JP2008258491A - Semiconductor manufacturing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to efficiently remove reaction products generated at the time of an RIE treatment. <P>SOLUTION: In order to jet an inert gas towards periphery portions Sa of a treatment substrate S by a gas supply mechanism 10, even if a lot of reaction products adhere, it is unnecessary to perform any chemical treatments of two or more processes, and the reaction products can be removed by a jet treatment of the inert gas. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a semiconductor manufacturing apparatus including an electrostatic chuck for electrostatically fixing a semiconductor substrate when etching is performed by a reactive ion etching (RIE (Reactive Ion Etching)) method using plasma.

  When a conductive film or an insulating film is formed on a processing substrate and the film is etched to be processed into a desired shape, an RIE method using plasma may be used. When performing the etching process by the RIE method, it is necessary to fix the processing substrate. Therefore, a semiconductor manufacturing apparatus including an electrostatic chuck for electrostatically fixing a processing substrate is provided (for example, see Patent Document 1).

  When the processing substrate is etched by the RIE method, a reaction product is generated during the etching processing. This reaction product also adheres to the peripheral edge portion and back surface portion of the treatment substrate surface. Since reaction products deposited on the front side of the processing substrate are reduced by ions and radicals, the amount of lamination is small, but the influence of the reaction is small at the back peripheral edge and hardly reacts on the back side of the processing substrate. Therefore, a large amount of reaction product remains on the back peripheral edge and back surface of the processing substrate.

  If this reaction product is not peeled off, dust will be generated, equipment used in subsequent processes will be contaminated, and process characteristics will be mutated. Therefore, it is necessary to remove the reaction product. Although the reaction product can be sufficiently peeled off after one or several steps of post-treatment on the surface of the treated substrate, it is insufficient for peeling off the reaction product attached to the back surface portion or the back peripheral edge portion. In particular, when the reaction product on the back surface is peeled off, it becomes necessary to newly add a large number of steps for the peeling treatment. In addition, a large amount of chemicals are required.

In addition, when the multilayer structure film is collectively processed for the purpose of process reduction, the types and compositions of the reaction products are different because the types, flow rates, and high-frequency outputs of the gases used are different. Therefore, the reaction product also has a multilayer structure.
Although an electrostatic chuck for a CVD apparatus is disclosed in Patent Document 2, it is not suitable for removing a reaction product generated by processing by the RIE method.
JP-A-2005-64460 JP 2000-54137 A (FIG. 3)

  An object of the present invention is to provide a semiconductor manufacturing apparatus capable of efficiently removing reaction products generated during RIE processing.

  One embodiment of the present invention is an electrostatic chuck that electrostatically fixes a processing substrate when the processing substrate is etched by a reactive ion etching method, and an inert gas is applied to the back peripheral edge of the processing substrate. Provided is a semiconductor manufacturing apparatus including an electrostatic chuck having a hole to be ejected and a gas supply mechanism for supplying the inert gas to be ejected from the hole.

  One embodiment of the present invention is an electrostatic chuck that electrostatically fixes a processing substrate when the processing substrate is etched by a reactive ion etching method. An electrostatic chuck having a groove portion extending from the hole portion to the outer peripheral end along the upper surface, and supplying the inert gas to the hole portion, and the processing substrate is mounted on the electrostatic chuck. A semiconductor manufacturing apparatus comprising a gas supply mechanism for injecting an inert gas to the back peripheral edge of the processing substrate in a placed state.

  According to one embodiment of the present invention, a reaction product generated during RIE processing can be efficiently removed.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 schematically shows a cross-sectional structure of a semiconductor manufacturing apparatus.

  The semiconductor manufacturing apparatus 1 includes a metal chamber 2 and includes a disk-shaped mounting table (susceptor) 3 that is a support portion for supporting the processing substrate S in the chamber 2. . The mounting table 3 is made of a metal such as aluminum and is held by an insulating cylindrical holding member 4. An exhaust path 5 is provided between the side wall of the chamber 2 and the holding member 4. An exhaust device 6 is connected to the exhaust path 5, and the exhaust device 6 is configured to maintain a predetermined degree of vacuum in the chamber 2. A high frequency power source 7 for generating plasma is electrically connected to the mounting table 3. When the high frequency power supply 7 applies high frequency power of, for example, several tens of MHz to the mounting table 3, the mounting table 3 functions as an electrode for generating plasma.

