JPS6086267A - Preparation of electric insulating film - Google Patents

Abstract

PURPOSE:To obtain an electric insulating film having high heat conductivity, by subjecting polymerizable gas formed by combining gaseous hylogenated hydrocarbon, gaseous hydrocarbon, hydrogen and gaseous halogen in a predetermined combination to plasma polymerization reaction at a predetermined electron temp. CONSTITUTION:Halogenated hydrocarbon gas A, hydrocarbon gas B, hydrogen gas C and halogen gas D are prepared. 10 kinds of gases are prepared in the combination of only gas A, gases A and B, gases A and C, gases A and D, gases A, B and C, gases A, B and D, gases A, C and D, gases A, B, C and D, gases B and D, and gases B, C and D. One or more of these combined gases is mixed so as to adjust the ratio of the number of halogen atoms and the number of hydrogen atoms to 1:5-5:1. This polymerizable gas is subjected to plasma polymerization reaction at the plasma electron temp. of 2,000-60,000K in a reaction zone.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an electrically insulating film having high thermal conductivity.

Generally, electrical insulating materials with high thermal conductivity are used in various electronic components that generate heat, diodes, transistors, and ICs.
It is used in semiconductor devices such as , LSI, and other heat sink materials to improve heat dissipation in addition to electrical insulation. However, conventional insulating materials listed in II7+ generally exhibit lower thermal conductivity than metals such as copper, so it has been difficult to flow a large amount of heat in a small area. In particular, with the miniaturization of various electronic components and semiconductor elements, it has become necessary to flow a large amount of heat per unit area.

Specifically, aluminum oxide and boron nitride caps are known as electrical insulating materials with high thermal conductivity close to that of copper, but these are ceramics and have the following drawbacks. (2) Since it is a sintered body, it is not easy to form a film arbitrarily to match the shape of the object to be coated, or to form a QIIA of any thickness according to the purpose15). (■Although it has high hardness, it is brittle and breaks easily. (The electrical resistance is high enough to be used as an insulating material, but the thermal conductivity is slightly lower than that of copper.

An object of the present invention is to provide a method for producing an electrical insulating material having a thermal conductivity higher than that of copper or the like and having a high failure resistance in an arbitrary thickness and in an arbitrary shape. .

According to the present invention, halogenated hydrocarbon scum (A),
Polymerization containing one or more gases selected from y&hydrogen gas (B), hydrogen gas (C) and halogen gas (D) in any combination of the following (1) to (lO) Gas for: (1) A only, (2) A+B, (3) A+C1 (4) A+D, (5) A+B 10, (B) A+B+D, (7) A+C+D, (8) A+B+C 10 D, (!' l) B + D, (10) B + C + p, in which the ratio of the number of halogen atoms to the number of hydrogen atoms in the combined waste is 1:5 to 5:1, and the electron temperature of the plasma in the reaction zone is is 2,000~130.0OOK
A method of manufacturing an electrical insulation in 11 minutes is provided, which comprises subjecting the electrical insulation to a plasma polymerization reaction.

The objects to be coated in the method of the present invention are usually electronic parts and elements that are actually used, but for example,
- By using a molded article made of lithium, potassium bromide, etc. as the object to be coated, and after coating, the object to be coated can be dissolved away to obtain a free membrane.

The present invention will be specifically explained below.

FIG. 1 shows an example of an apparatus suitable for carrying out the method of the present invention. In this device, a pair of plate-shaped electrodes 3.3° facing each other are provided in a vacuum container 2 to which a vacuum pump 1 is connected, and the electrodes 3.3° are connected to, for example, an AC power source 4. . On the other hand, the vacuum vessel 2 includes one or more gas supply pipes 5 for supplying gas into the vacuum vessel 2.
is connected. During operation, a glass fiber encasement (.
The rest belt 8 is made to run between the 1111 electrodes 3.3'' by the rolls 6A and 6B, and the electrically insulating film having high thermal conductivity of the present invention is formed in the following manner.

That is, while the inside of the vacuum container 2 is deaerated by the vacuum pump 1, a polymerization gas already adjusted to the above-mentioned composition is introduced into the vacuum container 2 via the monomarcus supply pipe 5, or the above-mentioned gas ( One or more of A) to (D) are separately introduced into the vacuum vessel 2 so that a polymerization gas having a desired composition is adjusted within the vessel. The polymerization gas introduced or adjusted here has a ratio of the number of halogen atoms to the number of hydrogen atoms in the vacuum container 2 of 1:5 to 5:
1, preferably in the range of 1:3 to 2:1.

While the atmosphere inside the vacuum container 2 is kept constant as described above, power is supplied to the electrodes 3.3'' from the AC power source 4, thereby generating plasma by discharge between the electrodes 3.3''. Further, the electron temperature is 2,000 to so, oo at the position where the plasma passes through the heald 8 on which the object to be coated, for example a silicon wafer, is placed.

