JPH0322561A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To prevent a resistor from varying in resistance with dispersion by a method wherein a dummy metal layer is provided onto the resistor of a patterned semiconductor layer through the intermediary of an insulating film. CONSTITUTION:A polycrystalline silicon layer 3 is formed on a silicon dioxide layer 2 provided onto a substrate 1, and impurity such as boron or the like is ion-implanted. Then, the polycrystalline silicon layer 3 is patterned into resistors 31 and 32. Next, a silicon dioxide film 4 is formed on the whole face, which is patterned to form a contact window 5, and impurity such as boron or the like is ion-implanted for the purpose of compensating contact, an aluminum layer is formed on the whole face, which is patterned to form a wiring 6. Then, a PSG film 7 is formed, and an SOG layer 8 is formed on a step to flatten the surface. Then, an aluminum layer is formed, which is patterned to form a dummy aluminum metal layer 9 on the resistor 31 on which no aluminum wiring is formed, and a PSG film 10 is formed on the whole face.

Description

[Detailed Description of the Invention] [Summary] Regarding the improvement of a resistor made of a semiconductor layer used in a semiconductor device and a method for manufacturing the same, it is necessary to form a metal layer such as a wiring in the upper layer of the resistor. However, the object of the present invention is to provide a resistor and a method for manufacturing the same, in which the resistance value decreases uniformly due to heat treatment and there is no variation in resistance value, and a patterned semiconductor layer. The semiconductor device includes a metal layer formed on a resistor made of the above, with an insulating film interposed therebetween.

[Industrial application field]

The present invention relates to improvements in a resistor made of a semiconductor layer used in a semiconductor device and a method for manufacturing the same, and particularly to an improvement in preventing variations in resistance value from occurring during a heat treatment process.

[Conventional technology]

In a semiconductor device, a semiconductor layer is formed on an insulating film,
A method of patterning this to form a resistor is widely used. The reason for this is that the semiconductor layer can be easily formed on an insulating film using the CVD method, etc., and that it is easy to form multiple layers, which is effective in reducing the size of semiconductor devices, and that the P-N junction This is because the semiconductor device has the advantage that the operating speed of the semiconductor device can be increased because the parasitic capacitance is small. A method for manufacturing a resistor according to the prior art will be described below.

Refer to FIG. 9. On the silicon dioxide layer 2 formed on the substrate 1, CVD
A polycrystalline silicon layer 3 is formed using a method or the like, and impurities such as boron are ion-implanted at an acceleration energy of 35 KeV and a dose of 8.times.10'3/cm2.

Using the photolithography method as shown in FIG. 10, polycrystalline silicon layer 3 is
is patterned to form a resistor 31, and then CV
A silicon dioxide film 4 is deposited on the entire surface using the D method or the like.
OO Form to about the thickness of a person.

Using the photolithography method as shown in FIG. 11, the silicon dioxide film 4 is
A contact hole 5 is formed by patterning, and impurities such as boron are applied at an acceleration energy of 35 KeV and a dose of I x 10''/cm for the purpose of contact compensation.
” to implant ions.

Refer to FIG. 12. After forming an aluminum layer using a sputtering method or the like and patterning this to form a wiring 6, a PSG film 7 is formed on the entire surface using a CVD method or the like.

[Problem to be solved by the invention]

However, the resistor formed as described above has a problem in that its resistance value fluctuates due to a heat treatment process performed thereafter.

See Figure 8. Figure 8 shows the resistance value of the resistor before and after heat treatment.
It is a graph showing how it changes. The graph indicated by A in the figure shows the relationship between the impurity dose and sheet resistance of the resistor before heat treatment. When this resistor is heat-treated, if no metal layer is formed on the upper layer of the resistor, its sheet resistance value changes as shown in the graph indicated by B in FIG. When a metal layer is formed, the sheet resistance value changes greatly as shown in the graph shown by C in FIG. 8, and the rate of change is larger for a resistor with a smaller impurity dose. This variation in the amount of change in the resistance value of the resistor after heat treatment due to the presence or absence of the metal layer is undesirable from the standpoint of reliability and stabilization of performance of the semiconductor device.

The purpose of the present invention is to overcome this drawback and has two independent objectives.

The first purpose is to ensure that the resistance value decreases uniformly due to heat treatment, regardless of whether a metal layer such as wiring is formed on the upper layer of the resistor, and that the resistance value does not fluctuate. It is an object of the present invention to provide a resistor that does not cause variations.

A second object is to provide a method for manufacturing the above-mentioned resistor.

[Means for Solving the Problems] Of the above two objectives, the first objective is to form an insulating film (7) on a resistor (31) made of a patterned semiconductor layer.
) is achieved by a semiconductor device having a dummy metal layer (9) formed through the dummy metal layer (9).

Of the above two purposes, the second purpose is to
A semiconductor layer (3) is formed on top of the semiconductor layer (3), and this semiconductor 1! (3) is patterned to form a resistor (31), an insulating film (7) is formed on this resistor (31), and a dummy metal layer (9) is formed on at least the resistor (31). This is achieved by a method for manufacturing a semiconductor device, which includes the steps of forming the semiconductor device and then performing heat treatment.

[Function] When a metal layer is formed on the upper layer of the resistor, the resistance value changes greatly due to heat treatment due to the presence of the metal layer or the insulating layer interposed between the metal layer and the resistor. This is thought to be because the hydrogen contained in the resistor diffuses into the resistor at high temperatures.

