GB2273816A - Method for forming a contact plug of a semiconductor device - Google Patents
Method for forming a contact plug of a semiconductor device Download PDFInfo
- Publication number
- GB2273816A GB2273816A GB9325796A GB9325796A GB2273816A GB 2273816 A GB2273816 A GB 2273816A GB 9325796 A GB9325796 A GB 9325796A GB 9325796 A GB9325796 A GB 9325796A GB 2273816 A GB2273816 A GB 2273816A
- Authority
- GB
- United Kingdom
- Prior art keywords
- tungsten
- contact plug
- forming
- semiconductor device
- contact
- 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
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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
- H01L21/76838—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 conductors
- H01L21/76877—Filling of holes, grooves or trenches, e.g. vias, with conductive material
- H01L21/76879—Filling of holes, grooves or trenches, e.g. vias, with conductive material by selective deposition of conductive material in the vias, e.g. selective C.V.D. on semiconductor material, plating
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Internal Circuitry In Semiconductor Integrated Circuit Devices (AREA)
- Chemical Vapour Deposition (AREA)
Description
2273816 METHOD FOR FORM[ING A CONTACT PLUG OF A SENUCONDUCTOR DEVICE The
present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for forming a contact plug by filling a via contact with a selective tungsten, which is formed for establishing multi-level interconnections of a semiconductor device.
As the integration of semiconductor devices increases, a method to form a plug having a superior step coverage in a high aspect ratio contact is required. In the conventional method for filling the contact using aluminum sputtering, defects such as voids are generated due to the increased aspect ratio of the contact, and the step coverage becomes poor. As a result, a short between interconnections or a hillock is induced, which thereby deteriorates the reliability of the semiconductor device. Accordingly, various approaches to forming the contact plug by chemical vapor deposition (CVD) have been is progressed recently. Among these, a method of selective CVD tungsten providing the superior step coverage has emerged.
Fig. 1 of the accompanying drawings is a graphical diagram for illustrating the conventional method for forming the contact plug of semiconductor device using the selective CV1) tungsten, and Fig. 2 of the accompanying drawings is a scanning electron microscopy (SEM) photograph showing a planar view of the contact plug formed by the above method.
2 An insulating film is formed on a lower conductive layer, for example, an aluminum layer formed on a semiconductor substrate, and then the insulating film is partially etched according to a photo-etching process, thereby to form a via contact for connecting the lower conductive layer with an upper conductive layer which will be formed in the subsequent process.
Then, a contact plug is formed by filling the via contact with a selective tungsten using a CVI) method.
In general, the deposition of selective tungsten is realized by (1) depositing the tungsten after a capping material such as M is deposited on the aluminum layer, o-r (2) by depositing the tungsten by performing a silane (SiH4) reduction process under the conditions of a tungsten hexafluoride (WF6) flow of 40scem, a SiR4flow of 10sccm, a hydrogen (112) flow of 1,000sccm, and a temperature above 40WC, after carrying out a pre treatment process for removing a native oxide formed on the aluminum layer, Le, a dry cleaning such as a high-temperature heat treatment process or plasma treatment process, or a wet cleaning such as hydrofluoric acid (HF) treatment (refer to Fig.1). Here, the tungsten is deposited at a high temperature so that a contact resistance is decreased, since the amount of aluminum trifluoride (A1F3), generated by reaction of aluminum and WF6 upon the initial deposition of tungsten, is reduced.
The important problem in the course of the formation of a plug in the via contact using the selective CVI) tungsten is to maintain the selectivity of 3 the tungsten. In other words, the tungsten must be deposited only on the surface of the metal layer such as aluminum layer, and not on the insulating film. However, the selectivity is greatly affected by deposition temperature, the insulating material employed, the level of contamination in the surface of the metal, and the flow rates of the reaction gases. Accordingly, maintaining the selectivity is absolutely necessary in the method of selective CV1) tungsten.
A plasma-enhanced SiH4 (PE-SiH4) oxide film is generally used as a insulating film for via contact in the conventional method. However, among the various insulating materials, PE-SiH4oxide has a very low selectivity for depositing tungsten. Therefore, if a plasma pre-treatment is performed or the tungsten is deposited at high temperature by a SiH4 reduction process, the tungsten is also deposited on the PE-SiH4oxide film, which thereby causes a short between the lower conductive layer and the upper conductive layer which will be formed in the subsequent process (refer to Fig.2).
Accordingly, the object of the present invention is to provide a method for forming a contact plug having a stable contact characteristics, to enhance selectivity and to simplify a process.
According to the present invention there is provided a method for forming a via contact plug using a selective CVI) tungsten, the method comprising the steps of depositing first tungsten on a lower portion of the via contact by performing a high-temperature H, reduction process, and then 4 depositing second tungsten on said first tungsten by performing a low temperature SW4reduction process, to thereby fill the via contact with said first and second tungsten.
