JPS5931050A - Resistor and forming process thereof - Google Patents

Abstract

PURPOSE:To form a resistor with excellent controllability and reproducibility by a method wherein a resistance controller is composed of an insulating film such as an ion implanted silicon oxide film or silicon nitride film, etc. CONSTITUTION:The arsenic dope polycrystalline silicon layers 3, 3' are deposited as an electrode of high resistor to form an opposing electrode on SiO2 film 2 by means of photoetching. A molybdenum layer 4 is deposited on the polycrystalline silicon layers 3, 3' and the SiO2 film 2. The molybdenum layer 4 on the SiO2 layer 2 between the polycrystalline silicon layers 3, 3' is removed by means of photoetching. An ion implanted layer 5 is formed on the surface of the SiO2 film 2 between said polycrystalline silicon layers 3, 3'. Finally the boron ion is implanted to remove the molybdenum layer 4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resistor used in a semiconductor multiplication circuit and a method for forming the resistor.

Resistance elements that are required on the East & (Ro) roads, especially 10
A high resistance material of about 10"Ω has conventionally been produced by introducing impurities such as arsenic, phosphorus, boron, etc. into non-doped polycrystalline silicon deposited by CvD method or the like using an ion implantation method to increase the resistance of the polycrystalline silicon. This resistor has the ability to control the resistance value, as described below.
The reproducibility was poor, and serious problems were encountered especially when obtaining a resistance of 10'Ω phase or higher, which is widely considered safe.

Figure 1 shows arsenic k 1 in a non-doped polycrystalline silicon layer with a thickness of 4500 nm deposited by CVD on a silicon oxide film.
This figure shows the complete dependence of the sheet resistance of the polycrystalline silicon layer on the ion implantation amount after ion implantation with an implantation energy of 50 keV and heat treatment at 1000° C. for 30 minutes in a nitrogen atmosphere. In this high-resistance region, the dependence of the resistance value on the ion implantation amount, that is, the dependence on the impurity concentration, is very strong, and even a small change in the amount of impurity can significantly change the resistance value, making it difficult to control. Have difficulty. Furthermore, the diffusion coefficient of impurities in polycrystalline silicon is extremely large; for example, ion-implanted arsenic, phosphorus, chain threads, etc. can be diffused uniformly in the film thickness direction by heat treatment at 1000°C for about 30 minutes. to be distributed. Therefore, the controllability of the ion implantation amount is usually within 1%, but since the polycrystalline silicon film thickness varies by about 5%, the impurity concentration varies by more than 5X. Therefore, as can be seen from Fig. 1, the sheet resistance is less than 1%, and the tIil controllability is low.

This was a major problem in terms of reproducibility. Furthermore, in order to take out the electrodes from the resistor, both ends of the high-resistance element must be made low in resistance by introducing impurities in a high concentration. The lateral diffusion length of the impurity from this low resistance layer to the high resistance part is:
For example, heat treatment at 1000° C. for about 30 minutes results in a thickness of 2 to 3 μm, which is a major problem in the production of fine, high-density integrated circuits.

The present invention was proposed to solve the above-mentioned problems of conventionally used polycrystalline silicon high-resistance elements. Another object of the present invention is to obtain, by ion implantation, a fine high-resistance material having excellent open-side uniformity and dust resistance.

(3) In order to achieve the above object, the present invention provides a resistor consisting of an electrode and a resistance value control part, and the resistance value control part is formed by an insulating film such as an ion-implanted silicon oxide film or silicon nitride film. The gist of the invention is the resistor body having all the features of the structure.

Furthermore, the present invention provides a resistor characterized by comprising a step of providing an electrode on an insulating film such as a silicon oxide film or a silicon nitride film, and a step of forming a resistance value control portion by implanting ions into the insulating film. The gist of the invention is a method for forming a body.

Next, we will explain about the embodiments of the present invention and the attached drawings. It should be noted that the embodiments are merely illustrative, and that various epicenters or improved sound materials may be used without departing from the spirit of the present invention.

FIG. 2 shows an example of forming a sieve resistor according to the invention. Molybdenum 5 is an ion-implanted layer. Figure 2 (
As shown in a), (4) an stO2 film 2 to be used as a high resistance material is formed on a silicon substrate 1 by thermal oxidation or CVD.

