JP4147203B2 - Semiconductor device - Google Patents

Description

  The present invention relates to a semiconductor device that prevents analysis of the configuration of a circuit configuration unit and makes it difficult to imitate, duplicate, or alter information.

  In general, a semiconductor device has a configuration in which a large number of semiconductor elements are arranged on a substrate, and wiring is provided between electrodes of the respective semiconductor elements. In such a semiconductor device, a circuit component is covered with an insulating protective film such as silicon oxide or silicon nitride in order to protect the above configuration from the influence of an external atmosphere such as α rays, moisture, and stress. As a result, malfunction due to moisture mixing or the like, characteristic fluctuation due to stress, and the like can be prevented.

  In addition, there are some circuit components in the circuit of the semiconductor device that require a long time for development and those that have excellent originality, and there are some that are preferably prevented from being imitated or duplicated by others. In addition, there are memory elements in which important information is stored in a circuit of a semiconductor device, and it is preferable that the information is not falsified.

  However, the protective film described above is disposed for the purpose of protecting the circuit components from the external atmosphere, and optically has many excellent visible light and far-infrared transmittances. The circuit configuration part is easily recognized through the protective film. As a result, there is a risk of imitation, duplication, and alteration of information in the storage element unit. Conventionally, the following methods have been adopted in order to prevent them.

  (1) In the structure disclosed in Patent Document 1, as shown in FIG. 14, the integrated circuit covers a circuit configuration unit 40 in which a large number of semiconductor elements arranged on a semiconductor substrate are wired to each other, and covers them. And an insulating protective film 42. The protective film 42 is made of, for example, silicon nitride, and a conductive metal film 43 is disposed therein. The surface of the circuit component 40 is covered only with the protective film 42 in areas where security is not required. In the main area, the lower layer 42a of the protective film 42, the metal film 43, and the upper layer 42b of the protective film 42 are sequentially formed. Covering.

  As a result, even if the protective film 42 is etched, only the upper layer part 42b in the protective film 42 on the metal film 43 covering the entire main part area and the entire protective film 42 located above the area where the security is not required. Is removed. Accordingly, since the metal film 43 is not removed, the main part that requires security protection is not exposed and cannot be visually recognized. Even if the metal film 43 is removed by etching in this state, the circuit pattern 40 cannot be analyzed because the wiring pattern 41 made of the same material as the metal film 43, eg, aluminum, is removed. Thus, by covering the main part of the circuit component 40 with the conductive metal film 43 via the insulating protective film 42, the integrated circuit is prevented from being imitated or duplicated by others.

(2) Patent Document 2 discloses a structure as shown in FIG. Specifically, an insulator separation layer 51 made of silicon dioxide (SiO ₂ ) is deposited on one main surface of the semiconductor substrate 50 on which the integrated circuit is formed, the insulator separation layer 51 is made of aluminum, and the integrated circuit The first and second wirings 52 and 53 connected to each other and the shielding layer 54 made of aluminum are embedded and formed. Moreover, openings 54a and 54b are provided in the shielding layer 54, and connection layers 55 and 56 made of aluminum are formed in the same layer as the shielding layer 54 in the openings 54a and 54b. Further, both ends of the connection layer 55 are connected to the cut end portion 52a of the first wiring 52 through the via 57 made of W, and both ends of the connection layer 56 are connected to the second wiring 53 through the via 58 made of W. A surface protective layer 51a is formed on the surface of the shielding layer 54 in connection with the cut end 53a.

  In this structure, the integrated circuit is concealed by the shielding layer 54, and the shielding layer 54 and the connection layers 55 and 56 are made of the same material and are formed in the same layer. Therefore, when the shielding layer 54 is removed by etching, The connection layers 55 and 56 are also removed at the same time. In this way, the shielding layer 54 that optically shields the wiring is formed, and the connection layers 55 and 56 that form a part of the wiring are formed in the same layer as the shielding layer 54, so that observation in the circuit operation state can be performed. It can prevent the analysis of the circuit operating state where illegal activities are the purpose.

  (3) Patent Document 3 discloses a structure as shown in FIG. In this structure, a multi-layer wiring structure in which a polysilicon gate and wiring 62 are formed on a silicon substrate 61, and a metal first layer wiring 64 and a metal second layer wiring 66 are formed on insulating films 63 and 65, respectively. Have. The metal second layer wiring 66 is covered with a passivation film 67. On the insulating film 65, an opaque conductive shielding film 60 is formed in the same layer with a gap from the metal second layer wiring 66.

In this structure, the integrated circuit is concealed by the conductive shielding layer 60, and when the conductive shielding film 60 is removed, the wiring in the same layer is cut off. Thus, reverse engineering of the semiconductor integrated circuit is prevented by having a defense mechanism that optically blocks internal observation.
Japanese Patent Laid-Open No. 1-165129 (Publication Date: June 29, 1991) Japanese Patent Laid-Open No. 11-154664 (Publication date: June 9, 1999) JP 10-270562 A (publication date: October 9, 1999)

  However, the above structure has the following problems.

