JPH02199865A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To correct a resistance value formed off a design value to a value close to the design value in a posterior process by a method wherein, after impurity ions have been implanted into a polycrystalline silicon film, the polycrystalline silicon film is etched when a measured resistance value is lower than the design value and the ions are implanted again when the value is higher. CONSTITUTION:An oxide film 2 is formed on a semiconductor substrate 1; a polycrystalline silicon film 3 is deposited on it; after that, this film is patterned. Then, impurities are introduced into the silicon film 3; after that, a first interlayer insulating film 4 such as a silicon dioxide film or the like is deposited. A resistance value of the silicon film 3 is measured in a state that opening parts 5 have been formed in the insulating film 4 on both end parts of the silicon film 3. When the resistance value is off a design value toward a smaller value, a photoresist is formed on the whole surface; the photoresist at an upper layer in the central part of the silicon film 3 is removed; after that, the insulating film 4 at the upper layer of the silicon film 3 and the surface of the silicon film 3 are removed partly. Then, the photoresist 6 is removed; after that, a second interlayer insulating film 7 is deposited; a contact hole 8 is formed in the insulating film 7; a prescribed connection is executed by using a wiring part 9; this device is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a semiconductor device, and particularly to a method for manufacturing a polycrystalline silicon resistor.

[Conventional technology]

Conventionally, this type of polycrystalline silicon resistor was produced by depositing polycrystalline silicon on an oxide film 2 formed on the surface of a semiconductor substrate 1, as shown in FIG. Thereafter, impurities are introduced into the polycrystalline silicon film 3 by, for example, ion implantation. Next, the entire surface is covered with a first interlayer insulating film such as a silicon oxide film or a silicon nitride film, and openings are provided at both ends of the polycrystalline silicon film 3 for wiring attachment parts, and then a second interlayer insulating film 7 is formed as an upper layer. A contact hole is provided in the opening, and a wiring 9 made of aluminum or the like is patterned. In this way, a polycrystalline silicon resistor having a predetermined resistance value is realized and good contact with the wiring 9 is obtained.

[Problem to be solved by the invention]

In the conventional manufacturing method of polycrystalline silicon resistors described above, variations in film thickness in the process of forming the polycrystalline silicon film, variations in length and width in the patterning process of the polycrystalline silicon film, and even variations in the length and width of the patterned polycrystalline silicon film occur. There are many factors that cause the resistance value to deviate from the designed value, such as variations in impurity concentration during the ion implantation process into the silicon film. However, in a series of conventional manufacturing methods, there was no means for correcting a resistance value that deviated from a designed value. Therefore, there was a drawback that the electrical characteristics etc. that were assumed at the time of circuit design could not be obtained sufficiently.

〔the purpose〕

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a semiconductor device in which the value of a resistor formed outside the design value during the manufacturing process can be corrected to be close to the design value in a subsequent process.

[Means to solve the problem]

The method for manufacturing a polycrystalline silicon resistor of the present invention includes a step of depositing polycrystalline silicon on a semiconductor substrate and patterning it, a step of introducing impurities into the patterned polycrystalline silicon film, and a step of depositing a first insulating film on the entire surface. forming an opening in the first insulating film on a predetermined region of the polycrystalline silicon film to expose the polycrystalline silicon film; and forming a resistance value of the polycrystalline silicon film through the opening. a step of measuring
A step of forming a photoresist film from which at least a portion of the polycrystalline silicon film is removed, and if the measured resistance value is smaller than a predetermined value, the photoresist film is used as a mask to form a first insulating film and the polycrystalline silicon film. If the measured resistance value is larger than a predetermined value, the first insulating film is removed by etching using the photoresist film as a mask to expose the polycrystalline silicon film and introduce impurities. a step of forming a second insulating film on the entire surface after removing the photoresist film, and forming a contact hole in the second insulating film over the opening so that it is connected to the polycrystalline silicon film through the contact hole. and a step of forming wiring.

Therefore, in the present invention, variations in the resistance value from the designed value obtained by introducing impurities into the polycrystalline silicon film can be corrected in a later process.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIGS. 1(a) to 1(d) are process cross-sectional views of a first embodiment of the present invention. Oxide-2 is formed on a semiconductor substrate 1, and a polycrystalline silicon film 3 is deposited thereon and then patterned. Next, after impurities are introduced into the polycrystalline silicon film 3 by, for example, ion implantation, a first interlayer insulating film 4 such as a silicon oxide film is deposited. As shown in FIG. 1(a), openings 5 are formed in the first interlayer insulating film 4 on both ends of the polycrystalline silicon film 3.
The resistance value of the polycrystalline silicon film 3 is measured in the state in which the polycrystalline silicon film 3 is formed.

