Abstract:
Disclosed herein are a semiconductor device capable of avoiding an increase in pattern ratio and allowing wiring dummy patterns to improve global steps developed by CMP upon insertion of the dummy patterns different from an actual wiring pattern. The semiconductor device has a configuration wherein a gate wiring pattern is formed on a semiconductor substrate, a plurality of dummy patterns are provided therearound, and a BPSG oxide film flattened by CMP is formed on the gate wiring pattern and the dummy patterns as an interlayer insulating film. In the semiconductor device, the dummy patterns are formed so as to include pattern non-forming regions such as slits.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a semiconductor device wherein dummy patterns are formed on a semiconductor substrate together with a wiring pattern, and a method of manufacturing the semiconductor device.  
         [0003]     2. Description of the Related Art  
         [0004]     In an interlayer film CMP (Chemical mechanical polishing) process, batch polishing has heretofore been performed to reach an intended or target remaining film thickness set value. When, at this time, a polishing pad brought into contact with the surface of a wafer is elastically deformed due to pressure from an underlying step at a polishing initial stage, the pressure applied from the polishing pad increases when a pattern density is low, whereas the pressure applied from the polishing pad is dispersed and becomes low when the pattern density is high, thus causing a difference in polishing rate between wiring pattern loose and dense portions.  
         [0005]     Thus, the remaining film thickness differences (hereinafter might be called “global steps”) occur among the wiring pattern loose and dense portions after polishing. Each of the global steps consists of a difference in film thickness at the loosest portion and the densest portion of the underlying wiring pattern. The global steps are different from one another according to a wiring layout. Therefore, when the global step is large in the interlayer film CMP process, the underlying wiring pattern is exposed or disappears at the loose portion of the underlying wiring pattern, and the residual step occurs due to cutting insufficiency at the dense portion thereof.  
         [0006]     When such exposure, disappearance and residual steps of the underlying wiring pattern occur, no wiring is formed upon forming each wiring in a subsequent process, thus causing degradation in yield and reliability.  
         [0007]     Therefore, dummy patterns (pseudo dummy patterns) different from an actual wiring pattern are inserted into the entire surface of a Chip to set the global steps as low as possible (refer to, for example, a patent document: Japanese Unexamined Patent Publication No. 2003-140319). The global steps vary depending on whether the dummy patterns exist. The insertion of the dummy patterns provides an improvement in global step.  
         [0008]     However, a disadvantage occurs in that when the dummy patterns are inserted, a pattern ratio (pattern proportion) of a mask becomes too large to carry out an end point detector (EPD) upon etching at the formation of a wiring pattern. Therefore, there is a demand for suppressing the insertion of the dummy patterns as low as practicable to thereby reduce the global steps.  
         [0009]     While the dummy patterns may preferably be inserted to improve the global steps in this way, a disadvantage occurs in that when the pattern ratio become excessively large, EPD cannot be detected upon etching of the wiring pattern.  
       SUMMARY OF THE INVENTION  
       [0010]     With the foregoing problems in view, the present invention therefore provides a semiconductor device capable of avoiding an increase in pattern ratio and allowing wiring dummy patterns to improve global steps developed by CMP upon insertion of the dummy patterns different from an actual wiring pattern, and a method of manufacturing the semiconductor device.  
         [0011]     The above problems are solved by the following means:  
         [0012]     A semiconductor device of the present invention comprises a wiring pattern and a plurality of dummy patterns different from the wiring pattern, and an insulating film formed on the wiring pattern and the dummy patterns by a chemical vapor deposition method, wherein the dummy patterns are provided with pattern non-forming regions each having a width filled by plus sizing of the insulating film upon formation of the insulating film.  
         [0013]     The pattern non-forming regions of the dummy patterns-may be formed in stripe form or may be-formed in character or graphical form.  
         [0014]     In the semiconductor device of the present invention, the pattern non-forming regions of the dummy patterns may preferably be shaped in character or graphical forms different every dummy patterns.  
         [0015]     In the semiconductor device of the present invention, the dummy patterns may preferably be square. Also the dummy patterns may preferably be arranged in lattice form.  
         [0016]     On the other hand, a method of manufacturing a semiconductor device, according to the present invention comprises the following steps of:  
         [0017]     forming a wiring pattern;  
         [0018]     forming a plurality of dummy patterns different from the wiring pattern together with the wiring pattern; and  
         [0019]     forming an insulating film on the wiring pattern and the dummy patterns by a chemical vapor deposition method,  
         [0020]     wherein in the dummy pattern forming step, the dummy patterns are formed so as to be provided with pattern non-forming regions each having a width filled by plus sizing of the insulating film upon formation of the insulating film.  
         [0021]     In the dummy pattern forming step, the pattern non-forming regions of the dummy patterns may be formed in stripe form or may be formed in character or graphical form.  
         [0022]     In the dummy pattern forming step, the pattern non-forming regions of the dummy patterns may preferably be shaped in character or graphical forms different every dummy patterns.  
         [0023]     In the dummy pattern forming step, the dummy patterns may be shaped in square form. Also the dummy patterns may be arranged and formed in lattice form.  