  In the structure of (1), since the upper layer part 42b made of the same material as the lower layer part 42a exists on the metal film 43, the etching of the protective film 42 is stopped while the metal film 43 is exposed, whereby the metal film 43 Only etching is possible. Accordingly, the lower layer circuit configuration can be recognized in this state, and circuit measurement can also be performed.

  The structure (2) aims to prevent analysis of circuit operation by damaging the wiring when removing the shielding metal film. However, if only the shielding layer 54 is exposed by photolithography after chemically or physically removing the shielding layer 54 and the upper protective film of the connection layers 55 and 56 of the same layer, the shielding metal film is removed. It is possible. Similarly, the conductive shielding layer 60 can also be removed in the structure (3).

  As described above, in the conventional technology, there is a method for easily avoiding the countermeasures against imitation, duplication, and information falsification of the circuit, and it is difficult to completely protect the circuit information.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a semiconductor device that can effectively prevent visual recognition of a circuit and reliably prevent analysis of an internal circuit.

  In order to solve the above problems, a semiconductor device according to the present invention is a semiconductor device having a structure in which a circuit component formed on a semiconductor substrate and a main body wiring arranged on the semiconductor substrate are connected. A light-shielding film provided so as to cover the main part of the constituent part; a coating film that is laminated so as to completely cover the light-shielding film and formed of a corrosion-resistant film material; and an opening on the main body wiring And an insulating protective film having a first insulating protective film having an opening and a second insulating protective film for sealing the opening.

  Alternatively, the semiconductor device of the present invention covers a main part of the circuit component in the semiconductor device having a structure in which a circuit component formed on the semiconductor substrate and a main body wiring arranged on the semiconductor substrate are connected. Insulating protective film having a light-shielding film laminated in such a manner and having corrosion resistance, a first insulating protective film having an opening opening on the main body wiring, and a second insulating protective film sealing the opening It is characterized by having.

  According to the above configuration, the light-shielding film, which has a light-shielding property and is difficult to transmit visible light and IR light, is arranged so as to cover the main part of the circuit component part, so that the lower circuit pattern is recognized. It can be impossible. Further, since the coating film is formed of a material having corrosion resistance, it is difficult to remove the coating film by chemical treatment or the like.

  Furthermore, when the second insulating protective film is chemically removed for the purpose of circuit analysis, an opening of the first insulating protective film on the main body wiring appears. Therefore, it is possible to directly damage the main body wiring by the chemical solution or the like entering through the opening.

  In the semiconductor device according to the above-described invention, the coating film is preferably made of aluminum oxide.

  According to said structure, the corrosion resistance effect of a coating film can be enlarged because film | membrane material is an aluminum oxide.

  In the semiconductor device according to the above-described invention, aluminum oxide is preferably dyed.

  According to said structure, an aluminum oxide film can have light-shielding property by dye | staining aluminum oxide.

  In the semiconductor device described above, the surface of the insulating protective film is preferably planarized.

  According to the above configuration, by flattening the surface of the protective film that covers the circuit component, the shape of the lower layer wiring does not rise as a step on the surface of the protective film, so that it is impossible to recognize the wiring pattern due to the step. it can.

  In the semiconductor device according to the above-described invention, the light shielding film is preferably made of tantalum or niobium.

  According to said structure, the corrosion resistance of a light shielding film can be made high by making a light shielding film into a tantalum or niobium metal film.

  As described above, the semiconductor device of the present invention is a semiconductor device having a structure in which a circuit component formed on a semiconductor substrate is connected to a main body wiring arranged on the semiconductor substrate. A light shielding film provided so as to cover the portion, a coating film that is laminated so as to completely cover the light shielding film and formed of a film material having corrosion resistance, and an opening that opens on the main body wiring. The first insulating protective film has an insulating protective film having a second insulating protective film that seals the opening.

  Alternatively, the semiconductor device of the present invention covers a main part of the circuit component in the semiconductor device having a structure in which a circuit component formed on the semiconductor substrate and a main body wiring arranged on the semiconductor substrate are connected. Insulating protective film having a light-shielding film laminated in such a manner and having corrosion resistance, a first insulating protective film having an opening opening on the main body wiring, and a second insulating protective film sealing the opening It is the structure equipped with.

  As a result, a light-shielding film that has a light-shielding property and is difficult to transmit visible light and IR light is disposed so as to cover the main part of the circuit component, and the coating film is formed of a corrosion-resistant material. Therefore, it is possible to make the lower layer circuit pattern unrecognizable and make it difficult to remove the coating film by chemical treatment or the like. Therefore, there is an effect that the analysis of the internal circuit can be made difficult.

