TWI629719B - Multi-stage cleaning method for susceptor - Google Patents

Abstract

A multi-stage method for removing a substrate for removing residual substances comprising ruthenium and osmium on a substrate, comprising applying a first stage cleaning step to the substrate, wherein the first operating temperature employed is lower than the melting point of ruthenium, Remove cockroaches. A second stage cleaning step is applied to the substrate wherein a second operating temperature is employed that is above the melting point of the crucible to substantially remove the antimony material.

Description

Multi-stage method for removing substrate

This invention relates to a semiconductor fabrication technique, and more particularly to a method of multi-stage removal of a substrate that can be used to remove residual materials comprising ruthenium and ruthenium on a substrate.

Due to the development of semiconductor manufacturing technology, the manufacture of semiconductor electronic components has not been limited to the use of germanium materials, and germanium materials have also been combined with germanium materials to design the structure of semiconductor components.

For a fabrication process comprising a germanium material and a germanium material, it is generally desirable to form a germanium/germanium (SiGe) thin film layer on the germanium wafer. Instead, a thin film layer is formed on the germanium wafer by depositing a thin film layer on the substrate. Then, after the wafer is placed on the ruthenium film layer, a layer of ruthenium/ruthenium film is deposited. Thereafter, after removing the ruthenium wafer, the substrate can be recycled and reused after removing the ruthenium/ruthenium residue. The substrate is generally a graphite (SiC) substrate.

For graphite substrates used in ruthenium/niobium deposition, in the cleaning process to remove ruthenium/ruthenium residues to enable reuse of the substrate, the conventional approach is in the purge chamber. In the middle, the removal is performed at a high temperature, for example, an operating temperature of 1140 °C. However, this conventional approach at least causes gradual damage to the graphite substrate, thus reducing the useful life of the graphite substrate.

The following is a discussion of the conventional method of removing the substrate from the present invention, which causes damage to the graphite substrate. 1A-1G are schematic cross-sectional views showing the flow of a conventional substrate removal process.

Referring to FIG. 1A, a tantalum film layer 102 is first deposited on a substrate 100. Next, the wafer 104 is placed on the tantalum film layer 102. The size of the germanium wafer 104 may be smaller than the size of the substrate 100, so that a portion of the germanium film layer 102 may be exposed around the wafer 104. Referring to FIG. 1B, a ruthenium/iridium film layer 106 is then deposited on the exposed surface of the ruthenium film layer 102 and the exposed surface of the wafer 104. Referring to FIG. 1C, the wafer 104 covered with the ruthenium/iridium film layer 106 is removed from the substrate 100 for subsequent fabrication. The substrate 100 needs to remove the ruthenium film layer 102 and the residual ruthenium/ruthenium film layer 106, so that the substrate 100 can be reused.

The following is a description of the traditional way to remove 矽/锗 residues. Referring to Fig. 1D, the step of removing the 矽/锗 residual material is carried out in a clean room, and 矽/锗 is etched away by HCl. The operating temperature of the clean room is, for example, approximately 1140 °C. This temperature is above the melting point temperature of hydrazine, but below the melting point temperature of hydrazine. The melting point temperature of hydrazine is 938 ° C, and the melting point temperature of hydrazine is 1414 ° C. The ruthenium/ruthenium residue is removed at a high temperature, and in the initial process, the ruthenium material, including the ruthenium film layer 102, is initially removed by HCl etching, and the ruthenium material in the ruthenium/ruthenium film layer 106 is also melted at the same time. At least a portion of the ruthenium material that is melted will seep into the substrate 100 as indicated by the arrows.

Referring to FIG. 1E, the ruthenium which infiltrates into the substrate 100 then chemically reacts with the surface of the substrate 100 and the substrate 100 of graphite (SiC) to produce two substances of GeSi and C, wherein GeSi is also etched under HCl. It will react with HCl to produce substances such as SiCl ₂ , Ge, H _{2 ,} etc., in which SiCl ₂ and H ₂ will be removed. Therefore, the intermediately generated C and 锗106' remain in the surface layer of the substrate 100 of graphite, which surrounds the periphery of the wafer 104. Here, the size of C and 锗 106 ′ shown is only a schematic diagram indicating that it will be produced on the surface layer of the substrate 100 .

