JPS605878A - Control method of discharge impedance of sputtering device - Google Patents

Abstract

PURPOSE:To increase the number of substrates to be treated per sheet of target by decreasing gradually the current to be passed to an electromagnet which generates a magnetic field on the front furface of a target disposed oppositely to a substrate holder and maintaining the discharge impedance approximately constant. CONSTITUTION:Negative potential is applied from a spouttering power source 5 to a target 4 disposed oppositely to a substrate holder 3 holding a substrate 2 in a vacuum chamber 1 and said target 4 is sputtered by the magnetron discharge generated by the effect of the magnetic field of an electromagnet 6 to form a film on the substrate 2. The change in the discharge impedance with a decrease in the thickness of the target 4 owing to erosion 9 according to progression of the sputtering with such sputtering device is detected with the ammeter 11 or voltmeter 12 of the sputtering power source 5 and the current of a DC power source 8 for exciting the electromagnet 6 is decreased according to the detected current or voltage vlaue so that the above-mentioned discharge impedance is maintained constant. The target 4 is sputtered until the target is thinned by the above-mentioned disposition, by which the number of the substrates to be treated per sheet of the target is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetron search snow ξ tutting device; the discharge impedance ili'l (ff11 method of q).

Conventionally, in this type of device, a substrate such as Si ware 1 in a Makabe chamber is attached, and an A4 or other target is provided facing the substrate holder.
A difference of 7 degrees from the CC voltage is applied, and a magnetic field from a lid magnet or a permanent magnet is applied to the front surface of the D metal target to generate magnetron radiation, which sputters the target material onto the substrate surface. In general, it is a material that forms a thin film of material. Therefore, the target is 1 (one mouth,) with the spatter
The magnetic flux density W of the electromagnet that faces the target increases with the thinning, which causes the following problems. . That is, as the magnetic flux density increases, the discharge impedance decreases, and at C, the Sunotsuta current gradually increases by 3?il, and finally, at Q, it reaches the rated value of the Sunotsuta power supply. Therefore, constant I1. :,, 1r1j
Thin films were sequentially formed using the following steps: (film thickness of the plate and traces of the final substrate) 1. However, there is a disadvantage that there is a large difference between the two targets, and it is not economical because many substrates cannot be processed with one target.

The purpose of the present invention is to solve the problem of 15 cases, etc., and a target is provided in a facing manner to a substrate holder in which a substrate is mounted in a vacuum chamber.
2222154 Apply a negative potential to the bottom K Df;
Targera) (D 15i1 iM VC'r'rL
iin stone (7) fa world? It acts to generate magnetron emission Tχ, and the target is exposed to snow? In the vine type, the current flowing through the electromagnet is lowered by 1 so that the discharge impedance is kept approximately constant λ.

An embodiment of the present invention will be explained with reference to the drawings.(1) shows the odor exhaust pipe 1. A thin film was formed on (2) J7. (3) is a board holder that can completely defeat the board (21), (4)
) indicates a target, a holder (3) and a target (4) are provided facing each other in the viewing area (1), and a C or RF sputter source (5) is provided as shown in the figure. For example, connect holder (3) and target (4) 1■1
1, no difference is given. (18) is the 'l'ijl magnet provided behind the targets i and ll via the backing plate (7), and 18) is the 7Q;
) to excite I) CL7) Electricity (,;

Sputtering of <7″ I □Pure bX tf:,
This is a conventionally known method, in which the vacuum chamber (1) is evacuated, Ar and other rare gases are injected, the electromagnetic field (electromagnetic field) is excited, and the sputtering power source (5) is turned on and the target (4) is turned on. A magnetron discharge occurs in front of the substrate (2), and the material of the target (4) is splattered by the excited ions and forms a thin film (114) on the surface of the substrate (2)! It adheres to the shape.

f o target (4) e.g.) -9sa3 cTn A
/- and 4i'# 3jV.

