JP2013191818A - Semiconductor device and method of manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a transistor having a different dielectricity of a gate insulating film at a low cost.SOLUTION: In a method of manufacturing a semiconductor device, a lantern-containing silicone oxide film 103 is formed on a substrate 101, and an electrode layer 104 is formed on the lantern-containing silicone oxide film 103. In a specified region, the electrode layer 104 and the lantern-containing silicone oxide film 103 are processed into a specified shape, so that a side wall of the lantern containing silicone oxide film 103 is exposed, and oxidization chemical liquid is made to contact to the side wall of the lantern-containing silicone oxide film 103. The lantern-containing silicone oxide film 103 contacts to the oxidization chemical liquid and at least a part of it is changed to a silicone oxide film 110.

Description

  Embodiments described herein relate generally to a semiconductor device and a method for manufacturing the semiconductor device.

  As the speed and scale of ULSI increase, the gate insulating film is thinned to increase the capacitance (gate capacity), or a high dielectric constant film (high-K film) is used for the gate insulating film. doing. Since ULSI increases power consumption due to higher speed and scale, it suppresses the subthreshold current that flows between the source and drain when the operation is off and the gate leakage current that penetrates perpendicularly from the gate to the substrate direction. There is a need to reduce it.

  For example, a technique is known in which the thickness of the gate oxide film of a transistor is changed for each region, and the gate leakage is reduced in the region where the gate oxide film is thickened. However, such a conventional method has a problem that the manufacturing process becomes complicated, the number of processes increases, and the manufacturing cost increases.

JP 2010-182964 A

  An object of the present invention is to provide a method for manufacturing a semiconductor device capable of manufacturing transistors having different dielectric constants of a gate insulating film at low cost, and a semiconductor device manufactured by such a method.

  According to this embodiment, a method for manufacturing a semiconductor device includes forming a lanthanum-containing silicon oxide film on a substrate, forming an electrode layer on the lanthanum-containing silicon oxide film, and forming the electrode layer and the lanthanum in a predetermined region. The silicon oxide film is processed into a predetermined shape to expose the sidewall of the lanthanum-containing silicon oxide film, and an oxidizing chemical solution is brought into contact with the sidewall of the lanthanum-containing silicon oxide film. The lanthanum-containing silicon oxide film is at least partially changed to a silicon oxide film by contacting with the oxidizing chemical solution.

It is process sectional drawing explaining the manufacturing method of the semiconductor device by 1st Embodiment. It is process sectional drawing following FIG. FIG. 3 is a process cross-sectional view subsequent to FIG. 2. FIG. 4 is a process cross-sectional view subsequent to FIG. 3. FIG. 5 is a process cross-sectional view subsequent to FIG. 4. FIG. 6 is a process cross-sectional view subsequent to FIG. 5. FIG. 7 is a process cross-sectional view subsequent to FIG. 6. FIG. 8 is a process cross-sectional view subsequent to FIG. 7. FIG. 9 is a process cross-sectional view subsequent to FIG. 8. It is a figure which shows the EDS analysis result of a silicon oxide film. It is sectional drawing of the semiconductor device by 2nd Embodiment. It is sectional drawing of the semiconductor device by 3rd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  (First Embodiment) FIGS. 1 to 9 are process sectional views for explaining a method of manufacturing a semiconductor device according to a first embodiment.

  First, as shown in FIG. 1, source / drain regions (not shown) are formed on the surface portion of the substrate 101. For example, the substrate 101 is a p-type semiconductor substrate, and source / drain regions can be formed by ion implantation of phosphorus or arsenic into the p-type semiconductor substrate.

  Then, a lanthanum aluminum silicon oxide film 103 serving as a gate insulating film material, a polysilicon film 104 serving as an electrode layer material, and a silicon nitride film 105 serving as a mask material are sequentially formed on the substrate 101. The lanthanum aluminum silicon oxide film 103 is amorphous and has a film thickness of 3 to 30 nm. The polysilicon film 104 is, for example, an n-type polysilicon film.

  Next, as shown in FIG. 2, a resist 106 is formed on the silicon nitride film 105. Then, the resist 106 in the region A1 that does not require speed performance is patterned by lithography. The resist 106 in the region A2 that requires speed performance is not patterned. Here, the region A1 that does not require speed performance is, for example, a peripheral circuit region. The region A2 is a circuit region in which, for example, a high-speed switching operation of a transistor is required.

  Next, as shown in FIG. 3, the silicon nitride film 105 is processed using the resist 106 as a mask by RIE (Reactive Ion Etching). Thereby, the pattern of the resist 106 is transferred to the silicon nitride film 105. Thereafter, the resist 106 is removed.

