JPS5942748B2 - Sputtering method using ion beam - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Ion beam processing machines have developed rapidly in recent years as a method for processing minute parts.

This method utilizes the sputtering phenomenon (
1) Any solid material, whether metal or non-metal, can be etched. (2) Complex shapes can be formed by sweeping the ion beam or using a mask. (3) The processing depth can be adjusted by sputtering. It can be easily controlled using time. It has the following characteristics. However, due to the nature of the ion beam, the minimum beam diameter is approximately 1 μm, and unless a mask is used, processing of less than 1 μm is currently impossible, and even if an ion source with a large current is used, the etching rate is 10 μm or less. ~103 A/min, which is smaller and takes longer processing time than other etching methods. On the other hand, laser etching
It has features such as a minimum spot diameter of 0.5 μm and a short machining time, but since it uses the evaporation phenomenon of substances, it is difficult to control the machining depth of A order, and the machining interface changes in quality due to heat.

The present invention relates to a new ion etching method that overcomes the drawbacks of these two methods.

In other words, when processing a material using a sputtering process using ions, radiation, such as laser light, is irradiated onto the area to be etched at the same time as ions, and the sputtering rate of that area is lower than that of other areas that are not irradiated with laser light. It is characterized by its ability to dramatically increase its size and process substances into arbitrary shapes. The present invention will be explained below with reference to Examples.

FIG. 1 shows an example in which a laser gas is installed in an ion beam etching apparatus.

Ions 2 created by the Tuoplasmatron 1 are extracted by an extraction lens 3, accelerated and focused, pass through a slit 4, and become a focused beam. The focused ion beam is deflected and scanned by the scanning electrode 5 and impacts the material to be processed 6, causing sputtering and etching. Note that the device is differentially pumped with exhaust systems 11, 12, and 13. Depending on whether or not the mask 14 is used, sputter etching is roughly divided into two methods: (a) ion beam milling and (b) ion beam etching. Ion beam milling is a method in which an ion beam is focused to a minimum size of 1 μm and directly impacts the material to be processed 6 without using a mask 14 to perform desired processing.

In this case, the amount of beam current generally decreases due to the convergence of the ion beam, and therefore the sputtering rate also decreases. Further, since ion beams of 1 μm or less are not currently available, microfabrication of 1 μm or less is difficult. In ion beam etching, the ion beam is spread uniformly or the ion beam is scanned to make the current density widely uniform, and the material to be processed 6 is bombarded through the mask 14.
This method performs the desired sputter etching process.

By using the mask 14, this method allows complex processing and processing on the order of 0.1 μm. However, because it requires spreading the beam uniformly and scanning,
The ion current density is even lower than that of ion beam milling, and the processing time is longer. In this way, ion etching takes a long processing time and
The use of a mask is essential for processing smaller than m.

However, during these ion etchings, in the figure,
When the laser beam 10 produced by the laser generator 9 is simultaneously irradiated onto the workpiece material 5 through the view ink port 8, the surface temperature of the workpiece material increases due to absorption of the laser light, and the temperature dependence of the sputtering rate increases. Due to the nature of the process, the sputtering rate in the heated part is higher than in other parts.

The temperature dependence of the sputtering rate for several substances is shown in FIG. 2, and the melting points are shown in the following table. As shown in the figure, the sputtering rate tends to increase rapidly from temperatures below the melting point of the material.

That is, by appropriately selecting the wattage and pulse number of the laser beam, heating the surface of the workpiece to a temperature below the melting point of the workpiece, and simultaneously bombarding the workpiece with an ion beam, the area irradiated with the laser beam is heated. Etching can be performed at a sputtering rate several to several tens of times higher than that of the least irradiated portion, and since the etching is performed at a temperature below the melting point of the material, thermal alteration of the processed interface is thought to be small. When this phenomenon was used for ion beam milling, by synchronizing the laser beam and the ion beam, processing was possible at a high sputtering rate, and the processing time was significantly shortened.

Furthermore, processing time could be easily controlled by changing the number of pulses of laser light. In addition, in the case of ion beam etching, by scanning the laser beam during ion bombardment, the portion irradiated with the laser beam could be etched at a higher speed than the portion irradiated with the last irradiation.
This method does not use a mask and can form a pattern that corresponds to the spot diameter of the laser beam, although some parts other than the desired part are processed, so it would not be possible without a mask. It was also possible to process a hot 0.5 μm pattern. Furthermore, even when using a mask, the ion etching speed can be easily increased by scanning the laser beam and using a heater (7 in Figure 1) to heat the material to be processed, thereby shortening and controlling the processing time. I was able to do that. Further, no thermal alteration of the processed interface was observed.
A similar effect can be achieved by using an electron beam instead of a laser beam.

In this case, temperature increase of the workpiece occurs due to absorption of electron energy, and is therefore greatly influenced by the current density of the electron beam. If there is an electron beam generator that can generate a large current, the electron beam can be easily converged to micrometers or less, so finer processing than is possible using laser light is possible. As mentioned above,
According to the present invention, the processing time, which was a major drawback of conventional ion etching methods, can be easily shortened, and the processing time can be arbitrarily selected over a wide range.

Further, etching can be performed in accordance with the spot diameter of the laser beam without using a mask, and a fine pattern of .mu.m or less can be formed. Since this method utilizes sputtering below the melting point of the material, thermal alteration of the processed interface is extremely small.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the configuration of an ion beam etching apparatus according to the present invention, and FIG. 2 shows the temperature dependence of the sputtering rate. 1... Teyuo Plasmatron, 2...
Ion, 6... Material to be processed, 9... Loser generator, 10... Laser light.

Claims (1)

[Claims] 1. A sputter processing method using an ion beam, characterized in that a radiation beam is simultaneously irradiated during ion beam irradiation to etch a material to be processed. 2 Claim 1 in which the radiation is a laser beam
Sputter processing method using an ion beam as described in Section 1.