• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
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  • 优先权
    • 专利摘要:
    The present invention discloses a semiconductor device capable of reducing contact resistance and a method of manufacturing the same. The disclosed invention is a semiconductor device comprising a contact portion of a word line and a bit line, wherein the word line is a doped polysilicon film, a first tungsten silicide film in which an appropriate amount of silicon and tungsten are bonded thereon, and an upper portion thereof. And a second tungsten silicide film containing excess silicon relative to tungsten, wherein the bit line includes a doped polysilicon film and a tungsten silicide film, and the second tungsten silicide film of the word line and the doping of the bit line The polysilicon film is contacted.
    公开号:KR20000004780A
    申请号:KR1019980026298
    申请日:1998-06-30
    公开日:2000-01-25
    发明作者:박상욱；장민식
    申请人:김영환；현대전자산업 주식회사；
    IPC主号:
    专利说明:

    Semiconductor device and manufacturing method
    BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a method of manufacturing the same, and more particularly, to a contact structure of a word line and a bit line capable of reducing contact resistance and a method of manufacturing the same.
    In general, in a memory device, a word line serves to select a cell, and a bit line serves to transfer data to the selected cell. Here, the word line and the bit line are contacted in the peripheral region of the memory device.
    In order to prevent signal delay, such word lines and bit lines are made of a material capable of maintaining conduction characteristics even at high temperatures. In the conventional word line and bit line, a polyside structure including a double layer of a doped polysilicon film and a tungsten silicide film having excellent conduction characteristics is used.
    That is, as shown in FIG. 1, a word line 3 is formed on the semiconductor substrate 1. Here, the semiconductor substrate 1 is a structure including a gate oxide film (not shown), and the word line 3 has a laminated structure of the doped polysilicon film 3a and the tungsten silicide film 3b. Then, an interlayer insulating film 5 is formed on the semiconductor substrate 1 on which the word line 3 is formed, and the tungsten silicide film 3b of the word line 3, that is, the word line 3, is exposed. Predetermined portions of the interlayer insulating film 5 are plasma etched to form contact holes. Subsequently, a bit line 7 is formed to contact the exposed word line 3. The bit line 7 is also formed in a stacked structure of a doped polysilicon film 7a and a tungsten silicide film 7b in order to improve conductivity. Here, in practice, the tungsten silicide film 3b of the word line 3 and the doped polysilicon film 7a of the bit line 7 are contacted.
    However, according to the above prior art, the word line 3 and the bit line 7 have the following problems in the contact portion.
    First, practically, the contact portions of the word line 3 and the bit line 7 are the tungsten silicide film 3b of the word line and the doped polysilicon film 7a of the bit line 7 as described above. Here, the general tungsten silicide film and the doped polysilicon film have different work functions (ψ poly , ψ wsix ), as shown in FIG. 2. At this time, since the barrier height defined by the difference between the two work functions (ψ poly , ψ wsix ) is about 0.65 eV, the movement of electrons is not smooth, and the tunneling current is reduced. Contact resistance is also increased.
    Second, during the plasma etching process of the interlayer insulating film 5 to form the contact hole, the tungsten silicide film 3b of the word line 3 may be partially lost by the plasma gas. At this time, the tungsten silicide film 3b is made of two materials, tungsten and silicon, and the bonding force between tungsten and silicon (w-si) and the bonding force between silicon and silicon (si-si) are different from the plasma etching gas. Respond. The sputtering yield of different reactivity between the two materials constituting such a material is sputtered yield. Thus, during the contact hole etching process, tungsten and silicon are etched at different ratios, thereby the surface of the tungsten silicide film 3b. This becomes rough. Therefore, when contacting the bit line, it is difficult to secure a stable contact interface and the contact resistance is increased.
    Thirdly, in the above-described plasma etching process, tungsten (W) constituting the tungsten silicide film 3b and the plasma gas, for example, on the surface of the word line 3, that is, the tungsten silicide film 3b, O 2 ), fluorocarbon (CF 4 ), hydrocarbon (CH 4 ), and the like are reacted to form an etch byproduct such as WO 2 , WO 3 , WC.
    In this case, as the by-products, as shown in Table 1, as the heat generated by the reaction has a negative value, the process by-products are generated on the surface of the word line 3 without performing a separate reaction.
    compound ΔH (KJ / mole) WC, SiC + To -20.5 SiO 2 + ~ -17 WN x -12.6 W 2 N -72 WO 2 -533 WO 3 -843
    This etching by-product causes the contact resistance to be increased during the subsequent bit line 7 contact process.
