TW497133B - Device and method for preventing over-thick film deposition on the edge of a wafer - Google Patents

Abstract

The present invention provides an isolation ring attached on a discharge electrode for preventing non-uniform thickness of the deposited film caused by the tip discharge effect. The isolation ring device is formed by insulating material or conductive material, and is secured to the discharge electrode by a plurality of stands. By adjusting the distance between the isolation ring and the discharge electrode, it is able to achieve an optimal effect of preventing the tip discharge. Alternatively, the clamp for fixing the wafer has a ring-shape isolation ring. The isolation ring is located above the wafer and connected to the substrate, so as to be used as a clamp for fixing the wafer and also provide an isolating tip discharge effect for preventing non-uniform thickness of the deposited film on the edge of a wafer. The isolation ring can be formed by insulating material or conductive material.

Description

497133 V. Description of the invention α) 5-1 Field of the invention: The present invention relates to a device and method for thin film deposition, and particularly to a method for preventing thin film deposition on the edge of a wafer. 5-2 Background of the Invention: In the current deposition methods, atmospheric pressure chemical vapor deposition and low pressure chemical vapor deposition are heated or heated to the surface to generate a chemical reaction to form a thin film. Plasma chemical deposition method is to introduce plasma into the reaction space of atmospheric pressure chemical vapor deposition method and low pressure chemical vapor deposition method, so that the gas existing in the space is activated, and it can be produced at a lower temperature. Developed into a thin film case. In the semiconductor manufacturing process, it has been put into practical use for low-temperature (200 ° C to 400 ° C) production and research of nitride films, oxide films, and phosphor-silicon glass films. For example, in the case of a nitrided broken film, the atmospheric pressure chemical vapor deposition method or the low pressure chemical vapor deposition method must be 100 ° C. If this method is used, the film can be prepared at about 300 ° C. Others The same is true for oxides. i Plasma chemical vapor deposition method is to send easily decomposable gas containing elements to be formed into the reaction space, and use plasma to activate it to make a thin film. The effect of the plasma during the reaction is to reduce the gas temperature (not particularly high temperature), and

497133 V. Description of the invention (2) It can produce chemically active excitation actives, which are generated by the collision of low-speed electrons and gases in the plasma. The plasma chemical vapor deposition method is used to form a thin film. Although it can be performed at a low temperature, the device is shown in the first figure. 10 is a substrate. The wafer 20 is fixed on the substrate 10 by several jigs. The discharge electrode 3 0 is relatively above the substrate 10, and the plasma 40 is generated by the discharge electrode 30. However, in the density distribution of the plasma 40 discharge, a higher density appears at the edge of the discharge electrode 30, which is called tip discharge 5 0, as shown in the first figure, the flow direction of the plasma 40 can be clearly seen, and a vertical discharge appears in the central part. The closer to the edge, the higher the discharge density and outward diffusion. This phenomenon will cause the wafer 2 The non-uniformity of the thin film deposited on the surface. The thickness of the deposited wafer 20 is measured and measured from the center point of the wafer 20. The measurement result is shown in the second figure, and the horizontal coordinate in the figure is the wafer. The horizontal distance position of the unit is calculated in centimeters, and the ordinate is the thickness of the film deposited in units of angstroms. It can be seen from the curve of the second figure that the closer to the outer edge of the wafer 20, the thickness of the film increases significantly, and the film thickness increases sharply at about one centimeter of the wafer 20 edge. Because of this 50-point tip discharge effect, the thickness of the deposited film is non-uniform, which leads to the peeling of the deposited film when the wafer is removed after deposition, or during subsequent deposition processes, such as the deposition of an internal dielectric layer , Which even causes the uneven thickness distribution of the inner dielectric layer, which affects the etching step, or the chemical mechanism, respectively.

497133 V. Description of the invention (3) The mechanical polishing process, even when coating the photoresist layer, will cause unevenness of the photoresist layer, affecting the exposure conditions and exposure results. Disadvantages such as the above result in lower yields and lower productivity. Although other methods have been proposed to solve the problem of stripping the deposited film, such as through a tempering process, or depositing a thin film, etc., they cannot completely solve the problem of uneven film thickness at the edge of the wafer caused by the deposition. 5-3 Purpose and Summary of the Invention: In view of the above-mentioned background of the invention, the conventional plasma chemical vapor deposition method has many disadvantages, the present invention provides a device and method for preventing wafer edge film from being deposited too thickly: Another purpose is to use a simple structure of the isolation ring device on the discharge electrode to effectively isolate the tip discharge generated by the discharge electrode. Another object of the present invention is to isolate the electrode with an isolation ring on the discharge electrode, which can effectively solve the problem of uneven deposition thickness and peeling caused by tip discharge. Yet another object of the present invention is to use an isolation ring on a discharge electrode to isolate the subsequent deposition processes or planarization processes to obtain a uniform thin film.

