Abstract:
A manufacturing method of a semiconductor device to perform processing, including pre-processing and post-processing, on a semiconductor substrate, a characteristic of the processed semiconductor substrate is inspected, whether the semiconductor substrate complies with a predetermined standard is judged, and a semiconductor substrate not complying with the standard is re-processed so that the semiconductor substrate complies with the standard.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a method of and a system for manufacturing a semiconductor device, and more particularly, to a method of and a system for manufacturing a semiconductor device in which inspection is followed by re-processing.  
           [0002]    [0002]FIG. 10 is a manufacturing step diagram for a conventional semiconductor device. These manufacturing steps are used to form side walls  45  as those shown in FIG. 4, for example. Now, steps of forming the side walls  45  will be described with reference to FIG. 4.  
           [0003]    First, at a step  101 , pre-processing for depositing an insulation film  43  is executed so as to cover a semiconductor substrate  41  and a gate electrode  42  formed on the semiconductor substrate  41 .  
           [0004]    Next, at a step  102 , a film thickness of the insulation film  43  is measured. At a step  103 , a condition for a step  104  is set up based on a result of the measurement at the step  102 .  
           [0005]    Next, at the step  104 , post-processing is executed, in which the insulation film  43  is etched back in accordance with an etching condition determined at the step  103  and the side walls  45  are consequently formed on the both sides of the gate electrode  42 .  
           [0006]    Next, at a step  105 , widths of the side walls  45  are measured and whether the widths comply with a predetermined standard is inspected.  
           [0007]    Next, at a step  106 , whether a result of the inspection at the step  105  complies with a predetermined standard is judged. If compliance with the standard is found, the sequence proceeds to a step  107  for commercialization. On the other hand, if there is not compliance with the standard, the sequence proceeds to a step  108  for discarding.  
           [0008]    However, discarding semiconductor substrates despite slight incompliance of the result of the inspection at the step  105  prevents an improvement to a production yield and makes it difficult to reduce production costs.  
         SUMMARY OF THE INVENTION  
         [0009]    Noting this, the present invention aims at providing a method of and a system for manufacturing a semiconductor device which re-process a semiconductor substrate failing to comply with a predetermined standard to comply with the standard, and thereby improve a production yield.  
           [0010]    The present invention is directed to a manufacturing method of a semiconductor device in which a semiconductor substrate is subjected to processing includes pre-processing and post-processing, comprising: a pre-processing step to process a semiconductor substrate; a measurement step to measure a characteristic of the semiconductor substrate processed at the pre-processing step; a setup step to set a processing condition for post-processing based on a result of the measurement at the measurement step; a post-processing step to process the semiconductor substrate using the processing condition; and an inspection step to inspect a characteristic of the semiconductor substrate processed at the post-processing step and to judge whether compliance with a predetermined standard is found or not, and characterized in further comprising re-processing step to re-process the semiconductor substrate judged not complying with the standard at the inspection step such that the semiconductor substrate complies with the standard.  
           [0011]    Using this manufacturing method, a semiconductor substrate judged not complying with a predetermined standard during inspection after the processing step is re-processed so as to comply with the standard. This makes it possible to improve a production yield of semiconductor devices. Further, this makes it possible to reduce production costs.  
           [0012]    A processing condition for the re-processing step is determined based on a result of the inspection at the inspection step.  
           [0013]    The re-processing step may be one step selected from a group including the pre-processing step and the post-processing step.  
           [0014]    This is because executing either the pre-processing step or the post-processing step sometimes allows a characteristic of a semiconductor substrate to comply with a predetermined standard.  
           [0015]    The re-processing step may include the pre-processing step, the measurement step, the setup step and the post-processing step.  
           [0016]    This is because executing these steps sometimes allows a characteristic of a semiconductor substrate to comply with a predetermined standard.  
           [0017]    It is preferable that the pre-processing step is a step at which an insulation film is deposited on the semiconductor substrate, and the post-processing step is a step at which the insulation film is etched using an etching condition determined from a measurement result regarding a film thickness of the insulation film.  