Referring to FIG. 1F, in the next process in which HCl removes the ruthenium/ruthenium residue, the ruthenium 106' in the surface layer of the substrate 100 continues to be etched and removed by reaction with HCl, while the C on the surface layer of the substrate 100 remains. The surface layer of the substrate 100.

Referring to Figure 1G, since H ₂ is naturally generated during the reaction with HCl, the residual C will be reacted with H ₂ to form a hydrocarbon and removed. Here, since the residual C and the crucible 106' are a part of the substrate 100 originally belonging to graphite, which is produced by the reaction conversion, when the residual C and the crucible 106' in the substrate 100 are removed, A recess is left on the substrate 100. Therefore, each cleaning process slightly damages the substrate 100, causing the substrate 100 to be reused several times, for example, resulting in uneven thickness, and can no longer be used.

The present invention has been made in view of the conventional manner of removing ruthenium/ruthenium remaining on a substrate, and has found that at least a cavity is formed to damage the substrate. How to avoid the generation of pits and prolong the service life of the substrate 100 is one of the subjects to be considered in research and development.

The present invention provides a multi-stage method of removing a substrate for removing residual materials comprising ruthenium and osmium on a substrate, which can reduce damage to the substrate during removal of ruthenium/ruthenium residues on the substrate.

A multi-stage method for removing a substrate of the present invention for removing residual substances containing ruthenium and osmium on a substrate. The method of removing the substrate includes applying a first stage cleaning step to the substrate, wherein the first operating temperature employed is below the melting point of the crucible to substantially remove the germanium material. Further, a second stage cleaning step is applied to the substrate wherein the second operating temperature employed is above the melting point of the crucible to substantially remove the antimony material.

In an embodiment of the invention, in the method of removing the substrate in the multi-stage, the first operating temperature is between 700 ° C and 800 ° C, and the second operating temperature is used to remove the germanium material.

In an embodiment of the present invention, in the multi-stage method for removing a substrate, the first operating temperature is 700 ° C to 800 ° C, and the second operating temperature is for removing the germanium substance, and the first and the first The two-stage purge step is a HCl purge process.

In an embodiment of the invention, in the method of removing the substrate in the multi-stage, the second operating temperature is 1000 ° C or higher and is below the melting point of the crucible.

In an embodiment of the invention, in the multi-stage method of removing a substrate, the substrate is graphite, and the ruthenium material and the ruthenium material are stacked on the substrate.

A multi-stage method for removing a substrate of the present invention is for removing a residual substance comprising a first substance and a second substance on a substrate, the first substance having a melting point lower than a melting point of the second substance. The method of removing a substrate includes applying a first stage cleaning step to the A substrate, wherein the first operating temperature employed is lower than the melting point of the first material to substantially remove the first material. Further, a second stage cleaning step is applied to the substrate wherein a second operating temperature is employed that is higher than the melting point of the first material to substantially remove the second material.

In an embodiment of the invention, in the method of removing the substrate in the multi-stage, the first substance is ruthenium, the second substance is ruthenium, and the substrate is graphite.

In an embodiment of the invention, in the multi-stage method of removing a substrate, the ruthenium material and the ruthenium material are stacked on the substrate.

In an embodiment of the present invention, in the multi-stage method for removing a substrate, the first operating temperature is 700 ° C to 800 ° C, and the second operating temperature is for removing the germanium substance, and the first and the first The two-stage purge step is a HCl purge process.

In an embodiment of the invention, in the method of removing the substrate in the multi-stage, the second operating temperature is 1000 ° C or higher.

In an embodiment of the present invention, in the multi-stage method of removing a substrate, the first stage cleaning step is to substantially only remove the first substance at the first operating temperature, and the second stage cleaning step is At the second operating temperature, the second substance is removed.

In an embodiment of the present invention, in the method of multi-stage cleaning of a substrate, wherein the second substance and the first substance are stacked on the substrate, wherein if the first substance remains in the second operation At the temperature, it will be melted and penetrated to the substrate.