  An electrostatic chuck 8 is disposed at the upper center of the mounting table 3. The electrostatic chuck 8 includes a base portion 8a installed on the mounting table 3 and a fixing portion 8b provided at the center upper portion of the base portion 8a. The upper surface of the fixing portion 8b is formed as a flat surface. Moreover, the side wall surface of the fixing | fixed part 8b is comprised so that it may be located inside the side wall surface of the base 8a. A DC power supply is applied to the fixed portion 8b. The processing substrate S has a back surface portion S1 placed on the upper surface of the fixing portion 8b, and the fixing portion 8b generates a Coulomb force or a Johnson-Rahbek force based on a given DC power source, thereby electrostatically treating the processing substrate S. Fixed. The part 9 is composed of protective parts such as a focus ring and an electrostatic chuck cover. Of these, the focus ring has a ring shape in plan view, and is disposed along the outer periphery of the electrostatic chuck 8. The parts 9 are provided at a predetermined interval outside the fixed portion 8b.

FIG. 2 is an enlarged view of a part and a processing substrate installation part.
As shown in FIG. 2, the part 9 includes a lower part 9a and an upper part 9b. The inner peripheral end portion of the lower portion 9 a is fixed on the outer peripheral end portion of the base portion 8 a of the electrostatic chuck 8. The inner peripheral side wall of the upper part 9b provided on the lower part 9a is configured to be located outside the inner peripheral side wall of the lower part 9a. The peripheral side wall surface 8bb of the fixed portion 8b of the electrostatic chuck 8 is formed in a vertical plane perpendicular to the upper surface of the fixed portion 8b. At the time of processing by the RIE method, the processing substrate S is fixedly installed on the fixing portion 8b with the peripheral edge portion Sa (back peripheral edge portion) protruding outward from the peripheral side wall surface 8bb of the fixing portion 8b of the electrostatic chuck 8. Thereby, deterioration of the electrostatic chuck 8 due to plasma exposure is prevented as much as possible.

  Further, when the back surface portion S1 of the processing substrate S is installed on the fixed portion 8b, a clearance is provided between the upper portion 9b of the part 9 and the peripheral edge portion Sa of the processing substrate S. In addition, the process board | substrate S is formed in flat form, The peripheral part Sa is processed as the chamfered bevel part.

  A hole 8z, which is a gas ejection port, is formed in the peripheral side wall surface 8bb of the fixed portion 8b of the electrostatic chuck 8. As shown in the perspective view of FIG. 2B, a plurality of holes 8z are provided on the peripheral side wall surface 8bb of the electrostatic chuck 8 so as to be spaced apart in the circumferential direction. As shown in FIG. 2A, the hole 8z is formed from the base 8a to the fixed part 8b side of the electrostatic chuck 8, and radially from the center side of the electrostatic chuck 8 to the peripheral side wall surface 8bb of the upper part 8b. Is formed. Further, the hole 8z is formed so that the direction thereof is inclined in the upward oblique direction which is the upper surface side of the fixed portion 8b with respect to the peripheral side wall surface 8bb.

  The hole 8z is connected to the gas supply mechanism 10. The gas supply mechanism 10 is provided to supply an inert gas (for example, He gas) to the periphery of the processing substrate S. The gas supply mechanism 10 ejects an inert gas from the hole 8z toward the outer side of the peripheral side wall surface 8bb. Note that a temperature control during processing of the processing substrate S is performed by providing a heater (not shown).

  The operation of the above configuration will be described. The gas supply mechanism 10 ejects an inert gas from the peripheral side wall surface 8bb of the electrostatic chuck 8 toward the upper outer side. The ejected inert gas escapes above the processing substrate S through a clearance provided between the part 9 and the peripheral side wall surface 8bb of the electrostatic chuck 8. Since the peripheral edge portion Sa of the processing substrate S is installed so as to protrude outward from the peripheral side wall surface 8bb, the inert gas is supplied to the bevel portion on the back surface side of the peripheral edge portion Sa of the processing substrate S.

  When the processing substrate S is etched by the RIE method in the semiconductor manufacturing apparatus 1 as described above, it is confirmed that the reaction product is deposited particularly on the back surface portion S1 of the processing substrate S and the back side of the peripheral edge portion Sa. Since the inert gas is supplied from the back surface side of the processing substrate S to the bevel portion of the peripheral edge portion Sa, the reaction product attached to the back surface side (back peripheral edge portion) of the peripheral edge portion Sa can be removed. The inventors have conducted an experiment for confirming the effect of removing a reaction product by an inert gas.

FIG. 3 shows a state after the processing substrate is etched.
The processing substrate S is a silicon oxide film 12 formed by thermally oxidizing the silicon substrate 11 on the silicon substrate 11, and a silicon oxide film formed by using TEOS (Tetra Ethoxy Silane: Tetra Ethyl Ortho Silicate) as a source gas. (Hereinafter referred to as a TEOS film) 13, an organic film 14, a coating-type insulating film (silicon oxide film) 15, and a resist 16 are sequentially formed, and then a substrate in which the resist 16 is patterned into a desired shape is applied.