           [0018]    This is because executing these steps makes it possible to form a side wall, an inter-layer insulation film or the like.  
           [0019]    It is preferable that the pre-processing step is a step at which a field oxide film is formed on the semiconductor substrate, and the post-processing step is a step at which the field oxide film is etched using an etching condition determined based on a measurement result regarding at least one dimension selected between a film thickness of the field oxide film and a width of an active layer region sandwiched by the field oxide film, from a table showing a relationship between the width of the active layer region and an etching quantity of the field oxide film such that the width of the active layer region has a predetermined dimension.  
           [0020]    The measurement step is preferably a step to measure one dimension selected between a film thickness and a width of a predetermined portion of the semiconductor substrate.  
           [0021]    The present invention is also directed to a manufacturing system for semiconductor device including a pre-processing apparatus and a post-processing apparatus, comprising: a pre-processing apparatus to perform pre-processing on a semiconductor substrate; a measurement apparatus to measure a characteristic of the semiconductor substrate processed by the pre-processing; a setup apparatus to set a processing condition for post-processing based on a result of the measurement performed by the measurement apparatus; a post-processing apparatus to perform post-processing on the semiconductor substrate using the processing condition; an inspection apparatus to inspect a characteristic of the semiconductor substrate processed by the post-processing; and an evaluation apparatus to judge whether a result of the inspection by the inspection apparatus complies with a predetermined standard or not, and further characterized in that said pre-processing apparatus and/or the post-processing apparatus re-process(es) the semiconductor substrate judged not complying with the standard by the evaluation apparatus such that the semiconductor substrate complies with the standard.  
           [0022]    The present invention may also include a re-processing condition setup apparatus which sets a re-processing condition for said pre-processing apparatus and/or the post-processing apparatus based on the result of the inspection by the inspection apparatus.  
           [0023]    It is preferable that said pre-processing apparatus is a deposition apparatus and the post-processing apparatus is an etching apparatus.  
           [0024]    It is preferable that the measurement apparatus is an apparatus which measures one dimension selected between a film thickness and a width of a predetermined portion of the semiconductor substrate.  
           [0025]    As clearly described above, the manufacturing method according to the present invention requires to re-process a semiconductor substrate judged not complying with a predetermined standard during inspection after processing, and therefore, makes it possible to ensure compliance with the standard.  
           [0026]    This allows improving a production yield of semiconductor devices, and hence, reduces production costs. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0027]    [0027]FIG. 1 is a manufacturing step diagram according to the present invention;  
         [0028]    [0028]FIG. 2 is a re-processing step diagram according to the present invention;  
         [0029]    [0029]FIG. 3 is a manufacturing step diagram according to the example 1 of the present invention;  
         [0030]    [0030]FIGS. 4A and 4B are a cross sectional view showing manufacturing steps according to the example 1 of the present invention;  
         [0031]    [0031]FIG. 5 is a manufacturing step diagram according to the example 2 of the present invention;  
         [0032]    [0032]FIGS. 6A and 6B are a cross sectional view showing manufacturing steps according to the example 2 of the present invention;  
         [0033]    [0033]FIGS. 7A and 7B are a cross sectional view showing manufacturing steps according to the example 3 of the present invention;  
         [0034]    [0034]FIG. 8 is a manufacturing step diagram according to the example 4 of the present invention;  
         [0035]    FIGS.  9 A- 9 E are a cross sectional view showing manufacturing steps according to the example 4 of the present invention; and  
         [0036]    [0036]FIG. 10 is a manufacturing step diagram of conventional manufacturing. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0037]    [0037]FIG. 1 is a manufacturing step diagram for a semiconductor device according to a preferred embodiment of the present invention. From a pre-processing step generally denoted at  1  to a commercialization step generally denoted at  7  are similar to the conventional manufacturing steps  101  to  107  shown in FIG. 10.  
         [0038]    The steps according to the preferred embodiment are different from the conventional manufacturing steps in that when it is judged at a step  6  that an inspection result obtained at a step  5  does not comply with a standard, re-processing is executed at a step  8 .  
