US20020031906A1 - Defect and etch rate control in trench etch for dual damascene patterning of low-k dielectrics - Google Patents
Defect and etch rate control in trench etch for dual damascene patterning of low-k dielectrics Download PDFInfo
- Publication number
- US20020031906A1 US20020031906A1 US09/947,966 US94796601A US2002031906A1 US 20020031906 A1 US20020031906 A1 US 20020031906A1 US 94796601 A US94796601 A US 94796601A US 2002031906 A1 US2002031906 A1 US 2002031906A1
- Authority
- US
- United States
- Prior art keywords
- etch
- forming
- layer
- trench
- dielectric
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
- H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
- H01L21/768—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics
- H01L21/76801—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the dielectrics, e.g. smoothing
- H01L21/76802—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the dielectrics, e.g. smoothing by forming openings in dielectrics
- H01L21/76807—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the dielectrics, e.g. smoothing by forming openings in dielectrics for dual damascene structures
- H01L21/76808—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the dielectrics, e.g. smoothing by forming openings in dielectrics for dual damascene structures involving intermediate temporary filling with material
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3105—After-treatment
- H01L21/311—Etching the insulating layers by chemical or physical means
- H01L21/31127—Etching organic layers
- H01L21/31133—Etching organic layers by chemical means
- H01L21/31138—Etching organic layers by chemical means by dry-etching
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3105—After-treatment
- H01L21/311—Etching the insulating layers by chemical or physical means
- H01L21/31144—Etching the insulating layers by chemical or physical means using masks
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3105—After-treatment
- H01L21/311—Etching the insulating layers by chemical or physical means
- H01L21/31105—Etching inorganic layers
- H01L21/31111—Etching inorganic layers by chemical means
- H01L21/31116—Etching inorganic layers by chemical means by dry-etching
Definitions
- the invention is generally related to the field of forming interconnect layers in integrated circuits and more specifically to dual damascene interconnect processes with Cu and low-k dielectrics.
- the aluminum (and any barrier metals) are deposited, patterned, and etched to form the interconnect lines.
- an interlevel dielectric (ILD) is deposited and planarized.
- the ILD is formed first.
- the ILD is then patterned and etched.
- the metal is then deposited over the structure and then chemically-mechanically polished to remove the metal from over the ILD, leaving metal interconnect lines. A metal etch is thereby avoided.
- FIGS. 1 A-E One prior art damascene process, a dual damascene process, is described with reference to FIGS. 1 A-E.
- a silicon nitride layer 12 is deposited over a semiconductor body 10 .
- Semiconductor body 10 will have been processed through a first metal interconnect layer.
- a via level dielectric 14 is deposited over silicon nitride layer 12 .
- Via dielectric layer 14 comprises FSG (fluorine-doped silicate glass).
- Another silicon nitride layer 18 is deposited over via level dielectric 14 and a second, trench level dielectric 20 is deposited over silicon nitride layer 18 .
- a via 22 is then patterned and etched through the trench level dielectric 20 , silicon nitride layer 18 and via level dielectric 14 .
- Silicon nitride layer 12 is used as an etch-stop.
- a spin-on organic barc (bottom anti-reflection coating) 24 is deposited to fill a portion of via 22 .
- the result is approximately 600 ⁇ of barc over dielectric 20 and a thickness of ⁇ 2000-2500 ⁇ inside the via 22 .
- Barc 24 protects via 22 during the subsequent trench etch.
- the trench pattern 26 is formed on the structure as shown in FIG. 1C.
- Trench pattern 26 exposes areas of trench level dielectric 20 (with about 600 ⁇ of barc on top of dielectric 20 ) where the metal interconnect lines are desired.
- the trench etch to remove portions of FSG layer 20 is performed.
- Oxide ridges 28 may undesirably form on the edges of via 22 .
- Pattern 26 is removed as shown in FIG. 1E. Oxide ridges impair device reliability due to the fact that it is difficult to ensure that a metal barrier completely covers the oxide ridges.
- a dual damascene process for low-k and ultra-low-k dielectrics is disclosed herein.
- a trench is etched using a less-polymerizing fluorocarbon added to an etch chemistry comprising a fluorocarbon and low N 2 /Ar ratio.
- the low N 2 /Ar ratio controls ridge formation during the trench etch.
- the combination of a less-polymerizing fluorocarbon with a high-polymerizing fluorocarbon achieves a high etch rate and defect-free conditions.
- An advantage of the invention is providing a dual damascene process that avoids or minimizes the formation of via ridges while maintaining a high etch rate and good CD control.
- FIGS. 1 A- 1 E are cross-sectional diagrams of a prior art dual damascene process at various stages of fabrication
- FIGS. 2 A- 2 E are cross-sectional diagrams of a dual damascene process according to the invention at various stages of fabrication
- FIG. 3 is a cross-sectional drawing of a trench/via with oxide ridges
- FIG. 4 is a cross-section drawing of a trench/via without oxide ridges but with a low etch rate chemistry
- FIG. 5 is a cross-sectional diagram of a trench/via etched according to the invention with no oxide ridges and high etch rate when a less-polymerizing fluorocarbon was added to the trench etch chemistry.
- a fabrication process according to an embodiment of the invention will now be discussed with reference to FIGS. 2 A- 2 E.
- a semiconductor body 100 is processed through the formation of a first interconnect layer 102 as is known in the art.
- layer 102 may be any interconnect layer except the uppermost interconnect layer.