    Accordingly, the present invention is to solve the above-mentioned conventional problems, it is characterized in that the contact resistance of the contact between the word line and the bit line can be reduced.
    1 is a cross-sectional view of a semiconductor device showing contact between a word line and a bit line of a conventional semiconductor device.
    2 is an energy band diagram of a tungsten silicide film of a conventional word line and a doped polysilicon film of a bit line.
    3 is a cross-sectional view of a semiconductor device showing contact between a word line and a bit line of the semiconductor device according to the present invention.
    4 is an energy band diagram of a tungsten silicide film of a word line and a doped polysilicon film of a bit line of the present invention.
    (Explanation of symbols for the main parts of the drawing)
    11: semiconductor substrate 13: word line
    13a: doped polysilicon film 13a: first tungsten silicide film
    13b: second tungsten silicide film 15: interlayer insulating film
    17 bit line 17a doped polysilicon film
    17b: tungsten silicide film of bit line
    In order to achieve the above object of the present invention, according to one aspect of the present invention, a semiconductor device comprising a contact portion of a word line and a bit line, the word line is a doped polysilicon film, and a suitable amount of silicon on the top And a first tungsten silicide film in which tungsten is bonded, a second tungsten silicide film containing an excessive amount of silicon on top of the tungsten, and the bit line includes a doped polysilicon film and a tungsten silicide film. The second tungsten silicide film of the word line and the doped polysilicon film of the bit line are contacted.
    Further, according to another aspect of the invention, the step of sequentially stacking and forming a polysilicon film doped with a word line, a first tungsten silicide film and a second tungsten silicide film on a semiconductor substrate, and comprising the word line Forming an interlayer insulating film on a semiconductor substrate, etching the interlayer insulating film to expose the word line surface, and forming a bit line of a polysilicon film and a tungsten silicide film doped to contact the exposed word line. Forming a step.
    According to the present invention, when the word line and the bit line are contacted, the work function difference between the doped polysilicon film forming the bit line and the word line can be reduced to facilitate the movement of electrons.
    In addition, since most of the word line surfaces form silicon bonds, the responsiveness to the plasma etching gas is almost the same. Therefore, the surface of the word line exposed during the contact hole etching may be smooth, thereby reducing the contact resistance.
    In addition, since a small amount of tungsten is included on the word line surface, etching by-products such as WO x and WC are not generated during etching to form contact holes, thereby reducing contact resistance.
    (Example)
    Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
    Figure 3 is a cross-sectional view of a semiconductor device according to an embodiment of the present invention, Figure 4 is an energy band diagram between the tungsten silicide of the word line and the doped polysilicon of the bit line.
    First, referring to FIG. 3, a word line 13 is formed on the semiconductor substrate 11. Here, the word line 13 is a doped polysilicon film is formed by:: (13b Wsi x), tungsten silicide film (doped polysilicon 13a) and a tungsten silicide film (Wsi x: 13b) is a silicon and tungsten combined in a suitable amount The first tungsten silicide film (Wsi x : 13b-1) and the second tungsten silicide film (Wsi x : 13b-2) containing excess silicon.
    Here, the doped polysilicon film 13a is formed by chemical vapor deposition at a temperature of 500 to 700 ° C. using SiH 4 gas. Here, PH 3 gas is used as the dopant providing gas, and the mixing ratio of SiH 4 gas to PH 3 gas, which is the main gas, is about 1.1 to 1.5 to 1.5 to 1.8.
    The tungsten silicide films (Wsi x : 13b-1, 13b-2) are formed by reacting SiH 2 Cl 2 gas and WF 6 gas at a temperature of 550 to 600 ° C., and the tungsten silicide films 13b-1 and 13b. -2) is also formed by chemical vapor deposition. Here, the mixing ratio of SiH 2 Cl 2 gas to WF 6 gas in the first tungsten silicide film (Wsi x : 13b-1) is 8 to 10 to 1.5 to 2, and the chemical equivalent ratio x is about 2.3 to 2.5. At this time, when x is 2.3 to 2.5, the adhesive strength between the first tungsten silicide film (Wsi x : 13b-1) and the doped polysilicon film 13a is excellent. In addition, the first tungsten silicide layer (Wsi x : 13b-1) is preferably formed to a thickness of about 500 to 700 GPa.
    In addition, in the second tungsten silicide film (Wsi x : 13b-2), the amount of silicon is increased by the mixing ratio of SiH 2 Cl 2 gas to WF 6 gas of 9 to 11 to 0.8 to 1.2, while the amount of tungsten is small. Decrease. Here, the chemical equivalent ratio x is about 2.8 to 2.9. At this time, since the silicon content is high, the second tungsten silicide film (Wsi x : 13b-2) is almost siliconized. The second tungsten silicide film (Wsi x : 13b-2) is formed to a thickness of about 100 to 300 kPa.
