JPS59136930A - Reactive ion etching device - Google Patents

Abstract

PURPOSE:To contrive to enhance uniformity of etching on the surfaces of wafers to be etched by a method wherein depth of a wafer accommodating place is formed in the same depth substantially with thickness of the wafers to be accommodated, and the cooling surface of a coolant to come in contact with the electrode plate of a cooling mechanism is formed on the whole surface of the electrode plate excluding the pin penetrating parts. CONSTITUTION:The surface 1b of an electrode plate 1 is formed smoothly, a pedestal 2 is covered on the electrode plate 1, and a wafer accommodating place 31 of depth the same substantially with thickness of wafers 4 is formed on the surface of the pedestal thereof. The coolant of a cooling mechanism passes through a coolant path 46 formed inside of the electrode plate 1 to cool directly the electrode plate 1. The planar construction of the coolant path 46 is constructed as follows. The cooling surface of the coolant is formed on the substantially whole surface of the electrode plate 1 excluding the penetrating parts 5b, 5c and when the coolant is introduced from a lead-in port 46a, the coolant is guided by partitioning banks 46c to pass in the neighborhood of the pin penetrating parts 5b of the vertically transferring mechanism of the first wafer, and reaches in neighborhood of pin penetrating parts 5c for the second wafer, and similarly the coolant passes in the neighborhood of the pin penetrating parts 5d, 5e for the other wafers to flow to an exhaust port 46b.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to reactive ion etching, and more particularly, to reactive ion etching suitable for dry coating ultra-high density semiconductor devices. This invention relates to an improved electrode structure of the device.

[Technical Implications of the Invention] Recently, dry etching such as plasma etching has been increasingly used instead of wet etching to etch fine patterns in the production of ultra-high density semiconductor devices. In particular, reactive ion etching is often used because the etching rate in the lateral direction is smaller than that in the thickness direction due to anisotropic etching, enabling highly accurate etching, and the etching mask can use a normal photoresist pattern. It's starting to look like this.

However, as mentioned above, the electrode structure of conventional reactive ion etching equipment is
3C has been spared to ensure uniform etching, and D3 has been made to deal with damage to the resist pattern due to reaction heat. For this purpose, the need for improvement in the electrode structure is acutely felt.

1 Problems with the technology Reaction t Two flat plate electrodes facing the J5 are placed in a vacuum vessel into which the reaction residue is introduced, and one of the electrodes (this J-
When attempting to twitch, a plasmon of scum introduced by applying high-frequency power is emitted, and a field is generated by the reactive ion acceleration of the ion sheath into Fl. This is a device that can perform heat coating.

Fig. 1 is a plan view showing the electrode structure of a conventional device in which the lower electrode is connected to the lower electrode, and Fig. 2 is a partial sectional view taken along the line ■-■ in Fig. 1. Please refer to both figures below. The conventional electric FAW4 structure and its problems will be explained in detail. Both figures have J5 and 1
2 is an electrode plate, 2 is a pedestal that is covered when it is necessary to prevent impurities from entering the electrode plate 1 during etching, 3 is a recessed hole for accommodating the plate 1 to be etched 4, and 5 is a recessed hole. A wafer vertical movement mechanism consisting of a pin 5a passing through the electrode plate 1 (including the pedestal 2 if there is a pedestal); 6 an IC water cooling pipe held by the electrode plate to cool the electrode plate 1; Reference numeral 7 denotes a central axis of an electrode plate incorporating a cooling water inlet passage 6a and a cooling water discharge passage 6b, which is rotated by an external drive mechanism. When the wafer 4 with the resist mask pattern formed above the lower electrode plate 1 is transported from the loader (U in the figure) into the reaction vessel, the bin 5a of the upward and upward movement mechanism is pushed up to receive the wafer 4. Counterbored Hole]-Ha is stored in storage location 3. The electrode plate 1 containing the wafer is rotated while etching is performed, and during etching, the temperature of the wafer 4 rises to H due to reaction heat, but the reaction heat is transferred to the pedestal 2.
and is cooled via the electrode plate 1 by a water cooling vibro. When the etching is finished, cover the moving mechanism 5) 1
Press 4 and transfer to transfer device 2 (not shown).

