JP3422261B2 - Manufacturing method of thin film resistor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a thin film resistor having a desired shape by etching a thin film resistor layer and a barrier metal layer laminated on the surface of a substrate.

[0002]

As a semiconductor device, especially in an IC (integrated circuit), there is one in which a thin film resistor is formed on an insulating film and used as a constituent element thereof, whereby the chip is miniaturized as a whole. We are trying to reduce costs. In this case, as the thin film resistor, a CrSi-based material such as CrSi or CrSiN whose resistance value can be adjusted by a laser is used.

FIG. 8 shows, for example, Cr as a material for a thin film resistor.
It shows a manufacturing process of a thin film resistor when SiN is used. An insulating separation film and a circuit element such as a MOSFET and a bipolar transistor are formed (not shown) on a single crystal silicon substrate 1 serving as a substrate by a known method, and an interlayer insulating film is formed to ensure insulation with metal wiring. The silicon oxide film 2 is deposited by the CVD method and heat-treated to improve the film quality.

After that, a CrSi type film 3 as a thin film resistor layer is formed on the silicon oxide film 2, and a TiW film 4 as a barrier metal layer is laminated. Subsequently, a photoresist layer 5 patterned into a predetermined shape by photolithography is provided (see FIG. 8A), and using this as a mask member, the TiW film 4 is etched by a well-known wet etching process to form the CrSi-based film 3. It is exposed (see FIG. 2B).

Next, the CrSi-based film 3 is patterned by etching. This is performed by plasma dry etching using the photoresist layer 5 and the TiW film 4 which is the barrier metal layer as a mask member (see FIG. 3C). This method is described in, for example, Japanese Patent Laid-Open No.
No. 3,358,311. Then, after that, the photoresist layer 5 is removed, and the electrode wiring 6 made of aluminum or the like is formed by a well-known photolithography process (see FIG. 3D). As a result, a thin film resistor made of the CrSi-based film 3 is formed.

By the way, in the manufacturing process as described above, when the TiW film 4 which is the barrier metal layer is etched, an etching residue thereof is generated or the etching residue is generated as shown in FIG.
As shown in (b), since there is side etching from the edge of the photoresist layer 5 toward the inside (side etching width Δd), with respect to the initial pattern dimension d1 (see (a) in the figure). As a result, the width of each side is etched by 2 [Delta] d to form a shorter dimension d2 (= d1-2 [Delta] d), resulting in a large variation in the processing width. This means that when the miniaturization of the pattern that determines the minimum value of the dimension d1 is promoted, considering that the value of Δd is about the same as the etching accuracy, this has a large adverse effect on the whole, and as a result,
This limits the improvement of processing accuracy.

The present invention has been made in view of the above circumstances, and an object thereof is to improve the processing accuracy in the etching process in forming such a thin film resistor, and to improve the barrier metal and the thin film. It is an object of the present invention to provide a method for manufacturing a thin film resistor, which enables each resistor to be etched with good selectivity.

[0008]

According to the invention of claim 1, an oxide film is arranged and formed on the surface of the substrate. In the mask pattern forming step, a mask material layer is formed on the surface of the barrier metal layer. To form a mask pattern,
Then, in the etching process, plasma dry
Tetrafluorocarbon, which is a fluorine compound, using an etching device
The barrier metal layer is selectively etched by plasma-activating an etching gas in which an elemental (CF ₄ ) gas and an oxygen (O ₂ ) gas are mixed to perform a dry etching process, and subsequently, a thin film resistor layer is formed. Selectively etch. At this time, etch the barrier metal layer
In the case of etching, acid
The ratio of the elemental gas is in the range of 20 to 70%, and the thin film resistance is
When etching the antibody layer, the entire etching gas
Oxygen gas accounts for 80% or more of the flow rate
Is set so that

After that, the thin film resistor can be formed on the surface of the substrate by removing the mask pattern.
As a result, in the etching process step, the barrier metal layer and the thin film resistor layer can be continuously performed in the same dry etching step, and the number of steps can be reduced and side etching and the like can be performed. It becomes possible to suppress as much as possible and perform highly accurate machining.