In a preferred embodiment the H2reduction process performed at high temperature is a process for reducing contact resistance, by depositing the first tungsten with a thickness below 1,000A on the lower portion of the via contact using CVI) method for 30 120 seconds under the conditions of a WF6flow being 5 1 Osccm, an H2flow being 500 1,000sccm and the temperature being 3504OWC.
Preferably, the SiH4reduction process performed at low temperature is a process for increasing a selectivity of tungsten, by depositing the second tungsten on the first tungsten using CVI) method for 60 300 seconds under the conditions of a W6flow being 2040secm, a SiH4flow being 1020scem, an H2flow being 500 1,000sccm and the temperature being 250 30WC.
For the purpose of suppressing a selectivity loss phenomenon which is produced by an adsorption site generated on a surface of oxide film by depositing selective tungsten, the present invention forms the contact plug using a two-step deposition method. That is, the first tungsten is deposited on a lower portion of via contact by performing a H, reduction process at high temperature (above 350"C), without removing a native oxide formed on the conductive layer. Then, the second tungsten is deposited with a required thickness on the first tungsten by performing a SW4 reduction process at low temperature (below 30WC), thereby to fill the via contact with the first and second tungsten.
According to the present invention, since the tungsten deposition is suppressed on the oxide film wherein the via contact is formed, a short between metal interconnections is prevented, which thereby enhances the reliability of the manufactured semiconductor device.
Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
Figs. 1 is a graphical diagram for illustrating the conventional method for forming a contact plug of semiconductor device; Fig.2 is a SEM photograph showing a planar view of the contact plug formed by the conventional method; Fig.3 and Fig.4 are sectional views for illustrating a method for forming a contact plug of semiconductor device according to an embodiment of the present invention; Fig.5 is a graphical diagram showing a process condition for forming a contact plug of semiconductor device according to an embodiment of the present invention; Fig.6 is a bar graph showing the relationship between a contact resistance and the size of a via contact formed according to the conventional method and an embodiment of the present invention, respectively; and 6 Fig.7 and Fig.8 are SEM photographs showing planar and sectional views of contact plug formed according to an embodiment of the present invention. respectively.
The present invention will be described in more detail, hereinbelow, with reference to the accompanying drawings.
Figs.3 and 4 are sectional views for illustrating a method for forming a contact plug of semiconductor device according to an embodiment of the present invention, and Fig.5 is a graphical diagram showing a process condition for forming the contact plug.
Fig.3 shows the step for forming a via contact (h). An oxide film 12 is formed on a lower conductive layer 10, for example, an aluminum layer formed on a semiconductor substrate (not shown), as a interlayer insulating film. Then, oxide film 12 is partially etched by a photo-etching process, thereby to form the via contact (h) for connecting lower conductive layer 10 with an upper conductive layer which will be formed in the subsequent process.
Fig.4 shows the step for filling the via contact (h) with a first and second tungsten 14 and 16. As shown in Fig.5, for the purpose of forming a contact plug in the via contact (h), a first tungsten 14 is thinly deposited on the contact's lower portion by performing a H, reduction process for 60 seconds under the conditions of a WF6flow of 5sccm, a H. flow of 1,000sccm, and a high temperature (above 350"C). To continue, a second 7 tungsten 16 is deposited with a required thickness on first tungsten 14 by performing a SiH4 reduction process for 270 seconds under the conditions of a WF6flow of 20sccm, a Si114flow of 10sccm, a H. flow of 1,000sccm; and a temperature of 27TC. As a result, the via contact (h) is filled with first and second tungsten 14 and 16, while preventing a selectivity loss phenomenon.
Here, the selectivity loss phenomenon is one in which an adsorption site, which can adsorb the SiH4and WF6 reaction gas, exists on the surface of oxide film, which thereby generates a tungsten site on the oxide film through the adsorption site. In general, as the deposition temperature increases, the selectivity loss is readily observed. Among these, SiF4, SiF, and A1F3 etc.
are known as the above adsorption site, and SiF4 and SiF, are by-products generated by the SW4 reduction process.
Accordingly, for the purpose of suppressing the generation of the above adsorption site, the first tungsten is thinly deposited on the lower portion of the via contact for a short duration and at a high temperature (above 350T) as a first step, by performing an H, reduction process wherein Sil---14is not included within the reaction gases. Then, as a second step, the second tungsten is formed with a required thickness on the first tungsten at a low temperature (below 30OT), by performing the SW4 reduction process wherein a fast deposition speed of the tungsten is provided. Consequently, the via contact is filled by a two-step deposition of s elective tungsten, thereby to form the contact plug.
8 Also, in the low-temperature process of the second step, the tungsten selectivity is enhanced by increasing its deposition speed, which thereby prevents shorts from occurring between the lower conductive layer and the upper conductive layer which will be formed in the subsequent process.
Fig.6 is a bar graph showing the relationship between a contact resistance and the size of the via contact, which are formed according to the conventional method illustrated in the Fig. 1 and an embodiment of the present invention, respectively.
