JP2005191067A - Semiconductor device and method of managing manufacturing process using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device which can early detect contamination and to provide a method of managing a manufacturing process using the same. <P>SOLUTION: The semiconductor device includes a first film 2 which is considered to be anxious about the generation of minute contamination on a dummy wafer 1, a first insulating film 3 covered in a high step coverage with the minute contamination and displaying an image enlarged and projected on the front surface from the minute contamination, and a first metal film 4 formed to allow the enlarged and projected image to be easily reflected. Thus, the minute contamination is detected by irradiating the laser beam, etc, to the first metal film 4 by a contamination inspecting device 50 in an in-line inspection, thereby detecting the minute contamination, and managing the manufacturing process by this result. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a semiconductor device and a manufacturing process management method using the same, and in particular, a semiconductor device in which a pattern is formed on a semiconductor substrate for inspection and in-line inspection using the semiconductor device, and the process is managed by the number of foreign matters generated. The present invention relates to a technique effective when applied to a manufacturing process management method.

  For example, in a semiconductor device manufacturing process, in-line inspection using a foreign substance inspection apparatus is performed after various film forming processes. This foreign matter inspection apparatus, for example, irradiates the surface of a semiconductor substrate for inspection with a pattern or without a pattern, or a semiconductor substrate that becomes a product with or without a pattern, and detects the scattered light. This detects foreign matter on the surface of the semiconductor substrate.

  By the way, as a result of the study of the technique of the semiconductor device manufacturing process as described above, the following has been clarified.

  For example, in the foreign matter inspection apparatus described in the background art, when the inspection after forming the insulating film is taken as an example, a device having a size of 0.25 μm or more is practically detected as a foreign matter. The size of the foreign matter to be detected is determined by comprehensively judging the detection sensitivity and throughput of the foreign matter inspection apparatus and the size of the foreign matter that can be fatal to the product.

  However, according to the study of the present inventor, even a foreign matter such as 0.1 μm, which is not particularly problematic in a single film, can become a fatal foreign matter while the films are stacked. found. In this case, the stacked film processes are wasted, resulting in a significant loss in manufacturing cost. As a countermeasure, it may be possible to increase the detection sensitivity of the foreign substance inspection apparatus. However, in this case, various problems such as a decrease in throughput as described above, detection of foreign objects more than necessary in some cases, and investment costs are required if the detection sensitivity of the device is insufficient. Will arise. For this reason, there is a demand for a method for early detection of foreign matter as described above without changing the detection sensitivity of the foreign matter inspection apparatus.

  Accordingly, an object of the present invention is to provide a semiconductor device that enables early detection of foreign matter and a manufacturing process management method using the same.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  A semiconductor device according to the present invention includes a first film, a first insulating film formed on the first film, and a first film formed on the first insulating film on a semiconductor substrate for inspection. And a metal film. The first film is a film for detecting foreign matter generated in connection with the film forming process, and the first insulating film is formed when the foreign matter is generated in the first film. It is a film representing an image obtained by enlarging and projecting the foreign matter on the first insulating film by covering the foreign matter with high step coverage, and the first metal film reflects the light and projects the enlarged projection. It is a film that facilitates detection of an image by a foreign matter inspection apparatus.

  Accordingly, for example, when a minute foreign matter is generated in the film forming process of the first film, the minute foreign matter is reliably detected by the foreign matter inspection device by the first insulating film and the first metal film. become able to.

  Here, the first insulating film can be, for example, a TEOS oxide film using a plasma CVD method. This provides high step coverage. In this case, the thickness of the TEOS oxide film is preferably 300 nm to 800 nm. As a result, the image of the minute foreign matter appearing on the TEOS oxide film can be made a size that can be sufficiently detected by the foreign matter inspection apparatus, and the image can be prevented from being flattened. .

  And if such a semiconductor device is manufactured, it is inspected by a foreign substance inspection apparatus, and a manufacturing process management method is constructed so as to determine whether or not a semiconductor substrate as a product can be started by checking the number of occurrences of the foreign substance. Therefore, it is possible to prevent the creation of minute foreign matters in the product and the occurrence of defects due to the occurrence.

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  (1) On a semiconductor substrate for inspection, an insulating film that covers the generated foreign matter with high step coverage and a metal film that reflects light are provided on the insulating film. By conducting a test using a foreign substance inspection apparatus on the semiconductor substrate for inspection, early detection of foreign substances becomes possible.

