JPH062119A - Ion plating method - Google Patents

Abstract

PURPOSE:To stably form a metal thin film on a rugged surface in uniform thickness at the time of forming a metal thin film on a substrate having the rugged surface by ion plating by using a pulse current of specified shape. CONSTITUTION:A metallic substrate 1 having a rugged surface is used as a negative electode in a vacuum vessel and with a vaporization source 2 as a positive electrode, both electrodes are connected to an ionizing pulse power source 14, an inert gas such as Ar is introduced into the vessel to generate a low-pressure Ar atmosphere, the metal in the vaporization source 2 is heated and vaporized by electronic beams, and a glow discharge is generated between the substrate 1 and the source 2 by a pulse current to ionize the vaporized metal atom which is adosrbed on the substrate 1. In this case, the positive polarity pulse duration TON in the pulse voltage to supply a pulse current is controlled to 0.1-10<6>mus, power supply is suspended after the positive polarity pulse current is supplied, a negative voltage -Vp with the absolute value smaller than then peak voltage Vp of the positive polarity pulse current is the impressed, and immediately the positive polarity pulse voltage Vp is impressed to supply a pulse current.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides an adhesion layer having a uniform thickness at each part and having no swelling due to wraparound adhesion to a substrate body having an uneven surface such as a multilayer substrate of electronic equipment. This is an ion plating processing method for forming.

[0002]

2. Description of the Related Art A conventional ion plating method is to apply a DC voltage to both of the substrates in a 1 × 10 ^-2 to 10 ^-3 Torr argon gas atmosphere with the substrate being minus and the thin film forming evaporation source being plus. Then, the evaporation source (metal) is evaporated, the evaporated atoms are ionized, and this is adsorbed on the substrate surface to form a thin film.

[0003]

In the above-mentioned conventional ion plating method, when a substrate for electronic equipment having fine irregularities is targeted, the corners on the substrate have particularly high electric field strength and a large amount of ion plating is applied. Is tinged. That is, as shown in FIG. 7, when ion plating is performed using a substrate obtained by laminating a metal plate 23 on one surface of a resin substrate 22 provided with a large number of small holes 21, a resin substrate corner at the upper end of the small holes 21 is formed. Ions are concentrated in the portion 24, and the thin film layer formed on the metal plate 23 in the narrow hole 21 expands only to that portion and becomes non-uniform, and the adhered metal layer formed in the adjacent small holes 21 and 21 disappears. There are drawbacks such as binding to each other and causing a short circuit in the circuit. In FIG. 7, θ represents a wraparound angle (°), which serves as a standard for the swelling portion of the thin film formed in the small hole 21. The ideal form is when θ is 90 ° or more.

[0004]

According to the present invention, a positive polarity pulse width τ _{ON is applied} in a processing method of ion-plating a substrate by energizing the evaporation source for thin film formation as positive and the substrate as negative under a reduced pressure. 0.1 to 1 × 10 ⁶
The method is characterized in that a pulse current of μs is applied. The present invention is also a method of energizing a positive pulse current, stopping the energization for each energization, and then energizing a negative pulse current. When the negative polarity pulse is applied, the absolute value of the peak voltage of the negative polarity pulse current may be smaller than the peak voltage of the positive polarity pulse current.

The reason why the pulse width τ _ON is set in the range of 0.1 to 1 × 10 ⁶ μs is that it is difficult to manufacture the current pulsed power source if it is less than 0.1 μs, and τ longer than 1 × 10 ⁶ μs. _{When ON} , the result is almost the same as that of conventional DC,
The bulge of the thin film becomes large, causing a short circuit, and the effect is lost.

As the substrate material, a single-sided copper-clad substrate, a double-sided copper-clad substrate, a multi-layered substrate, a flexible substrate, a bonding substrate, a high-density substrate, etc. are targeted, and as an evaporation source,
Gold, silver, copper, platinum, palladium, etc. are used.