- An etch-stop layer 104 is deposited over the first interconnect layer 102 .
- Etch-stop layer 104 typically comprises silicon nitride, but other suitable etch-stop layers are known in the art (e.g., SiC).
- the thickness of etch-stop layer 104 may be on the order of 1000 ⁇ (e.g., 500 ⁇ -1000 ⁇ ).
- ILD 106 and IMD 108 are formed over etch-stop layer 104 .
- ILD 106 and IMD 108 can be a single layer.
- OSG is the material used for ILD 106 and IMD 108 .
- OSG is a low-k material having a dielectric constant in the range of 2.7 ⁇ 3.0.
- ILD 106 and IMD 108 may comprise a low-k ( ⁇ 3.5) or an ultra-low-k ( ⁇ 2.7) dielectric.
- the combined thickness of ILD 106 and IMD 108 may be approximately 9000 ⁇ .
- An etch-stop layer is not necessary between ILD 106 and IMD 108 . However, one could be included if desired. Eliminating the etch-stop layer between the ILD 106 and IMD 108 has the advantage of reducing parasitic capacitance.
- a capping layer 110 is formed over IMD 108 .
- oxide capping layer may be deposited using a plasma enhanced tetraethyoxysilane (PETEOS) process.
- PETEOS plasma enhanced tetraethyoxysilane
- the thickness of oxide capping layer is approximately 1500 ⁇ .
- Silicon nitride could also be used as a capping layer. It should be noted that a barc layer is often used under the resist for both via and french pattern. In the preferred embodiment, no hardmask is used.
- vias 112 are etched through the barc and the capping layer 110 (if present), IMD 108 , and ILD 106 .
- Vias 112 are formed in areas where connection is desired between two metal interconnect layers. If an additional etch-stop layer was included between IMD 108 and ILD 106 , the via etch also etches through this additional etch-stop layer.
- the via etch chemistry comprises C 5 F 8 , N 2 and CO.
- a spin-on barc 114 is coated to fill a portion of via 112 .
- the result is approximately 850 ⁇ of barc over capping layer 110 and a thickness of 4500 ⁇ -7000 ⁇ inside the via 112 (the barc thickness inside the via depends on the via density.).
- Barc 114 protects the bottom of via 112 during the subsequent trench etch.
- trench pattern 120 is formed. Trench pattern 120 exposes the areas where metal interconnect lines of a second or subsequent metal interconnect layer are desired.
- the trench 121 etch is performed to etch IMD 108 as shown in FIG. 2C.
- a timed etch is used. If, however, an additional trench etch-stop layer is formed between ILD 106 and IMD 108 , an endpoint etch could be used. It should be noted however, that the incorporation of a silicon-nitride etch-stop layer increases the parasitic capacitance between metal interconnect layers.
- the trench etch comprises an etch chemistry of a less-polymerizing fluorocarbon with a more-polymerizing fluorocarbon, nitrogen and argon.
- a low N 2 /Ar ratio ( ⁇ 1:3) is used.
- the etch chemistry for the trench etch is critical.
- One proposed etch for etching OSG is C 4 F 8 /N 2 /Ar.
- C 4 F 8 is a higher-polymerizing fluorocarbon.
- a high N 2 /Ar ratio results in high etch rate.
- oxide ridges 130 form around the vias, as shown in FIG. 3.
- 10 sccm of C 4 F 8 and a N 2 /Ar ratio of 300:100 results in an etch rate of approximately 4600 ⁇ /min.
- Oxide ridges 130 remain even after clean-up and significantly impact reliability.
- oxide ridges may fall into the vias during subsequent processes (e.g., pre-sputter etch), resulting in poor metal barrier coverage.
- a low N 2 /Ar ratio eliminates the oxide ridges as shown in FIG. 4. Unfortunately, the etch rate also reduces significantly. When 10 sccm of C 4 F 8 is used with a N 2 /Ar ratio of 50:450, the etch rate reduces to approximately 1350 ⁇ /min. The low etch rate reduces throughput.
- the etch chemistry combines a less-polymerizing fluorocarbon, such as CF 4 with a higher-polymerizing fluorocarbon, such as C 4 F 8 , and low N 2 /Ar ratio.
- the low N 2 /Ar ratio eliminates the oxide ridges, as shown in FIG. 5.
- the combined fluorocarbons improve etch rate without increasing oxide ridges or increasing CD bias.
- CF 4 is a less-polymerizing fluorocarbon
- adding it to the etch chemistry increases the etch rate significantly.
- it does not increase the CD bias or cause the formation of ridges.
- the etch rate and ridge formation can be controlled independently.
- by adjusting the flow rates of the two fluorocarbons various C:F ratios can be achieved. This is not possible with a single fluorocarbon.
- the resist and barc from trench pattern 120 is removed, for example, by ashing.
- the capping layer is thin (e.g., ⁇ 500 ⁇ )
- it can be removed during etch-stop layer etch.
- the capping layer is >500 ⁇ , it is removed during metal CMP.
- Processing then continues with the formation of the second metal interconnect layer 122 , as shown in FIG. 2E.
- layer 122 can be any metal interconnect layer other than the lowest interconnect layer.
- a barrier layer 124 such as tantalum-nitride (TaN) is deposited first.
- barrier layer 124 Due to the fact that no oxide pillars are formed, it is fairly easy to form a continuous barrier layer 124 in the trench/via. This advantage also increases the process margin.