         [0024]     In the present invention, dummy patterns formed together with a wiring pattern are respectively provided with pattern non-forming regions each having a predetermined width. The predetermined width of the pattern non-forming region is defined as a width filled with an insulating film by plus sizing of the insulating film upon formation of the insulating film. Then the insulating film is formed on the wiring pattern and the dummy patterns.  
         [0025]     Here, the plus sizing of the insulating film is to deposit an insulating film material not only on a pattern upper surface but also on pattern sidewalls upon vapor phase growth of the insulating film and increase the size of each pattern at a predetermined rate. The width of each of the pattern non-forming regions of the dummy patterns is equivalent to the shortest distance between the pattern sidewalls at individual points lying in the pattern non-forming regions.  
         [0026]     Therefore, since the pattern non-forming regions are filled with the insulating film material deposited on the pattern sidewalls upon vapor phase growth of the insulating film, the coverage of the insulating film remains unchanged at dummy patterns (conventional dummy patterns) provided with no pattern non-forming regions and the dummy patterns provided with the pattern non-forming regions.  
         [0027]     When the formed insulating film is planarized, global steps equivalent to ones obtained when the dummy patters provided with no pattern non-forming regions are provided, can be obtained while reducing a pattern ratio by the provision of the pattern non-forming regions at the dummy patterns.  
         [0028]     According to the semiconductor device of the present invention and its manufacturing method, an advantageous effect is brought about in that upon insertion of dummy patterns different from an actual wiring pattern, a pattern ratio can be prevented from increasing, and the wiring dummy patterns enable an improvement in global step of CMP. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0029]     While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention, it is believed that the invention, the objects and features of the invention and further objects, features and advantages thereof will be better understood from the following description taken in connection with the accompanying drawings in which:  
         [0030]      FIG. 1  is a partly plan view (A) and a partly sectional view (B) showing a semiconductor device according to a first embodiment of the present invention;  
         [0031]      FIG. 2  is a process view illustrating a method of manufacturing the semiconductor device according to the first embodiment of the present invention;  
         [0032]      FIG. 3  is a partly plan view (A) and a partly sectional view (B) showing a semiconductor device according to a second embodiment of the present invention;  
         [0033]      FIG. 4  is a partly plan view (A) and a partly sectional view-(B) illustrating a semiconductor device according to a third embodiment of the present invention; and  
         [0034]      FIG. 5  is a partly plan view (A) and a partly sectional view (B) depicting a semiconductor device according to a fourth embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0035]     The present invention will be described hereinbelow with reference to the accompanying drawings. Incidentally, structural components each substantially having the same function will be explained with the same reference numerals given thereto through all the drawings.  
         [0000]     &lt;First Embodiment&gt; 
         [0036]      FIG. 1  is a partially plan view (A) and a partially sectional view (B) showing a semiconductor device according to a first embodiment of the present invention.  FIG. 2  is a process view showing a method of manufacturing the semiconductor device according to the first embodiment of the present invention.  
         [0037]     In the semiconductor device according to the present embodiment, as shown in  FIG. 1 (A), a gate wiring pattern  12  (wiring pattern) is formed on a semiconductor substrate  10 , and a plurality of dummy patterns  14  are formed therearound. As shown in  FIG. 1 (B), a BPSG (Boro Phospho Silicate Glass) oxide film  16  (insulating film) planarized by CMP is formed on the gate wiring pattern  12  and the dummy patterns  14  as an interlayer insulating film. Here,  FIG. 1 (B) is a sectional view taken along line B-B in  FIG. 1 (A).  
         [0038]     In the dummy patterns  14 , stripe-like slits  14   b  (pattern forming regions) are provided among a plurality of linear patterns  14   a.    
         [0039]     The width of each of the slits  14   b  provided at the dummy patterns  14  is set as such a width that the slit  14   b  is filled by plus sizing of each dummy pattern upon formation of the interlayer insulating film. Described specifically, the width filled by plus sizing is 72 μm or less, for example.  
         [0040]     A method of manufacturing the semiconductor device according to the present embodiment will next be described.  
         [0041]     First, a plurality of dummy patterns  14  are formed on a semiconductor substrate  10  together with a gate wiring pattern  12  by using a gate electrode forming mask (see  FIG. 2 (A)).  
         [0042]     Next, a BPSG oxide film  16  is formed on the gate wiring pattern  12  and the dummy patterns  14  by a chemical vapor deposition method. Since plus sizing of the dummy patterns firstly occurs at this time, a constituent material used for a BPSG oxide film  16  is deposited from the side surfaces of linear patterns  14   a  so that slits  14   b  of the dummy patterns  14  are filled (see  FIG. 2 (B)). Thereafter, a BPSG oxide film  16  is formed (see  FIG. 2 (C)).  
         [0043]     Afterwards, the surface of the BPSG oxide film  16  is smoothed by CMP (see  FIG. 2 (D)). The semiconductor device is fabricated in this way.  