         [0039]    [0039]FIG. 2 shows detailed contents of the re-processing step generally denoted at  8 .  
         [0040]    When it is judged at the step  6  that there is incompliance with the standard, at the step  8 , first, re-processing at a step  81  is selected. The re-processing is selected either as a pre-processing step  82 , a post-processing step  85 , or the pre-processing step  82  and the post-processing step  85 . The pre-processing step  82  is a step with a change to a processing condition for the pre-processing denoted at  1 . Moreover the step  85  is a step with a change to a processing condition for the post-processing denoted at  4 .  
         [0041]    After the re-processing step  8 , the inspection step of step  5  is performed once again to thereby judge at the step  6  whether compliance with the standard is found.  
         [0042]    When compliance with the standard is found at the step  6  by the re-processing step  8 , the sequence proceeds to the step  7  of commercialization.  
         [0043]    When compliance with the standard is not found even after the re-processing step  8 , the re-processing step  8  may be performed once again or discarding may be performed.  
         [0044]    In this manner, according to the preferred embodiment, the pre-processing step  82  and/or the post-processing step  85  are/is executed once again at the re-processing step  8  when a semiconductor substrate already subjected to the pre-processing step  1  and the post-processing step  4  fails to comply with a predetermined standard, and therefore, it is possible to ensure compliance with the predetermined standard. As a result of this, it is possible to improve a production yield of semiconductor devices and reduce production costs, etc.  
       EXAMPLE 1  
       [0045]    [0045]FIG. 3 is a manufacturing step diagram for a side wall, using the present invention. Among these manufacturing steps, first, an insulation film is deposited on a semiconductor substrate, as pre-processing at a step  11 . Used at the step  11  is a deposition apparatus such as a CVD machine, for instance.  
         [0046]    [0046]FIG. 4A is a cross sectional view of a semiconductor substrate  41  as it is at the step  11 . A gate electrode  42  is formed on the semiconductor substrate  41 . An insulation film  43  is deposited so as to cover a surface of the semiconductor substrate  41  and the gate electrode  42 . As the insulation film  43 , a silicon oxide film, a silicon nitride film, etc., may be used.  
         [0047]    Next, at a step  12 , a film thickness of the insulation film  43  is measured.  
         [0048]    Next, at a step  13 , using a result of the measurement at the step  12 , an etching condition to etch back the insulation film  43  is set up. For setup of the etching condition, materials, a film thickness and the like of the insulation film and corresponding appropriate etching conditions are stored in a database in advance, and an etching condition proper to the film thickness measured at the step  12  is selected from the database.  
         [0049]    Next, at a step  14 , using the etch back condition set up at the step  13 , the insulation film  43  is etched back. For the etch back, an etching apparatus such as a sputtering machine is used, for example.  
         [0050]    [0050]FIG. 4B is a cross sectional view of the semiconductor substrate  41  as it is at the etch back step. In FIG. 4B, the etch back is realized using an ion beam  44 . The etch back step leaves the insulation film on the both sides of the gate electrode  42 , which will become side walls  45 .  
         [0051]    Next, at a step  15 , widths of the side walls  45  are measured.  
         [0052]    Next, at a step  16 , whether a result of the measurement on the widths of the side walls  45  complies with a predetermined standard is judged. When there is compliance with the standard, the manufacturing is furthered, for example, at a step  17  for the purpose of commercialization into a semiconductor device.  
         [0053]    On the other hand, when there is incompliance with the standard, a step  18  of re-processing is executed. For instance, when the widths of the side walls  45  are smaller than the standard, the step  11  (pre-processing), the steps  12 ,  13  and  14  (post-processing) are executed, whereby the side walls  45  are further formed.  
         [0054]    Meanwhile, when the widths of the side walls  45  are larger than the standard, the step  14  (post-processing) is carried out, whereby the side walls  45  are etched.  
         [0055]    The measurement result at the step  15  as well is used to determine processing conditions for the steps  11  and  14  during the re-processing.  