- a purpose of the barrier layer is to prevent diffusion of the subsequently formed metal into the IMD/ILD. Breaks in the barrier layer allow metal diffusion and thus reduce yield and reliability. The invention thus improves both the yield and reliability by preventing the formation of oxide ridges and reducing defects in the via. It also improves trench etch throughput.
- a copper seed layer is typically formed. This is followed by the formation of the copper interconnect 126 and a top nitride (Si 3 N 4 ) capping layer 128 . The above process can then be repeated to form subsequent metal interconnect layers.
Abstract
A dual damascene process for low-k or ultra low-k dielectric such as organo-silicate glass (OSG). After the via (112) etch, a trench (121) is etched in the OSG layer (108) using a less-polymerizing fluorocarbon added to an etch chemistry comprising a fluorocarbon and low N2/Ar ratio. The low N2/Ar ratio controls ridge formation during the trench etch. The combination of a less-polymerizing fluorocarbon with a higher-polymerizing fluorocarbon achieves a high etch rate and defect-free conditions.
Description
- The following co-pending application is related and hereby incorporated by reference:
- U.S. patent application Ser. No. 09/521,325, filed Mar. 9, 2000 by Tsu et al.
- The invention is generally related to the field of forming interconnect layers in integrated circuits and more specifically to dual damascene interconnect processes with Cu and low-k dielectrics.
- As the density of semiconductor devices increases, the demands on interconnect layers for connecting the semiconductor devices to each other also increase. Therefore, there is a desire to switch from the traditional aluminum metal interconnects to copper interconnects. Unfortunately, suitable copper etches for a semiconductor fabrication environment are not readily available. To overcome the copper etch problem, damascene processes have been developed.
- In a conventional interconnect process, the aluminum (and any barrier metals) are deposited, patterned, and etched to form the interconnect lines. Then, an interlevel dielectric (ILD) is deposited and planarized. In a damascene process, the ILD is formed first. The ILD is then patterned and etched. The metal is then deposited over the structure and then chemically-mechanically polished to remove the metal from over the ILD, leaving metal interconnect lines. A metal etch is thereby avoided.
- One prior art damascene process, a dual damascene process, is described with reference to FIGS.1A-E. Referring to FIG. 1A, a
silicon nitride layer 12 is deposited over asemiconductor body 10.Semiconductor body 10 will have been processed through a first metal interconnect layer. A via level dielectric 14 is deposited oversilicon nitride layer 12. Viadielectric layer 14 comprises FSG (fluorine-doped silicate glass). Anothersilicon nitride layer 18 is deposited over via level dielectric 14 and a second, trench level dielectric 20 is deposited oversilicon nitride layer 18. Avia 22 is then patterned and etched through the trench level dielectric 20,silicon nitride layer 18 and via level dielectric 14.Silicon nitride layer 12 is used as an etch-stop. - Referring to FIG. 1B, a spin-on organic barc (bottom anti-reflection coating)24 is deposited to fill a portion of
via 22. The result is approximately 600 Å of barc over dielectric 20 and a thickness of ˜2000-2500 Å inside thevia 22. Barc 24 protects via 22 during the subsequent trench etch. Next, thetrench pattern 26 is formed on the structure as shown in FIG. 1C.Trench pattern 26 exposes areas of trench level dielectric 20 (with about 600 Å of barc on top of dielectric 20) where the metal interconnect lines are desired. Referring to FIG. 1D, the trench etch to remove portions ofFSG layer 20 is performed.Oxide ridges 28 may undesirably form on the edges of via 22.Pattern 26 is removed as shown in FIG. 1E. Oxide ridges impair device reliability due to the fact that it is difficult to ensure that a metal barrier completely covers the oxide ridges. - Newer technologies are switching to even lower-k dielectrics such as organo-silicate glass (OSG) in place of FSG. Dual damascene processes for working with the newer dielectrics are needed.
- A dual damascene process for low-k and ultra-low-k dielectrics is disclosed herein. After the via etch, a trench is etched using a less-polymerizing fluorocarbon added to an etch chemistry comprising a fluorocarbon and low N2/Ar ratio. The low N2/Ar ratio controls ridge formation during the trench etch. The combination of a less-polymerizing fluorocarbon with a high-polymerizing fluorocarbon achieves a high etch rate and defect-free conditions.
- An advantage of the invention is providing a dual damascene process that avoids or minimizes the formation of via ridges while maintaining a high etch rate and good CD control.
- This and other advantages will be apparent to those of ordinary skill in the art having reference to the specification in conjunction with the drawings.
- In the drawings:
- FIGS.1A-1E are cross-sectional diagrams of a prior art dual damascene process at various stages of fabrication;
- FIGS.2A-2E are cross-sectional diagrams of a dual damascene process according to the invention at various stages of fabrication;
- FIG. 3 is a cross-sectional drawing of a trench/via with oxide ridges;
- FIG. 4 is a cross-section drawing of a trench/via without oxide ridges but with a low etch rate chemistry;
- FIG. 5 is a cross-sectional diagram of a trench/via etched according to the invention with no oxide ridges and high etch rate when a less-polymerizing fluorocarbon was added to the trench etch chemistry.
- The invention will now be described in conjunction with a dual damascene copper interconnect process. It will be apparent to those of ordinary skill in the art that the benefits of the invention can be applied to other fabrication processes such as other dual damascene processes.