According to the second aspect of the present invention, since the compound containing chromium (Cr) and silicon (Si) is used as the thin film resistor layer, for example, by adopting a compound such as CrSiN, the thin film resistor having a small temperature coefficient. Since it can be formed as a body, the characteristics of the device can be improved, and titanium (T
Since i) or a layer made of a compound containing tungsten (W) is formed, it is possible to prevent an undesirable reaction due to direct contact with a wiring metal electrically connected to the thin film resistor layer.

According to the third aspect of the invention, in the etching treatment step, the barrier metal layer is selectively etched by increasing the mixing ratio of the fluorine component of the etching gas. Therefore, even if overetching is performed, the mask pattern or It is possible to etch the barrier metal layer with high accuracy without excessively etching the thin film resistor layer. In the next etching, the mixing ratio of the oxygen component of the etching gas is increased to selectively select the thin film resistor. Since the etching is performed, the thin film resistor layer can be etched using the barrier metal layer as a mask pattern, and the thin film resistor can be formed with high accuracy.

According to the fifth aspect of the present invention, carbon tetrafluoride (C
Since a mixture of F ₄ ) gas and oxygen (O ₂ ) gas is used, the barrier metal layer containing Ti or W can be etched by CF 4 gas, while CF 4 gas is used.
_The thin film resistor containing chromium (Cr) or silicon (Si) can be etched by the ₄ gas and the O ₂ gas. As a result, it becomes possible to selectively perform the etching process of the barrier metal layer and the etching process of the thin film resistor by using the same kind of gas and changing the flow rate thereof. It became possible to do without continuous gas exchange,
The processing can be performed quickly and reliably.

According to the invention of claim 6, as a gas ratio for etching the barrier metal layer, the flow rate of oxygen to the entire etching gas is set to 20 to 70%, whereby the barrier metal layer to the thin film resistor layer is set. It becomes possible to increase the etching selection ratio. Also,
Regarding the gas ratio when etching the thin film resistor, the flow rate ratio of oxygen is set to 80% or more to increase the etching selectivity of the thin film resistor layer to the oxide film formed on the underlying substrate surface. It will be possible to put it in a standing state.

According to the seventh aspect of the invention, since the gas ratio for etching the barrier metal layer is such that the flow rate of oxygen with respect to the entire etching gas is 50% or less, the etching selection ratio of the barrier metal layer to the thin film resistor layer. Can be effectively increased.

According to the eighth and ninth aspects of the present invention, an organic material containing at least C—H bonds is used as the mask material layer, and a chemical dry etch is used in the etching process.
In this case, since the substrate temperature is heated to a predetermined temperature higher than room temperature during the etching process, the etching rate of the barrier metal layer can be improved and the barrier metal layer can be etched. The CF4 gas used facilitates replacement of H in the C—H bond portion of the mask material with fluorine F, so that the entire surface can be C—F bond. By thus forming the C—F bond on the surface of the mask material layer, in the next process step of etching the thin film resistor,
Even when the etching gas is performed under the condition that the oxygen gas ratio is increased, the O etching resistance of the surface of the mask material is increased. As a result, the etching amount of the mask material is suppressed when the thin film resistor layer is etched. Will be able to.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 schematically shows a cross section corresponding to a manufacturing process when a thin film resistor 12 is formed on a single crystal silicon substrate 11 which is a substrate. FIG. 1D shows a thin film formed by this method. The cross-sectional structure of the resistor 12 is shown.

That is, in the figure, a silicon oxide film 13 as an interlayer insulating film is formed on the surface of a single crystal silicon substrate 11 which is a semiconductor substrate after a device is formed through a predetermined device forming process. ing. On the surface of the silicon oxide film 13, a thin film resistor 12 patterned into a predetermined shape is formed.

The thin film resistor 12 is, as will be described later,
It is made of a CrSiN film 14 (see FIG. 10A) formed by sputtering a CrSi sintered body as a resistor material in an atmosphere containing nitrogen gas, and has a film thickness of about 15 nm. The CrSiN film 14 forming the thin-film resistor 12 contains nitrogen so that the temperature coefficient (T
(CR) can be made small, and thereby the operational stability with respect to temperature can be improved.