In an embodiment of the present invention, in the multi-stage method of removing a substrate, the first and second stage cleaning steps are in addition to the first operating temperature and the second operating temperature The difference in degrees is the same cleaning process.

The multi-stage method for removing the substrate of the present invention adopts a multi-stage cleaning step, while maintaining a lower operating temperature in the first stage, does not cause the enthalpy to melt, but substantially removes the cerium material first, thereby effectively avoiding A recess is left on the substrate.

The above described features and advantages of the invention will be apparent from the following description.

100,200‧‧‧Substrate

102, 202‧‧‧矽 film layer

104, 204‧‧‧ wafer

106, 206‧‧‧矽/锗 film layer

106’‧‧‧锗

1A-1G are schematic cross-sectional views showing the flow of a conventional substrate removal.

2A-2F are schematic cross-sectional views showing a flow of removing a substrate according to an embodiment of the invention.

The present invention provides a multi-stage method of removing a substrate for removing residual materials containing ruthenium and osmium on a substrate. The invention is illustrated by the following examples, but the invention is not limited to the examples.

2A-2F are schematic cross-sectional views showing a flow of removing a substrate according to an embodiment of the invention.

Referring to FIG. 2A on the wafer, a tantalum film layer 202 is deposited on the substrate 200. Next, the wafer 204 is placed on the tantalum film layer 202. The size of the germanium wafer 204 will be smaller than the size of the substrate 200, so at the periphery of the wafer 204, a portion The divided tantalum film layer 202 is exposed. Referring to FIG. 2B, a tantalum/iridium film layer 206 is then deposited on the exposed surface of the tantalum film layer 202 and the exposed surface of the wafer 204. This ruthenium/iridium film layer 206 is a ruthenium/ruthenium film layer containing a high concentration of Ge, however, a film layer which is only ruthenium is not excluded. That is, the ruthenium/iridium film layer 206 represents a considerable amount of Ge component. Since Ge is damaged by reaction with a substrate in a conventional cleaning mode, the present invention can effectively prevent Ge from reacting with a substrate in a multi-stage cleaning process, as will be described later. Referring to Figure 2C, the wafer 204 covered with the ruthenium/iridium film layer 206 is removed from the substrate 200 for subsequent fabrication. The substrate 200 requires the ruthenium film layer 202 and the residual ruthenium/ruthenium film layer 206 to be removed, so that the substrate 200 can be reused.

The following is a description of the manner in which the present invention removes residual hydrazine/hydrazine. Referring to Fig. 2D, the ruthenium/iridium material which removes the ruthenium film layer 202 and the ruthenium/iridium film layer 206 is carried out in a clean room in which ruthenium/iridium is etched away using HCl. In the first stage cleaning step of the present invention, the temperature of the clean room is at a first operating temperature, for example, about 750 °C. Here, the melting point temperature of hydrazine is 938 ° C, and the melting point temperature of hydrazine is 1414 ° C. The range of the first operating temperature needs to be below the melting point temperature of the crucible, without causing melting of the crucible, while still maintaining an effective etching rate for the crucible. The range of the first operating temperature is, for example, 700 ° C to 800 ° C. In this first stage, the ruthenium/iridium film layer 206 is gradually removed. The cerium material remains in the solid state and does not penetrate the substrate 200. That is, the cleaning step at the first operating temperature, due to the lower operating temperature, is essentially only the etching of the germanium, and no or only a trace of the germanium material is etched. In the first stage of the cleaning step, since the germanium remains in the solid state, and the germanium substance is not substantially etched, the germanium does not penetrate into the substrate 200 and react with the SiC, and can effectively avoid leaving the surface of the substrate as in the conventional manner. Undercut phenomenon.

Referring to FIG. 2E, after the first stage cleaning step at the first operating temperature of FIG. 2D substantially removes the enthalpy, the transition to the second stage cleaning step begins, and the first operating temperature is maintained under the mechanism of maintaining the HCl scavenger. Warm up to the second operating temperature. The second operating temperature is above the melting point temperature of the crucible, for example, as conventionally at about 1140 ° C, and for example above 1000 ° C. However, based on the cost-effective considerations of the operating temperature, it is generally possible to maintain the temperature at which the crucible does not melt. The second stage cleaning step also effectively removes the tantalum film layer 202 to obtain the cleaned substrate 200. The surface layer of the substrate 200 does not have an intermediate reactant such as carbon (C) remaining in the substrate 200, and thus does not leave a void in the surface layer of the substrate 200.

