KR20080039144A - Method of manufacturing semiconductor device - Google Patents

Abstract

A method of manufacturing a semiconductor device is provided to reduce the fraction defective by preventing bit lines from being collapsed, and preventing short phenomenon between adjacent bit lines. An etch stop layer(46) and a first hard mask layer(47) are formed on a semiconductor substrate(41). A groove is formed by etching the first hard mask layer and the etch stop layer. A bit line, which is made of a stacked structure including a barrier layer and a metal layer for lines, is formed within the groove. A second hard mask layer(52) is formed on the first hard mask including the bit line. A bit line spacer surrounding the bit line is formed by etching the first and second hard masks and the etch stop layer.

Description

Method of manufacturing semiconductor device

1 is a cross-sectional view showing a bit line of a conventional semiconductor device.

2 is a cross-sectional view showing a problem with a bit line of a conventional semiconductor device.

3A to 3F are cross-sectional views of processes for forming a bit line of a semiconductor device according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

41: semiconductor substrate 42: device isolation film

43: first interlayer insulating film 44: landing plug

45: second interlayer insulating film 46: etch stop film

47: first hard mask film 48: home

49a, 49b: barrier film 50: wiring metal film

51: bit line conductive film 52: second hard mask film

53: bit line 54: third interlayer insulating film

The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for forming a bit line of a semiconductor device capable of preventing collapse due to size reduction.

As a wiring material of a semiconductor element such as DRAM, aluminum and tungsten having excellent electrical conductivity are mainly used. Among them, tungsten has a slightly lower electrical conductivity than aluminum, but has excellent thermal stability and excellent buried characteristics, and thus, tungsten is mainly used in metal wiring processes before forming capacitors represented by bit lines. The bit line is formed to be in contact with the junction region of the cell region, and supplies a current through the channel to store charge in the capacitor, or transmits a difference in charge amount between the capacitors to a sense amplifier so that the charge stored in the capacitor can be converted into data. It serves to convey.

1 is a cross-sectional view illustrating a semiconductor device in which a conventional bit line is formed.

As shown, a first interlayer insulating film 3 and a landing plug 4 are formed on a semiconductor substrate 1 having the device isolation film 2, and the first interlayer insulating film 3 and the landing plug ( 4) A second interlayer insulating film 5 is formed.

The barrier film 7, the wiring metal film 8, and the first hard mask film 6 are sequentially formed on the second interlayer insulating film 5, so that the barrier film 7 and the wiring metal film 8 are formed. And a bit line conductive layer 13 formed of the first hard mask layer 6, and a spacer is formed in the second hard mask layer 10 in a structure surrounding the formed bit line conductive layer 13. To form. In addition, a third interlayer insulating film 9 is formed on the entire surface of the substrate 1 including the bit lines on which the spacers are formed.

However, the bit line formed by the conventional method for manufacturing a bit line of the semiconductor device described above has a capacitance between many conductive layers passing through the cell array when the cell capacitance of the semiconductor device cannot be secured due to the trend of high integration, high performance and high capacity of the semiconductor device. As a result, the signal sensing margin of the signal amplifier is reduced, thereby deteriorating its characteristics.

Therefore, parasitic capacitors between neighboring bit lines should be reduced in order to prevent a decrease in signal sensing margin of the signal amplifier as described above, and as the width of the bit lines decreases, the tungsten film is etched to form the bit lines. As described above, a bit line collapse phenomenon occurs in which the etched bit line conductive layer collapses, thereby causing a short between the bit line conductive layers.

In addition, as described above, short circuit between the bit line conductive films causes a failure rate of the semiconductor element to increase, thereby reducing the reliability and manufacturing yield of the wiring.

Accordingly, the present invention provides a method of manufacturing a semiconductor device capable of preventing short circuit between the bit line conductive layers by removing the fall of the bit line conductive layer when forming the bit lines.

In addition, the present invention provides a method of manufacturing a semiconductor device that can reduce the reliability of the wiring and the yield decrease by reducing the bit line defect rate by preventing the short circuit between the bit line conductive film as described above.

The present invention provides a method of manufacturing a semiconductor device, comprising: sequentially forming an etch stop film and a first hard mask film on a semiconductor substrate; Etching the first hard mask layer and the etch stop layer to form a groove; Forming a bit line having a stacked structure of a barrier film and a wiring metal film in the groove; Forming a second hard mask layer on the first hard mask layer including the bit line; And etching the second and first hard mask layers and the etch stop layer to form bit line spacers surrounding the bit lines.

The etch stop layer is formed of an undoped polysilicon layer.

The etch stop layer is formed to have a thickness larger than the combined size of the barrier layer and the spacer.

The groove is characterized in that it is formed to have a width of 600 ~ 2000Å.

The first and second hard mask films are formed of a nitride film.

(Example)

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

In the present invention, in forming a bit line, a non-doped poly insulation layer and a first hard mask layer are sequentially formed before forming the bit line, so that the poly insulation layer and the first hard mask layer are etched to form grooves in the bit line formation region. Next, after the bit line is formed by filling the conductive layer in the groove, the second hard mask layer and the etch stop layer are etched again to form the bit line.