If the resistance value deviates from the designed value, a photoresist 6 is formed on the entire surface, and the photoresist at the upper center of the polycrystalline silicon film 3 is removed as shown in FIG. 1(b). After patterning, using this as a mask, the insulating film 4 on the upper layer of the polycrystalline silicon film 3 and the surface of the polycrystalline silicon film 3 are partially removed. Next, as shown in FIG. 1(c), after removing the photoresist 6, a second interlayer insulating film 7 is deposited, and a contact hole 8 for wiring is formed in the second layer above the opening 5.
The structure shown in FIG. 1(d) is obtained by forming an interlayer insulating film 7 and making predetermined connections using wiring 9 made of aluminum or the like. In this way, the resistance value is measured during the manufacturing process of the polycrystalline silicon resistor, and depending on the result, a part of the polycrystalline silicon resistor is etched away to reduce the cross-sectional area of the polycrystalline silicon film. The resistance value can be controlled to be high.

This example shows a correction method when the resistance value due to the polycrystalline silicon film is formed smaller than the design value. Therefore, by etching away a part of the polycrystalline silicon film,
Reduced cross-sectional area. However, in reality, the direction of the variation in resistance value is uncertain, so if the resistance value is larger than the designed value, after patterning the photoresist 6 as shown in FIG. 1(b), 1 interlayer insulating film 4
After removing the polycrystalline silicon film 4 by etching, the polycrystalline silicon film 4 is exposed, and impurity ions are implanted again. In this way, it is possible to increase the impurity concentration in the polycrystalline silicon film 4 and reduce the resistance value. Thereafter, the steps shown in FIGS. 1(C) and 1(d) are followed.

Further, in this embodiment, in the etching or exposing process of the polycrystalline silicon film 3 using the photoresist 6 as a mask, the vicinity of the center of the polycrystalline silicon film 3 is etched,
Exposed, but not limited to.

FIG. 2 is a longitudinal sectional view of a second embodiment of the invention. A wiring 9 made of aluminum or the like is formed extending over the polycrystalline silicon film 3 . Therefore, compared to the conventional example shown in FIG. 3, the distance between the polycrystalline silicon film 3 and the wiring 9 becomes smaller, and the capacitance between the polycrystalline silicon film and the wiring becomes larger. This is effective, for example, when a resistor used in a memory cell requires a capacitance in order to increase the alpha ray resistance capacity.

〔Effect of the invention〕

As explained above, in the present invention, after impurity ion implantation into a polycrystalline silicon film, if the measured resistance value is lower than the designed value, the polycrystalline silicon film is etched, and if it is higher, it is exposed and ionized again. By performing implantation, a polycrystalline silicon resistor having a resistance value close to the design value can be realized.

[Brief explanation of the drawing]

1(a) to (d) are sectional views of a first embodiment of the present invention, FIG. 2 is a longitudinal sectional view of the second embodiment, and FIG. 3 is a sectional view of a conventional example. 1... Semiconductor substrate, 2... Oxide film, 3
...Polycrystalline silicon film, 4...First interlayer insulating film (first insulating film), 5...Opening, 6
... Photoresist, 7 ... Second interlayer insulating film (second insulating film), 8 ... Contact hole, 9 ... Aluminum wiring. Agent: Patent Attorney Shinsuke Uchihara

Claims (1)

[Claims] 1. Depositing and patterning polycrystalline silicon on a semiconductor substrate, introducing impurities into the patterned polycrystalline silicon film, and forming a first insulating film on the entire surface. forming an opening in the first insulating film on a predetermined region of the polycrystalline silicon film to expose the polycrystalline silicon film; and removing at least a portion on the polycrystalline silicon film. forming a photoresist film, using the photoresist film as a mask, etching away a portion of the first insulating film and the polycrystalline silicon film, and etching a photoresist film over the entire surface after removing the photoresist film. a step of forming a second insulating film over the opening, and a step of forming a contact hole in the second insulating film over the opening and forming a wiring to connect to the polycrystalline silicon film through the contact hole. A method for manufacturing a semiconductor device, comprising: 2. Using the photoresist film as a mask, instead of etching away part of the first insulating film and the polycrystalline silicon film, using the photoresist film as a mask, removing the first insulating film by etching. 2. The method of manufacturing a semiconductor device according to claim 1, further comprising the steps of exposing the polycrystalline silicon film and introducing impurities into the polycrystalline silicon film.