A TiW film 15, which is a barrier metal layer for preventing deterioration due to a reaction with the electrode portion, is formed on the surface of the electrode contact portion at both ends of the thin film resistor 12. The TiW film 15 is formed to have a film thickness of about 250 nm. Then, an aluminum electrode pattern 16 as a metal electrode is formed so as to cover the TiW film 15 on both ends of the thin film resistor 12. Accordingly, the thin film resistor 12 is provided between the aluminum electrode patterns 16.
Thus, the resistor is formed.

Next, in the process of forming the thin film resistor 12 having the above-mentioned structure, the structure of the etching apparatus used when performing the etching process of the present invention will be briefly described. FIG. 2 shows a schematic structure of a chemical dry etching apparatus 17. The inside of the apparatus is roughly divided into an etching reaction chamber 18 and a plasma generation chamber communicating with the etching reaction chamber 18 through a gas passage 19. 20 and 20.

A gas introduction port 21 for introducing an etching gas is opened in the plasma generating chamber 20 so that CF ₄ and O ₂ are supplied to the inside as an etching gas. Further, the plasma generation chamber 20 has a waveguide 2
The microwave is radiated to the inside through the line 2. Then, when the microwave is introduced into the plasma generation chamber 20, the etching gas supplied inside is excited into a plasma state and activated, and the activated etching gas is etched through the gas passage 19. It is adapted to be guided to the reaction chamber 18.

Next, in the etching reaction chamber 18,
The gas rectifying plate 23 is provided on the upper portion, and the substrate mounting portion 24 is provided on the center of the lower portion. The gas rectifying plate 23 is arranged so as to rectify the etching gas introduced through the gas passage 19 and uniformly contact the substrate (wafer) 25 to be etched, which is placed on the substrate placing part 24. There is. The substrate mounting portion 24 has support pins 24a.
Is provided so as to support the substrate 25, and the etching process can be performed while heating the substrate 25 by the radiant heat of the heating lamp 26 provided below.

An exhaust port 27 communicating with an exhaust system for exhausting the etching gas and its reaction products and for reducing the pressure inside is provided at the side of the lamp 26 below the substrate mounting portion 24. In the figure, in order to show the flow path of the etching gas in each state, ○ indicates the etching gas before excitation, Δ indicates the activated etching gas, and □ indicates the reaction generated by the etching. Showing the thing.

Now, a manufacturing process for forming the thin film resistor 12 will be described with reference to FIG. First, although not shown, an insulating separation film and a circuit element such as a MOSFET and a bipolar transistor are formed on the single crystal silicon substrate 11 by a known method, and an interlayer is formed on the insulating film to ensure insulation with metal wiring. A silicon oxide film 12 as an insulating film is deposited and formed by the CVD method. After that, the silicon oxide film 12 is annealed under predetermined conditions to make the film quality dense.

After that, a CrSiN film 14 as a thin film resistor layer is formed on the silicon oxide film 13, and a TiW film 15 as a barrier metal layer is laminated. In this case, the CrSiN film 14 is formed by converting the CrSi sintered body into nitrogen (N
₂ ) formed by reactive sputtering in an atmosphere containing a gas and argon (Ar) gas, and has a film thickness of 1
It is about 5 nm. The TiW film 15 is made of CrSiN.
Membrane 14 and Aluminum Electrode Pattern 16 Formed on Top
It is provided to prevent deterioration due to the reaction between and, and is similarly formed with a film thickness of about 250 nm by sputtering in an argon (Ar) atmosphere.

Subsequently, a photoresist made of an organic material is applied on the TiW film 15 so as to have a film thickness of, for example, about 1 μm, and is patterned into a shape corresponding to the shape of the thin film resistor 12 by a well-known photolithography process. Then, the mask pattern 28 is formed (see FIG. 1A). In this case, the photoresist forming the mask pattern 28 is made of, for example, phenol novolac resin, and this resin contains carbon-hydrogen bonds (C—H bonds).

Next, when proceeding to the etching process, Ti of the single crystal silicon substrate 11 which has been formed to the above-mentioned state by using the above-mentioned chemical dry etching apparatus 17 is used.
The W film 15 and the CrSiN film 14 are etched. First, as the substrate 25, the single crystal silicon substrate 11 is used.
Are supported by the support pins 24 a of the substrate platform 24.
In this state, an etching gas is introduced to carry out an etching process.