  (2) According to the above (1), it is possible to prevent the creation of minute foreign matters in the product and the occurrence of defects due to the occurrence.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

  FIG. 1 is a cross-sectional view showing an example of the configuration of a semiconductor device according to an embodiment of the present invention. The semiconductor device shown in FIG. 1 has, for example, a first film 2, a first insulating film 3, and a first metal film 4 on a semiconductor substrate for inspection (hereinafter referred to as a dummy wafer) 1. doing. The first film 2 is a film to be inspected for the generation of foreign matter, and is a film for which a minute foreign matter is concerned in connection with the film forming process and it is desired to detect it. As an example thereof, for example, an SOG (Spin On Glass) film in which a minute foreign matter due to a coating process is a concern, or a TEOS (Tetra-Ethyl-Ortho-Siliconate) in which a minute foreign matter is feared by a CMP (Chemical Mechanical Polishing) process. ) An oxide film, and an oxide film or a polysilicon film in which a minute foreign matter is a concern in a film forming process using a low pressure CVD (Chemical Vapor Deposition) apparatus.

  When there is a minute foreign matter on the first film 2, the first insulating film 3 covers this minute foreign matter on the first insulating film 3 by covering the minute foreign matter with high step coverage. It is a film that magnifies and projects foreign matter. Examples of such a film include a TEOS oxide film using a CVD method, and among them, a TEOS oxide film using a plasma CVD method is preferably used. When the TEOS oxide film is used, the film thickness h1 of the first insulating film 3 is preferably 300 nm to 800 nm as will be described later.

  The first metal film 4 stands out from the enlarged projection image on the first insulating film 3 and sufficiently reflects the incident light from the foreign substance inspection apparatus, so that a minute foreign substance (enlarged projected image) can be obtained. It is a membrane that allows easy detection. Examples of such a film include a TiN (titanium nitride) film, a laminated film of Ti (titanium) -TiN (titanium nitride), and films of various other metal materials.

  By using the semiconductor device having such a configuration, it is possible to detect, for example, a foreign substance as shown in FIG. 2 that may occur on a semiconductor substrate (hereinafter referred to as a product wafer) as a product. FIG. 2 is an example of a device cross-sectional view for explaining the foreign matter detected by the configuration of FIG. 1 in the semiconductor device of one embodiment of the present invention.

  The device shown in FIG. 2 shows an example of a part of a multilayer wiring structure formed on a product wafer (not shown). For example, conductive barrier films 22a and 22b are sandwiched between the insulating film 21 and the device. A metal film (contact plug) 24 for connecting the first-layer metal film to the second-layer metal film, and a contact plug 24. A conductive barrier film 22c that is connected and becomes a part of the second-layer metal film is provided. These metal films are covered with a plurality of insulating films formed on the insulating film 21 in the order of, for example, a TEOS oxide film 25a, an SOG film 26, and a TEOS oxide film 25b.

  The material of the wiring layer 23 is, for example, Al (aluminum), Cu (copper), and the material of the conductive barrier films 22a, 22b, 22c is, for example, TiN (titanium nitride) or Ti (titanium)- For example, a laminated film of TiN (titanium nitride). The TEOS oxide films 25a and 25b are formed by, for example, a plasma CVD method.

  Here, when attention is paid to the coating process for forming the SOG film 26, for example, there is a possibility that a minute foreign material 27 may be adhered during annealing after coating. If the size of the foreign material 27 is 0.2 to 0.3 μm, for example, there is a possibility that it can be detected by a foreign material inspection test after the coating process of the SOG film 26. However, when the size of the foreign matter 27 is very small, for example, 0.1 μm, it is considered difficult to detect by the foreign matter inspection test after the coating process.

  In this case, after the coating process of the SOG film 26, the TEOS oxide film 25b is formed using a plasma CVD method or the like while the minute foreign matter 27 is formed. If the thickness h2 of the TEOS oxide film 25b is assumed to be 300 nm, an image obtained by enlarging and projecting the 0.1 μm foreign matter 27 appears on the TEOS oxide film 25b due to the step coverage of the TEOS oxide film 25b. Since this image has a circular shape with a thickness r of 300 nm (0.3 μm) and a radius r1, the size of this image is about 0.6 μm, which is the diameter w1 of the circle.

  Therefore, if a foreign matter inspection test is performed after the film formation step of the TEOS oxide film 25b, there is a high possibility that the 0.1 μm foreign matter can be detected. However, because the TEOS oxide film 25b does not sufficiently reflect the laser beam from the foreign substance inspection device due to its material, there is a possibility that it cannot be detected. Then, the step of reliably detecting the 0.1 μm foreign matter 27 is performed after the TEOS oxide film 25b deposition process, the contact plug 24 lithography process, the contact plug 24 deposition process, and the conductive barrier film 22c. That is, after the film forming step is performed. Therefore, the process after the generation of the minute foreign matter 27 is wasted, resulting in a great loss in manufacturing cost.

  In addition, when this foreign material is not detected, it is possible that the defect as shown, for example in FIG. 3 generate | occur | produces. FIG. 3 is a diagram for explaining an example of a defect caused by a minute foreign substance in the semiconductor device according to the embodiment of the present invention. FIG. 3A is a top view of the device, and FIG. ) Shows a cross-sectional view of the device between AA 'in (a).