  Further, when the second insulating protective film is chemically removed for the purpose of circuit analysis, an opening of the first insulating protective film on the main body wiring appears, so that a chemical solution enters through the opening. It becomes possible to directly damage the main body wiring by such means. Therefore, there is an effect that the analysis of the internal circuit can be made difficult.

  In the above-described semiconductor device, since the coating film is made of aluminum oxide, the coating film made of aluminum oxide having a high corrosion resistance is disposed on the light shielding film, making it difficult to remove the light shielding film. Can do. Therefore, there is an effect that the visibility of the lower layer circuit pattern can be further reduced.

  In addition, since the aluminum oxide is dyed, the aluminum oxide film can have a light-shielding property. Accordingly, the visibility of the lower layer circuit pattern can be further reduced.

  In the semiconductor device described above, since the surface of the insulating protective film is planarized, the shape of the lower layer wiring does not rise as a step on the surface of the protective film, and the wiring pattern cannot be recognized. Therefore, there is an effect that visual recognition of the internal circuit can be prevented.

  In the above semiconductor device, since the light shielding film is made of tantalum or niobium, the light shielding film becomes a metal film having high corrosion resistance, and it is difficult to remove the light shielding film. Therefore, there is an effect that the visibility of the lower circuit pattern can be lowered.

  Reference embodiments and embodiments of the present invention will be described with reference to FIGS.

[Reference form 1]
The first reference embodiment of the present invention will be described with reference to FIGS. 1 to 5 as follows.

  FIG. 1 is a cross-sectional view of a principal part of a semiconductor device which is one embodiment of the reference of the present invention. On the semiconductor substrate 1 on which the circuit main portion 1a and the resistance detection circuit portion 1b are formed on the silicon substrate, wirings 2 for connecting the respective semiconductor elements in the circuit main portion 1a on the semiconductor substrate 1 are provided. .

  The circuit main part 1a is a main part of the circuit configuration part that requires security protection. FIG. 2 shows an example of the resistance detection circuit unit 1b.

  The resistance detection circuit unit 1b includes a resistor R1 and an inverter element 25. The resistor R1 is connected in series with a resistor R2 that becomes a resistance detection upper wiring 9 described later, and the connection point P is connected to the input terminal of the inverter element 25. The other end of the resistor R1 is connected to the power supply line of the voltage Vcc, and the other end of the resistor R2 is grounded (GND). The inverter element 25 inverts the voltage level at the connection point P and outputs it.

  The resistor R2 is a resistance component of the resistance detection upper wiring 9 (resistance detection / light shielding upper wiring 10 described later), and its resistance value increases after the wiring is removed. A resistor R1 is formed as a resistor under the insulating protective film 4, and an inverter element 25 is formed. Here, the resistance value of the resistor R2 is set to be smaller than the resistance value of the resistor R1.

  The inverter element 25 outputs a high-level output signal out because the potential at the connection point P is smaller than the inversion threshold value of the inverter element 25 in a normal state. On the other hand, when the resistance value of the resistor R2 increases and the potential at the connection point P exceeds the inversion threshold value of the inverter element 25, the inverter element 25 outputs a low-level output signal out.

  In order to protect the lower layer portion of the wiring 2, the entire upper layer of the semiconductor substrate 1 is covered with an insulating protective film 4. The wiring 2, the resistance detection upper wiring 9, and the light shielding film 5 An aluminum oxide film 7 and a light shielding upper wiring 8 are formed. The insulating protective film 4 includes a lower protective film 4a formed on the semiconductor substrate 1 and an upper protective film 4b formed on the protective film 4a. The resistance detection upper wiring 9 is formed on the protective film 4a, and is connected to the resistance detection circuit unit 1b via the connection part 3 penetrating the protective film 4a. The light shielding film 5 is formed on the protective film 4a similarly to the resistance detection upper wiring 9, and is disposed so as to cover the circuit main part 1a. The aluminum oxide film 7 is disposed so as to completely cover the light shielding film 5, and the light shielding upper wiring 8 is further disposed on the aluminum oxide film 7.

  Since the light shielding film 5 is a conductive metal film and has a light shielding property that makes at least visible light and IR light difficult to pass, it is possible to prevent the circuit main portion 1a from being visually recognized. Further, since the light shielding upper wiring 8 also has a light shielding property, the light shielding upper wiring 8 can be more effectively prevented from being visually recognized by being disposed so as to cover the circuit main portion 1a. Furthermore, the visibility of the lower layer circuit pattern can be further lowered by dyeing the aluminum oxide film 7 to impart light shielding properties.