In the etching process, the TiW film 1
Two-step etching performed under different conditions is adopted for each of the Cr 5 and CrSiN films 14. As shown in FIG. 3, the condition in each etching process is that the mixing ratio of carbon tetrafluoride gas (CF ₄ ) which is a fluorine compound gas mainly used as etching gas and oxygen gas (O ₂ ) is made different. It is set.

That is, the first step is the TiW film 1
In the etching treatment of No. 5, the value of the ratio R (%) of the flow rate of oxygen gas to the total flow rate of etching gas is set to 20.
By setting the range of about 70% to 70% as an appropriate range, for example, by setting it to 30%, the mixing ratio of the fluorine component is set high.

Considering the condition that the CrSiN film 14 is difficult to be etched, the above ratio R (%) is obtained from FIG.
The value of is preferably about 50% or less, and
From the result of FIG. 5, a ratio R is obtained in terms of increasing the etching selection ratio between the CrSiN film 14 and the TiW film 15.
The value of (%) is preferably about 50% or less. Then, the lower limit of the value of the ratio R (%) is set to such an extent that the film is not formed on the CrSiN film 14 due to the decrease in the flow rate of the oxygen gas and the etching in the second step is not adversely affected, for example. It is preferably about 20% or more.

The second step is the CrSiN film 1
In the etching process of No. 4, the value of the ratio R (%) is 80 to 9
By setting the range of 5% as an appropriate range, for example, 90%, the mixing ratio of oxygen components is set high.

Then, as other setting conditions, the etching gas pressure, the microwave output and the substrate temperature are set under the same conditions in the first step and the second step. Etching gas pressure (Torr) is 0.6 ± 0.4
An appropriate range of Torr is set to about 0.3 Torr, and the microwave output is 1000 ± 60.
The range of 0 W is set as an appropriate range, for example, 1000 W, and the substrate temperature (° C.) heated by the lamp 26 is room temperature to
The range of 200 ° C. is set as an appropriate range, for example, 100 ° C.

The upper limit of the substrate temperature of 200 ° C. is within the range in which the mask material formed can be used as an etching mask, and preferably 1
It is about 50 ° C. Furthermore, setting the temperature higher than room temperature can improve the etching rate of the barrier metal layer and accelerate the substitution reaction (reaction of substituting C—H bond to C—F bond) described later by heating. This is because we also consider that it can be done.

Now, in the case of performing the first and second etching treatments under the above-mentioned etching conditions,
When a gas is introduced into the plasma generation chamber 20 and is irradiated with microwaves, the molecules of the etching gas are excited and the fluorine component becomes a fluorine radical, and the oxygen component becomes an oxygen radical and becomes a highly reactive particle. Gas passage 1
9 and 9 into the etching reaction chamber 18.

Then, an etching process is performed by using these fluorine radicals and oxygen radicals.
5 and the interlayer insulating film 13 are mainly etched by fluorine radicals, and the CrSiN film 14 is mainly etched by both fluorine radicals and oxygen radicals.

This is a reaction represented by the following reaction equations (1) to (3) with respect to the TiW film 15, the interlayer insulating film 13 made of a silicon oxide film and the CrSiN film 14 by the fluorine radicals and oxygen radicals. It is considered that the etching process is performed due to the occurrence of the phenomenon. That is, the TiW film 15 is made of titanium (T
i) and tungsten (W) are combined with fluorine and oxygen to be etched away, and the CrSiN film 14 is combined with chromium (Cr) and silicon to be combined with fluorine and oxygen to be removed by etching. Silicon combines with fluorine and is removed by etching.

TiW + F * + O * → TiF ₄ ↑ + WF ₆ ↑ + WOFx ↑ (1) CrSi + F * + O * → CrOxFy ↑ + SiF ₄ ↑ (2) SiO ₂ + F * → SiF ₄ ↑ (3) The above formula In, F * is a fluorine radical and O * is an oxygen radical.

As described above, the flow rates of the carbon tetrafluoride (CF ₄ ) gas and the oxygen gas are set as shown in FIGS. 4 and 5.
As shown in, based on the data of the etching rate (nm / min) of each film and the data of the etching selectivity between each film when the value of the mixing ratio R is changed to the horizontal axis, The results are obtained as the first step etching conditions effective for the TiW film 15 etching process and the second step etching conditions effective for the CrSiN film 14 etching process.