         [0044]     In the present embodiment as described above, the dummy patterns  14  are provided with the slits  14   b  each having a predetermined width, and the slits  14   b  are filled by dummy pattern plus sizing upon vapor phase growth of the BPSG oxide film  16 . Therefore, the BPSG oxide film  16  is formed at the coverage no different from dummy patterns  14  (conventional dummy patterns) with no slits  14   b.    
         [0045]     Therefore, when the BPSG oxide film  16  is planarized, global steps equivalent to ones obtained when the conventional dummy patters are provided, can be obtained while reducing a pattern ratio by the provision of the slits  14   b  at the dummy patterns  14 .  
         [0046]     Since the dummy patterns  14  are arranged in lattice form in the present embodiment, the interval between lattices is varied to make it possible to easily optimize the pattern ratio. It is thus possible to suppress an increase in global step more effectively.  
         [0000]     &lt;Second Embodiment&gt; 
         [0047]      FIG. 3  is a partially plan view (A) and a partially sectional view (B) showing a semiconductor device according to a second embodiment of the present invention.  
         [0048]     As shown in  FIG. 3 , the present embodiment takes a form in which arbitrary graphical (“square” in the present embodiment) openings  14   c  (pattern non-forming regions) are respectively provided at the centers of square dummy patterns  14 . Here,  FIG. 3 (B) is a sectional view taken along line B-B in  FIG. 1 (A). Since elements of structure other than the above are similar to those employed in the first embodiment, the description thereof will be omitted.  
         [0049]     The first embodiment has explained the form in which the plurality of linear patterns  14   a  have built up the dummy patterns  14  (the dummy patterns  14  provided with the slits  14   b ) arranged at the predetermined intervals. Since, however, the dummy patterns are constituted of the plurality of linear patterns  14   a  in this case, the number of graphic forms increases and hence the dummy patterns  14  (linear patterns  14   a ) are inserted in large numbers. As a result, a problem arises in that since the number of graphic forms increases as compared with the capacity of a design data file (GDS2 data) at the insertion of mere square dummy patterns (dummy patterns  14  with no slits  14   b ), data capacity is inevitable and its practical handing is inconvenient.  
         [0050]     Thus, the square dummy patterns  14  provided with the arbitrary graphical openings  14   c  at their centers are formed to thereby suppress an increase in the number of graphical forms in the present embodiment. The width of the opening  14   c  is similar to the width of the slit  14   b  employed in the first embodiment. Also the form of the opening  14   c  is not limited to the square but can be configured as an arbitrary graphical form.  
         [0051]     Therefore, the present embodiment is capable of obtaining a global step equivalent to one obtained where the conventional dummy patterns are provided, while reducing the pattern ratio by the provision of the opening  14   c  at each dummy pattern  14 , in, a manner similar to the first embodiment. Further, the present embodiment is capable of reducing the design data file capacity (GDS2 data) and improving its practical handling.  
         [0000]     &lt;Third Embodiment&gt; 
         [0052]      FIG. 4  is a partially plan view (A) and a partially sectional view (B) showing a semiconductor device according to a third embodiment of the present invention.  
         [0053]     The present embodiment takes a form in which arbitrary character-shaped (“A” in the present embodiment) openings  14   c  (pattern non-forming regions) are respectively provided at the centers of square dummy patterns  14  as shown in  FIG. 4 . Here,  FIG. 4 (B) is a sectional view taken along line B-B in  FIG. 1 (A). Since elements of structure other than the above are similar to those employed in the second embodiment, the description thereof will be omitted.  
         [0054]     In the present embodiment, the gate wiring pattern  12  and the dummy patterns  14  can be easily identified since the shapes of the openings  14   c  are represented in arbitrary character form.  
         [0000]     &lt;Fourth Embodiment&gt; 
         [0055]      FIG. 5  is a partly sectional view showing a semiconductor device according to a fourth embodiment of the present invention.  
         [0056]     The present embodiment takes a form in which square dummy patterns  14  are respectively provided with arbitrary character-shaped or graphical (“numerals” in the present embodiment) openings  14   c  (pattern non-forming regions) different every dummy patterns  14  as shown in  FIG. 5 . Since the present embodiment is similar to the third embodiment except for the above, the description of the excepted elements of structure will be omitted.  
         [0057]     Since the shapes of the openings  14 c are set to the character-like or graphical forms different every dummy patterns  14  in the present embodiment, the dummy patterns  14  can be used as addresses. It is thus possible to easily identify a specific pattern lying in the semiconductor device.  
         [0058]     Although any of the embodiments has explained the gate electrode pattern as the wiring pattern by way of illustration, the present invention is not limited to it. The present invention can be applied even to a metal wiring pattern formed upon wiring multilayering, 3-dimensioning of a semiconductor device or the like. Although the BPSG oxide film has been described as the interlayer insulating film by way of illustration, the present invention is not limited to it. For example, one that causes a similar phenomenon, such as a high density plasma CVD (High Density Plasma-Chemical Vapor Deposition: HDP-CVD) oxide film is also applicable.  
         [0059]     While the present invention has been described with reference to the illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to those skilled in the art on reference to this description. It is therefore contemplated that the appended claims will cover any such modifications or embodiments as fall within the true scope of the invention.