In this example, a thermal oxidation method in a wet 02 atmosphere was used, and the film thickness was set to 5000^. Next, as shown in FIG. 2(b), arsenic-doped polycrystalline silicon is deposited by a kcVD method as an electrode of a high resistance material, and a counter electrode of p, 3.3' is formed by normal photoetching. Formed on k St Ot Z. In this example, the film thickness of polycrystalline silicon was 3000λ. Next, as shown in FIG. 2 <C), molybdenum 4 is placed on the polycrystalline silicon 3, 3' and Si 0.2 to be used as a mask for the next ion implantation.
is deposited by vacuum evaporation method or the like. It is necessary to select a film thickness of this molybdenum that can sufficiently block all ions, taking into account the ion ridge, implanter energy, and implantation amount for the next ion implantation. In this example, the film thickness of molybdenum 4 was 5000A. Next, among the deposited molybdenum, counter electrodes 3, 3
The molybdenum present in the Sf Oal between 1 and 2 is removed by the usual 7 steps. After that, all ions are implanted into the entire surface, and St 02 between the opposing electrodes 3 and 3' is
On the surface of the ion implantation layer 5 which is the resistance value control part of the Hatake resistor.
form. The ion gods are boron, phosphorus, arsenic, and silicon.

It may be one type of archon or a combination of two or more types. The power, injection energy, and injection force are determined according to the resistance value of the intended resistor. In this example, boron ions were implanted with an implantation energy of 50 KeV. Next, as shown in FIG. 2(d), the molybdenum 4 used in (7) is removed using the mask used for C1 ion implantation, for example, using a mixture of sulfuric acid and hydrogen peroxide. 3
``A high-resistance element can be formed as an e2 terminal.

FIG. 3 shows the dependence of the sheet resistance of the resistor formed as described above on the implantation amount. Figure 3 shows boron i
The ions were implanted with an implantation energy of 50 KeV. As shown here, 5lOt required for loquat
It can be seen that fla becomes electrically conductive by ion implantation with a vorticity of 1016 to IQ Ifti'' or higher.In the example shown here, 4 x 1010l6' to 2
X 101? 10″Ω for a range of crn-2 injection volumes.
A sheet resistance value of 107 ohms/low has been achieved. 1
When obtaining a high resistance of about 0.07Ω/Ω or more, the resistor according to the present invention can be used.As is clear from a comparison of FIG. 1 and FIG. In comparison, it has the advantage that the dependence of the resistance value on the injection amount is much smaller, that is, the resistance value is better controllable and easier to develop. Further, in the resistor according to the present invention, the ion implantation method is used.
02 Because only the part near the surface of the membrane is made into a sound conductive layer, 5
Variations in the 102 film thickness do not affect the resistance value, and it has excellent open side uniformity and reproducibility. Further, according to the present invention, since there is no lateral expansion unlike in the case of using conventional polycrystalline silicon, there are advantages such as miniaturization.

The above describes the case of performing 4 ion implantations into the 5102 film, but
A similar effect is expected when ions are implanted into a silicon nitride film or an insulating film such as alumina or sapphire. Furthermore, although we have described the case where the electrodes are opposite electrodes, it goes without saying that concentric electrodes may also be used.

(7) In addition, in this example, after the electrodes have been completely removed, ions are implanted into the S10□ film.
Similar effects can be expected even if electrodes are provided afterwards.

FIG. 4 shows another embodiment of the present invention, in which a p1 buried type resistor is formed by high-energy ion implantation. Figure 4(a).

As shown in (b), 5i formed on the silicon substrate 1
Molybdenum 4, which is used as an ion implantation mask, is formed on OJ2 in the same manner as in the first embodiment, and then 5I
For example, boron ions are implanted into the O2 film. here,
For example, if the boron implantation energy is B 150 KeV, the surface of the 5i02 film is not 810
A conductive layer 5 is formed in the two films. Next, as shown in FIG. 4(C), after removing the molybdenum used as a mask for ion implantation,
02 Experiment 2: Open the through hole 6 using the normal 7-tightening process. Next, as shown in FIG. 4(d), by forming an electrode 7 of gold Nf4 or low resistance polycrystalline silicon (8) on the through hole, the conductive layer becomes stoichiometric.
, st. In this embodiment as well, the same effects as in the first embodiment can be obtained, and it is possible to form a fine resistor with good resistance value controllability and ladleability.

FIG. 5 shows another embodiment of the present invention, in which a resistor '11
Both the single pole and the conductive layer are of the buried type. As shown in FIG. 5(a), SiO formed on a silicon substrate
, 1llk2, low resistance polycrystalline silicon: (', 3'
A 'fIL pole consisting of
Sin, test 8 is deposited. In this example, Si
The thickness of the film 8 was 5000A. As shown in Fig. 5 (b), using molybdenum 4 as a mask, electrodes 3, 3'
Boron ions are selectively implanted into the 5i02 films 8 and 2 between them, for example, at an implantation energy of 200 Ke. 2
The penetration depth of boron in 8102 at 00 KeV is
The thickness of 02 film 8 is 5000 yos, so
As shown in FIG. 5), a conductive layer 5 can also be formed on the 5in2 films 82 and 2. Next, see Figure 5 (
As shown in C), the molybdenum used as a mask for ion implantation can be removed by forming the entire resistor consisting of the electrodes 3, 3' and the conductive layer 5. If L = 3,3'' is used as the i wiring in multiplication circuit manufacturing, it is possible to manufacture an integrated circuit in which a resistor having a desired resistance value is connected between the wirings tM3 and 3'. The resistor forming force method using the method enables the controllability of the resistance value and the formation of a fine resistor with a 41-it property, as described in the first embodiment.