When performing continuous dry etching of such a Ti, W-based / CrSi-based thin film, it is generally desirable to perform the etching in one step. Under the condition that the selection ratio of the system is set to be high, the amount of the photoresist of the mask pattern 28 to be scraped increases due to the oxygen radicals. The two-step etching shown in the embodiment is adopted.

Therefore, in the etching process of the TiW film 15 which is the first step of the etching process, the TiW film 15 is selectively etched under the above-mentioned etching conditions (see FIG. 1B). At this time, as described later, in the vicinity of the mask pattern 28, Ti
Since the etching rate of the W film 15 has a property of being reduced to about 2/3 as compared with the other portions, in order to eliminate this, 5
Over-etching of 0% or more is performed (the etching process is performed for 1.5 times the etching time obtained from the etching rate). As a result, it is possible to prevent the TiN film 15 of the other portion from being left by etching, and yet to prevent the peripheral neighboring portion from being left in a trailing state, so that the TiW film 15 can be surely etched.

However, in this case, when the TiW film 15 remaining only in the vicinity of the peripheral portion is etched, the Cr
Since the SiN film 14 is exposed, the C
It is necessary to set the etching rate for the rSiN film 14 to be low. This is because the thickness of the CrSiN film 14 is much smaller than that of the TiW film 15, so that the CrS film is formed during overetching.
When the iN film 14 is removed by etching and the underlying interlayer insulating film 13 is exposed, fluorine radicals are consumed by the etching of the interlayer insulating film 13, which further reduces the etching rate of the TiW film 15. This is because the film thickness of the interlayer insulating film 13 is reduced.

Therefore, in the present embodiment, in consideration of the above points, it is preferable to set the condition for obtaining the selection ratio of 10 or more with respect to the CrSiN film 14 in the etching process of the TiW film 15. As the above, the flow rate of the etching gas shown in the first step of FIG. 3 is set.

It should be noted that, without considering the etching selection ratio of the CrSiN film 14 to the TiW film 15, the conditions for merely reducing the amount of resist abrasion of the mask pattern 28 and the etching of the TiW film 15 for the interlayer insulating film 12 are performed. In the two-step etching under the condition for increasing the selection ratio, the following problems occur.

For example, as shown in FIG. 7, when the etching process is started from FIG. 7A in the same state as FIG. 1A, TiW generated near the periphery of the mask pattern 28.
Due to the decrease in the etching rate of the film 15, the underlying interlayer insulating film is exposed in a portion other than the mask pattern 28, and the unetched region P is left in a skirted state with a gentle slope from the vicinity of the periphery toward the outer periphery. This is the case (see FIG. 7B). Therefore, it is necessary to perform excessive over-etching to remove the remaining portion by etching. This is because, as a result, the scraping amount Q of the underlying interlayer insulating film 13 increases (see FIG. 7C).

That is, the CrSiN film 14 is the TiW film 15
Etching conditions that act as an etching stopper when etching are required. Specifically, it is necessary to consider an etching condition such that the CrSiN film 14 is not removed by the etching process until the bottom region of the TiW film 15 near the mask is removed by etching.

Next, the CrSiN film 14 is etched as the second step of the etching process (see FIG. 1).
(See (c)). In this case, the etching process is performed using both the mask pattern 28 and the TiW film 15 as a mask member. And in this second step,
Over-etching treatment of 100% or more is performed. In addition,
At this time, by including a large amount of oxygen radicals as a component in the etching gas, the amount of abrasion of the underlying interlayer insulating film 13 due to etching can be suppressed to about 50 nm or less. On the other hand, a large amount of oxygen radicals cannot be included. The resist material of the mask pattern 28 is etched at a high etching rate.

However, the mask pattern material is C--H.
Since a material having a bond (here, for example, phenol novolac resin) is included, H is easily replaced by fluorine radicals during the etching process of the TiW film 15. At this time, the substrate temperature is set to 100 ° C. and heated. Since it has the effect of accelerating the substitution reaction,
The C-H bond becomes a C-F bond. This C—F bond is stronger than the C—H bond, so CrNiS
Even under the condition that the number of oxygen radicals increases during the etching of the i film 14, it is possible to suppress the substitution and react with the oxygen radicals, and as a result, prevent the mask pattern material itself from being etched. Will be able to. The etching rate of the photoresist shown in FIG. 4 is when the surface of the photoresist is not altered by fluorine radicals.