  Next, as shown in FIG. 4, using the silicon nitride film 105 as a mask, the polysilicon film 104 and the lanthanum aluminum silicon oxide film 103 are processed using the RIE method. Thereby, the polysilicon film 104 is processed into the gate electrode shape in the region A1. In the region A1, the side surface of the lanthanum aluminum silicon oxide film 103 under the gate electrode (polysilicon film 104) is exposed.

  Next, as shown in FIG. 5, a mixed aqueous solution of sulfuric acid and hydrogen peroxide solution is supplied to the region A1, and the lanthanum aluminum silicon oxide film 103 whose side surface is exposed is changed to a silicon oxide film 110. The lanthanum aluminum silicon oxide film 103 becomes a silicon oxide film 110 when the mixed aqueous solution of sulfuric acid and hydrogen peroxide solution enters from the exposed side surface and lanthanum and aluminum are dissolved. FIG. 10 shows a result of detecting constituent elements of the silicon oxide film 110 by EDS (Energy dispersive X-ray spectrometry). 10 that the silicon oxide film 110 does not contain lanthanum or aluminum.

  Next, as shown in FIG. 6, a silicon nitride film 120 that covers the side surfaces of the polysilicon film 104 and the silicon oxide film 110 and the surface of the substrate 101 is formed in the region A1. The side walls of the gate electrode are protected by the silicon nitride film 120. Then, a silicon oxide film 121 is formed on the silicon nitride film 120, and planarized by CMP (chemical mechanical polishing) using the silicon nitride film 105 as a stopper. The silicon oxide film 121 is an element isolation insulating film that electrically isolates adjacent gate electrodes.

  Next, as shown in FIG. 7, a resist 130 is formed on the silicon nitride film 105 and the silicon oxide film 121. Then, the resist 130 in the region A2 is patterned by lithography processing. The resist 130 in the region A1 is not patterned.

  Next, as shown in FIG. 8, the silicon nitride film 105 is processed using the resist 130 as a mask by RIE. Thereby, the pattern of the resist 130 is transferred to the silicon nitride film 105. Thereafter, the resist 130 is removed.

  Next, as shown in FIG. 9, using the silicon nitride film 105 as a mask, the polysilicon film 104 and the lanthanum aluminum silicon oxide film 103 in the region A2 are processed using the RIE method. Thereby, the polysilicon film 104 is processed into the gate electrode shape in the region A2. Thereafter, a silicon nitride film 140 that protects the sidewall of the gate electrode and a silicon oxide film 141 that serves as an element isolation insulating film are formed in the region A2 by a method similar to the process shown in FIG.

  In this manner, a transistor whose gate insulating film is the silicon oxide film 110 can be formed in the region A1, and a transistor whose gate insulating film is the lanthanum aluminum silicon oxide film 103 can be formed in the region A2. Since the silicon oxide film 110 is obtained by dissolving lanthanum and aluminum from the lanthanum aluminum silicon oxide film 103, the silicon oxide film 110 and the lanthanum aluminum silicon oxide film 103 have substantially the same film thickness.

  Thus, according to this embodiment, transistors having different dielectric constants of the gate insulating film can be manufactured at a low cost by a simple method.

  (Second Embodiment) In the first embodiment, a part of the gate insulating film (lanthanum aluminum silicon oxide film 103) in the region A2 may be changed to a silicon oxide film. For example, in the step shown in FIG. 9, after processing the gate electrode and before forming the silicon nitride film 140, a mixed aqueous solution of sulfuric acid and hydrogen peroxide solution is supplied to the region A2. Then, the lanthanum aluminum silicon oxide film 103 whose side surfaces are exposed is brought into contact with a sulfuric acid / hydrogen peroxide mixed solution for a predetermined time. Here, the time for which the lanthanum aluminum silicon oxide film 103 is brought into contact with the sulfuric acid / hydrogen peroxide mixed solution is shorter than the time for which the lanthanum aluminum silicon oxide film 103 is brought into contact with the sulfuric acid / hydrogen peroxide mixed solution in the step shown in FIG. To do.

  By such processing, both end portions of the lanthanum aluminum silicon oxide film 103 are changed to the silicon oxide film 210 as shown in FIG.

  According to this embodiment, while maintaining the thickness of the gate insulating film, the dielectric constant of both ends is lowered, and the threshold voltage of the transistor is used by using a stable central portion without using the gate end where leakage current easily flows. Can be controlled.