  The inventors place the processing substrate S on the fixing portion 8b of the electrostatic chuck 8 in the semiconductor manufacturing apparatus 1 and fix it, and as shown in FIG. 3, each layer is formed using the patterned resist 16 as a mask. 11 to 15 are dry-etched by the RIE method, and then the state of the peripheral edge (bevel portion) Sa from the back surface S1 side of the processed substrate S is observed with a scanning electron microscope (SEM), and the attached reaction product The film thickness is measured.

The etching process of each of the layers 11 to 15 includes (A) a processing process of the coating type insulating film 15 performed using the resist 16 as a mask, and (B) thereafter, Processing is performed in three steps: (C) and then processing of the TEOS film 13 and the silicon oxide film 12 performed using the organic film 14 as a mask. The processing (A) is performed using a mixed gas of a fluorocarbon-based gas such as CHF ₃ gas and oxygen. The processing of (B) is performed using a mixed gas of methane gas, carbon monoxide, oxygen and nitrogen. The processing (C) is performed using a mixed gas of fluorocarbon-based gas, oxygen, and argon.

FIG. 4 shows the measurement result of the film thickness of the reaction product attached to the processing substrate.
After the etching process at each stage, the thickness of the reaction product attached to the processing substrate S was measured, and the thickest part was measured to be about 35 nm (see the measurement result after (2) RIE processing in FIG. 4). . When a similar measurement was performed using a semiconductor manufacturing apparatus having a conventional structure in which the gas supply mechanism 10 was not provided, the film thickness was measured to be about 150 nm (measurement results after (1) after RIE processing in FIG. 4). reference). Therefore, the removal effect of the reaction product could be confirmed.

  In addition, after the etching process, the inventors added an ashing process using oxygen, and similarly observed the cross section by SEM. As a result, when the semiconductor manufacturing apparatus 1 is used, it is confirmed that the reaction product is completely peeled off (refer to the measurement result (2) after the ashing process in FIG. 4). In the case of the conventional structure, the film thickness is not substantially changed to 148 nm (see the measurement result after (1) in FIG. 4). In the case of the conventional structure, it has been confirmed that it is necessary to add two steps of chemical treatment in order to remove all reaction products.

According to the present embodiment, since the inert gas is ejected toward the peripheral edge Sa (back peripheral edge) on the back surface side of the processing substrate S by the gas supply mechanism 10, even if a large amount of reaction product adheres. The reaction product can be removed by an inert gas jetting process without the need for chemical treatment beyond the steps.
Further, since the inert gas is ejected in the upward oblique direction with respect to the surface S2 of the processing substrate S by the gas supply mechanism 10, the effect of removing the reaction product by the inert gas can be enhanced.

(Second Embodiment)
FIG. 5 shows a second embodiment of the present invention. The difference from the previous embodiment is that a groove is provided on the upper surface of the electrostatic chuck and an inert gas is ejected from the groove. . In addition to the gas supply mechanism 10 of the above-described embodiment, an inert gas supply mechanism for temperature control is provided. The same parts as those of the above-described embodiment are denoted by the same reference numerals and description thereof is omitted, and only different parts will be described below.

FIG. 5A shows the state of the holes and grooves formed in the surface portion of the electrostatic chuck, and FIG. 5B schematically shows a cross-sectional view of the inside of the electrostatic chuck.
As shown in FIG. 5A, the electrostatic chuck 8 has a plurality of holes 8e. The plurality of holes 8e are spaced apart from each other in the circumferential direction with respect to the peripheral edge 8d of the upper surface 8c of the electrostatic chuck 8, and a groove 8f couples the plurality of holes 8e to electrostatically. It is formed along the circumferential direction concentrically with the peripheral edge portion 8 d of the chuck 8. The hole 8e is formed so as to be connected to a groove 8g formed in the upper surface 8c. The groove 8g is formed radially from the hole 8e toward the peripheral edge 8d. The gas supply mechanism 10 is connected to the hole 8e, and with the processing substrate S placed on the upper surface portion 8c, the gas supply mechanism 10 causes the inert gas to be applied to the bevel portion on the back side of the peripheral edge Sa of the processing substrate S. Supplied.

  In addition to the hole 8e, a plurality of holes 8y are provided on the center side of the surface 8c of the electrostatic chuck 8. A gas supply mechanism 11 is connected to the plurality of holes 8y. The gas supply mechanism 11 is configured to eject an inert gas for temperature control (for cooling) to the back surface portion 8c of the processing substrate S through the hole 8y.