  Since aluminum oxide is an insulating material and has a very large corrosion resistance effect, by disposing the aluminum oxide film 7 on the light shielding film 5, the aluminum oxide film 7 can be chemically treated by a chemical solution or the like. Can be prevented from being peeled off. Further, since the light shielding upper wiring 8 and the resistance detection upper wiring 9 are formed of the same material, they can be formed in one step. Moreover, since the material is inferior in corrosion resistance to the aluminum oxide film 7, when the chemical solution removal of the aluminum oxide film 7 is attempted, the resistance detection upper wiring 9 becomes a chemical solution before the aluminum oxide film 7. Invaded.

  As a result, when the resistance detection upper wiring 9 is disconnected or thinned, the resistance value of the resistor R2 increases, thereby increasing the potential at the connection point P. When the inversion threshold value of the inverter element 25 is exceeded, the output signal out is inverted. To do. As a result, the resistance detection circuit unit 1b detects an increase in the resistance value and causes the CPU built in the main body circuit to recognize a change in the signal, thereby causing the main body to malfunction or become inoperable on the software side, or the resistance R2 An abnormal increase in the resistance value itself can cause a malfunction of the circuit.

  As described above, when the peeling of the light shielding upper wiring 8 (chemical solution removal) is attempted chemically in order to see the circuit main portion 1a, the resistance detection made of the same material as that of the light shielding upper wiring 8 is simultaneously performed. As a result, the resistance upper wiring 9 increases in resistance. By causing the resistance detection circuit unit 1b to detect the increase in the resistance value, the main circuit may malfunction or become inoperable, or the circuit may malfunction due to an abnormal increase in the resistance value of the resistance detection upper wiring 9 itself. Can cause.

  By adopting the above structure, first, the internal circuit cannot be visually recognized from the outside, and further, when the film of the resistance detection upper wiring 9 is peeled off, the circuit does not operate normally. Analysis can be prevented.

  A manufacturing procedure of the semiconductor device according to the present embodiment will be described with reference to a process flowchart shown in FIG.

  First, as shown in FIG. 3A, an aluminum or other conductive metal film is formed to a thickness of 900 nm, for example, by sputtering on the semiconductor substrate 1 having the circuit main part 1a, and resist patterning is performed. Then, dry etching is performed to form the wiring 2. A protective film 4a made of silicon oxide, silicon nitride or the like is formed on the wiring 2 to a thickness of 2000 nm by, for example, plasma CVD (hereinafter referred to as P-CVD) (FIG. 3B). The raised portion on the wiring 2 on the surface of the protective film 4a is shaved by a thickness of 1000 nm, for example, by CMP (Chemical Mechanical Polishing) method to eliminate the surface morphology and flatten it (FIG. 3C).

  Next, a conductive metal film made of a material similar to or other than that of the wiring 2 or a thin film made of a light-shielding and conductive material similar to metal, such as a titanium nitride film, is formed to a thickness of 300 nm by sputtering. A thin film is formed by patterning, resist patterning, and dry etching to form a light shielding film 5 having a desired shape on the circuit main portion 1a (FIG. 3D). The surface portion of the protective film 4a where the light shielding film 5 does not exist is covered with a resist 13 and patterned (FIG. 3E). At this time, the pattern end portion of the resist 13 is slightly separated from the light-shielding film 5 in order to completely cover the light-shielding film 5 with the portion that will become the aluminum oxide film 7 in a later step.

  The aluminum film 14 is formed with a thickness of 150 nm on the entire substrate by sputtering, for example (FIG. 3F). Subsequently, the aluminum film 14 is oxidized by an anodic oxidation method. The substrate is immersed in an electrolytic solution such as ammonium tartrate, a positive voltage of about several tens of volts is applied to the aluminum film 14 on the substrate, and the thickness of the aluminum film 14 is oxidized. Since the oxide film has fine pores, the oxide film is immersed in boiling pure water for sealing treatment. Thereby, an aluminum oxide film 7 is formed on the entire surface of the substrate (FIG. 3G).

  The aluminum oxide film 7 may be dyed by immersing the substrate in a dye solution before the sealing treatment. Since the aluminum oxide film 7 before the sealing treatment is porous and has fine pores, when immersed in a dye solution, the dye molecules are deposited in the pores and dyed. The dye used here is selected from the group of dyes such as acidic dyes, acidic metal-containing complex salts, and acidic mordanting. In terms of chemical structure, monoazo dyes, disazo dyes, anthraquinone dyes, phthalocyanine dyes, triphenylmethane dyes, and the like can be given. The amount of dye applied to the aluminum oxide film 7 is controlled by adjusting the dyeing time during constant density dyeing.

  After the dye is applied to the aluminum oxide film 7, the substrate is immersed in boiling pure water to perform sealing treatment. Thereby, a dye can be fixed to the aluminum oxide film 7, and the aluminum oxide film 7 is dyed. Thus, by dyeing the aluminum oxide film 7, the visibility of the internal circuit from the outside can be further deteriorated.