In this case, the present invention forms a bit line by forming a groove in which the bit line is formed smaller than that of the conventional art, thereby realizing low parasitic capacitance between neighboring bit lines as the distance between the bit lines increases. .

In addition, when the first and second hard mask layers are etched, the first and second hard mask layers may be formed as spacers of bit lines, thereby preventing shorts due to collapse between bit lines.

In addition, by preventing the short circuit caused by the fall between the bit lines as described above, it is possible to reduce the defective rate of the semiconductor device accordingly to prevent the degradation of the reliability and the yield of the wiring.

3A to 3F are cross-sectional views of processes for forming a bit line of a semiconductor device according to an embodiment of the present invention.

Referring to FIG. 3A, a semiconductor substrate including an isolation layer 42, a gate (not shown) and a landing plug 44 formed on an active region, and a first interlayer insulating layer 43 that insulates a gate conductive layer from each other. After the 41 is formed, a second interlayer insulating film 45 is again formed on the semiconductor substrate 41. An etch stop layer 46 and a first hard mask layer 47 are sequentially formed on the second interlayer insulating layer 45. In this case, the etch stop layer 46 is an undoped poly insulation layer, and the first hard mask layer 47 is formed of a nitride layer.

Referring to FIG. 3B, the first hard mask layer 47 and the etch stop layer 46 are patterned and etched to form grooves 48, which are regions in which a subsequent bit line conductive layer is to be filled. Here, the groove 48 is formed to have a width of 600 kPa to 2000 kPa.

Referring to FIG. 3C, a bit line conductive film 51 having a stacked structure of barrier films 49a and 49b and a wiring metal film 50 is embedded in the groove 48. Here, the barrier films 49a and 49b are formed of Ti and TiN, and the wiring metal film 50 is formed of tungsten.

Referring to FIG. 3D, a second hard mask film 52 is formed on the entire surface of the substrate including the groove 48 in which the bit line conductive film 51 is embedded. In this case, the second hard mask film 52 is formed of a nitride film.

Referring to FIG. 3E, the first and second hard mask layers 47 and 52 are patterned and etched until the etch stop layer 46 is exposed, and then, the etch stop layer 46 is etched. The bit line 53 is formed such that the first hard mask layer 47 has a structure surrounding the bit line conductive layer 51. Alternatively, the bit line 53 is formed by etching the first and second hard mask layers 47 and 52 and etching the etch stop layer 46.

In the present invention, the etched first and second hard mask layers 47 and 52 serve as spacers of the bit line conductive layer 51, thereby shortening a process of depositing spacers.

Referring to FIG. 3F, a third interlayer insulating layer 54 is formed on the entire surface of the semiconductor substrate 41 including the formed bit line 53 to complete the bit line of the semiconductor device according to the embodiment of the present invention.

As described above, in the present invention, even when a narrow bit line is formed by a bit line forming method of a conventional semiconductor device, the hard mask film plays a role of a spacer, so that shorts due to collapse between bit lines can be prevented.

In addition, by preventing the short circuit caused by the fall between the bit line as described above, it is possible to reduce the defective rate of the semiconductor device thereby to prevent the degradation of the reliability and the yield of the wiring.

In addition, unlike the bit lines formed by the well-known bit line forming method, the width of the bit line conductive film is made smaller than that of the conventional one, so that as the spacing between the bit lines increases, the low parasitic capacitance between neighboring bit lines is increased. Implementation is possible.

As mentioned above, although this invention was shown and demonstrated with respect to the specific Example, this invention is not limited to this, The following claims are various in this invention as long as it does not deviate from the mind and field of this invention. It can be easily understood by those skilled in the art that can be modified and modified.

As described above, the present invention can prevent the fall between the bit lines, and thereby prevent the short between the adjacent bit lines, thereby reducing the defect rate of the semiconductor device.

In addition, the present invention can reduce the defective rate of the semiconductor element, thereby preventing the lowering of the reliability and the yield of the wiring.

In addition, the present invention can form a bit line having a larger size than the conventional one, and thus, as the spacing between the bit lines increases, low parasitic capacitance between neighboring bit lines can be realized.

Claims (5)

Sequentially forming an etch stop layer and a first hard mask layer on the semiconductor substrate; Etching the first hard mask layer and the etch stop layer to form a groove; Forming a bit line having a stacked structure of a barrier film and a wiring metal film in the groove; Forming a second hard mask layer on the first hard mask layer including the bit line; And Etching the second and first hard mask layers and an etch stop layer to form a bit line spacer surrounding the bit line; Method of manufacturing a semiconductor device comprising a. The method of claim 1, The etch stop film is a semiconductor device manufacturing method, characterized in that formed by undoped polysilicon film. The method of claim 1, The etch stop film is a semiconductor device manufacturing method, characterized in that formed to have a thickness larger than the combined size of the barrier film and the spacer. The method of claim 1, The groove is formed to have a width of 600 ~ 2000Å, the manufacturing method of a semiconductor device. The method of claim 1, The first and second hard mask films are formed of a nitride film.

Images