JP2007335580A - Semiconductor device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device and a manufacturing method therefor surely obtaining a resistor having an accurate resistance value, regarding the semiconductor device loading a polysilicon resistor as an element. <P>SOLUTION: In the semiconductor device, the polysilicon resistor in the semiconductor device loading the polysilicon resistor comprises a polysilicon layer (113) formed in a desired shape, and an impurity diffusion layer (114) formed so as to diffuse impurities to the side inner than the shape of the polysilicon layer (113) in the polysilicon layer (113). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a semiconductor device and a manufacturing method thereof, and more particularly to a semiconductor device in which a polysilicon resistor is mounted as an element and a manufacturing method thereof.

  A resistor is mounted on the semiconductor device. A polysilicon resistor is known as a resistor mounted on a semiconductor device.

  6 and 7 are views for explaining a conventional method for manufacturing a polysilicon resistor of a semiconductor device.

  First, as shown in FIG. 6A, the polysilicon resistor is formed by growing a polysilicon layer 13 on the semiconductor substrate 11 via the insulating layer 12, and further oxidizing the surface of the polysilicon layer 13 to form an insulating layer. 14 is formed.

  Next, as shown in FIG. 6B, impurities are ion-implanted over the entire surface and annealed to diffuse the impurities over the entire surface of the polysilicon layer 13.

  Next, a resist 15 is formed in the shape of a resistor as shown in FIG. 6C, and etching is performed, so that the insulating film 14 and the polysilicon layer 13 in which impurities are diffused are formed as shown in FIG. The resist 15 is removed leaving the lower part.

  Next, as shown in FIG. 7B, a resist having a desired shape is formed by removing the resist 15.

  FIG. 8 shows a configuration diagram of a conventional polysilicon resistor. 8A is a plan view and FIG. 8B is a cross-sectional view.

  At this time, in the conventional polysilicon resistor, the polysilicon layer 13 in which the impurities are diffused is formed into a desired shape by etching. Therefore, when the pattern becomes dense, a chemical solution or gas for etching is interposed between the resist patterns. Since it becomes difficult to enter, for example, the shape of the polysilicon layer 13 after etching is not stable as shown by the broken line in FIG.

  For this reason, there existed problems, such as resistance value becoming unstable.

In order to stabilize the resistance value of the polysilicon resistor, a polysilicon layer is formed on the semiconductor substrate via an insulating layer, an oxide film is formed on the polysilicon layer, and a resistor is formed by diffusing impurities. A method to do this has been proposed (Patent Document 1).
JP-A-8-195476

  However, in the conventional method in which an oxide film is formed on the polysilicon layer and the resistance is formed by diffusing impurities throughout the polysilicon layer, the shape of the polysilicon layer after etching is stable depending on the pattern layout. And there is a problem that an accurate resistance value cannot be obtained.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a semiconductor device and a method for manufacturing the semiconductor device that can reliably obtain a resistance having an accurate resistance value.

  In the semiconductor device of the present invention, in the semiconductor device on which the polysilicon resistor is mounted, the polysilicon resistor has a polysilicon layer (113) formed into a desired shape, a polysilicon layer (113), and a polysilicon layer (113). ), An impurity diffusion layer (114) formed by diffusing impurities inside.

  The polysilicon resistor is characterized in that the resistance value can be set by changing the concentration distribution of the impurity diffusion layer (114).

  The semiconductor device manufacturing method of the present invention is a semiconductor device manufacturing method in which a polysilicon resistor is mounted on a semiconductor substrate (111). The polysilicon resistor is a polysilicon layer (113) formed in a desired shape. ) And an impurity diffusion layer (114) formed by diffusing impurities into the polysilicon layer (113). The impurity diffusion layer (114) is formed into a desired shape. After that, it is formed on the polysilicon layer (113) inside the shape of the polysilicon layer (113).

  At this time, the resistance value is set by changing the concentration distribution of the impurity diffusion layer (114).

  In addition, the said reference symbol is a reference to the last, and a claim is not limited by this.

  According to the present invention, a polysilicon layer formed into a desired shape of a polysilicon resistor and an impurity diffusion layer formed by diffusing impurities into the polysilicon layer inward of the shape of the polysilicon layer are configured. By doing so, the resistance value is not influenced by the shape of the polysilicon layer formed by etching, and can be determined by the concentration distribution of the impurity diffusion layer formed by diffusion, so that the resistance having an accurate resistance value can be obtained with certainty.

  FIG. 1 shows a configuration diagram of an embodiment of the present invention. FIG. 1A is a plan view and FIG. 2B is a cross-sectional view.

  The semiconductor device 100 according to this embodiment is configured such that an impurity diffusion layer 114 is formed on a polysilicon layer 113 formed on a semiconductor substrate 111 via an insulating layer 112 and covered with an insulating layer 141.

  The semiconductor substrate 111 is a semiconductor substrate made of silicon or the like. The insulating layer 112 is silicon oxide and is formed by oxidizing the semiconductor substrate 111. Note that the semiconductor substrate 111 may be formed by stacking silicon oxide.

  The polysilicon layer 113 is formed into a desired shape by forming polysilicon (Poly-Si) over the entire surface of the insulating layer 112, applying a resist, and etching. Since the polysilicon layer 113 is formed by etching, the accuracy of the shape is not sufficiently guaranteed.