  Further, by scrubbing the substrate surface, the aluminum oxide film 7 from the portion having a relatively weak step coverage of the oxide film near the bottom of the resist 13 to the resist 13 is scraped off, and then the resist 13 is removed using a stripping solution. . When burrs exist in the formed aluminum oxide pattern, the burrs are removed by scrubbing the substrate surface in that state (lift-off method), and cleaning is performed. Thus, the aluminum oxide film 7 is formed on the light shielding film 5 (FIG. 3H).

  Then, the protective film 4a on the resistance detection circuit portion 1b is subjected to patterning etching, and a tungsten plug is provided to form the connection portion 3 (FIG. 3 (i)). Thereafter, the same material as the light-shielding film 5 or other materials, that is, a conductive metal film made of a material inferior to the aluminum oxide film 7 in terms of corrosion resistance, or a thin film made of a material having a light-shielding property and conductivity similar to metals, For example, a titanium nitride film 17 is formed by sputtering to a thickness of 300 nm, and the resist 15 formed thereon is patterned and dry-etched to form a light shielding upper wiring 8 on the circuit main part 1a. On the resistance detection circuit portion 1b, a portion to be the resistance detection upper wiring 9 is formed simultaneously (FIG. 3 (j)). Finally, the protective film 4b is formed with a thickness of 300 nm by, for example, P-CVD (FIG. 3K).

  Through the above steps, the structure shown in FIG. 1 is manufactured. As described above, the semiconductor circuit structure shown in FIG. 1 can be easily realized by using an existing process technology.

  The semiconductor device according to the first embodiment shown in FIG. 1 includes a light shielding upper wiring 8 and a resistance detection upper wiring 9 which are electrically separated by patterning. Instead, FIG. As shown in the cross-sectional view of the main part of the semiconductor device, an upper wiring 10 for resistance detection and light shielding, which is an upper wiring for both resistance detection and light shielding, may be provided.

  The resistance detection / light-shielding upper wiring 10 is arranged on the upper layer of the aluminum oxide film 7 with the insulating protective film 4 interposed therebetween, and is connected to the resistance detection circuit portion 1b through the connection portion 3. . However, the insulating protective film 4 has protective films 4c and 4d instead of the protective film 4b described above. The protective film 4 c is formed on the protective film 4 a so as to cover the aluminum oxide film 7. The protective film 4d is formed on the protective film 4c so as to cover the resistance detection and light shielding upper wiring 10 formed on the protective film 4c.

  The resistance detection and light shielding upper wiring 10 has both a function as an element for detecting a change in resistance value (resistance detection upper wiring 9) and a function as a light-shielding film (light shielding upper wiring 8). . Therefore, if the upper wiring for resistance detection / light-shielding 10 is to be removed physically (polishing, etc.) or chemically (chemical treatment, etc.) in order to visually recognize the main circuit portion 1a, the resistance detection / light-shielding upper wiring 10 is changed. Disconnection or thinning occurs and the resistance value increases. Therefore, the resistance detection circuit unit 1b can be operated more sensitively than the configuration of FIG.

  Here, a manufacturing procedure of the semiconductor device configured as described above will be described based on a process flow diagram shown in FIG. Here, until the aluminum oxide film 7 is formed (FIGS. 5A to 5H), it is the same process as the manufacturing process of the semiconductor device shown in FIG. 1 (FIGS. 3A to 3H). Therefore, the description thereof is omitted, and the subsequent steps are described.

  An insulating protective film 4c is formed on the protective film 4a so as to cover the aluminum oxide film 7 with a thickness of 300 nm, for example, by P-CVD, and patterning etching is performed on the resistance detection circuit portion 1b to form a tungsten plug. The connection part 3 is formed by providing (FIG.5 (i)). Next, a conductive metal film made of a material similar to or other than that of the light-shielding film 5, that is, a material having corrosion resistance and inferior to the aluminum oxide film 7, or a thin film made of a material having a light-shielding property and conductivity similar to a metal, for example, A titanium nitride film is formed by sputtering to a thickness of 300 nm, and a resist 16 is formed thereon (FIG. 5 (j)). The resist 16 is subjected to patterning, dry etching, and resist stripping to form the resistance detection / light shielding upper wiring 10 on the circuit main portion 1a and the resistance detection circuit portion 1b (FIG. 5 (k)). Finally, the insulating protective film 4d is formed with a thickness of 300 nm by, for example, P-CVD (FIG. 5L). Thus, the structure of FIG. 4 is manufactured.

[Reference form 2]
The second embodiment of the present invention will be described below with reference to FIGS. Note that, in the present reference embodiment, components having functions equivalent to those of the components in the reference embodiment 1 are denoted by the same reference numerals and description thereof is omitted.