However, in the above conventional electrode structure, as shown in FIG. 2, counterbore holes 1a are also provided on the surface of the electrode plate 1 corresponding to the counterbore holes 3 for accommodating wafers in the pedestal. An electrode plate 1 provided with a bored hole 1a was covered with a pedestal 2 of uniform thickness, and a counterbore hole 3 for accommodating a wafer was formed on the surface of the pedestal 2.

Moreover, the depth of the bore hole 3 for accommodating the wafer is approximately 6 mm.
It is formed at a depth of n, and the thickness of the upper part is usually 0.
, 6 ml, so the soil 4 was coated in the deep hole 3 of 1f.

In this way, if the electrode plate 1 with the If-bored hole 1a is etched while being accommodated deeply in the counterbore hole 3 for accommodating the wafer, the electric field distribution becomes non-uniform.
It was found that the reason why the etching within the surface was not uniform was found.

Next, in the conventional electrode structure described above, since the cooling structure is such that the water cooling 1 vibro is held on the back side of the electrode plate corresponding to the outer periphery of the wafer storage bore hole 3, the water cooling 1 vibro is placed in the center of the wafer 4. It has been found that the heat of the etching reaction is difficult to cool, and as a result, the upper limit of the heat resistance of Regime 1 to mask material may be exceeded, and this is the reason why the dimensional accuracy of etching at the center of the wafer is reduced.

[Objective of the Invention] The object of the present invention is to solve the above-mentioned problems obtained by the inventors through various tests and to improve the in-plane etching uniformity of a wafer to be etched. Another object of the present invention is to provide an electrode structure that can improve the uniformity of the etching process between the central part and the peripheral part of the wafer.

[Summary of the Invention] The present invention provides a wafer storage location for one electrode on which a wafer is placed in a parallel plate type reactive ion etching apparatus.
When providing a pedestal to cover the electrode plate, cover the pedestal with a smooth chemical electrode plate, provide a counterbore hole with a depth substantially equal to the wafer thickness on the surface of the pedestal, and do not cover the pedestal with the electrode plate. In this case, the first feature is to provide a hole in the electrode surface with a depth substantially equal to the thickness of the electrode, and the refrigerant cooling surface of the cooling mechanism The second feature C is that the movable device bottle is formed on substantially the entire surface of the electrode plate except for the portion where the bottle of the mobile device penetrates the electrode plate.

The first feature is that the device of the present invention is constructed as a means for making the electric field distribution (ion sheath) uniform. Then, the electrode on which the wafer is placed is configured in such a way that the wafer is placed on the platform on which the wafer is placed on the 1ζ part electrode, and also when placed on the upper electrode.

Furthermore, there are two methods for connecting the electrode on which the plate is placed to a high frequency power source: a cathode coupling method and an anode coupling method, and the present invention is applicable to both methods.

Therefore, since the second feature is compatible with the first feature, there is a means for fully exerting the effect of the first feature, and the scales of Regis 1~, This makes it possible to expand the allowable range of various conditions that apply to the reaction of bamboo and soil, such as engineering regulations.

An electrode structure composed of only the first feature or the second feature is not practical.

[Embodiments of the Invention] Examples of the present invention will be described below with reference to the drawings. FIG. 3 is a plan view showing the refrigerant cooling surface of the electrode in Example (2), and FIG. 4 is a partial sectional view of the electrode along line I■-IV in FIG. 3. The parts indicated by the same reference numerals as in FIGS. 1 and 2 are the same as the parts indicated by the corresponding numbers in FIG.

The electrode of this example has a base covered with it.
As shown in FIG. 4, the surface 1b of the electrode plate 1 is formed to be smooth, and the pedestal 2 is coated on the electrode plate 1. A wafer storage space 31 is formed. Therefore, the surface 2a of the C-C pedestal 2 and the etched surface 4a of the J-C 4 are on the same level.

As the pedestal 2, a polymer film such as a polynisder film or a poly]-ethylene film can be pasted, or a carbon plate, an aluminum base, a quartz plate, a silicon plate, a silicon nitride plate, or a silicon carbide plate can be used.
It is preferable to take the incense powder in close contact with the electrode plate and to react with a reactive gas positive containing a halogen element (4).