    Subsequently, after the interlayer insulating layer 15 is formed on the resultant, the interlayer insulating layer 15 is etched to expose the word line 13, that is, the second tungsten silicide layer 13b-2, which is the uppermost part of the word line 13. As a result, contact holes are formed. Since most of the second tungsten silicide layer 13b-2 is a bond between silicon (Si-Si) during the etching process, even though some etching is performed, etching is uniformly performed.
    Thereafter, a bit line 17 is formed to contact the exposed word line 13. Here, the bit line 17 also consists of a doped polysilicon film 17a and a tungsten silicide film 17b, wherein the doped polysilicon film 17a is a doped polysilicon film 17a of the word line 13. It may be formed under the same conditions as), or may be formed by other general methods. The doped polysilicon film 17a is formed to a thickness of about 500 to 700 GPa.
    The tungsten silicide film (WSi x : 17b) of the bit line is formed by reaction of SiH 4 gas and WF 6 gas at 350 to 400 ° C., and the mixing ratio of SiH 4 gas to WF 6 gas is about 90 to 100 to 1 to 4 desirable. In the tungsten silicide film (WSi x : 17b), the chemical equivalent ratio x is preferably about 2.3 to 2.9, and the tungsten silicide film (WSi x : 17b) is formed to a thickness of about 900 to 1300 kPa.
    Thereafter, heat treatment is performed at a temperature of 600 to 900 ° C. to stabilize the tungsten silicide films 13b-1, 13b-2, and 17b, that is, tetragonal lattice.
    When the word line 13 and the bit line 17 are formed in this manner, first, the difference in the work function is reduced to facilitate the movement of electrons. That is, when the second tungsten silicide film 13b containing excess silicon is formed at the top of the word line 13, since the silicon atoms have lower conductivity than the tungsten atoms, the work function of the tungsten silicide film on the word line surface is Will be lowered. Accordingly, as shown in FIG. 4, since the work function difference between the doped polysilicon film 17a of the bit line 17 and the tungsten silicide film 13b of the word line 13 is reduced, the movement of electrons is smoothed. As a result, tunnel current is increased. Therefore, there is an effect of reducing the contact resistance.
    In addition, the second tungsten silicide layer 13b of the word line 13 is mostly bonded to silicon (Si-Si) rather than a bond between tungsten and silicon (W-Si). The difference rarely occurs. Therefore, even if the second tungsten silicide film 13b is partially etched, it is etched uniformly.
    In addition, since the tungsten silicide film 13b contains a small amount of tungsten, tungsten does not easily react with the plasma gas. Therefore, even though tungsten has a very high heat of reaction (ΔH) generated by the plasma gas, the amount of participating in the reaction is very small, so that no process by-products such as WO x and WC are generated.
    As described in detail above, according to the present invention, a polysilicon film doped with a word line of a memory device, a first tungsten silicide film in which an appropriate amount of tungsten and silicon are combined, and a second tungsten containing excess silicon It is formed of a silicide film. As a result, when the word line and the bit line are contacted, the work function difference between the doped polysilicon layer constituting the bit line and the word line is reduced to facilitate electron movement.
    In addition, since most of the word line surfaces form silicon bonds, the responsiveness to the plasma etching gas is almost the same. Therefore, the surface of the word line exposed during the contact hole etching may be smooth, thereby reducing the contact resistance.
    In addition, since a small amount of tungsten is included on the word line surface, etching by-products such as WO and WC are not generated during etching to form contact holes, thereby reducing contact resistance.
    In addition, this invention can be implemented in various changes within the range which does not deviate from the summary.
    权利要求:
    Claims (22)
    [1" claim-type="Currently amended] A semiconductor device comprising a contact portion of a word line and a bit line,
    The word line includes a doped polysilicon film, a first tungsten silicide film in which an appropriate amount of silicon and tungsten are combined thereon, and a second tungsten silicide film in which an excess of silicon is contained in the upper portion thereof,
    The bit line includes a doped polysilicon film and a tungsten silicide film,
    And a second tungsten silicide film of the word line and a doped polysilicon film of the bit line are contacted.
    [2" claim-type="Currently amended] The semiconductor device according to claim 1, wherein the first tungsten silicide film of the word line comprises SiH 2 Cl 2 and WF 6 components, and a component ratio between them is 8 to 10 to 1.5 to 2.