  FIG. 3B is a cross-sectional view after the formation of the second-layer metal film. After the formation of the conductive barrier film 22c in FIG. 2, the second-layer wiring layer 28 and the upper portion thereof are electrically conductive. A conductive barrier film 22d is formed. In FIG. 3B, the etching residue is generated in the conductive barrier film 22c and the second wiring layer 28 due to the minute foreign matter 27. As a result, the second-layer metal films are short-circuited with each other. When this is viewed from the top, it becomes as shown in FIG. 3A, and the second-layer metal films are connected to each other by the metal film remaining after etching.

  In order to prevent such a defect in advance and to prevent a loss of manufacturing cost due to the formation of the defect as described with reference to FIG. 2, it is necessary to detect the minute foreign matter 27 at an early stage. Therefore, when detecting the foreign matter 27 in the SOG film 26 described with reference to FIGS. 2 and 3, the semiconductor device of FIG. 1 is used, and the first film 2 in FIG. For example, the flow shown in FIG. 4 may be performed by using the TEOS oxide film 1 as the TEOS oxide film and the Ti-TiN laminated film as the first metal film 4 as in the device structure of FIG. .

  FIG. 4 is a flowchart showing an example of a manufacturing process management method using the semiconductor device of FIG. 1 in the manufacturing process management method of the semiconductor device according to the embodiment of the present invention. The flow shown in FIG. 4 is performed as follows, for example.

  In S401, a pattern is formed on the dummy wafer. That is, the semiconductor device of FIG. 1 is manufactured. Here, as described above, assuming the case where foreign matter is detected in the SOG film, an SOG film is applied as the first film 2 on the dummy wafer 1, and then the plasma CVD method is used as the first insulating film 3. A TEOS oxide film is formed by, for example, and then a Ti—TiN laminated film is formed as the first metal film 4 by a CVD method or the like. It is assumed that minute foreign matters are generated in the coating process of the SOG film. Then, the process proceeds to S402.

  In S402, a test using a foreign substance inspection device is performed on the semiconductor device (patterned dummy wafer) manufactured in S401. This foreign matter inspection test is performed, for example, as shown in FIG. FIG. 5 is an explanatory view showing an example of a foreign matter inspection test using the semiconductor device of FIG. 1 in the manufacturing process management method of the semiconductor device of one embodiment of the present invention.

  In FIG. 5, the first film (SOG film) 2, the first insulating film (TEOS oxide film) 3, and the first metal film (Ti-TiN laminated film) contain minute foreign matter generated in S401. ) The semiconductor device provided with 4 is irradiated with light such as laser light from the foreign matter inspection device 50. The foreign matter inspection apparatus 50 determines the presence or absence of foreign matter by detecting scattered light with respect to the laser beam or the like by a sensor, and counts the number of foreign matters existing on the semiconductor device.

  Incidentally, in FIG. 5, when the thickness of the TEOS oxide film 3 is about 300 nm, as described in FIG. 2, a 0.1 μm foreign matter is enlarged and projected to about 0.6 μm on the Ti—TiN laminated film. Therefore, it can be reliably detected by the foreign substance inspection device 50. However, when the film thickness of the TEOS oxide film 3 exceeds 800 nm, the image projected on the Ti—TiN laminated film is flattened on the contrary, and may be difficult to detect. is there. Therefore, the thickness of the TEOS oxide film is desirably 300 nm to 800 nm. Then, the process proceeds to S403.

  In S403, the number of foreign matters on the semiconductor device detected in S402 is determined. If the number of foreign objects is equal to or less than the management value, the process proceeds to S404, and if it exceeds the management value, the process proceeds to S405.

  In S404, assuming that there is no problem in the SOG film coating process, the SOG film coating process is started on the product wafer.

  In S405, since there is a problem with the coating process of the SOG film, the construction of the coating process of the SOG film on the product wafer is suspended and a detailed investigation of the coating process is performed.

  In the above description, the foreign matter due to the coating process of the SOG film has been described as an example. However, the present invention is of course not limited to this. For example, an oxide film or a polysilicon film using a CMP process or a low pressure CVD apparatus is used. It is possible to detect minute foreign matters in the film forming process such as.

  That is, for example, in the CMP process for the TEOS oxide film, there is a concern about residual slurry due to insufficient cleaning or the like. Therefore, first, the semiconductor device of FIG. 1 is manufactured according to the flow of FIG. That is, a TEOS oxide film is formed on the dummy wafer 1 by a plasma CVD method or the like, this TEOS oxide film is polished and washed by a CMP process, and a TEOS oxide film is formed thereon with a film thickness of 300 nm to 800 nm. Then, a metal film such as a TiN film is formed. Then, a foreign substance inspection test may be performed on the semiconductor device to determine whether or not to start a product wafer.

