KR960007445B1 - Method of patterning metal - Google Patents

Abstract

The method for forming a metal pattern is disclosed in which a main etching step(201), overetching step(202) and passivation step(203) are sequentially carried out to etch a metal layer using a photoresist pattern as a mask, and the etching selectivity of the photoresist to the metal layer is controlled not to generate polymer.

Description

Metal pattern formation method

1 is a process flow showing a metal pattern forming method according to the conventional method.

2 is a process flow showing a metal pattern forming method according to the present invention.

The present invention relates to a method of manufacturing a semiconductor device, and more particularly, to a method of forming a metal pattern, wherein the photoresist is removed without etching the metal using a photoresist as an etch mask and then treating it with an etch solution. will be.

During the metal etching process, which is a late process of the semiconductor device manufacturing process (particularly, a DRAM (Dynamic Random Access Memory) process), a process of dipping a metal in an etching solution (Solvent), which is common worldwide, is needed. This is even more important in the semiconductor device that is being integrated because even a small contamination damages the electrical characteristics of the device.

FIG. 1 shows a process flow showing a metal pattern forming method according to a conventional method. The conventional process is a process of forming a photoresist pattern by applying a photoresist (P / R) onto a metal and then photographing / developing it. (10), a step of etching the metal using the photoresist pattern as an etching mask (20), a step of dipping the resultant in a predetermined etching solution to remove the polymer produced during the metal film etching step (30), and a photo It can be seen that the process proceeds to step 40 of removing the resist pattern.

In this case, the metal film etching process 20 is divided into a stock engraving step 21 and a transient drawing step 22, and each process is performed under different process conditions.

At this time, the step (30) of dipping the resultant in a predetermined etching solution, in the previous step 20, that is, the step (20) of etching the metal using the photoresist pattern as an etching mask, or The other impurities combine to form a polymer on the metal sidewall, which proceeds to remove the polymer because it causes various problems such as disconnection and deterioration of electrical properties.

However, the method of removing the polymer by using the etching solution as described above, although the effect of preventing the deterioration of electrical properties such as disconnection by forming a metal pattern cleanly, it caused another problem economically or physically. In detail, first, it is expensive because a machine for processing metal in an etching solution is expensive, and second, an additional worker must be assigned. Third, a line is processed by this process for processing metal in an etching solution. Humidity inside increases to accelerate the corrosion of the metal. Moreover, there is a disadvantage in that the device manufacturing cycle is long because one process is added.

SUMMARY OF THE INVENTION An object of the present invention is to provide a metal pattern forming method capable of removing a polymer after metal etching, without treating the metal in an etching solution.

In order to achieve the above objects, the present invention, in the metal pattern forming method, during the metal etching process using the photoresist pattern as an etching mask, the etching is performed sequentially in the stock etching step, the transient etching step and the passivation step, the polymer is produced The etching selectivity of the photoresist with respect to the metal is characterized in that each of the above steps is carried out under controlled process conditions.

Hereinafter, with reference to the accompanying drawings will be described in more detail the present invention.

2 is a process flow showing the metal pattern forming method according to the present invention, and it can be seen that the process of processing the wafer in the etching solution (30 in FIG. 1) is omitted unlike the conventional method.

That is, the step (10) of forming a photoresist pattern by applying a photoresist on a metal and then photographing / developing, the step (200) of etching the metal using the photoresist pattern as an etching mask, and removing the photoresist pattern It can be seen that the process proceeds to step 40.

In order to omit the step of processing the wafer in the etching solution (30 in FIG. 1), during the step (200) of etching the metal using the photoresist pattern as an etching mask, the etching conditions of the photoresist with respect to the metal are used. The selectivity can be reduced to minimize the formation of polymers on the sidewalls of the metal pattern.

That is, as shown in the drawings, the metal etching process 200 according to the present invention is subdivided into a stock etching step 201, a transient etching step 202, and a passivation step 203, thereby minimizing polymer. As the etching proceeds.

Of course, since the process of cleaning in DI water is involved between the processes of each semiconductor device (which is also a process involved in the conventional method), the process of rinsing after the passivation step 202 is performed. What is necessary is just to carry out the process 40 of removing this.

According to this process, since the polymer formed on the sidewall of the metal pattern can be removed without the process of immersing the metal in the etching solution, it is possible to solve a variety of problems encountered in the conventional method.

The metal etching process 200 includes a stock etching step 201, a transient etching step 202, and a passivation step 203. The process conditions (limited to R / B4620) and pure washing process conditions of each step are as follows. Same as

Stock Equity Process (M.E);

Pressure: 100mTorr∼200mTorr

Power: 250Watt ~ 300Watt

BCl ₃ : 30SCCM ~ 70SCCM

N ₂ : 30SCCM

Cl ₂ : 40SCCM ~ 50SCCM

Transient etching (O.E);

Pressure: 100mTorr ～ 150mTorr

Power: 400Watt ~ 500Watt

BCl ₃ : 30SCCM ~ 70SCCM

N ₂ : 30SCCM ~ 30SCCM

Cl ₂ : 10SCCM ~ 20SCCM

Passivation;

Pressure: 800mTorr∼1200mTorr

Power: 250Watt ~ 350Watt

CF ₄ : 50SCCM-100SCCM

O ₂ : 10SCCM ~ 20SCCM

Pure washing (APM);

Rinse: 300RPM, 20Sec ~ 30Sec

Dry: 200RPM, 20Sec ~ 40Sec

As described above, according to the present invention, the stock angle and the transient etching are performed under process conditions that lower the etching selectivity of the photoresist with respect to the metal to minimize the formation of the polymer on the metal pattern sidewall, and then rinse the passivation step and DI water. By eliminating the wet cleaning process to remove polymers, the method eliminates the need for equipment purchases and allows the metal etch worker to perform the process alone without assigning personnel, thereby reducing labor costs, equipment purchase costs, and processing time. And it has the effect of reducing the cost by simplifying the process.

Claims (5)

In the metal pattern forming method, during the metal etching process 200 using the photoresist pattern as an etching mask, etching is performed sequentially by the stock etching step 201, the transient etching step 202, and the passivation step 203, and the polymer And performing each of said steps under controlled process conditions such that the etch selectivity of the photoresist to metal is not produced. The method of claim 1, wherein each of the stocks comprises a pressure of 100 mTorr to 200 mTorr, a power of 250 Watts to 300 Watts, BCl ₃ 30 SCCM to 70 SCCM, N _{2 30} SCCM, and Cl ₂ 40 SCCM to 50 SCCM. The method of claim 1, wherein the transient etching step comprises pressure 100 mTorr to 150 mTorr, power 400 Watt to 500 Watt, BCL ₃ 30 SCCM to 70 SCCM, N ₂ 30 SCCM to 30 SCCM, and CL _{2 10} SCCM to ₂₀ SCCM. The method of claim 1, wherein the passivation step comprises a pressure of 800 mTorr to 1200 mTorr, a power of 250 Watts to 350 Watts, CF ₄ 50 SCCM to 100 SCCM, and O _{2 10} SCCM to ₂₀ SCCM. The method of claim 1, wherein after the passivation step, pure water is washed, the photoresist pattern is removed.