- A fabrication process according to an embodiment of the invention will now be discussed with reference to FIGS.2A-2E. A
semiconductor body 100 is processed through the formation of afirst interconnect layer 102 as is known in the art. (Although referred to herein as thefirst interconnect layer 102,layer 102 may be any interconnect layer except the uppermost interconnect layer.) An etch-stop layer 104 is deposited over thefirst interconnect layer 102. Etch-stop layer 104 typically comprises silicon nitride, but other suitable etch-stop layers are known in the art (e.g., SiC). As an example, the thickness of etch-stop layer 104 may be on the order of 1000 Å (e.g., 500 Å-1000 Å). - The via level dielectric106 (sometimes referred to as interlevel dielectric—ILD) and trench level dielectric 108 (sometimes referred to as intrametal dielectric—IMD) are formed over etch-
stop layer 104. As shown in FIG. 2A,ILD 106 andIMD 108 can be a single layer. In the preferred embodiment, OSG is the material used forILD 106 andIMD 108. OSG is a low-k material having a dielectric constant in the range of 2.7˜3.0. Alternatively,ILD 106 andIMD 108 may comprise a low-k (<3.5) or an ultra-low-k (<2.7) dielectric. The combined thickness ofILD 106 andIMD 108 may be approximately 9000 Å. - An etch-stop layer is not necessary between
ILD 106 andIMD 108. However, one could be included if desired. Eliminating the etch-stop layer between theILD 106 andIMD 108 has the advantage of reducing parasitic capacitance. - Sometimes a
capping layer 110 is formed overIMD 108. As an example, oxide capping layer may be deposited using a plasma enhanced tetraethyoxysilane (PETEOS) process. In the preferred embodiment, the thickness of oxide capping layer is approximately 1500 Å. Silicon nitride could also be used as a capping layer. It should be noted that a barc layer is often used under the resist for both via and french pattern. In the preferred embodiment, no hardmask is used. - Referring to FIG. 2A, vias112 are etched through the barc and the capping layer 110 (if present),
IMD 108, andILD 106. The via etch-stops on etch-stop layer 104.Vias 112 are formed in areas where connection is desired between two metal interconnect layers. If an additional etch-stop layer was included betweenIMD 108 andILD 106, the via etch also etches through this additional etch-stop layer. In the preferred embodiment, the via etch chemistry comprises C5F8, N2 and CO. - Referring to FIG. 2B, a spin-on
barc 114 is coated to fill a portion of via 112. The result is approximately 850 Å of barc over cappinglayer 110 and a thickness of 4500 Å-7000 Å inside the via 112 (the barc thickness inside the via depends on the via density.).Barc 114 protects the bottom of via 112 during the subsequent trench etch. - Still referring to FIG. 2B, the
trench pattern 120 is formed.Trench pattern 120 exposes the areas where metal interconnect lines of a second or subsequent metal interconnect layer are desired. - Next, the
trench 121 etch is performed to etchIMD 108 as shown in FIG. 2C. In the preferred embodiment, a timed etch is used. If, however, an additional trench etch-stop layer is formed betweenILD 106 andIMD 108, an endpoint etch could be used. It should be noted however, that the incorporation of a silicon-nitride etch-stop layer increases the parasitic capacitance between metal interconnect layers. - The trench etch comprises an etch chemistry of a less-polymerizing fluorocarbon with a more-polymerizing fluorocarbon, nitrogen and argon. A low N2/Ar ratio (<1:3) is used. A less-polymerizing fluorocarbon refers to a C:F ratio of less than 1:3. Examples of less-polymerizing fluorocarbons include CF4, NF3, C2F6, and CXF3X+Y (Y>=0). Examples of more-polymerizing fluorocarbons include C4F8, C5F8, C4F6, CXHYF2X+Z (Z>=0, Y>=0).
- The etch chemistry for the trench etch is critical. One proposed etch for etching OSG is C4F8/N2/Ar. C4F8 is a higher-polymerizing fluorocarbon. A high N2/Ar ratio results in high etch rate. However, when a high N2/Ar ratio is used,
oxide ridges 130 form around the vias, as shown in FIG. 3. 10 sccm of C4F8 and a N2/Ar ratio of 300:100 results in an etch rate of approximately 4600 Å/min.Oxide ridges 130 remain even after clean-up and significantly impact reliability. When the subsequently deposited metal barriers are formed, it is difficult to ensure thatoxide ridges 130 are completely covered. In addition, oxide ridges may fall into the vias during subsequent processes (e.g., pre-sputter etch), resulting in poor metal barrier coverage. - A low N2/Ar ratio eliminates the oxide ridges as shown in FIG. 4. Unfortunately, the etch rate also reduces significantly. When 10 sccm of C4F8 is used with a N2/Ar ratio of 50:450, the etch rate reduces to approximately 1350 Å/min. The low etch rate reduces throughput.
- The etch chemistry according to the invention, combines a less-polymerizing fluorocarbon, such as CF4 with a higher-polymerizing fluorocarbon, such as C4F8, and low N2/Ar ratio. The low N2/Ar ratio eliminates the oxide ridges, as shown in FIG. 5. The combined fluorocarbons improve etch rate without increasing oxide ridges or increasing CD bias. A 10 sccm C4F8, N2:Ar=100:300 and 30 sccm CF4 etch chemistry results in no oxide ridges, an etch rate of approximately 3480 Å/min and a CD bias of approximately 0.003 μm.
- Because CF4 is a less-polymerizing fluorocarbon, adding it to the etch chemistry increases the etch rate significantly. However, it does not increase the CD bias or cause the formation of ridges. Thus, the etch rate and ridge formation can be controlled independently. Furthermore, by adjusting the flow rates of the two fluorocarbons, various C:F ratios can be achieved. This is not possible with a single fluorocarbon.