  The inventors have measured the film thickness of the reaction product in the same manner as in the previous embodiment. As a result, the film thickness of the thickest part after the etching process is measured to be 43 nm. That is, it has been confirmed that the amount of adhesion is greatly reduced as compared with the conventional structure in which the gas supply mechanism 10 is not provided. Further, it has been confirmed that the reaction product can be sufficiently peeled off by performing the ashing treatment.

  According to the present embodiment, the gas supply mechanism 10 includes the grooves 8g that are formed radially from the plurality of holes 8e provided at intervals to the peripheral edge 8d of the electrostatic chuck 8 to the peripheral end of the electrostatic chuck 8. Since the inert gas is jetted through, substantially the same effects as those of the above-described embodiment can be obtained.

(Third embodiment)
FIG. 6 shows a third embodiment of the present invention. The difference from the second embodiment is that the groove portion 8f is not provided along the circumferential direction. As shown in FIG. 6, it has been confirmed that substantially the same effect as that of the above-described embodiment can be obtained without providing the groove 8f.

(Fourth embodiment)
FIG. 7 shows a fourth embodiment of the present invention. The difference from the previous embodiment is that a hole 8z is provided instead of the groove 8g of the upper surface 8c of the electrostatic chuck 8. FIG. As shown in FIG. 7, the hole 8 z is formed slightly below the upper surface 8 c of the electrostatic chuck 8. The hole 8z is formed so as to be connected to the hole 8e, and is formed radially from the hole 8e toward the peripheral edge 8d. The gas supply mechanism 10 is connected to the holes 8e and 8z, and the inert gas is supplied to the bevel portion on the back surface side of the peripheral edge Sa of the processing substrate S by the gas supply mechanism 10 as in the above-described embodiment. Thereby, substantially the same operation effect as the above-mentioned embodiment is obtained.

(Other embodiments)
The present invention is not limited to the above embodiment, and for example, the following modifications or expansions are possible.
Ar gas may be applied as the inert gas instead of the He gas.
In the above-described embodiment, the gas supply mechanism 11 ejects the inert gas for temperature control. However, the reaction product attached to the back surface portion 8c may be removed by the inert gas. When a part of the inert gas for temperature control is used, it has been confirmed that the residual film thickness of the reaction product is about 70 nm, and the reaction product can be sufficiently peeled off. In addition, although the gas supply mechanisms 10 and 11 are separate paths, some of them may be the same path.

1 is a schematic configuration diagram of a semiconductor manufacturing apparatus according to a first embodiment of the present invention. (A) is an enlarged sectional view schematically showing an inert gas ejection mechanism, and (b) is an enlarged perspective view schematically showing an inert gas ejection port. Explanatory drawing of processing contents of processing board Figure showing experimental results FIG. 2A is a top view of an electrostatic chuck showing a second embodiment of the present invention, and FIG. 2B is an equivalent view of FIG. FIG. 5A equivalent view showing the third embodiment of the present invention FIG. 2 (a) equivalent view showing the fourth embodiment of the present invention

Explanation of symbols

  In the drawings, 1 is a semiconductor manufacturing apparatus, 8 is an electrostatic chuck, 8bb is a peripheral side wall surface of the electrostatic chuck (side wall surface of the electrostatic chuck), 8d is a peripheral edge portion of the electrostatic chuck, 8f and 8g are groove portions, 8e, 8y and 8z are hole portions, 10 and 11 are gas supply mechanisms, S is a processing substrate, S1 is a back surface portion of the processing substrate, and Sa is a peripheral portion of the processing substrate.

Claims (5)

An electrostatic chuck for electrostatically fixing a processing substrate when the processing substrate is etched by a reactive ion etching method, comprising a hole for injecting an inert gas at a back peripheral edge of the processing substrate. An electrostatic chuck;
A semiconductor manufacturing apparatus comprising a gas supply mechanism for supplying the inert gas ejected from the hole.   The semiconductor manufacturing apparatus according to claim 1, wherein the hole is configured such that the inert gas is ejected in an upward oblique direction with respect to the peripheral side wall surface. An electrostatic chuck for electrostatically fixing a processing substrate when the processing substrate is etched by a reactive ion etching method, wherein a plurality of holes are connected to the upper surface along the upper surface. An electrostatic chuck including a groove provided from the hole to the outer peripheral end;
A gas supply mechanism for supplying the inert gas to the hole and ejecting the inert gas to a back peripheral edge of the processing substrate in a state where the processing substrate is placed on the electrostatic chuck; A semiconductor manufacturing apparatus.   The semiconductor manufacturing apparatus according to claim 3, wherein a groove connecting the plurality of holes is formed on the upper surface of the electrostatic chuck.   The semiconductor manufacturing apparatus according to claim 3, further comprising a temperature control mechanism for the processing substrate.

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