This plasma is applied to the silicon wafer to continuously form an electrically insulating film having a high thermal conductivity and made of a plasma polymerized film using the monomer gas on the surface of the silicon wafer.

The electron temperature in the present invention is disclosed in Japanese Patent Application Laid-Open No. 54-135574.
It is measured using a heated probe as described in the same publication. This can be done by inserting the heating probe P into the plasma region other than the so-called plasma sheath region near the electrode surface in a direction perpendicular to the plane of the paper in FIG. 1, as shown in FIG. 1, and its temperature can be controlled. For example, AC power supply 4
This can be carried out by changing and adjusting the electric power supplied to the electrode 3.3°, the degree of vacuum in the vacuum vessel 2, and other conditions.

The degree of vacuum in the vacuum vessel 2 is preferably 101 torr or less, and the degree of vacuum in plasma polymerization 1.1 is usually about 10 to 1 torr. When the number of halogen atoms in the polymerization gas exceeds 5 times the number of hydrogen atoms, the film growth rate decreases; It has low resistance.

In addition, in the present invention, the plasma involved in the formation of the film must have an electron temperature of 2,000 to 80,000 K, and if it is less than 2,000 K, it does not necessarily have high thermal conductivity. No film was formed and 60
, 0OOK, it becomes difficult to obtain a uniform film in terms of thickness, properties, etc.

In the present invention, the plasma electron temperature is 2,000~G
If it is within the range of o, QOQK, there will be no side-stage constraints, but with the electron temperature of 30.0OOK as a rough boundary, the characteristics of the insulating film formed in each electron temperature range above and below it are A difference is recognized as a tendency, and there is a tendency that the characteristics of insulation +1Q are more preferable when it is 5,0OOK or more and less than 30,000. Table 1 shows the characteristic values when an electrical insulating film is formed in each electron temperature range. The sample was obtained by forming a plasma polymerized film in the same manner as in the formation of an electrical insulating film in Example 1 described below, except that a measurement substrate was used and the electron temperature of the plasma was changed. be.

From the values in Table 1, it can be seen that electrical insulating films with different characteristics are formed by plasmas with different electron temperatures, and that electrical insulating films with excellent properties are formed regardless of the plasma in which electron temperature range. It is understood that it is formed.

The gas used in the present invention is the gas described above (A
) to (D), or may optionally contain an inert gas such as Ar or He. Among these gases, halogenated hydrocarbons are hydrocarbons in which at least one hydrogen atom is replaced by a halogen atom of the hydrocarbon. Preferred are halogenated saturated hydrocarbons having 1 to 8 carbon atoms, such as 1 to 4 fluorinated methane, 1 to 6 fluorinated ethane, 1 to 6 fluorinated ethane,
~87 Fluorinated propane, etc., and compounds in which all or part of these fluorine atoms are replaced with chlorine atoms can be mentioned. Among these, 1-4 fluorinated methane, 1-4
Particularly preferred is hexafluoroethane.

Preferred hydrocarbon gases are saturated hydrocarbons having 1 to 8 carbon atoms, such as methane, ethane, propane, butane, and the like. Particularly preferred are methane and ethane.

As the halogen gas, one or more of fluorine, chlorine, bromine, and iodine can be arbitrarily used, and fluorine or chlorine is particularly preferred.

The electrical insulating film of the present invention having high conductivity and V has a thermal conductivity comparable to or higher than that of metals such as copper, and has a sufficient electrical resistance as an electrical insulating material. Therefore, the effect is extremely large.
Insulating films for dissipating heat from SI and tIiLSI substrates, dielectric films for small high-power thin film resistors, small high-power capacitors, and even small printed circuit board materials and substrate materials for optical elements. It can be used as, etc.

In addition to these 41f lengths, it must be emphasized that the method of the present invention is carried out by plasma polymerization, which is a dry process. That is, the shape and size of the object to be coated can be freely adjusted, and a film suitable for the object can be easily formed.

The thickness of the film can be formed arbitrarily within the range of several amps to several pm.

There are no problems with waste liquid treatment or pollution caused by it. Furthermore, since the raw material gas does not contain heavy metals or toxic elements, it is safe to work with and there is no risk of pollution. Therefore, it is extremely advantageous in industrialization.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these.

[Example 1] Using the apparatus shown in Fig. 1, a glass plate on which gold was vacuum-deposited as a measurement substrate and a photoacoustic f fill measurement substrate (copper plate) were subjected to plasma treatment according to the method of the present invention as follows. A polymer film was formed.

For methane and tetrafluoride methane as monomer gas, the flow rate is 20cc (STP) / min and 1
It was 0cc (STP)/min. The degree of vacuum was maintained at 50 mTorr by adjusting the pumping speed.