  FIG. 6 is a cross-sectional view of a main part of a semiconductor device which is one embodiment of the reference of the present invention. As shown in FIG. 6, the semiconductor device according to the present embodiment has a wiring 2, a connection section 3, a semiconductor substrate 1 on which a circuit main portion 1 a and a resistance detection circuit portion 1 b are formed, as in the first embodiment. An insulating protective film 4, a light shielding upper wiring 8, and a resistance detection upper wiring 9 are provided. The light shielding upper wiring 8 and the resistance detection upper wiring 9 are arranged in the same layer, and a corrosion-resistant light-shielding film 6 having corrosion resistance is provided on the surface of the light-shielding upper wiring 8 on the semiconductor substrate 1 side. . The insulating protective film 4 includes a lower protective film 4e formed on the semiconductor substrate 1 and an upper protective film 4f formed on the protective film 4e.

  In the semiconductor device configured as described above, it is possible to prevent the circuit main portion 1a from being visually recognized by the corrosion-resistant light-shielding film 6 as with the light-shielding film 5 of Reference Embodiment 1. In addition, by using a corrosion-resistant light-shielding film 6 made of a metal film such as tantalum or niobium having high corrosion resistance instead of the light-shielding film 5, the aluminum oxide film 7 does not have to be disposed as shown in FIG. 6 itself can be made difficult to remove, and the visual recognition effect can be enhanced.

  A manufacturing procedure of the semiconductor device according to the present embodiment will be described with reference to a process flowchart shown in FIG.

  First, as shown in FIG. 7A, an aluminum or other conductive metal film is formed to a thickness of 900 nm, for example, by sputtering on the semiconductor substrate 1 having the circuit main portion 1a, and resist patterning is performed. Then, dry etching is performed to form the wiring 2. A protective film 4e made of silicon oxide, silicon nitride or the like is formed on the wiring 2 with a thickness of 2000 nm by, for example, P-CVD (FIG. 7B). A raised portion on the wiring 2 on the surface of the protective film 4e is cut by a thickness of 1000 nm, for example, by a CMP method to eliminate the surface morphology and flatten it (FIG. 7C).

  Next, patterning and dry etching are performed on the surface of the protective film 4e with a resist 18 to form depressions on the main circuit portion 1a (FIG. 7D). The depth of the recess may be equal to the thickness of the corrosion-resistant light-shielding film 6. Subsequently, a corrosion-resistant light-shielding film 6 is formed on the entire substrate, for example, a tantalum or niobium film with a thickness of 150 nm by sputtering (FIG. 7E). The corrosion-resistant light-shielding film 6 is scraped off by the metal CMP method (FIG. 7F). By this treatment, only the corrosion-resistant light-shielding film 6 where the depression of the protective film 4e is not formed can be scraped off.

  Then, the protective film 4e on the resistance detection circuit portion 1b is subjected to patterning etching, and a tungsten plug is provided to form the connection portion 3 (FIG. 7 (g)). Thereafter, a conductive metal film made of a material that is inferior in corrosion resistance to the corrosion-resistant light-shielding film 6 or a thin film made of a light-shielding and conductive material similar to metal, such as a titanium nitride film 17, for example, 300 nm by sputtering. Then, patterning is performed with the resist 19 formed thereon (FIG. 7 (h)) (FIG. 7 (i)). Finally, the protective film 4f is formed with a thickness of 300 nm by, eg, P-CVD (FIG. 7 (j)).

  The structure shown in FIG. 6 is manufactured through the above steps. As described above, the semiconductor circuit structure shown in FIG. 6 can be easily realized by using the existing process technology.

  The semiconductor device according to the second embodiment shown in FIG. 6 includes a light shielding upper wiring 8 and a resistance detection upper wiring 9 which are electrically separated by patterning. Instead, FIG. As shown in the cross-sectional view of the main part of the apparatus, an upper wiring 10 for resistance detection and light shielding, which is an upper wiring that serves both for resistance detection and light shielding, may be provided.

  The resistance detection / light-shielding upper wiring 10 is disposed in an upper layer of the corrosion-resistant light-shielding film 6 via the insulating protective film 4 and is connected to the resistance detection circuit part 1b via the connection part 3. . However, the insulating protective film 4 has protective films 4g and 4h instead of the protective film 4f described above. The protective film 4g is formed on the protective film 4e so as to cover the corrosion-resistant light-shielding film 6. The protective film 4h is formed on the protective film 4g so as to cover the resistance detection and light shielding upper wiring 10 formed on the protective film 4g.

  The resistance detection and light shielding upper wiring 10 has both a function as an element for detecting a change in resistance value (resistance detection upper wiring 9) and a function as a light-shielding film (light shielding upper wiring 8). . Therefore, if the resistance detection / light shielding upper wiring 10 is to be removed physically (polished, etc.) or chemically (chemical solution treatment, etc.) in order to visually recognize the circuit main part 1a, the resistance detection / light shielding upper wiring 10 is changed. Disconnection or thinning occurs and the resistance value increases. Therefore, the resistance detection circuit unit 1b can be operated more sensitively than the configuration of FIG.