  Further, for example, in the oxide film forming process using a low-pressure CVD apparatus, the generation of minute foreign matters in the process and the generation of etching residue in the subsequent etching process can cause problems. Therefore, first, the semiconductor device of FIG. 1 is manufactured according to the flow of FIG. That is, an oxide film is formed on the dummy wafer 1 by using a low pressure CVD apparatus, the oxide film is etched, a TEOS oxide film is formed with a film thickness of 300 nm to 800 nm, and then a metal film such as a TiN film is formed. Is deposited. Then, a foreign substance inspection test may be performed on the semiconductor device to determine whether or not to start a product wafer.

  As described above, by using the semiconductor device as shown in FIG. 1 and managing the manufacturing process as shown in FIG. 4, a minute foreign object is detected at an early stage before the production wafer is started. It becomes possible to do. As a result, it is possible to prevent defects such as those described with reference to FIG. 3 and prevent the start of useless processes as described with reference to FIG.

  In addition, such a technology is considered to become increasingly important as product miniaturization progresses. In other words, as the product is further miniaturized, the occurrence of defects due to finer foreign matter becomes a problem. However, if this fine foreign matter is directly detected by the foreign matter inspection device, the problem is as described above. In addition, a decrease in throughput and the cost of the inspection apparatus become problems. In addition, how much a minute foreign matter affects the film deposition depends on the structure of the deposited film and the manufacturing conditions. For this reason, when detecting directly with a foreign material inspection apparatus, it cannot be said that it is easy to determine what size is regarded as a foreign material.

  On the other hand, when the semiconductor device as shown in FIG. 1 is used and the manufacturing process management as shown in FIG. 4 is performed as in the present invention, a high-performance foreign matter inspection device is unnecessary and can be realized at low cost. Further, since the influence can be determined after the film is actually deposited as in the case of the product, a more reliable foreign object can be detected.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  For example, when it is desired to see the generation of foreign matter due to an etching process or a lithography process, it can be similarly evaluated by reflecting it on the first film 2 of the semiconductor device of FIG.

  The semiconductor device and the manufacturing process management method using the semiconductor device of the present invention can be applied as a manufacturing process management method to general semiconductor products such as memory products and system LSIs in which minute foreign matters are particularly problematic. Furthermore, the present invention is not limited to semiconductor products, but can also be applied as a manufacturing process management method for products made by laminating films such as magnetic film products, hard disks, and compact disks.

In the semiconductor device of one embodiment of this invention, it is sectional drawing which shows an example of the structure. FIG. 2 is an example of a device cross-sectional view for explaining the foreign matter detected by the configuration of FIG. 1 in the semiconductor device of one embodiment of the present invention. In the semiconductor device of one embodiment of the present invention, it is a diagram for explaining an example of a defect caused by a minute foreign matter, (a) is a device top view, (b) is ( The device sectional view between AA 'of a) is shown. FIG. 2 is a flowchart showing an example of a manufacturing process management method using the semiconductor device of FIG. 1 in the manufacturing process management method of the semiconductor device according to the embodiment of the present invention. FIG. 3 is an explanatory diagram showing an example of a foreign matter inspection test using the semiconductor device of FIG. 1 in the semiconductor device manufacturing process management method according to the embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dummy wafer 2 1st film | membrane 3 1st insulating film 4 1st metal film 21 Insulating film 22a, 22b, 22c, 22d Conductive barrier film 23, 28 Wiring layer 24 Contact plug 25a, 25b TEOS oxide film 26 SOG film 27 Foreign matter 50 Foreign matter inspection device

Claims (5)

A semiconductor device having a first film, a first insulating film formed on the first film, and a first metal film formed on the first insulating film on a semiconductor substrate for inspection Because
The first film is a film for detecting foreign matter generated in connection with the film forming process,
The first insulating film represents an image obtained by enlarging and projecting the foreign matter on the first insulating film by covering the foreign matter with high step coverage when the foreign matter is generated in the first film. A membrane,
The semiconductor device according to claim 1, wherein the first metal film is a film that reflects light so that the enlarged projected image can be easily detected by a foreign substance inspection apparatus. The semiconductor device according to claim 1,
The semiconductor device according to claim 1, wherein the first insulating film is a TEOS oxide film using a plasma CVD method. The semiconductor device according to claim 2,
The semiconductor device is characterized in that the thickness of the first insulating film is 300 nm to 800 nm. The semiconductor device according to claim 1,
The size of the foreign matter is 0.1 μm or less. A manufacturing process management method using the semiconductor device according to claim 1,
Manufacturing the semiconductor device;
Inspecting the manufactured semiconductor device using a foreign matter inspection device, obtaining the number of foreign matters generated,
And a step of judging whether or not to start a semiconductor substrate as a product by comparing the number of generated foreign substances with a predetermined management value.

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