  The impurity diffusion layer 114 is formed by diffusing impurities inside the shape of the polysilicon layer 113 on the polysilicon layer 113 formed into a desired shape by etching. At this time, the depth of the impurity diffusion layer 114 is set to be smaller than the depth of the polysilicon layer 113 and the width thereof is set to be narrower than the width of the polysilicon layer 113. Since the impurity diffusion layer 114 does not use etching, it can be formed with high accuracy.

  The insulating layer 141 is made of silicon oxide, is formed on the polysilicon layer 113 on which the impurity diffusion layer 114 is formed, and protects the polysilicon layer 113. An opening 121 is formed in the insulating layer 141. The openings 121 are formed at both ends of the impurity diffusion layer 114, and the wiring is brought into contact with the impurity diffusion layer 114.

  According to the semiconductor device 100 of the present embodiment, it is possible to reliably maintain a desired shape by forming the impurity diffusion layer 114 by diffusing impurities on the polysilicon layer 113, thereby obtaining a stable resistance value. Can do.

〔Production method〕
2 and 3 are views for explaining a manufacturing process of a semiconductor device according to an embodiment of the present invention.

  First, as shown in FIG. 2A, an insulating layer 112, a polysilicon layer 113, and an insulating layer 115 are formed over the entire resistance forming portion of the semiconductor substrate 111.

The insulating layer 112 is made of silicon oxide (SiO ₂ ) and is formed, for example, by oxidizing the semiconductor substrate 111. Note that the insulating layer 112 may be formed by stacking oxides such as silicon oxide.

  The polysilicon layer 113 is formed by growing polysilicon on the insulating layer 112. The insulating layer 115 is formed by oxidizing the surface of the polysilicon layer 113.

  Next, as shown in FIG. 2B, a resist 131 is formed in the shape of a resistor. Next, by performing etching as shown in FIG. 2C, the polysilicon layer 113 and the insulating layer 115 are formed into the shape of the resist 131, and as shown in FIG. 2D, the resist 131 and the insulating layer 115 are formed. Remove.

  Next, as illustrated in FIG. 3A, an insulating layer 141 and a resist 151 are formed. An opening 161 is formed in the resist 151. The insulating layer 141 is formed by oxidizing the polysilicon layer 113, for example. Opening 161 is formed in a shape corresponding to the shape of impurity diffusion layer 114, that is, the shape of polysilicon layer 113.

  Next, as shown in FIG. 3B, an impurity diffusion layer 114 is formed by implanting impurities from the opening 161.

  Next, by removing the resist 151 as shown in FIG. 3C, the polysilicon resistor of this embodiment is created.

  FIG. 4 is a diagram for explaining the operation of one embodiment of the present invention.

  According to the present embodiment, as shown in FIG. 4, even if the polysilicon resistors 100a and 100b of the present embodiment are arranged adjacent to each other, the impurity diffusion layer 114 is formed on the different polysilicon layer 113. The impurity diffusion layer 114 does not interact with the silicon resistor 100a and the polysilicon resistor 100b, so that a stable resistance value can be obtained.

  FIG. 5 shows a configuration diagram of a modification of the present invention. In the figure, the same components as in FIG.

  Although the resistance on a straight line has been described with reference to FIG. 1, the linear pattern may be formed in a folded shape. The polysilicon layer 113 has a shape in which a linear pattern is folded back by etching. The impurity diffusion layer 114 is formed on the polysilicon layer 113 in a shape corresponding to the shape of the polysilicon layer 113.

  Further, the impurities constituting the impurity diffusion layer 114 may be either those for making the polysilicon layer 113 n-type or those for p-type.

  In addition, this invention is not limited to the said Example, A various modification can be considered in the range which does not deviate from the summary of this invention.

It is a block diagram of one Example of this invention. It is a figure for demonstrating the manufacturing process of the semiconductor device of one Example of this invention. It is a figure for demonstrating the manufacturing process of the semiconductor device of one Example of this invention. It is operation | movement explanatory drawing of one Example of this invention. It is a block diagram of the modification of this invention. It is a figure for demonstrating the production method of the polysilicon resistance of the conventional semiconductor device. It is a figure for demonstrating the production method of the polysilicon resistance of the conventional semiconductor device. It is a block diagram of the conventional polysilicon resistor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Semiconductor device 111 Semiconductor substrate, 112, 115, 141 Insulating layer, 113 Polysilicon layer 114 Impurity diffusion layer 121 Opening

Claims (4)

In a semiconductor device equipped with a polysilicon resistor,
The polysilicon resistor includes a polysilicon layer formed in a desired shape,
A semiconductor device comprising an impurity diffusion layer formed by diffusing impurities on the polysilicon layer inward of the shape of the polysilicon layer. 2. The semiconductor device according to claim 1, wherein a resistance value of the polysilicon resistor is set by changing a concentration distribution of the impurity diffusion layer. In a method for manufacturing a semiconductor device in which a polysilicon resistor is mounted on a semiconductor substrate,
The polysilicon resistor includes a polysilicon layer formed in a desired shape,
An impurity diffusion layer formed by diffusing impurities in the polysilicon layer,
The method of manufacturing a semiconductor device, wherein the impurity diffusion layer is formed on the polysilicon layer inside the shape of the polysilicon layer after the polysilicon layer is formed into a desired shape. 4. The method of manufacturing a semiconductor device according to claim 3, wherein the resistance value is set by changing the concentration distribution of the impurity diffusion layer.

Images