The plasma was excited using a 20 kHz AC power source, and the electron temperature near the measurement substrate was maintained at 1.5×10 K by adjusting the supplied power.

A plasma-polymerized film having a film thickness of approximately 1 grn was formed on the measurement substrate by keeping the measurement substrate in plasma for 50 minutes.

The electrical resistance is determined by the glass formed by plasma polymerization 11Q (
Gold was deposited again on the plate and the volume resistivity between the second gold layer and the underlying gold layer was determined to be n11. Thermal conductivity was measured using the method of M. J. Adams et al. (A
Table 2 shows the results of fixing and determining Jllll in a photoacoustic measurement cell according to Nalyst, 102 p., 1378 (197?)).

[Comparative Example 1] In Example 1, except that the electron temperature near the measurement substrate was changed to 7.5×10 K, plasma polymerization was performed under the same conditions as in Example 1. In the same manner as in Example 1, the volume resistivity and thermal conductivity were added by 411. The results are shown in Table 2.

[Comparative Example 2] In Example 1, the flow rates of methane and tetrafluoromethane were set to 30 cc (STP)/min and 5 cc (STP)/min, respectively.
A plasma polymerized film was formed under exactly the same conditions except that the volume resistivity and thermal conductivity were set to 1.
111 was established. The results are shown in Table 2.

[Example 2] Set the electron temperature to 4. Except that it was set to OX 10K.

A plasma polymerized film was formed under the same conditions as in Example 1, and the volume resistivity and thermal conductivity were determined as Al1. The results are shown in Table 2.

[Example 3] Hexafluoroethane and hydrogen were selected as monomer gases, and the first
A plasma polymerized film was formed on the surface of the measurement substrate using the apparatus shown in the figure. The measurement substrate is the same as in Example 1. The flow rates of hexafluoroethane and hydrogen were each 10 cc (STP
) /min and 30cc (STP) /win. A 13.58 MHz RF main power source was used as a plasma excitation power source, and the 4° electron temperature near the measurement substrate was maintained at 2.5×10 K. By keeping the measurement substrate in the plasma for about 40 minutes, a plasma polymerization film having a thickness of about 1Lm was formed on the measurement substrate.

The results of evaluation using the same method as in Example 1 are shown in Table 3 together with Example 4 and Comparative Examples 3 to 5.

[Example 4] A plasma polymerized film was formed in the same manner as in Example 3 except that the cow electron temperature was 5.5×10 K.

[Comparative Example 3] A plasma polymerized film was formed under the same conditions as in Example 3, except that the electron temperature was set to 7; OX 1 OK.

[Comparative Example 4] The flow rates of hexafluoroethane and hydrogen were each 10 cc (S
TP)/win and 2cc(STP)/min
An attempt was made to produce a plasma polymerized film under the same conditions as in Example 3, except that In this case, almost no plasma polymerized film was formed.

[Comparative Example 5] The flow rates of hexafluoroethane and hydrogen were each 2 cc (ST
P)/min and 40cc(STP)/min
A plasma polymerized film was formed under the same conditions as in Example 3 except for the following points.

[Examples 5 to 12'l Plasma polymerized films were formed according to Example 1 using the apparatus shown in FIG. 1, and the electrical resistance and thermal conductivity were measured in the same manner as in Example 1.

The type of monomercus used in each example, the supply flow rate, the electron temperature near the 1111 regular substrate during plasma polymerization, and the polymerization time are as shown in Table 4, respectively. Further, in all Examples, the degree of vacuum during polymerization was maintained at 50 mTorr, and the plasma was excited using a 20 kHz AC power source. In each case, a 7° lasma film with a thickness of about 1 pm was formed. Table 4 shows the measurement results of volume resistivity and thermal conductivity.

[Brief explanation of the drawing]

FIG. 1 represents an example of equipment used to practice the invention. 1... Vacuum pump, 2... Vacuum container, 3.3'...
・Electrode, 5... Monomer gas supply pipe, 6... Held, 7... Coated object Patent applicant: Hiki Synthetic Rubber Co., Ltd. Representative Patent attorney: Shushi Iwamiya

Claims (1)

[Claims] 1. Halogenated hydrocarbon gas (A), )R hydrogen gas (B), hydrogen gas (C), and halogen gas ([))
Utilization gas containing one or more gases selected from the following combinations of (1) to (10): (1) A only, (2) A+B, (3) A+C1 ( 4) A+D, (5) A+B+C1 (6) A+B+D, (7) A+C+D, (8) A+B+c+D, (9) B+D, (10) B + C+ D, and the number of /\logen atoms in the polymerization gas and the number of hydrogen atoms is 1:5 to 5:1, and the electron temperature of the plasma in the reaction zone is 2,000 to 60.0OO.
A method for producing an electrical insulating film, which comprises subjecting K to a plasma polymerization reaction.