  Here, a manufacturing procedure of the semiconductor device configured as described above will be described with reference to a process flowchart shown in FIG. Note that the steps up to the formation of the corrosion-resistant light-shielding film 6 (FIGS. 9A to 9F) are the same as the steps for manufacturing the semiconductor device shown in FIG. 6 (FIGS. 7A to 7F). The description will be omitted, and the subsequent steps will be described.

  A protective film 4g is formed on the protective film 4e so as to cover the corrosion-resistant light-shielding film 6 with a thickness of, for example, 300 nm by P-CVD, and patterning etching is performed on the resistance detection circuit unit 1b to provide a tungsten plug. Thereby, the connection part 3 is formed (FIG. 9G). Next, a conductive metal film made of a corrosion-resistant material similar to or lower than the corrosion-resistant light-shielding film 6 or a thin film made of a light-shielding and conductive material similar to metal, such as a titanium nitride film, is sputtered to 300 nm. A film is formed in a thickness, and patterning is performed with the resist 20 formed thereon (FIG. 9H). Further, the resistance detection and light shielding upper wiring 10 is formed on the circuit main portion 1a by dry etching of the resist 20 (FIG. 9I). Finally, the protective film 4h is formed with a thickness of 300 nm by, for example, the P-CVD method (FIG. 9J). Thus, the structure of FIG. 8 is manufactured.

Embodiment
The embodiment of the present invention will be described with reference to FIGS. 10 to 13 as follows. In the present embodiment, components having the same functions as those in the reference embodiment 1 are denoted by the same reference numerals, and description thereof is omitted.

  FIG. 10 is a fragmentary cross-sectional view of a semiconductor device according to an embodiment of the present invention. On the semiconductor substrate 1 in which the circuit main part 1a is formed on the silicon substrate, wirings 2 for connecting the semiconductor elements in the circuit main part 1a are provided.

  In order to protect the lower layer part from the wiring 2, the entire upper layer of the semiconductor substrate 1 is covered with an insulating protective film 4, which includes the wiring 2, the light shielding film 5, the aluminum oxide film 7, and the upper part. A wiring 11 is formed. The insulating protective film 4 is formed on the semiconductor substrate 1 and has a lower protective film 4 i having an opening 12, and an upper protective film 4 j formed on the protective film 4 i and sealing the opening 12. It consists of. Further, the number of openings in the protective film 4i is not limited. The light shielding film 5 is formed on the protective film 4i and is disposed so as to cover the circuit main part 1a. The aluminum oxide film 7 is disposed so as to completely cover the light shielding film 5, and the upper wiring 11 is further disposed on the aluminum oxide film 7.

  In the above configuration, not only the light-shielding film 5 but also the upper wiring 11 has a light-shielding property. Therefore, the upper wiring 11 can be more effectively prevented from being visually recognized by being arranged so as to cover the circuit main part 1a. . Furthermore, the visibility of the lower layer circuit pattern can be further lowered by dyeing the aluminum oxide film 7 to impart light shielding properties.

  By providing a protective film 4i as a first insulating protective film having an opening 12 on the wiring 2 and covering the upper layer with a protective film 4j as a second insulating protective film, a light-shielding portion is applied by chemical treatment at the time of peeling analysis. When trying to remove, chemical damage can be given not only to the upper wiring 11 but also to the wiring 2 that transmits signals to the circuit main part 1a from the outside, and the resistance value is abnormal due to disconnection or thinning of the wiring 2 due to chemical damage. The normal operation of the circuit can be impaired by the increase.

  A manufacturing procedure of the semiconductor device of the present embodiment will be described based on a process flow chart shown in FIG.

  First, as shown in FIG. 11A, a conductive metal film made of aluminum or other material is formed to a thickness of 900 nm by, for example, sputtering on the semiconductor substrate 1 having the circuit main portion 1a. Then, resist patterning and dry etching are performed to form the wiring 2. A protective film 4i made of silicon oxide, silicon nitride or the like is formed on the wiring 2 to a thickness of 2000 nm by, for example, P-CVD (FIG. 11B). A raised portion on the wiring 2 on the surface of the protective film 4i is cut to a thickness of 1000 nm by, for example, a CMP method to eliminate the surface morphology and flatten it (FIG. 11C).

  Next, a conductive metal film made of a material similar to or other than that of the wiring 2 or a thin film made of a light-shielding and conductive material similar to metal, such as a titanium nitride film, is formed to a thickness of 300 nm by sputtering. Film formation is performed, and the thin film is patterned by resist patterning and dry etching to form a light shielding film 5 having a desired shape in the circuit main portion 1a (FIG. 11D). The surface portion of the protective film 4i where the light shielding film 5 does not exist is covered with a resist 21 and patterned (FIG. 11E). At this time, the pattern end portion of the resist 21 is slightly separated from the light-shielding film 5 in order to completely cover the light-shielding film 5 with the portion that will become the aluminum oxide film 7 in a later step.