FIG. 6 shows another embodiment of the present invention, in which the resistor is entirely formed in the vertical direction. Figure 6 (as shown in a, l)
On the 5IU21iL 2 silicon substrate, 3 trays of low-resistance polycrystalline silicon, etc., which will become the poles of the resistor, and CVD
The stock is multiplied by a method, etc., and a film 8 is deposited thereon by Cvl) method.

In this example, the thickness of the Si02 film 8 was 500A. Alternatively, if a polycrystalline silicon substrate is used, this 5J02 film can also be obtained by thermally oxidizing a part of the polycrystalline silicon. Next, as shown in FIG. 6(b), using molybdenum 4 as a mask, 5tO21i! Ions are implanted to 1% 8 to form a conductive layer 5. The implantation energy at this time is 5fOJi!
It is necessary to select a conductive layer so that the conductive layer is formed entirely over the depth direction of 8. In this example, the As ion is 80 Ke
Injected at V. The injection amount is determined depending on the resistance value to be obtained.

Next, as shown in FIG. 6 <a>, after removing the molybdenum, a metal such as M is applied on the conductive JWi 5 to form an upper electrode 7. A resistor of a structure can be formed.

Similar to the embodiment described in Section 1, the method according to this embodiment is used to form a fine resistor with excellent secondary uniformity and spreadability. cβJ function. In particular, according to this embodiment, since a resistor having a vertical structure can be formed, it is possible to form a finer resistor.

As explained above, according to the present invention, the resistor is formed using ion implantation into the insulating film (11), so that high resistance values of about 107Ω/1 or higher can be achieved with good controllability and reproducibility. It has the advantage of being able to be miniaturized because there is no effect on the resistance value due to variations in insulation film thickness, and there is no transverse wave caused by diffusion of impurities. It is something.

[Brief explanation of drawings]

Figure 1 shows the ion implantation dose dependence of the sheet resistance of a resistor formed using conventional polycrystalline silicon, and Figure 2 (
a) to (d) are diagrams showing an example of forming a resistor according to the present invention, FIG. ) ~(
d), Figures 5(a) to (C). 6(a) to 6(e) respectively show other embodiments of forming a resistor according to the present invention. 1...Silicon substrate, 2...Silicon oxide film (thermal oxidation aa), 3,3'...Low resistance polycrystalline silicon, 4...Molybdenum , 5...
...Ion implantation layer, 6...Through hole, 7.
...Metal or low resistance polycrystalline silicon, 8...
・・・・Silicon oxide film (C(12) VD oxide film) Patent applicant Nippon Denso Kancho Corporation Figure 1 5Mo amount (cm-2) Figure 3 Silicone amount (C vinegar Figure 2 Figure 4

Claims (5)

[Claims] (1) A resistor comprising an electrode and a resistance control section, and the resistance control section is formed of an ion-implanted insulating film such as a silicon oxide film or a silicon nitride film. . (2) It consists of a step of placing all the electrodes on an insulating film such as a silicon oxide film or a silicon nitride film, and a step of forming the entire resistance value control part by implanting ions into the insulating film.
Method of forming a resistor with % characteristics. (3) A step of forming a resistance value control section by implanting ions into an insulating film such as a silicon oxide film or a silicon nitride film, a step of making a hole for taking out an electrode in the insulating film, and a step of making a hole for taking out the electrode. The method consists of a step of providing a hole for the purpose and an electrode on the insulating film? The resistor forming force method according to claim 2, characterized by % liver. (4) a step of forming an electrode on a first insulating film such as a silicon oxide film or a silicon nitride film; a step of forming a second insulating film on the electrode and the first insulating film; A method for forming a claim comprising the step of forming a resistance value control S by passing through a second insulating film and implanting ions into the first insulating film. (5) A step of providing one electrode of the resistor, a step of providing an insulating film such as a silicon oxide film or a silicon nitride film on the lower electrode, and a resistance value control section by implanting ions into the insulating film. A method for forming a resistor according to claim 2, comprising a step of forming a resistor and a step of providing an upper electrode on the resistance value control portion.