Experiments have confirmed that the multi-stage method for removing the substrate of the present invention can effectively prevent the substrate from being surrounded by the wafer, and is destroyed by removing the residue, that is, the thickness of the substrate can be maintained.

Referring to FIG. 2F, the substrate 200 after the material residue is removed can be reused, and then the substrate 200 can be further formed into a subsequent process such as the ruthenium film layer 202. Since the surface layer of the substrate 200 is not damaged by leaving a recess, the long life of the substrate 200 can be maintained.

The invention is not limited to the method of two-stage removal of the substrate, but can be used for the multi-stage method of removing the substrate, and comprises at least two stages, and the residual substance to be removed on the substrate comprises Ge and a substance having a higher melting point than Ge. Ge is purged using a low temperature first stage purge step, and a second stage purge step is applied to remove other residual species.

For further extended applications, the invention is not limited to the removal of Si/Ge. Ge and Si can be regarded as a first substance and a second substance, and the melting point of the first substance is lower than the melting point of the second substance. Therefore, the operating temperature of the first step is lower than the melting point of the first substance, and the operating temperature of the second step is higher than the melting point of the first substance.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

Claims (13)

A multi-stage method for removing a substrate for removing residual materials comprising ruthenium and osmium on a substrate, comprising: applying a first stage cleaning step to the substrate, wherein the first operating temperature employed is lower than the melting point of ruthenium, Substantially removing the ruthenium material; and applying a second stage removal step to the substrate wherein the second operating temperature employed is above the melting point of ruthenium to substantially remove the ruthenium species. The method of multi-stage cleaning of a substrate according to claim 1, wherein the first operating temperature is between 700 ° C and 800 ° C, and the second operating temperature is used to remove the antimony material. The method of multi-stage cleaning of a substrate according to claim 1, wherein the first operating temperature is 700 ° C to 800 ° C, and the second operating temperature is for removing the cerium material, and the first and the first The two-stage purge step is a HCl purge process. The method of multi-stage cleaning of a substrate according to claim 3, wherein the second operating temperature is 1000 ° C or higher. The method of multi-stage cleaning of a substrate according to claim 1, wherein the substrate is graphite, and the ruthenium material and the ruthenium material are stacked on the substrate. A multi-stage method for removing a substrate for removing a residual substance comprising a first substance and a second substance on a substrate, the first substance having a melting point lower than a melting point of the second substance, comprising: applying a first stage of removal Stepping on the substrate, wherein a first operating temperature employed is lower than a melting point of the first substance to substantially remove the first substance; A second stage cleaning step is applied to the substrate, wherein a second operating temperature is employed that is higher than the melting point of the first material to substantially remove the second material. The method of multistage cleaning of a substrate according to claim 6, wherein the first substance is cerium, the second substance is cerium, and the substrate is graphite. The method of multi-stage cleaning of a substrate according to claim 7, wherein the bismuth substance and the bismuth substance are stacked on the substrate. The method of multi-stage cleaning of a substrate according to claim 8, wherein the first operating temperature is 700 ° C to 800 ° C, the second operating temperature is for removing the cerium material, and the first and the first The two-stage purge step is a HCl purge process. The method of multi-stage cleaning of a substrate according to claim 9, wherein the second operating temperature is 1000 ° C or higher. The method of multi-stage cleaning of a substrate according to claim 6, wherein the first stage cleaning step is to substantially only remove the first substance at the first operating temperature, and the second stage cleaning step is At the second operating temperature, the second substance is removed. The method of multi-stage cleaning of a substrate according to claim 11, wherein the second substance and the first substance are stacked on the substrate, wherein if the first substance remains at the second operating temperature Next, it will be melted and infiltrated into the substrate. The method of multi-stage cleaning of a substrate according to claim 11, wherein the first and second stage cleaning steps are the same cleaning process except for the difference between the first operating temperature and the second operating temperature.