- Referring to FIG. 2D, the resist and barc from
trench pattern 120 is removed, for example, by ashing. (If the capping layer is thin (e.g., <500 Å), it can be removed during etch-stop layer etch. However, if the capping layer is >500 Å, it is removed during metal CMP.) Processing then continues with the formation of the secondmetal interconnect layer 122, as shown in FIG. 2E. (Although referred to as the second metal interconnect layer,layer 122 can be any metal interconnect layer other than the lowest interconnect layer.) Typically, abarrier layer 124, such as tantalum-nitride (TaN) is deposited first. Due to the fact that no oxide pillars are formed, it is fairly easy to form acontinuous barrier layer 124 in the trench/via. This advantage also increases the process margin. A purpose of the barrier layer is to prevent diffusion of the subsequently formed metal into the IMD/ILD. Breaks in the barrier layer allow metal diffusion and thus reduce yield and reliability. The invention thus improves both the yield and reliability by preventing the formation of oxide ridges and reducing defects in the via. It also improves trench etch throughput. - After the
barrier layer 124, a copper seed layer is typically formed. This is followed by the formation of the copper interconnect 126 and a top nitride (Si3N4) cappinglayer 128. The above process can then be repeated to form subsequent metal interconnect layers. - While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is therefore intended that the appended claims encompass any such modifications or embodiments.
Claims (18)
1. A method of forming an integrated circuit, comprising the steps of:
forming a dielectric layer having a dielectric constant less than 3.5 over a semiconductor body;
forming a via in said dielectric layer;
forming a trench pattern over said dielectric layer;
etching a trench through a portion of said dielectric layer using an etch chemistry comprising a less-polymerizing fluorocarbon, a higher-polymerizing fluorocarbon, nitrogen and argon with a low nitrogen:argon ratio; and
forming a metal layer in said via and said trench.
2. The method of claim 1 , wherein said etch chemistry comprises CF4 as the less-polymerizing fluorocarbon, C4F8, N2 and Ar.
3. The method of claim 1 , wherein the nitrogen: argon ratio is less than 1:3.
4. The method of claim 1 , wherein the nitrogen:argon ratio is approximately 100:400.
5. The method of claim 1 , wherein the step of forming a dielectric layer comprises the step of:
forming a first etch-stop layer over said semiconductor body;
forming an interlevel dielectric layer (ILD) over said first etch-stop; and
forming an intermetal dielectric layer (IMD) over said interlevel dielectric,
wherein said via extends through said ILD and said trench extends through said IMD.
6. The method of claim 5 , further comprising the step of forming a second etch-stop layer between said ILD and said IMD.
7. The method of claim 1 , further comprising the step of forming a capping layer over said dielectric prior to forming said via.
8. The method of claim 7 , wherein said capping layer comprises an oxide.
9. The method of claim 7 , wherein said capping layer comprises an oxide deposited by plasma enhanced tetraethyoxysilane.
10. The method of claim 1 , wherein said dielectric layer comprises organo-silicate glass.
11. The method of claim 1 , wherein said dielectric later comprises an ultra-low-k dielectric having a dielectric constant less than 2.7.
12. A method of forming an integrated circuit, comprising the steps of:
forming a first metal interconnect layer over a semiconductor body;
forming an etch-stop layer over said first metal interconnect layer;
forming a dielectric layer comprising organo-silicate glass over said etch-stop layer;
forming a via through said dielectric layer to said etch-stop layer;
forming a trench pattern over said dielectric layer;
dry etching a trench in said dielectric layer, said dry etching a trench step using an etch chemistry comprising a less-polymerizing fluorocarbon, a more-polymerizing fluorocarbon, nitrogen and argon; and
forming a metal layer in said via and said trench.
13. The method of claim 12 , wherein said less-polymerizing fluorocarbon comprises CF4.
14. The method of claim 12 , wherein said more-polymerizing fluorocarbon comprises C4F8.
15. The method of claim 12 , wherein said etch chemistry comprises a nitrogen: argon ratio of less than 1:3.
16. The method of claim 12 , wherein said etch chemistry comprises a nitrogen: argon ratio of approximately 100:400.
17. The method of claim 12 , wherein the step of forming a dielectric layer comprises the step of:
forming an interlevel dielectric layer (ILD) over said first etch-stop; and
forming an intermetal dielectric layer (IMD) over said interlevel dielectric.