The TiW film 15 of the barrier metal layer is
Since the etching rate is almost the same as that of the CrSiN film 14, even if the mask pattern 28 is peeled off by etching, the amount of abrasion of the TiW film 15 due to etching can be suppressed to about 30 nm. As a result, defects such as side etching of the TiW film 15 can be significantly improved, and the thin film resistance finally obtained with respect to the pattern width D1 of the mask pattern 28 (see FIG. 1A). The pattern width D2 of the body 12 (see FIG. 10D) can be obtained as a difference of about 0.2 μm, and patterning can be performed with high accuracy.

This is, for example, as shown in FIG. 6, when the etching results obtained when the pattern width dimension of the mask pattern 28 is set to about 4 μm are shown in the measurement results of the present inventors. It is clear from the result of. That is, when the conventional wet etching process is adopted, the center of 3.1 μm is ± 0.5 μm.
A large variation occurs in a width of about m. When continuous dry etching is performed in one step (etching conditions are shown in FIG. 3), it is 2.9 μm.
There is a variation of about ± 0.3 μm centering on m. On the other hand, when the two-step etching adopting the present embodiment is performed, it can be seen that the film is accurately formed with a small variation of about ± 0.1 μm or less centered on 3.8 μm.

Now, from the state shown in FIG. 1C, the mask pattern 28 is removed by a known technique, and then aluminum is formed on the entire surface by photolithography, and this is also formed into a thin film resistor. Etching is performed so as to form the aluminum electrode pattern 16 that contacts both end portions of 12. At this time, the TiW film 15 on the exposed surface of the thin film resistor 12 is removed. As a result, the thin film resistor 12 has a barrier metal layer of Ti.
It is formed in a state of being in electrical contact with the aluminum electrode pattern 16 through the W film 15.

According to this embodiment as described above, the TiW film 15 as the barrier metal layer and the Cr as the thin film electrode layer are formed.
In the etching process of the SiN film 14, by performing continuous dry etching process in two steps, the number of manufacturing processes can be reduced and the cost can be reduced, and the thin film resistance can be accurately adjusted with respect to the pattern width of the mask pattern 28. Since the body 12 can be formed, it is possible to reduce process variations during pattern formation and perform stable processing. Furthermore, it is not necessary to set a large margin in pattern design, and an occupied area for element formation is reduced. Can be prevented from increasing.

The present invention is not limited to the above embodiment, but can be modified or expanded as follows. CDE
Instead of the device, an RIE (Reactive Ion Etching) device, an ICP (Inductively Coupled Plasma) device, or the like can be used. A CrSi film may be used as the thin film resistor layer. Instead of the TiW film, a Ti film or a W film may be formed as a barrier metal layer. The flow rate of the etching gas can be set and changed to an appropriate flow rate by maintaining the mixing ratio, and in this case, the pressure, the microwave output, the substrate temperature, etc. may be adjusted as necessary.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view in each manufacturing process of a thin film resistor showing an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a chemical dry etching apparatus.

FIG. 3 is an explanatory view showing conditions of dry etching processing.

FIG. 4 is a correlation diagram of the etching rate of each film with respect to the oxygen mixture ratio.

FIG. 5 is a correlation diagram of the etching selection ratio between each film and the oxygen mixture ratio.

FIG. 6 is a pattern width value after each etching process

FIG. 7 is a diagram corresponding to FIG. 1 when a two-step etching process is performed under inappropriate conditions.

FIG. 8 is a view corresponding to FIG. 1 showing a conventional example.

[Explanation of symbols]

11 is a single crystal silicon substrate (substrate), 12 is a thin film resistor, 13 is an interlayer insulating film, 14 is a CrSiN film (thin film resistor layer), 15 is a TiW film (barrier metal layer), 16 is an aluminum electrode pattern, 17 Is a chemical dry etching device, 18 is an etching reaction chamber, 19 is a gas passage,
20 is a plasma generating chamber, 26 is a lamp, and 28 is a mask pattern.