The refrigerant of the cold 7J1+M structure of this embodiment passes through a refrigerant passage 46 formed inside the electrode plate 1, as shown in FIG. 4, and directly cools the electrode plate 1. As shown in FIG. 3, the planar configuration of the refrigerant passage 46 is such that when the refrigerant is introduced from the introduction point 046a, it is guided to the partition bank 46c and passes near the bottle penetrating portion 5b of the first wafer vertical movement mechanism. It reaches the vicinity of the pin penetration part 5C for the second wafer, and similarly passes through the vicinity of the pin penetration parts 5d, 5e for the second wafer and the first wafer.
One side of the refrigerant cooling is formed on substantially the entire surface of the electrode plate 1 except for the pin penetration parts E)b to 5C so that the refrigerant flows to the outlet II 46b. Naturally, there are various designs other than those shown in this embodiment that effectively cool the entire surface of the electrode plate.

It goes without saying that there are various methods of manufacturing such an electrode plate.

Comparing the electrode of the present invention shown above with an electrode of conventional structure, reactive ion etching of a polycrystalline silicon film was performed and the uniformity of the etching amount was significantly improved. Fig. 5 (conventional type! IJA) J5 and Fig. 6 (example electrode) show fluctuations in the inner ring suspension of a 100 mm diameter woofer. The reason why the average level of etching is lower in FIG. 6 is because the cooling effect of the electrode in the example is higher. The variation in the numerical values in both figures is 83 for the conventional electrode and 2
While it is 2.5%, the example electrode has only 8.1%.
%Met. In addition, the dimensional accuracy of the central part of the wafer and the dimensional accuracy of the peripheral part of the wafer are unchanged because there is no damage to the pattern. , high melting point metal silylide film, single crystal silicon, silicon oxide film, and silicon nitride film were all tested, and good results similar to those in -F were obtained.

[Effects of the Invention] As is clear from the results of the above examples, according to the reactive ion etching apparatus equipped with an electrode in which both the wafer storage space and the cold FIF1 mechanism are improved as in the present invention, wafer etching is possible. The uniformity is significantly improved and the problem of damage to the Regime 1 pattern in the center of the wafer is solved. This improvement is thought to be due to a combination of uniformity of the electric field distribution on the wafer and uniformity of the wafer's coldness.
Therefore, according to the present invention, the variation in the T culm of the reactive ion top layer is reduced, and the tolerance of the type of mask resist 1- used and the etching conditions is improved.
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[Brief explanation of drawings]

Figure 1 is a plan view of the electrode in the conventional reactive ion A-Tubung device, and Figure 2 is! ′! 1 is a partial sectional view taken along the line II-It in FIG. 1, FIG. 3 is a plan view showing the electrode plate refrigerant cooling surface of the device of the present invention, and FIG. 4 is a portion of the electrode along the line IV-IV in FIG. The top view, FIGS. 5 and 6 show the effects of the present invention.
This is a graph with two bright spots. 1... Electrode plate, 1a... Electrode counterbore, 3゜31... Uyuha, 5... 11 hand movement mechanism,
55#l...pin, 51r, 5c, 5c, 5d...
- Bottle penetration part, 6.46... Refrigerant passage. Patent applicant Tokyo Shibaura Electric Co., Ltd. Figure 1 Figure 2 86b7 Figure 3 Figure 5 Figure 6

Claims (1)

[Scope of Claims] 1. It has parallel plate type electrodes arranged opposite to each other and to which high frequency power is applied, and one of the electrodes is attached to the surface of the wafer L to be etched which is d34J on the surface of the -h electrode plate. A reactive ion system comprising a storage space, a pin passing through the one electrode plate as a shield, and a reactive ion transport mechanism and a cooling mechanism for cooling the one electrode plate.
The depth of the above-mentioned
The refrigerant cooling 114 surface that contacts the electrode plate of the cold moon 1 mechanism is formed on substantially the entire surface of the electrode plate except for the bottle 1 passage portion. A reactive injecting device characterized by: 2. Reactive Beon Etching according to Claim 1 JJ4, wherein the wafer storage location is formed at a depth substantially equal to the wafer thickness and is provided on the surface of the pedestal covering the smooth electrode plate. Device.