18. The method of claim 17 , further comprising the step of forming a second etch-stop layer between said ILD and said IMD.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/947,966 US6455411B1 (en) | 2000-09-11 | 2001-09-06 | Defect and etch rate control in trench etch for dual damascene patterning of low-k dielectrics |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US23181300P | 2000-09-11 | 2000-09-11 | |
US09/947,966 US6455411B1 (en) | 2000-09-11 | 2001-09-06 | Defect and etch rate control in trench etch for dual damascene patterning of low-k dielectrics |
Publications (2)
Publication Number | Publication Date |
---|---|
US20020031906A1 true US20020031906A1 (en) | 2002-03-14 |
US6455411B1 US6455411B1 (en) | 2002-09-24 |
Family
ID=26925455
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/947,966 Expired - Lifetime US6455411B1 (en) | 2000-09-11 | 2001-09-06 | Defect and etch rate control in trench etch for dual damascene patterning of low-k dielectrics |
Country Status (1)
Country | Link |
---|---|
US (1) | US6455411B1 (en) |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20030017694A1 (en) * | 2001-07-23 | 2003-01-23 | Applied Materials, Inc. | Selective etching of organosilicate films over silicon oxide stop etch layers |
US20040106293A1 (en) * | 2001-03-08 | 2004-06-03 | Yoshiki Igarashi | Method for etching organic insulating film and dual damasene process |
US20040132291A1 (en) * | 2002-02-22 | 2004-07-08 | Samsung Electronics Co., Ltd. | Method of fabricating dual damascene interconnections of microelectronic device using hybrid low k-dielectric and carbon-free inorganic filler |
US20050029229A1 (en) * | 2003-08-08 | 2005-02-10 | Applied Materials, Inc. | Selective etch process of a sacrificial light absorbing material (SLAM) over a dielectric material |
US6902870B1 (en) * | 2002-06-19 | 2005-06-07 | Advanced Micro Devices, Inc. | Patterning of dielectric with added layers of materials aside from photoresist for enhanced pattern transfer |
US20050272265A1 (en) * | 2004-06-03 | 2005-12-08 | Epion Corporation | Dual damascene integration structure and method for forming improved dual damascene integration structure |
US20060024910A1 (en) * | 2004-07-27 | 2006-02-02 | Amitava Chatterjee | Method to engineer the inverse narrow width effect (INWE) in CMOS technology using shallow trench isolation (STI) |
US20080111238A1 (en) * | 2006-11-09 | 2008-05-15 | Chartered Semiconductor Manufacturing Ltd. | Integrated circuit processing system |
US20110237015A1 (en) * | 2004-11-30 | 2011-09-29 | Spire Corporation | Nanophotovoltaic devices |
Families Citing this family (40)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4381526B2 (en) * | 1999-10-26 | 2009-12-09 | 東京エレクトロン株式会社 | Plasma etching method |
US6873087B1 (en) * | 1999-10-29 | 2005-03-29 | Board Of Regents, The University Of Texas System | High precision orientation alignment and gap control stages for imprint lithography processes |
EP2264523A3 (en) | 2000-07-16 | 2011-11-30 | Board Of Regents, The University Of Texas System | A method of forming a pattern on a substrate in imprint lithographic processes |
EP1303793B1 (en) | 2000-07-17 | 2015-01-28 | Board Of Regents, The University Of Texas System | Method and system of automatic fluid dispensing for imprint lithography processes |
JP4858895B2 (en) * | 2000-07-21 | 2012-01-18 | 富士通セミコンダクター株式会社 | Manufacturing method of semiconductor device |
KR101031528B1 (en) | 2000-10-12 | 2011-04-27 | 더 보드 오브 리전츠 오브 더 유니버시티 오브 텍사스 시스템 | Template for room temperature, low pressure micro- and nano- imprint lithography |
US7311852B2 (en) * | 2001-03-30 | 2007-12-25 | Lam Research Corporation | Method of plasma etching low-k dielectric materials |
US6914004B2 (en) * | 2001-09-28 | 2005-07-05 | Texas Instruments Incorporated | Method for via etching in organo-silica-glass |
US6905968B2 (en) * | 2001-12-12 | 2005-06-14 | Applied Materials, Inc. | Process for selectively etching dielectric layers |
US6686293B2 (en) * | 2002-05-10 | 2004-02-03 | Applied Materials, Inc | Method of etching a trench in a silicon-containing dielectric material |
US6926929B2 (en) | 2002-07-09 | 2005-08-09 | Molecular Imprints, Inc. | System and method for dispensing liquids |
US6908861B2 (en) * | 2002-07-11 | 2005-06-21 | Molecular Imprints, Inc. | Method for imprint lithography using an electric field |
US7019819B2 (en) | 2002-11-13 | 2006-03-28 | Molecular Imprints, Inc. | Chucking system for modulating shapes of substrates |
US6900881B2 (en) | 2002-07-11 | 2005-05-31 | Molecular Imprints, Inc. | Step and repeat imprint lithography systems |
KR100441685B1 (en) * | 2002-09-19 | 2004-07-27 | 삼성전자주식회사 | Dual damascene process |
US8349241B2 (en) | 2002-10-04 | 2013-01-08 | Molecular Imprints, Inc. | Method to arrange features on a substrate to replicate features having minimal dimensional variability |
US6980282B2 (en) * | 2002-12-11 | 2005-12-27 | Molecular Imprints, Inc. | Method for modulating shapes of substrates |
US6871558B2 (en) * | 2002-12-12 | 2005-03-29 | Molecular Imprints, Inc. | Method for determining characteristics of substrate employing fluid geometries |
US7229930B2 (en) * | 2003-01-13 | 2007-06-12 | Applied Materials, Inc. | Selective etching of low-k dielectrics |
US7041230B2 (en) * | 2003-01-21 | 2006-05-09 | Lam Research Corporation | Method for selectively etching organosilicate glass with respect to a doped silicon carbide |