         [0056]    After the re-processing at the step  18 , the steps  15  and  16  are executed to thereby judge once again whether the widths of the side walls  45  comply with the standard or not. When there is compliance with the standard, further manufacturing is performed at the step  17  for the purpose of commercialization into a semiconductor device. On the other hand, when there is not compliance with the standard, the re-processing of the step  18  may be carried out once again. Alternatively, discarding may be performed without the step  18 .  
       EXAMPLE 2  
       [0057]    [0057]FIG. 5 is a manufacturing step diagram for an inter-layer insulation film, using the present invention. Among these manufacturing steps, first, an insulation film is deposited on a semiconductor substrate, as pre-processing at a step  21 . FIG. 6A is a cross sectional view of a semiconductor substrate  61  as it is after the step  21 . A transistor (not shown), for instance, is formed on the semiconductor substrate  61 . Denoted at  62  is a gate electrode of the transistor. An insulation film  63  is deposited so as to cover a surface of the semiconductor substrate  61  and the gate electrode  62 . A silicon oxide film, for example, is used as the insulation film  63 .  
         [0058]    Next, at a step  22 , a film thickness of the insulation film  63  is measured.  
         [0059]    Next, at a step  23 , using a result of the measurement at the step  22 , an etching condition to etch back the insulation film  63  is set up. For setup of the etching condition, as in the example 1, an etching condition proper to the film thickness measured at the step  22  is selected from a database prepared in advance.  
         [0060]    Next, at a step  24 , using the etch back condition set up at the step  23 , the insulation film  63  is etched back. FIG. 6B is a cross sectional view of the semiconductor substrate  61  as it is at the etch back step. In FIG. 6B, the etch back is realized using an ion beam  64 . The etch back step reduces the film thickness of the insulation film  63  so that the insulation film  63  becomes an inter-layer insulation film  65  with a predetermined film thickness.  
         [0061]    Next, at a step  25 , a film thickness of the inter-layer insulation film  65  is measured.  
         [0062]    Next, at a step  26 , whether a result of the measurement on the film thickness of the inter-layer insulation film  65  complies with a predetermined standard is judged. When there is compliance with the standard, further manufacturing is performed at a step  27  for the purpose of commercialization into a semiconductor device. At the step  27 , a hole, for example, is formed in the inter-layer insulation film  65  to thereby form a contact hole (not shown) connected to the transistor formed on the semiconductor substrate  61 .  
         [0063]    On the other hand, when there is not compliance with the standard, re-processing is executed at a step  28 . When the film thickness of the inter-layer insulation film  65  is smaller than the standard, the step  21  (pre-processing) is carried out to further deposit the insulation film  63 .  
         [0064]    Meanwhile, when the film thickness of the inter-layer insulation film  65  is larger than the standard, the step  24  (post-processing) is carried out to etch the inter-layer insulation film  65 .  
         [0065]    After the re-processing at the step  28 , the steps  25  and  26  are executed to thereby judge once again whether the film thickness of the inter-layer insulation film  65  complies with the standard or not. When there is compliance with the standard, further manufacturing is performed at the step  27  for the purpose of commercialization into a semiconductor device. On the other hand, when there is not compliance with the standard, the re-processing of the step  28  may be carried out once again. Alternatively, discarding may be performed without the step  28 .  
       EXAMPLE 3  
       [0066]    The example 3 uses the manufacturing steps of the example 2 described above in order to form an inter-layer insulation film across a multilayer interconnection. Manufacturing steps of this example, as shown in FIG. 7A, are same as the manufacturing steps of the example 2, except for that a wiring layer  72  of aluminum or the like is formed on a semiconductor substrate  71 .  
         [0067]    As shown in FIG. 7B, at the step  24  an insulation film  73  on the semiconductor substrate  71  is etched back using an ion beam  74  and accordingly becomes an inter-layer insulation film  75  with a predetermined film thickness.  
         [0068]    Next, at the step  27 , a hole, for example, is formed in the inter-layer insulation film  75  to thereby form a through hole (not shown). The through hole connects the wiring layer  72  with a wiring layer (not shown) formed on the inter-layer insulation film  75 , whereby a multilayer interconnection is obtained.  