In the semiconductor device and the manufacturing method thereof according to the present invention,
A dummy metal layer is formed on the upper layer of the resistor where there is no metal layer such as wiring on the upper layer of the resistor, and hydrogen is uniformly diffused into all the resistors during the heat treatment process. This is to prevent variations in resistance value from occurring. Note that once the resistor is saturated with hydrogen, the resistance value becomes stable and does not change due to the subsequent heat treatment process.

〔Example〕

Hereinafter, methods for manufacturing resistors according to two embodiments of the present invention will be described with reference to the drawings.

'1' Refer to Figure 2. On the silicon dioxide layer 2 formed on the substrate 1, CVD is applied.
A polycrystalline silicon layer 3 is formed using a method or the like, and impurities such as boron are ion-implanted with an energy of 35 KeV and a dose of 8 x 10 ''/cm''.

Using the photolithography method shown in FIG.
are patterned to form resistors 31 and 32. Next, a silicon dioxide film 4 is formed on the entire surface using a CVD method or the like.
This is patterned using a photolithography method to form a contact window 5, and for the purpose of contact compensation, an impurity such as boron is implanted with ions at an energy of 35 KeV and a dose of I x 10 ''/CI''. After the implantation, an aluminum ξ layer is formed on the entire surface using a sputtering method or the like, and this is patterned using a photolithography method to form the wiring 6. child\
Here, it is assumed that a metal layer made of wiring 6 is formed on the upper layer of the resistor 32, but no metal layer is formed on the upper layer of the resistor 31.

Refer to FIG. 4 After forming the PSG film 7 using the CVD method etc., the SOG film 7 is
was applied and etched back, and a SOG layer 8 was applied to the step part.
to flatten the surface.

Refer to Fig. 1. Form an aluminum layer using a spatter method or the like, pattern it using a photolithography method,
Resistor 31 with no aluminum wiring formed on the upper layer
A dummy aluminum metal layer 9 is formed on the upper layer, and then the entire surface is coated with P S
form. The aluminum metal layer 9 of this layer 5 is not electrically connected to other wiring, for example, other signal wiring, aluminum wiring for power supply, etc.

In the first example, a dummy aluminum metal layer 9 was formed only on the upper layer of the resistor 31 on which no argonium wiring was formed, but in the second example, Assume that the aluminum ξ metal layer 9 is formed over the entire surface without patterning. However, in this case, the following steps are required when connecting to the first layer wiring 6 and forming the second layer wiring.

Refer to FIG. 6, P S is applied to the aluminum metal layer 9 using CVD method or the like.
GIIIO is formed, and the PSG film 10, aluminum metal layer 9, and PSG film 7 are patterned to form a contact opening l1. As a result, a dummy aluminum metal layer 9 is formed.

Referring to FIG. 7, a PSG film is formed using a CVD method or the like, and etched using a reactive ion etching method to form a PSG layer 12 only on the side wall of the opening 1l.

Next, an AlS layer is formed on the entire surface using a spatter method or the like, and this is patterned to form a second layer wiring 13, and then a PSG film 14 is formed on the entire surface using a CVD method or the like. There are parts where this second N wiring 13 is formed on the resistor 31, and there are parts where it is not formed on other resistors 31. After forming the first metal layer 9, some heat treatment step is performed. The fluctuation of the resistor 31 is the same whether or not the second layer wiring 13 is formed.

〔Effect of the invention〕

As explained above, in the semiconductor device and the manufacturing method of the same according to the present invention, a dummy metal layer is formed in the upper layer of the resistor on which a metal layer such as wiring is not formed in the upper layer. Since hydrogen diffuses uniformly from the metal layer to all resistors, the resistance value decreases uniformly, eliminating variations in the resistance values of the resistors, improving manufacturing yields, and improving semiconductor performance. Device performance becomes stable and reliability improves.

[Brief explanation of drawings]

1 to 4 are process diagrams illustrating a method for manufacturing a resistor according to a first embodiment of the present invention. 5 to 7 are process diagrams illustrating a method for manufacturing a resistor according to a second embodiment of the present invention. FIG. 8 is a graph showing the relationship between the impurity dose and the sheet resistance value of the resistor. A is before heat treatment, B is after heat treatment without a metal layer on the upper layer, and C is a graph with a metal layer on the upper layer. The sheet resistance value after heat treatment in a certain case is shown. 9 to 12 are process diagrams illustrating a method of manufacturing a resistor according to the prior art. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Insulator layer (silicon dioxide layer), 3... Semiconductor layer (polycrystalline silicon layer), 31, 32... Resistor, 4... Silicon dioxide film, 5 ... Contact hole, 6... Aluminum wiring (first layer wiring), 7... Insulating film (PSG film), 8... SOG layer, 9... Aluminum metal layer/dummy aluminum metal layer , 12 ・PSG film, ・Contact opening, ・PSG layer, ・Second layer wiring, ・PSG layer.

Claims (1)

[Claims] [1] A resistor (3) made of a patterned semiconductor layer
1) A semiconductor device characterized by having a dummy metal layer (9) formed thereon via an insulating film (7). [2] A step of forming a semiconductor layer (3) on the insulator layer (2), a step of patterning the semiconductor layer (3) to form a resistor (31), and a step of forming a resistor (31) on the resistor (31). forming an insulating film (7) on at least the resistor (31); and a dummy metal layer (9) on at least the resistor (31).
1. A method of manufacturing a semiconductor device, comprising: a step of forming a semiconductor device; and a step of subsequently performing heat treatment.