The present invention will be specifically described below with reference to the drawings. FIG. 1 is an example of an apparatus suitable for implementation, 1 is a substrate to be ion plated, and 2 is an evaporation source. An electron gun 3 introduces an inert gas such as argon from a gun nozzle 4. A spare pipe 5 is an inlet for reaction gas and the like. Reference numeral 6 denotes a vacuum pump, which has a degree of vacuum of about 10 ⁻² to 10 ⁻⁴ Torr with a displacement of about 600 l / sec.
Reference numeral 7 is a water cooling copper pipe, 8 is an electron beam generating power source, 9 is a high frequency power source, 10 is a substrate heating heater, and 11 is a heater power source. Reference numeral 12 is a substrate thermometer, 13 is a conventional ionization current power source, and 14 is an ionization pulse power source of the present invention. Reference numeral 15 is a fixing electromagnet coil of the evaporation source.

First, the inside of the vacuum apparatus is 2 × 10 ^{-1 to} 5 × 10
^-2 Torr argon atmosphere. The substrate 1 is made negative and the evaporation source 2 is made positive, and a pulse voltage is applied thereto. In order to evaporate the thin film forming material in the evaporation source 2, the electron gun is set to a minus and a separate power source is used to evaporate the raw material. In this atmosphere, the vaporized atoms are ionized and strongly absorbed and attached to the substrate surface.

[0009] The basic pulse waveform used in the present invention is as shown in FIG. _{2, (- V P = 0V} ,

As a sample, thickness 1.6 mm, size 10
A polyimide resin plate having a size of 0 mm was formed with a large number of small holes having a diameter of 0.2 mm, and a copper plate having a thickness of 1 mm was attached to one surface of the hole. Gold was used as the evaporation source for thin film formation.
Argon gas is used as a gas for glow discharge, and 0.05
The atmosphere was Torr. DC 40 between electron gun and evaporation source
Apply a voltage in which 20 to 30 V AC is superimposed on V, and
A large amount of evaporated metal atoms are generated by applying a current of 0 A. As the vaporized atoms pass through the glow discharge due to the pulsed electric field, the ionized atoms are strongly attracted and adhered onto the negative high potential substrate. The positive pulse width at this time was changed within the range of 0.1 to 1 × 10 ⁶ μs, and the wraparound angle θ was tested. The results are shown in Fig. 3. FIG. 3 shows a conventional case of direct current as a comparative example.

The wraparound angle θ becomes smaller as the positive polarity pulse width τ _ON increases. That is, it indicates that the bulge becomes large, which causes a short circuit on the electronic circuit. Although it depends on the pause pulse width τ _off , when the τ _ON is 30 to 50 μs or less, the wraparound angle θ becomes 90 ° or more. Also, τ _ON : τ _off =
It is better that τ _off is larger than 1: 1. When the pause pulse width is increased, the wraparound angle (θ) becomes 90 ° or more as shown in FIG. 3, and problems such as contact short-circuiting do not occur.

As can be seen from FIG. 4, the energization is stopped every time the positive polarity pulse current is applied, and then the negative pulse current is added to increase the pulse width, thereby increasing the wraparound angle θ. Further, by increasing the pulse width of the positive polarity by applying the negative pulse, the swelling portion is ionized by the negative pulse, so that there is no swelling at all, and the deposit portion> Not larger than the initial area,
Rather, it becomes a shape like a small cone or a pyramid. Since the adhesion layer has a continuous fine structure, the mechanical strength is high.

Further, increasing the positive polarity peak voltage V _P from FIG. 6 increases the wraparound angle. This is because the ion movement is increased to form continuous fine crystals on the adhesion surface. Moreover, it tends to be conical to significantly ionize the attachment surface to increase the negative peak voltage -V _P. In the attachment, the amount of ion movement is given by the product of the current IP proportional to V _P and the positive pulse width τ _ON . Therefore, from the positive polarity pulse V _P

[0014]

【Example】

Example 1 As a sample, a polyimide resin plate having a thickness of 1.6 mm and a size of 100 mm square was formed with a large number of small holes having a diameter of 0.2 mm, and a copper plate having a thickness of 1 mm was attached to one side thereof. This was made negative and copper (Cu) or silver (Ag) was used as the evaporation source. Argon gas was used as the gas for vacuum discharge, and the atmosphere was set to a vacuum degree of 0.03 Torr. As in the case of gold, the electron beam from the electron gun melted and evaporated copper or silver as the evaporation source. This vapor atom has V _P 1000 V, τ _off 50 μs, -V _P 0 V, -τ _ON 0
By passing through the glow discharge by the pulse current of μs, the ionized cations are impacted, diffused and adhered onto the substrate. Positive pulse width is 0.1 to 1 × 10 ⁶ μs
The wrap-around angle θ was tested by varying within the range.

