JPH0639693B2 - Dielectric Bias Sputtering Device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement in a dielectric bias sputtering apparatus.

(Prior Art) In forming an interlayer insulating film of a semiconductor integrated circuit or a protective film of a thin film magnetic head, when a circuit has a step portion, the formed film may be constricted or an abnormal layer may grow at the step portion. Therefore, the reliability of the device is often lowered. In order to improve this phenomenon, a film forming method using a bias sputtering method is often adopted.

Bias sputtering devices are roughly classified into coaxial type, parallel plate type, carousel type, and planetary type, but in terms of function and productivity, many substrates are placed on the cylindrical side surface of the substrate holder that rotates at the center. A carousel type in which the target is mounted and the target is arranged so as to surround the side surface thereof is advantageous. However, in the carousel type bias sputtering device, the structure of the rotating substrate holder that also serves as an electrode becomes complicated (the rotating substrate holder cannot be a simple structure because it is in a vacuum chamber or requires cooling of the substrate), and as a result, The exposed surface of the substrate holder becomes wider,
There is a drawback in that the power density of the power applied to the substrate part becomes small, and it does not reach the size necessary for obtaining good film quality.

For the purpose of solving this problem, conventionally, a method of covering the unnecessary exposed surface of the substrate with an insulator (FIG. 2) and a method of covering with a metal shield (FIGS. 3 and 4) have been adopted.

In the conventional carousel type dielectric bias sputtering apparatus (cross-sectional view) of FIG. 2, a cooling water channel 5 is connected to a high frequency power source 21 and a matching circuit 20 on a part of the wall of the vacuum container 1.
A target holder 2 and a target 3 each having a built-in are provided via an insulator 70, cooled by cooling water passing through a cooling water passage 5 (thick line) in the center of the vacuum container 1, and rotationally driven by using a rotary drive mechanism (not shown). A carousel-type rotating substrate holder is provided. Reference numeral 7 is an insulating bearing, and 6 is an exhaust pipe. At the same time, the rotating substrate holder 4 is connected to the high frequency power source 23 via the matching circuit 22 and also serves as one electrode.

Since the glow discharge is generated between the exposed surface of the rotating substrate holder 4 and the target 3, the unnecessary exposed surface of the rotating substrate holder 4 is changed as described above for the purpose of increasing the power density.
Measures are taken to prevent the surface of that portion from participating in glow discharge by providing a void of 0 to 2 mm and covering it with an insulator 100 having a thickness of 2 to 10 mm.

However, this method has a drawback that the processing cost is extremely high because it is necessary to process the insulator 100 such as a thick quartz plate according to the complicated shape of the substrate holder 4.

In the conventional carousel type dielectric bias sputtering apparatus of FIG. 3 (cross-sectional view), the same members as those in FIG. On the other hand, a metallic shield plate 110, which is provided with a gap of 2 to 3 mm and covers it, is attached (using legs 113) to the ceiling surface 111 of the vacuum container 1 above and to the bottom surface 112 below. .

Although the metallic shield plate 110 is low in material cost and processing cost, in this method, a large capacitance C is formed due to the coating of a large area, and a high frequency current flows through this capacitance C. There is a drawback that a part of the electric power applied to the rotating substrate holder 4 becomes ineffective, the shield plate generates heat, and cooling of the substrate is impaired. Further, if the shield plate 110 and the leg 113 to which a high frequency voltage is applied are long, a large L component is generated to reduce the shield effect, or the vacuum container 1
Unexpected man-hours are consumed for removing dust and adhering substances generated inside,
It also has the drawback of reducing maintainability.

The conventional carousel type dielectric bias sputtering apparatus shown in FIG. 4 is an improvement of a part of the apparatus shown in FIG. 3, and is intended to reduce the coating area of the metallic shield plate 110.
The pocket spaces 116 and 117 of the substrate holder 4 are covered with stainless steel plates 114 and 115. But,
Even in the apparatus shown in FIG. 4, the effects of C and L described above still remain.

(Object of the Invention) An object of the present invention is to solve the above problems and to provide an economical dielectric bias sputtering apparatus in which the power density of the power applied to the substrate portion is sufficiently high.

(Structure of the Invention) The present invention provides a carousel-type dielectric bias sputtering apparatus in which a barrier made of a flat plate-shaped insulator is provided on both upper and lower end surfaces in the rotation axis direction of a rotating substrate holder so that a pocket space of the substrate holder is turned into plasma. The above-mentioned object is achieved by partitioning it.

(Embodiment) FIG. 1 shows a dielectric bias sputtering apparatus (cross-sectional view) of an embodiment of the present invention, and the same members as those in FIGS. 2, 3 and 4 are designated by the same reference numerals. New thickness 1
The barriers 11 and 12 made of 0 mm insulator (quartz plate) are flat plates provided on both upper and lower end surfaces of the rotary substrate holder 4 in the rotation axis direction. The barriers 11 and 12 are formed against the plasma formed in the plasma discharge space between the side surface of the rotating substrate holder 4 and the target 3 surrounding it.
The pocket spaces 116 and 117 of the rotary substrate holder 4 are defined. With this compartment, pocket space 1
Plasma does not diffuse into the inside of 16, 117, and the surface of the rotating substrate holder 4 facing this pocket space does not participate in the discharge. Experiments have confirmed this. Therefore, the exposed area of the rotating substrate holder 4 is apparently small, and the power density of the substrate portion can be increased.

The barriers 11 and 12 made of an insulator isolate the back surface side of the substrate 10 in the figure, that is, the pocket spaces 116 and 117 from the plasma formed in the plasma discharge space between the substrate 10 and the front surface of the substrate 10, that is, the target 10. Then, a voltage drop occurs in the insulating layer, and plasma generation in the pocket spaces 116 and 117 is suppressed. The barriers 11 and 12 reduce the high-frequency power that flows into the rotating substrate holder in the pocket spaces 116 and 117, and the pocket spaces 11 and 12 during rotation.
6, 117 has the function of eliminating abnormal discharge that often occurs. Further, when this is compared with the conventional device having the structure shown in FIG. 4, the shield area is approximately 1/2, so that the power can be effectively utilized.

In addition to quartz, ceramics such as alumina can be selected as the material of the barriers 11 and 12 made of an insulating material according to the application, and in most cases, a simple flat plate or a perforated flat plate can be used, so that it can be added inexpensively.

(Effects of the Invention) The present invention has an effect of providing a dielectric bias sputtering apparatus which has a sufficiently high power density of power applied to a substrate portion and is highly economical.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a dielectric bias sputtering apparatus according to an embodiment of the present invention. Figures 2, 3 and 4 are similar to the conventional figures. 1 ... Vacuum container, 2 ... Target holding plate, 3 ... Target, 4 ... Rotating substrate holder, 11, 12 ... Barrier made of insulating material, 110 ... Shield plate.

Claims (1)

[Claims] 1. A rotary substrate holding a substrate, which has a carousel-type rotary substrate holder configured to rotatably hold a substrate on a side surface and a target arranged to surround the side surface of the rotary substrate holder. In a dielectric bias sputtering apparatus for forming plasma in a plasma discharge space between a side surface of a holder and a target to perform sputtering, a flat plate-shaped insulator is formed on both upper and lower end surfaces in the rotation axis direction of the rotating substrate holder. A dielectric bias sputtering apparatus characterized in that a barrier is provided to partition a pocket space of the substrate holder with respect to the plasma.