497133 V. Description of the invention (4) Another object of the present invention is to use a simple isolation ring fixture to avoid the phenomenon of tip discharge of the discharge electrode. Another object of the present invention is to use an isolation ring fixture to effectively solve the problem of peeling off the uneven thickness of the deposited film caused by tip discharge. Another object of the present invention is to use a spacer ring fixture to make subsequent deposition processes or planarization processes to obtain a uniform film. According to the above-mentioned object, the present invention provides an isolation ring attached to the discharge electrode to avoid non-uniformity in the thickness of the deposited film caused by the tip discharge effect. This isolation ring device is formed of an insulating material or a conductive material, and is composed of a plurality of Each bracket fixes the isolation ring on the discharge electrode, and the distance between the isolation ring and the discharge electrode can be adjusted to avoid the tip discharge effect. Another option is to use a ring-shaped isolation ring to fix the wafer. This isolation ring is located above the wafer and connected to the substrate. It can be used as a fixture to fix the wafer at the same time. It can also have the effect of isolating the tip discharge to avoid wafer edges. The thickness of the deposited film is not uniform. The isolation ring can be an insulating material or a conductive material. Φ 5-4 Detailed description of the invention: To solve the many disadvantages of traditional plasma chemical vapor deposition

Page 7 V. Description of the invention (5) Health ί Ξ i: When plasma chemical vapor deposition is used to 'produce children on the edge of the wafer = uniform situation, so the fundamental solution, as described in the present invention, the best The device of the embodiment is described below. Two first i a plasma chemical vapor deposition device, the cross-sectional view of which is shown in the figure: plus diagram-the wafer is fixed on a substrate 100, and a plurality of ^ 〇 ring 1 4 0 is fixed to the discharge On the electrode 1 2 0, there are 5 branches of the isolation ring 140 2 T, 130 and the discharge electrode 120 constitute a tip discharge isolation structure. The material of the isolation ring 1 4 0 can be conductive or non-conductive, and the branch 13 0 The device can be either conductive or non-conductive. "——The perspective view of this tip discharge isolation structure i 50 is shown in Figure 3B, and the isolation ring 1 4 0 is fixed below the discharge electrode 1 2 0 by filigree branches 1 3 0 and f / b is isolated. The distance between the ring 140 and the discharge electrode 120 can be adjusted through support, and the plurality of brackets may have a ring shape with a continuous surface and be connected to the isolation ring “0”. Among them, the electrical destruction 160 generated by the discharge 120 generates a sharp = discharge near the edge of the discharge electrode 12o, which will be able to reach the surface of the film in a vertical direction due to the effectiveness of the isolation ring 丨 40, and improve the crystal: Edge ^ Unevenness of film thickness. W-by-by-by-by-by-yet, another preferred embodiment of the present invention, the side view of which is shown in FIG. 4A, a device of an electro-chemical chemical vapor deposition method, a wafer 210 is fixed at a ring 2 3 0 On the substrate 2000, there is a discharge of 497133 above the substrate 200. V. Description of the invention (6) The pole 220 is replaced by an isolation ring 230 to fix the wafer 21 on the substrate 200, and becomes a The isolation ring fixes the wafer structure 24. This isolation ring 2 30 can be lifted to place the wafer 2 10, or the wafer can be placed and fixed in other ways: the plasma generated by the discharge electrode 22 0 250. The tip discharge effect during the deposition is caused by the effect of the isolation ring 230 on the wafer 210 to prevent excessive deposition and uneven film thickness. _ The top view of this isolation ring-fixed wafer structure 240 is shown in Figure 4b, 2 %% 2 3 0 has a fixed wafer 2 1 0 on the substrate, and the isolation tip discharge effect, the material can be selected from conductive materials or For non-conductive materials, the isolation width is adjusted according to each electrical: chemical vapor deposition operation. However, in this example, by measuring the thickness of the thin: thickness, a height difference is generated near the edge of the wafer 21 cm. The obvious position of the attack, so the width of the isolation ring 230 is designed to be about one centimeter wide. According to another embodiment of the present invention, a method of preventing the edge film of the wafer from being deposited too thickly, as shown in the schematic diagrams of Figures A and B, a voltage is applied to a wafer (the discharge electrode 120). In order to generate a discharge, the plasma 160 is electrically introduced onto the wafer 110 to deposit a thin film on the crystal 10, and the plasma 160 is guided to most of the paths of the wafer 110. An isolation ring 140 isolates the path on the outer edge of the portion to reduce the circle. The amount of thin film deposition at the edge, wherein the isolation ring 4o is adjusted and fixed above the wafer 1 with a plurality of forks 130. Another preferred embodiment of this method is shown in Figures 4A and 4

Page 9 497133 V. Description of the invention (7): A voltage is applied above a wafer 2 10 (discharge electrode 2 2 0) to generate a discharge, and a plasma is introduced into the wafer 250 to the wafer through the discharge. On 2 10, a thin film is deposited on the wafer 2 1 0, and a majority of the path from the plasma 2 5 0 to the wafer 2 1 0 is used to isolate the outside of the portion with a spacer 2 3 0 The path of the edge, wherein the isolation ring 230 is to simultaneously fix the wafer 210 to the substrate 200 to reduce the amount of thin film deposition on the edge of the wafer. The above are merely preferred embodiments of the present invention, and are not intended to limit the scope of patent application for the present invention; all other equivalent changes or modifications made without departing from the spirit disclosed by the present invention shall be included in the following Within the scope of patent application.

