

1 to 8 show the apparatus used in the method of the present invention, FIG. 1 is a side view of the immersion apparatus, FIG. 2 is a side view of the immersion apparatus with some parts omitted, and FIG. 3 is a side view of the immersion apparatus. The figure is a perspective view of Fig. 2, Fig. 4 is a front view of the vibration generator, and Fig. 5 is a perspective view of Fig. 4.
6 is a front view of the holder of the hybrid IC, FIG. 7 is a side view of FIG. 6, and FIG. 8 is a 70-level diagram of the servo motor control section of the control device. 9 and 10 show the conventional immersion method, FIG. 9 is an explanatory diagram showing the normal immersion method, and FIG. 10 is an explanatory diagram illustrating the immersion method in which immersion is performed while applying vibrations. 1...Hybrid tC 3...Coating agent Applicant Toyota Motor Corporation Representative Patent Attorney Hidehiko Okada (3 others) 1st hearing Figure 4 Figure 5E Force OA Figure 7

Claims (1)

[Claims] A method of forming a coating layer on the surface of a hybrid integrated circuit by immersing the hybrid integrated circuit in a liquid coating agent such as a resin, the method comprising: a dipping step of immersing the hybrid integrated circuit in the coating agent while vibrating the hybrid integrated circuit; a pulling step of pulling the integrated circuit out of the coating agent while vibrating the integrated circuit, and the frequency in the pulling step can be arbitrarily changed within a range smaller than the frequency in the dipping step.