       EXAMPLE 4  
       [0069]    [0069]FIG. 8 is a manufacturing step diagram for a transistor, using the present invention. Among these manufacturing steps, first, an oxide film and a nitride film are deposited on a semiconductor substrate, as pre-processing at a step  31 . FIG. 9A is a cross sectional view of a semiconductor substrate  91  of silicon or the like as it is after the step  31 . An oxide film  92  of SiO 2  and a nitride film  93  of SiN, for instance, are deposited sequentially on the semiconductor substrate  91 .  
         [0070]    Next, at a step  32 , the nitride film  93  and the oxide film  92  are etched using a resist mask (not shown) formed on the nitride film  93 , thereby exposing a surface of the semiconductor substrate  91  in a LOCOS formation area.  
         [0071]    Next, at a step  33 , an opening width, namely, a width of the exposed surface area of the semiconductor substrate  91  (denoted at x in FIG. 9B) is measured.  
         [0072]    Next, at a step  34 , using a thermal oxidation method, for instance, the exposed surface of the semiconductor substrate  91  is oxidized to thereby form a field oxide film. Following this, the nitride film  93  used as a mask and the oxide film  92  are removed by etching, so that LOCOS isolation areas  94  as those shown in FIG. 9C are formed.  
         [0073]    At this stage, a surface area of the semiconductor substrate  91  sandwiched by the LOCOS isolation areas  94  becomes a transistor formation area (field region) whose width is y1.  
         [0074]    Next, at steps  35  and  36 , a step is executed of forming an oxide film in a surface of the transistor formation area and removing the oxide film after through-implantation of ions via the oxide film, a step is executed of forming a gate oxide film in the transistor formation area and thereafter removing the gate oxide film in an unwanted area, etc. (not shown). At these steps, the oxide films are removed using hydracid fluoride (hydrofluoric acid), and therefore, the field oxide film in the LOCOS isolation areas  94 , too, is etched. In consequence, the width of the transistor formation area expands from y1 (FIG. 9C) to y2 (FIG. 9D)  
         [0075]    Particularly, at a step  35 , a condition for hydrofluoric acid processing (post-processing), such as a concentration of hydrofluoric acid and a processing time, is determined based on a value x calculated at a step  32 , using a database which stores in advance a relationship between processing conditions and a quantity of increase in the width y1 of the surface area of the semiconductor substrate  1  sandwiched by the LOCOS isolation areas  94 .  
         [0076]    Next, at a step  37 , the width (field dimension) y2 of the transistor formation area (FIG. 9D) is measured.  
         [0077]    Next, at a step  38 , whether a result of the measurement on y2 complies with a predetermined standard is judged. When there is compliance with the standard, further manufacturing, for instance, is performed at a step  39  for the purpose of commercialization into a semiconductor device.  
         [0078]    On the other hand, when there is not compliance with the standard, hydrofluoric acid processing (post-processing) is executed at a step  40 . More precisely, when the measured width y2 is narrower than a predetermined width, the field oxide film of the LOCOS isolation areas  94  is etched through further hydrofluoric acid processing, whereby the width of the transistor formation area increases from y2 to y3 (FIG. 9E).  
         [0079]    A condition for the hydrofluoric acid processing at the step  40  is determined from a database which stores in advance a relationship between processing conditions, such as a concentration of hydrofluoric acid, and a quantity of increase in the width y2 of the surface area of the semiconductor substrate  1  sandwiched by the LOCOS isolation areas  94 . The database used at the step  35  may be used as this database.  
         [0080]    After the hydrofluoric acid processing at the step  40 , the width y3 of the transistor formation area (FIG. 9E) is measured once again at the step  37 , in order to judge whether the width y3 complies with the standard or not. When there is compliance with the standard, further manufacturing is performed at the step  39  for the purpose of commercialization into a semiconductor device. On the other hand, when there is not compliance with the standard, the hydrofluoric acid processing of the step  40  may be executed once again. Alternatively, discarding may be performed without the step  40 .