Page 10 497133 Brief description of the diagram The first diagram is a perspective view of a conventional plasma chemical vapor deposition method. The second figure shows the measurement distribution of film thickness obtained by traditional plasma chemical vapor deposition. FIG. 3A is a side view of a plasma chemical vapor deposition apparatus having a tip discharge isolation structure according to the present invention. FIG. 3B is a perspective view of the tip discharge isolation structure of the present invention. FIG. 4A is a side view of a plasma chemical vapor deposition apparatus having an isolation ring fixed wafer structure according to the present invention. FIG. 4B is a top view of the isolation ring fixed wafer structure of the present invention. Symbols of the main parts: 10 substrates 2 0 wafers 3 0 discharge electrodes 4 0 plasma 5 0 tip discharge 10 0 substrates 1 10 wafers 1 2 0 discharge electrodes

Page 11 497133 Brief description of the diagram 13 0 Bracket 1 4 0 Isolation ring 1 5 0 Tip discharge isolation structure 16 0 Plasma 2 0 0 Substrate 2 10 Wafer 2 2 0 Discharge electrode 2 3 0 Isolation ring 2 4 0 Isolation bad Fixed wafer structure 2.5 plasma

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Claims (1)

497133 VI. Patent application scope 1. A device for thin film deposition, the device includes at least: a substrate for holding a wafer; a discharge electrode for introducing a plasma to deposit a thin film on the wafer, the The discharge electrode is located above the substrate; and an isolation ring is located between the discharge electrode and the wafer to prevent the film from being deposited too thick on the edge of the wafer. 2. For the device in the scope of patent application, the above-mentioned isolation ring can be adjusted and fixed on the discharge electrode by using a plurality of brackets. 3. For the device in the scope of patent application, the plurality of brackets mentioned above may be a continuous surface ring structure. 4. For the device in the scope of patent application, the material of the above-mentioned multiple brackets can be conductive or non-conductive. 5. For the device in the scope of patent application, the above-mentioned isolation ring can be located on the wafer to connect the substrate, and at the same time has the function of fixing the wafer. 6. For the device in the scope of patent application, the material of the isolation ring can be conductive or non-conductive. 7. A thin film deposition device, the device includes at least: a substrate for carrying a wafer; Page 13 497133 VI. Patent application scope A discharge electrode is introduced into the plasma to deposit a thin film on the wafer, the discharge electrode is located above the substrate; and an isolation ring is adjusted and fixed using a plurality of brackets. Between the discharge electrode and the wafer to prevent the film from being deposited too thickly on the edge of the wafer. 8. For the device in the scope of patent application item 7, the material of the above-mentioned isolation ring and the plurality of brackets can be selected from conductive materials or non-conductive materials. 9. A thin film deposition device, the device comprises at least: a substrate for carrying a wafer; a discharge electrode for introducing a plasma to deposit a thin film on the wafer, the discharge electrode being located above the substrate And an isolation ring is located on the substrate and has a fixture function for fixing the wafer to prevent the film from being deposited too thick on the edge of the wafer. 10. The device according to item 9 of the scope of patent application, in which the above-mentioned isolation ring material can be selected from a conductive material or a non-conductive material. 1 1. A method for preventing the edge film of a wafer from being deposited too thick, the method at least includes: applying a voltage on a wafer to generate a discharge; and introducing a plasma to the wafer through the discharge to Depositing a thin film on the wafer; and Page 14 497133 VI. Scope of patent application In the majority of the path that the plasma leads to the wafer, the path of the outer edge of the part is isolated to reduce the amount of thin film deposition on the edge of the wafer. 1 2. The method according to item 11 of the scope of patent application, wherein the path of the outer edge of the above-mentioned isolated part plasma is an isolation ring, which is located above the crystal circle. 1 3. The method according to item 12 of the patent application range, wherein the above-mentioned isolation ring can be adjusted and fixed on the wafer by using a plurality of brackets. 14. The method according to item 12 of the scope of patent application, wherein the material of the spacer ring and the plurality of brackets can be conductive or non-conductive. 15. The method according to item 11 of the scope of patent application, wherein the path of the outer edge of the plasma part of the above-mentioned isolation is an isolation ring, which is used to fix the wafer on the substrate. The method of item 15, wherein the material of the above-mentioned isolation ring may be a conductive material or a non-conductive material. sense, Page 15