Continuation of front page (56) Reference JP-A-6-29468 (JP, A) JP-A-10-144866 (JP, A) JP-A-8-250462 (JP, A) JP-A-6-291090 (JP , A) JP 5-90501 (JP, A) JP 5-175159 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/822 H01L 21/285 H01L 21/3065 H01L 27/04

Claims (9)

(57) [Claims] 1. A method of manufacturing a thin film resistor in which a thin film resistor having a desired shape is formed by etching a thin film resistor layer and a barrier metal layer formed on a substrate surface , wherein the substrate surface is an oxide film. There are disposed forming a mask pattern forming step of forming a mask pattern by patterning to form a mask material layer on the barrier metal layer, a fluorine compound using plasma dry etching apparatus
Some carbon tetrafluoride (CF ₄ ) gas and oxygen (O ₂ ) gas
An etching process for selectively etching the barrier metal layer by plasma-activating an etching gas mixed with silicon to perform a dry etching process and subsequently selectively etching the thin film resistor layer. Do Ri, in the etching of the barrier metal layer, the edge
The ratio of oxygen gas to the flow rate
In the range of 20 to 70%, the etching is performed in the etching of the thin film resistor layer.
The ratio of oxygen gas to the total flow rate of oxygen gas is 8
A method of manufacturing a thin film resistor , characterized in that the content is set to 0% or more . 2. The method of manufacturing a thin film resistor according to claim 1, wherein a layer made of a compound containing chromium (Cr) and silicon (Si) is formed as the thin film resistor layer, and titanium is formed as the barrier metal layer. A method of manufacturing a thin film resistor, characterized in that a layer made of a compound containing (Ti) or tungsten (W) is formed. 3. A thin film resistor layer laminated on the surface of a substrate.
And etching the barrier metal layer
Method of manufacturing thin film resistor for forming thin film resistor having desired shape
In, the thin film resistor layer is made of chromium (Cr) and silicon.
A layer made of a compound containing (Si),
The layer contains titanium (Ti) or tungsten (W).
And a mask material layer is formed on the barrier metal layer.
Mask to form a mask pattern by training
Pattern formation process and etching that mixed fluorine compound gas and oxygen gas
Plasma activation by increasing the mixing ratio of the fluorine component of the gas
The barrier is formed by dry etching
Selective etching of the metal layer and subsequent
Mixing ratio of oxygen component of the etching gas to the thin film resistor layer
Etching process to increase the etching and selectively etch
A method of manufacturing a thin film resistor , comprising : 4. The method of manufacturing a thin film resistor according to claim 3 , wherein in the etching process, an etching process is performed using a plasma dry etching apparatus. 5. The method for manufacturing a thin film resistor according to claim 4, wherein in the etching treatment step, carbon tetrafluoride (CF ₄ ) which is a fluorine compound is used as the etching gas.
A method of manufacturing a thin film resistor, characterized in that a gas and an oxygen (O ₂ ) gas are mixed and used. 6. The method of manufacturing a thin film resistor according to claim 5, wherein an oxide film is arranged and formed on the substrate surface, and in the etching treatment step, the etching is performed in etching the barrier metal layer. Oxygen gas accounts for 20 to 70% of the total gas flow rate, and 80% or more for etching the thin film resistor layer. Method. 7. The method for manufacturing a thin film resistor according to claim 1, 2, or 6 , wherein in the etching of the barrier metal layer, a ratio of oxygen gas to a total flow rate of the etching gas is A method for manufacturing a thin film resistor, characterized in that the content is set to 50% or less. 8. The method of manufacturing a thin film resistor according to claim 1, wherein a mask material for forming the mask material layer is:
An organic material containing at least a C—H (carbon-hydrogen) bond is used, an etching process is performed using a chemical dry etching apparatus in the etching process, and the substrate is kept at room temperature in a dry etching process of the barrier metal layer. A method for manufacturing a thin film resistor, characterized in that the heating is performed at a high predetermined temperature. 9. The method of manufacturing a thin film resistor according to claim 1, wherein a mask material for forming the mask material layer is:
An organic material containing at least a C—H (carbon-hydrogen) bond is used, an etching process is performed by using a chemical dry etching apparatus in the etching process step, and a dry etching process of the barrier metal layer is performed. Due to the action of the fluorine compound gas component, the C—H bond on the surface of the mask material layer is C—F.
A method of manufacturing a thin film resistor, which comprises performing a substitution reaction so as to form a (carbon-fluorine) bond.