  (Third Embodiment) In the step shown in FIG. 5 of the first embodiment, the lanthanum aluminum silicon oxide film 103 may be exposed to a sulfuric acid / hydrogen peroxide solution mixed solution for a longer time to be in an overprocessed state. . For example, the lanthanum aluminum silicon oxide film 103 is brought into contact with a sulfuric acid / hydrogen peroxide mixed solution for 40 minutes. As a result, the amount of the element eluted from the lanthanum aluminum silicon oxide film 103 is increased, and as shown in FIG. 12, a cavity 301 is formed in a part (for example, the central part) of the silicon oxide film 110. Since the gate electrode in which the cavity is formed in the gate insulating film is easily broken down, this semiconductor device can have a function as a fuse of the fuse transistor.

  In the first to third embodiments, the example in which the n-type polysilicon film is used as the material of the electrode layer has been described. However, as the electrode layer material, p-type polysilicon, polysilicon / metal (tungsten, molybdenum, titanium, Laminated film of tantalum, etc., metal carbide (tantalum, titanium, tungsten, etc.), metal nitride (tantalum, titanium, tungsten, molybdenum, etc.), metal (tantalum, titanium, tungsten, molybdenum, etc.) and at least one of these A laminated film containing a substance made of may be used.

  In the first to third embodiments, a mixed aqueous solution of sulfuric acid and hydrogen peroxide is supplied to change the gate insulating film of the transistor in the region A1 from the lanthanum aluminum silicon oxide film 103 to the silicon oxide film 110. However, other oxidizing chemicals such as sulfuric acid / ozone mixed water may be used.

  In the first to third embodiments, the lanthanum aluminum silicon oxide film 103 is formed as the material of the gate insulating film. However, a lanthanum silicon oxide film may be formed. When the lanthanum silicon oxide film comes into contact with the oxidizing chemical solution, lanthanum elutes and changes to a silicon oxide film.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

101 substrate 103 lanthanum aluminum silicon oxide film 104 polysilicon film 105 silicon nitride film 110, 210 silicon oxide film 301 cavity

Claims (7)

A lanthanum-containing silicon oxide film to which aluminum is added is formed on the substrate,
Forming an electrode layer on the lanthanum-containing silicon oxide film;
In the first predetermined region, the electrode layer and the lanthanum-containing silicon oxide film are processed into a predetermined shape to expose the sidewall of the lanthanum-containing silicon oxide film,
An oxidizing chemical solution is brought into contact with the side wall of the lanthanum-containing silicon oxide film to change the lanthanum-containing silicon oxide film into a silicon oxide film, and a cavity is formed in the silicon oxide film.
After the lanthanum-containing silicon oxide film is changed to a silicon oxide film, the electrode layer and the lanthanum-containing silicon oxide film are processed into a predetermined shape in a second predetermined region different from the first predetermined region, and the lanthanum Exposing the side wall of the silicon oxide film,
A manufacturing method of a semiconductor device, wherein an oxidizing chemical solution is brought into contact with a side wall of the lanthanum-containing silicon oxide film in the second predetermined region, and both ends of the lanthanum-containing silicon oxide film are changed to silicon oxide films. A lanthanum-containing silicon oxide film is formed on the substrate,
Forming an electrode layer on the lanthanum-containing silicon oxide film;
In a predetermined region, the electrode layer and the lanthanum-containing silicon oxide film are processed into a predetermined shape to expose a sidewall of the lanthanum-containing silicon oxide film,
A method of manufacturing a semiconductor device, wherein an oxidizing chemical solution is brought into contact with a sidewall of the lanthanum-containing silicon oxide film to change at least a part of the lanthanum-containing silicon oxide film into a silicon oxide film.   3. The method of manufacturing a semiconductor device according to claim 2, wherein both end portions of the lanthanum-containing silicon oxide film are changed to silicon oxide films.   An oxidizing chemical solution is brought into contact with the sidewall of the lanthanum-containing silicon oxide film to change at least a part of the lanthanum-containing silicon oxide film into a silicon oxide film, and a cavity is formed in the silicon oxide film. A method for manufacturing a semiconductor device according to claim 2.   5. The method of manufacturing a semiconductor device according to claim 2, wherein aluminum is added to the lanthanum-containing silicon oxide film.   In the predetermined region, after changing at least a part of the lanthanum-containing silicon oxide film to a silicon oxide film, the electrode layer and the lanthanum-containing silicon oxide film are processed into a predetermined shape in a region different from the predetermined region. The method of manufacturing a semiconductor device according to claim 2. A silicon oxide film formed in a first region on the substrate and including a cavity;
A first gate electrode formed on the silicon oxide film;
A lanthanum-containing silicon oxide film formed in the second region on the substrate;
A second gate electrode formed on the lanthanum-containing silicon oxide film;
A semiconductor device comprising:

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