US6900123B2 (en) * | 2003-03-20 | 2005-05-31 | Texas Instruments Incorporated | BARC etch comprising a selective etch chemistry and a high polymerizing gas for CD control |
US7323417B2 (en) * | 2004-09-21 | 2008-01-29 | Molecular Imprints, Inc. | Method of forming a recessed structure employing a reverse tone process |
US7186656B2 (en) * | 2004-05-21 | 2007-03-06 | Molecular Imprints, Inc. | Method of forming a recessed structure employing a reverse tone process |
JP4571785B2 (en) * | 2003-05-30 | 2010-10-27 | ルネサスエレクトロニクス株式会社 | Manufacturing method of semiconductor device |
US8211214B2 (en) | 2003-10-02 | 2012-07-03 | Molecular Imprints, Inc. | Single phase fluid imprint lithography method |
US8076386B2 (en) | 2004-02-23 | 2011-12-13 | Molecular Imprints, Inc. | Materials for imprint lithography |
US7906180B2 (en) | 2004-02-27 | 2011-03-15 | Molecular Imprints, Inc. | Composition for an etching mask comprising a silicon-containing material |
US7547504B2 (en) | 2004-09-21 | 2009-06-16 | Molecular Imprints, Inc. | Pattern reversal employing thick residual layers |
US7041604B2 (en) * | 2004-09-21 | 2006-05-09 | Molecular Imprints, Inc. | Method of patterning surfaces while providing greater control of recess anisotropy |
US7241395B2 (en) * | 2004-09-21 | 2007-07-10 | Molecular Imprints, Inc. | Reverse tone patterning on surfaces having planarity perturbations |
US7205244B2 (en) | 2004-09-21 | 2007-04-17 | Molecular Imprints | Patterning substrates employing multi-film layers defining etch-differential interfaces |
US7252777B2 (en) * | 2004-09-21 | 2007-08-07 | Molecular Imprints, Inc. | Method of forming an in-situ recessed structure |
US20060081557A1 (en) * | 2004-10-18 | 2006-04-20 | Molecular Imprints, Inc. | Low-k dielectric functional imprinting materials |
WO2006060757A2 (en) | 2004-12-01 | 2006-06-08 | Molecular Imprints, Inc. | Eliminating printability of sub-resolution defects in imprint lithography |
US7442649B2 (en) * | 2005-03-29 | 2008-10-28 | Lam Research Corporation | Etch with photoresist mask |
US7256131B2 (en) * | 2005-07-19 | 2007-08-14 | Molecular Imprints, Inc. | Method of controlling the critical dimension of structures formed on a substrate |
US20070077763A1 (en) * | 2005-09-30 | 2007-04-05 | Molecular Imprints, Inc. | Deposition technique to planarize a multi-layer structure |
US7282406B2 (en) * | 2006-03-06 | 2007-10-16 | Semiconductor Companents Industries, L.L.C. | Method of forming an MOS transistor and structure therefor |
JP2010050311A (en) * | 2008-08-22 | 2010-03-04 | Elpida Memory Inc | Semiconductor device, and method of manufacturing the same |
US9093387B1 (en) * | 2014-01-08 | 2015-07-28 | International Business Machines Corporation | Metallic mask patterning process for minimizing collateral etch of an underlayer |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3193335B2 (en) * | 1997-12-12 | 2001-07-30 | 松下電器産業株式会社 | Method for manufacturing semiconductor device |
US6326296B1 (en) * | 1998-07-01 | 2001-12-04 | Taiwan Semiconductor Manufacturing Company | Method of forming dual damascene structure with improved contact/via edge integrity |
US6211092B1 (en) * | 1998-07-09 | 2001-04-03 | Applied Materials, Inc. | Counterbore dielectric plasma etch process particularly useful for dual damascene |
US6380096B2 (en) * | 1998-07-09 | 2002-04-30 | Applied Materials, Inc. | In-situ integrated oxide etch process particularly useful for copper dual damascene |
US6284149B1 (en) * | 1998-09-18 | 2001-09-04 | Applied Materials, Inc. | High-density plasma etching of carbon-based low-k materials in a integrated circuit |
US6180540B1 (en) * | 1999-02-18 | 2001-01-30 | Taiwan Semiconductor Manufacturing Company | Method for forming a stabilized fluorosilicate glass layer |
US6204192B1 (en) * | 1999-03-29 | 2001-03-20 | Lsi Logic Corporation | Plasma cleaning process for openings formed in at least one low dielectric constant insulation layer over copper metallization in integrated circuit structures |
JP2000332008A (en) * | 1999-05-20 | 2000-11-30 | Fujitsu Ltd | Semiconductor device and manufacture thereof |
US6372634B1 (en) * | 1999-06-15 | 2002-04-16 | Cypress Semiconductor Corp. | Plasma etch chemistry and method of improving etch control |
US6316351B1 (en) * | 2000-05-31 | 2001-11-13 | Taiwan Semiconductor Manufacturing Company | Inter-metal dielectric film composition for dual damascene process |
-
2001
- 2001-09-06 US US09/947,966 patent/US6455411B1/en not_active Expired - Lifetime
Cited By (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20040106293A1 (en) * | 2001-03-08 | 2004-06-03 | Yoshiki Igarashi | Method for etching organic insulating film and dual damasene process |
US20050255697A1 (en) * | 2001-07-23 | 2005-11-17 | Applied Materials, Inc. | Selective etching of organosilicate films over silicon oxide stop etch layers |
US7244672B2 (en) | 2001-07-23 | 2007-07-17 | Applied Materials, Inc. | Selective etching of organosilicate films over silicon oxide stop etch layers |
US7183201B2 (en) * | 2001-07-23 | 2007-02-27 | Applied Materials, Inc. | Selective etching of organosilicate films over silicon oxide stop etch layers |
US20030017694A1 (en) * | 2001-07-23 | 2003-01-23 | Applied Materials, Inc. | Selective etching of organosilicate films over silicon oxide stop etch layers |