1, the surface is dense with horizontal magnetic flux, for example, 25'
A magnetic field of O Gauss is provided by an electromagnet (6). Further, the substrate (2) is sequentially and alternately positioned in the same direction as the target (4).

Terkera) +41 Next ε due to erosion of U Spack
It becomes thinner as shown by the dotted line (°C) in B, and the surface 7
．． (As a result of high flux density, the discharge impedance becomes small and when constant power operation is performed, snow ivy 'i'j'
The i and l baths (5) reach their full current rating.

The present invention focuses on changes in discharge impedance due to thinning of the target (4). Then, increase the current by 1 or increase the current until the current approaches the full rated current. When the pressure drops below the set value by 1, lower the current of the electromagnet (6) and reduce the discharge impedance. It was set to a constant K frill n.

To further explain this, as the erosion of the target 14) progresses, the tD5 current and pressure of the sputtering power source (5) gradually rise and fall as shown in A and B in Figure 2, respectively. A hole is observed, and the output current A reaches the full rated value shown at point C, or reaches the current value 't1, which is close to full, or the voltage B becomes lower than the set value E as shown by the dot. Lower F'N The current needle of circuit (10)) or 'B
4 pressure n [detected by ke a, 'i1i, magnet +6) electric jI
fe Lower F as shown at point G. Therefore, the discharge impedance is divided into approximately constant values as shown by the turntable H, and a large number of substrates (2) can be processed without exceeding the output of the sputtering space (5). As shown in the curved heddle, the film JV of the VC substrate (2) can also be obtained at a constant value of P[3. Comparing this f′L with the conventional case, the conventional case shows that the growth of the substrate 121 k 200 A/see J1r%
M When the number of sheets exceeds 321, which is about 1400 sheets in ML, the discharge impedance becomes small and the source (
5) becomes VC with full rated type outflow power, so the target (4
), but by lowering the '11z flow of the electromagnet (6) as in the present invention, the discharge impedance can be kept approximately constant even when the number of sheets processed exceeds 1400 sheets, and the target ( 4) can be effectively used in 1, where it becomes very thin.

What is the reason why the discharge impedance becomes approximately zero by lowering the current through 71 of the electromagnet (6)? 5. This is because the 6n flux density in front of the target (4) decreases by increasing the flow.

In the example, the snow ivy circuit (the voltage of 101 is 500 V
When the current falls below, lower the current of the electromagnet (6) by IA and f
ttlJ I, but circuit] 10) ammeter 0.3) or voltage > 3i To the subtractor ([3) connected to If21,
r, si'] may also be made to control the current of the power supply (8) of the magnet (to), and ril, the current of 1 to the magnet 1 is lowered by j'jj with more turns. It also has a power of 11, and can be lowered continuously.

In this way, according to the present invention, the current of the magnet is lowered by the first order, and the discharge impedance is reduced to approximately -1.
j; Since it has been made to last, even if the erosion of the target progresses, you can perform snow V tsuttering with a constant '71C force without having to overcome the +11 force of the sputter electric force, and cross the target 14. ) It is possible to process a large number of boards for a long time without having to do anything. 11. Efficiency is improved, it is economical as it is possible to effectively utilize the Kufut, and the thin and brittle thickness of the substrate O can be formed with a substantially constant thickness.

[Brief explanation of the drawing]

Figure 1 shows the fruit of the present invention 1t('j, shijl(7) heart diagram, ε
Figure P12 shows the substrate processing number and the electric current υ [shi,・i,)l:
It is a different diagram showing the 111j coefficient of Ii and discharge impedance. (1)...Vacuum chamber (2)...Substrate

Claims (1)

[Claims] A target rattler is provided facing the substrate holder to which the substrate is attached in the vacuum chamber, and a negative 154 position is applied to the target by a power source, which reaches the front of the target, and the field of the magnet acts to generate a magnetron discharge. In the method of sputtering a target, the above-mentioned 'II
A method for increasing the discharge impedance of a sputtering device p'4' by sequentially lowering the current flowing through the I magnet.