When the positive pulse width τ _ON is increased, the wraparound angle θ is also reduced in the case of copper and silver as in the case of gold. The range where θ is 90 ° or more is τ _ON 10μ for copper.
s _ON or less, and in the case of silver, τ _{ON is} 5 μs or less. This is because silver has the smallest ionization energy required to become a cation as compared with copper and gold, and the amount of sneak ions increases due to a large amount of ions.

Example 2 A method of stopping the energization every time the positive pulse current is applied and then applying a negative pulse current, the rest pulse width τ _{off is set} to 0.
The wraparound angle θ was similarly examined by changing the angle within the range of 1 to 1 × 10 ⁶ μs.

V _P 1000 V, τ _ON 30 μs, -V _P 20
Pause pulse width τ under the condition of 0 V, −τ _ON 10 μs
_{As with off} , the angle θ increases with increasing _off ,
The same applies to copper and silver. For copper, τ _off is 60 μs, and for silver, τ _off is 100 μs and θ = 90 °.

Further, the negative pulse width −τ _ON is set to 10 to 25 μm.
The angle θ (°) when changing to s was examined. τ _ON , τ _off
Etc. V _P 1000V, τ _ON 10 μs, τ _off 30 μs, −
Under the condition of V _{P of} 200 V, when −τ _ON is increased for both copper and silver, the shape becomes like a cone or a pyramid and the angle θ (°) becomes large within the range of deposition amount> ionization amount as in the case of gold.

[0019]

According to the present invention, a thin film having a uniform thickness and no swelling due to wraparound adhesion can be formed on a substrate surface having an uneven surface by an ion plating method, and a short circuit of a circuit can be achieved. It does not cause problems such as

[Brief description of drawings]

1 is an illustration of a device suitable for practicing the present invention.

FIG. 2 is an explanatory diagram of pulse waveforms used in the present invention.

FIG. 3 is a graph showing the relationship of the wraparound angle with respect to the positive pulse width in the present invention.

FIG. 4 is a graph showing a relationship between a wraparound angle and a pause pulse width in the present invention.

FIG. 5 is a graph showing the relationship between the wraparound angle and the negative pulse width in the present invention.

FIG. 6 is a graph showing the relationship between the wraparound angle and the peak voltage in the present invention.

FIG. 7 is an explanatory diagram of a wraparound angle (θ).

[Explanation of symbols]

 1 Substrate 2 Evaporation Source 3 Electron Gun 4 Gun Nozzle 5 Reactive Gas Inlet 6 Vacuum Pump 7 Water Cooling Copper Pipe 8 Electron Beam Generation Power Supply 9 High Frequency Power Supply 10 Substrate Heating Heater 11 Heater Power Supply 12 Substrate Thermometer 13 Ionization Current 14 Ionization pulse power supply 15 Electromagnet coil 21 Small hole 22 Resin substrate 23 Metal plate 24 Resin substrate corner

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuo Oba 4- 2-3 Matsuba-cho, Higashimatsuyama City, Saitama Prefecture (72) Inventor Yoshinori Shima 768-15 Ozenji, Aso-ku, Kawasaki City, Kanagawa Prefecture (72) Inventor Oba Chapter 3-205, 1-9 Hamasaki, Asagiri City, Saitama Prefecture

Claims (3)

[Claims] 1. In a processing method of ion-plating a substrate under a reduced pressure by energizing a thin film forming evaporation source with a plus and a substrate with a minus, a positive pulse width τ _ON is 0.1 to 1 × 10. An ion plating method characterized by applying a pulse current of ⁶ μs. 2. In a processing method of ion-plating a substrate by energizing the evaporation source for thin film formation as a plus and the substrate as a minus under a reduced pressure, a positive pulse width τ _ON is 0.1 to 1 × 10. An ion plating method, comprising: applying a pulse current of ⁶ μs, pausing the current for each pulse of the positive polarity, and then supplying a negative pulse current. 3. The ion plating method according to claim 2, wherein the peak voltage of the negative pulse current is made smaller in absolute value than the peak voltage of the positive pulse current.