US7183195B2 (en) * | 2002-02-22 | 2007-02-27 | Samsung Electronics, Co., Ltd. | Method of fabricating dual damascene interconnections of microelectronic device using hybrid low k-dielectric and carbon-free inorganic filler |
US20040132291A1 (en) * | 2002-02-22 | 2004-07-08 | Samsung Electronics Co., Ltd. | Method of fabricating dual damascene interconnections of microelectronic device using hybrid low k-dielectric and carbon-free inorganic filler |
US6902870B1 (en) * | 2002-06-19 | 2005-06-07 | Advanced Micro Devices, Inc. | Patterning of dielectric with added layers of materials aside from photoresist for enhanced pattern transfer |
US20070020944A1 (en) * | 2003-08-08 | 2007-01-25 | Applied Materials, Inc. | Selective etch process of a sacrificial light absorbing material (slam) over a dielectric material |
US20050029229A1 (en) * | 2003-08-08 | 2005-02-10 | Applied Materials, Inc. | Selective etch process of a sacrificial light absorbing material (SLAM) over a dielectric material |
US7300597B2 (en) * | 2003-08-08 | 2007-11-27 | Applied Materials, Inc. | Selective etch process of a sacrificial light absorbing material (SLAM) over a dielectric material |
US7309448B2 (en) | 2003-08-08 | 2007-12-18 | Applied Materials, Inc. | Selective etch process of a sacrificial light absorbing material (SLAM) over a dielectric material |
US20050272265A1 (en) * | 2004-06-03 | 2005-12-08 | Epion Corporation | Dual damascene integration structure and method for forming improved dual damascene integration structure |
US7759251B2 (en) * | 2004-06-03 | 2010-07-20 | Tel Epion Corporation | Dual damascene integration structure and method for forming improved dual damascene integration structure |
US7045436B2 (en) * | 2004-07-27 | 2006-05-16 | Texas Instruments Incorporated | Method to engineer the inverse narrow width effect (INWE) in CMOS technology using shallow trench isolation (STI) |
US20060024910A1 (en) * | 2004-07-27 | 2006-02-02 | Amitava Chatterjee | Method to engineer the inverse narrow width effect (INWE) in CMOS technology using shallow trench isolation (STI) |
US20110237015A1 (en) * | 2004-11-30 | 2011-09-29 | Spire Corporation | Nanophotovoltaic devices |
US8242009B2 (en) | 2004-11-30 | 2012-08-14 | Spire Corporation | Nanophotovoltaic devices |
US20080111238A1 (en) * | 2006-11-09 | 2008-05-15 | Chartered Semiconductor Manufacturing Ltd. | Integrated circuit processing system |
US7749894B2 (en) * | 2006-11-09 | 2010-07-06 | Chartered Semiconductor Manufacturing Ltd. | Integrated circuit processing system |
Also Published As
Publication number | Publication date |
---|---|
US6455411B1 (en) | 2002-09-24 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6455411B1 (en) | Defect and etch rate control in trench etch for dual damascene patterning of low-k dielectrics | |
US6461955B1 (en) | Yield improvement of dual damascene fabrication through oxide filling | |
US6696222B2 (en) | Dual damascene process using metal hard mask | |
US6638871B2 (en) | Method for forming openings in low dielectric constant material layer | |
US5801094A (en) | Dual damascene process | |
US6620727B2 (en) | Aluminum hardmask for dielectric etch | |
US6365506B1 (en) | Dual-damascene process with porous low-K dielectric material | |
US7015133B2 (en) | Dual damascene structure formed of low-k dielectric materials | |
US20030134505A1 (en) | Fine-pitch device lithography using a sacrificial hardmask | |
US20070085209A1 (en) | Anchored damascene structures | |
US20090283912A1 (en) | Damascene wiring fabrication methods incorporating dielectric cap etch process with hard mask retention | |
US20060024958A1 (en) | HSQ/SOG dry strip process | |
US6159661A (en) | Dual damascene process | |
US20020098673A1 (en) | Method for fabricating metal interconnects | |
US7169701B2 (en) | Dual damascene trench formation to avoid low-K dielectric damage | |
US6900123B2 (en) | BARC etch comprising a selective etch chemistry and a high polymerizing gas for CD control | |
US7572733B2 (en) | Gas switching during an etch process to modulate the characteristics of the etch | |
US7488687B2 (en) | Methods of forming electrical interconnect structures using polymer residues to increase etching selectivity through dielectric layers | |
EP1235263A2 (en) | Gas switching during an etch process to modulate the characteristics of the etch | |
US6346474B1 (en) | Dual damascene process | |
US20060118955A1 (en) | Robust copper interconnection structure and fabrication method thereof | |
US6262484B1 (en) | Dual damascene method for backened metallization using poly stop layers | |
US7037841B2 (en) | Dual damascene interconnecting line structure and fabrication method thereof | |
US6465340B1 (en) | Via filled dual damascene structure with middle stop layer and method for making the same | |
US20050189653A1 (en) | Dual damascene intermediate structure and method of fabricating same |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: TEXAS INSTRUMENTS INCORPORATED, TEXAS Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:JIANG, PING;CELII, FRANCIS G.;NEWTON, KENNETH J.;AND OTHERS;REEL/FRAME:012161/0039 Effective date: 20000908 |
|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |
|
FPAY | Fee payment |
Year of fee payment: 4 |
|
FPAY | Fee payment |
Year of fee payment: 8 |
|
FPAY | Fee payment |
Year of fee payment: 12 |