    [3" claim-type="Currently amended] The semiconductor device according to claim 1 or 2, wherein the second tungsten silicide film of the word line comprises SiH 2 Cl 2 and WF 6 components, and a component ratio between them is 9 to 11 to 0.8 to 1.2.
    [4" claim-type="Currently amended] The semiconductor device of claim 1, wherein the dopant in the doped polysilicon of the word line and the bit line is PH 3 gas.
    [5" claim-type="Currently amended] The semiconductor device according to claim 1 or 2, wherein the first tungsten silicide layer of the word line is WSix, x = 2.3 to 2.5.
    [6" claim-type="Currently amended] The semiconductor device according to claim 1 or 3, wherein the second tungsten silicide film of the word line is WSix, x = 2.6 to 2.9.
    [7" claim-type="Currently amended] 6. The semiconductor device of claim 5, wherein a thickness of the first tungsten silicide film of the word line is in the range of 500 to 700 GPa.
    [8" claim-type="Currently amended] The semiconductor device according to claim 6, wherein the thickness of the second tungsten silicide film of the word line is 100 to 300 kPa.
    [9" claim-type="Currently amended] Sequentially stacking and forming a polysilicon film doped with a word line on the semiconductor substrate, and a first tungsten silicide film and a second tungsten silicide film;
    Forming an interlayer insulating film on the semiconductor substrate including the word line;
    Etching the interlayer insulating film to expose the word line surface; And
    And forming a bit line comprising a doped polysilicon layer and a tungsten silicide layer in contact with the exposed word line.
    [10" claim-type="Currently amended] The method of claim 9, wherein the polysilicon film of the word line is formed by chemical vapor deposition at 500 to 700 ° C. 11.
    [11" claim-type="Currently amended] The method of claim 9, wherein the doped polysilicon layer is formed by reaction of SiH 4 gas and PH 3 gas.
    [12" claim-type="Currently amended] The method of claim 11, wherein the mixing ratio of the SiH 4 gas and the PH 3 gas is 1.1 to 1.5 to 1.5 to 1.8.
    [13" claim-type="Currently amended] The method of claim 9, wherein the first and second tungsten silicide layers of the word line are formed by chemical vapor deposition at 550 to 600 ° C. 11.
    [14" claim-type="Currently amended] The method of claim 9 or 13, wherein the first tungsten silicide film of the word line is formed by reaction of SiH 2 Cl 2 gas and WF 6 gas.
    [15" claim-type="Currently amended] The method of claim 14, wherein the SiH 2 Cl 2 gas and the WF 6 gas are included in a mixing ratio of about 8 to about 10 to about 1.5 to about 1.8.
    [16" claim-type="Currently amended] The method of claim 9 or 13, wherein the second tungsten silicide film of the word line is formed by reaction of SiH 2 Cl 2 gas and WF 6 gas.
    [17" claim-type="Currently amended] The method of claim 16, wherein the SiH 2 Cl 2 gas and the WF 6 gas have a mixing ratio of about 9-11 to about 0.8-2.
    [18" claim-type="Currently amended] 10. The method of claim 9, wherein the first tungsten silicide film of the word line is formed at about 500 to 700 GPa and the second tungsten silicide film is formed at about 100 to 300 GPa.
    [19" claim-type="Currently amended] The method of claim 9, wherein the tungsten silicide layer of the bit line is formed by chemical vapor deposition at a temperature of 350 to 400 ° C. 11.
    [20" claim-type="Currently amended] 20. The method of claim 19, wherein the tungsten silicide film of the bit line is formed by reaction of SiH 4 gas and WF 6 gas.
    [21" claim-type="Currently amended] The method of claim 20, wherein the SiH 4 gas and the WF 6 gas have a mixing ratio of about 90 to about 100 to about 1 to about 4.
    [22" claim-type="Currently amended] 22. The semiconductor device according to claim 9 or 21, wherein the doped polysilicon film of the bit line is formed to a thickness of about 500 to 700 GPa, and the tungsten silicide film of the bit line is formed to a thickness of 900 to 1300 GPa. Manufacturing method.
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    同族专利:
    公开号 | 公开日
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    1998-06-30|Application filed by 김영환, 현대전자산업 주식회사
    1998-06-30|Priority to KR1019980026298A
    1998-06-30|Priority claimed from KR1019980026298A
    2000-01-25|Publication of KR20000004780A
    2002-02-28|Application granted
    2002-02-28|Publication of KR100311208B1
    优先权:
    申请号 | 申请日 | 专利标题
    KR1019980026298A|KR100311208B1|1998-06-30|Semiconductor device and manufacturing method|
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