As shown in Fig.6, the contact plug formed according to an embodiment of the present invention has a lower contact resistance, as compared with the conventional method.
Figs.7 and 8 are SEM photographs showing planar and sectional views of contact plug formed according to an embodiment of the present invention, respectively.
is As shown in Figs.7 and 8, the via contact is filled with selective CVD tungsten without diminishing selectivity.
As described above, according to the present invention, the selectivity loss caused by deposition of selective tungsten for forming a via contact plug is prevented. Accordingly, as compared with the conventional method, the low contact resistance, high selectivity, and stable contact plug are obtained, which thereby achieve a reliable semiconductor device.
While the present invention has been particularly shown and described 9 with reference to particular embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be effected therein without departing from the scope of the invention.
Claims (6)
1. A method for forming a contact plug of a semiconductor device by filling a via contact with a selective chemical vapour deposition tungsten, said method comprising the steps of; depositing first tungsten on a lower portion of a via contact by performing H2reduction processing at a temperature which can reduce contact resistance; and depositing second tungsten on said first tungsten by performing SW4 reduction processing at a temperature which can improve the selectivity of tungsten, thereby to fill said via contact with said first and second tungsten.
2. A method for forming a contact plug of a semiconductor device according to claim 1 wherein the first tungsten is deposited at a temperature of at least 350C and the second tungsten is deposited at a temperature equal to or less than 30CC.
3. A method for forming a contact plug of a semiconductor device according to claim 1 or 2 wherein said H, reduction process is performed for 120 seconds under the conditions of a WF6flow of 5 10sccm, an H2 flow of 500 1,000sccm and a temperature of 350 40WC.
4. A method for forming a contact plug of a semiconductor device according to claim 1, 2 or 3, wherein said SW, reduction process is performed for 60300 seconds under the conditions of a WF6 flOW Of 2040sccm, a SiH4flow of 10 20sccm, an H, flow of 500 1,000sccm and a temperature of 25030TC.
5. A method for forming a contact plug of a semiconductor device according to any preceding claim wherein the thickness of said first tungsten is below 1,OOOA.
6. A method for forming a contact plug substantially as herein described with reference to Figures 3 to 5 of the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1019920024628A KR960006436B1 (en) | 1992-12-17 | 1992-12-17 | Manufacturing method of contact plug of semiconductor device |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9325796D0 GB9325796D0 (en) | 1994-02-16 |
| GB2273816A true GB2273816A (en) | 1994-06-29 |
| GB2273816B GB2273816B (en) | 1996-10-23 |
Family
ID=19345895
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9325796A Expired - Lifetime GB2273816B (en) | 1992-12-17 | 1993-12-16 | Method for forming a contact plug of a semiconductor device |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPH06224195A (en) |
| KR (1) | KR960006436B1 (en) |
| CN (1) | CN1042473C (en) |
| DE (1) | DE4342702A1 (en) |
| GB (1) | GB2273816B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6218298B1 (en) * | 1999-05-19 | 2001-04-17 | Infineon Technologies North America Corp. | Tungsten-filled deep trenches |
| CN105839069B (en) * | 2015-01-14 | 2019-03-01 | 中芯国际集成电路制造(上海)有限公司 | A kind of cleaning process for chemical vapor deposition |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0305143A2 (en) * | 1987-08-24 | 1989-03-01 | Fujitsu Limited | Method of selectively forming a conductor layer |
| GB2239661A (en) * | 1989-11-22 | 1991-07-10 | Samsung Electronics Co Ltd | Semiconductor devices provided with two metallic films |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3008223A1 (en) * | 1980-03-04 | 1981-09-10 | Vereinigte Glaswerke Gmbh, 5100 Aachen | HINGED FITTING FOR ALL-GLASS DOORS |
-
1992
- 1992-12-17 KR KR1019920024628A patent/KR960006436B1/en not_active IP Right Cessation
-
1993
- 1993-12-15 DE DE4342702A patent/DE4342702A1/en not_active Withdrawn
- 1993-12-16 GB GB9325796A patent/GB2273816B/en not_active Expired - Lifetime
- 1993-12-17 CN CN93119872A patent/CN1042473C/en not_active Expired - Fee Related
- 1993-12-17 JP JP5344335A patent/JPH06224195A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0305143A2 (en) * | 1987-08-24 | 1989-03-01 | Fujitsu Limited | Method of selectively forming a conductor layer |
| GB2239661A (en) * | 1989-11-22 | 1991-07-10 | Samsung Electronics Co Ltd | Semiconductor devices provided with two metallic films |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH06224195A (en) | 1994-08-12 |
| GB9325796D0 (en) | 1994-02-16 |
| GB2273816B (en) | 1996-10-23 |
| KR940016690A (en) | 1994-07-23 |
| CN1042473C (en) | 1999-03-10 |
| KR960006436B1 (en) | 1996-05-15 |
| CN1091552A (en) | 1994-08-31 |
| DE4342702A1 (en) | 1994-06-23 |
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