  An aluminum film 14 is formed with a thickness of 150 nm on the entire substrate by, for example, sputtering (FIG. 11F). Subsequently, the aluminum film 14 is oxidized by an anodic oxidation method to form an aluminum oxide film 7 on the entire surface of the substrate (FIG. 11G). Further, by scrubbing the substrate surface, the aluminum oxide film 7 from the portion where the step coverage of the oxide film near the bottom of the resist 21 is relatively weak to the resist 21 is scraped off, and then the resist 21 is removed using a stripping solution. . If burrs exist in the formed aluminum oxide pattern, the burrs are removed by scrubbing the substrate surface in that state, and cleaning is performed. Thus, the aluminum oxide film 7 is formed on the light shielding film 5 (FIG. 11H).

  Then, a conductive metal film made of the same material as the light-shielding film 5 or other materials, that is, a material inferior to the aluminum oxide film 7 in terms of corrosion resistance, or a thin film made of a light-shielding and conductive material similar to metal, for example, A titanium nitride film is formed to a thickness of 300 nm by sputtering, patterning of the resist 22 formed thereon (FIG. 11 (i)) and dry etching are performed, and the upper wiring 11 is formed on the circuit main part 1a. (FIG. 11 (j)).

Finally, the opening 12 is formed on the portion of the protective film 4i covering the wiring 2 by patterning etching.
(FIG. 11 (k)), and a protective film 4j is formed thereon with a thickness of 300 nm by, for example, P-CVD (FIG. 11 (l)) to cover the opening 12.

  Through the above steps, the structure shown in FIG. 10 is manufactured. As described above, the semiconductor circuit structure shown in FIG. 10 can be easily realized by using an existing process technology.

  In the semiconductor device of the present embodiment shown in FIG. 10, the aluminum oxide film 7 is disposed as a film having corrosion resistance. Instead, as shown in FIG. The film 5 may have corrosion resistance. A film provided with corrosion resistance on the light shielding film 5 is referred to as a corrosion resistant light shielding film 6, and an upper wiring 11 is disposed on the corrosion resistant light shielding film 6.

  The corrosion-resistant light-shielding film 6 can prevent visual recognition of the circuit main portion 1a. Moreover, by using the corrosion-resistant light-shielding film 6 made of a metal film such as tantalum or niobium having high corrosion resistance instead of the light-shielding film 5, the aluminum oxide film 7 does not have to be disposed as shown in FIG. It is possible to make it difficult to remove the light shielding film 6 itself, and to improve the visual recognition effect.

  Here, a manufacturing procedure of the semiconductor device configured as described above will be described based on a process flow chart shown in FIG.

  First, as shown in FIG. 13A, a conductive metal film made of aluminum or other material is formed on the semiconductor substrate 1 having the circuit main part 1a to a thickness of 900 nm by, for example, sputtering. Then, resist patterning and dry etching are performed to form the wiring 2. A protective film 4k made of silicon oxide, silicon nitride or the like is formed on the wiring 2 to a thickness of 2000 nm by, for example, P-CVD (FIG. 13B). The raised portion on the wiring 2 on the surface of the protective film 4k is cut to a thickness of 1000 nm by, for example, a CMP method to eliminate the surface morphology (FIG. 13 (c)), and the resist formed thereon Patterning 23 and dry etching are performed to form a recess in the protective film 4k on the circuit main portion 1a (FIG. 13D). The depth of the recess may be equal to the thickness of the corrosion-resistant light-shielding film 6.

  Next, the corrosion-resistant light-shielding film 6 is formed on the entire substrate, for example, a tantalum or niobium film with a thickness of 150 nm by sputtering (FIG. 13E), and the corrosion-resistant light-shielding film 6 on the substrate surface is formed by metal CMP. Then, the metal film thickness is removed (FIG. 13F). By this treatment, only the corrosion-resistant light-shielding film 6 in the portion where the depression of the protective film 4k is not formed can be removed.

  Then, a conductive metal film made of the same material as the corrosion-resistant light-shielding film 6 or other materials, that is, a material inferior to the aluminum oxide film in terms of corrosion resistance, or a thin film (upper part) made of a material having a light-shielding property and conductivity similar to metals. Wiring 11), for example, a titanium nitride film having a thickness of 300 nm is formed by sputtering, patterned with a resist 24 (FIG. 13G), and then an upper wiring 11 is formed on the corrosion-resistant light-shielding film 6 by dry etching. (FIG. 13 (h)).

  Finally, an opening 12 is provided by patterning etching in the portion of the protective film 4k covering the wiring 2 (FIG. 13 (i)), and the protective film 4l is formed on the protective film 4k by, for example, the P-CVD method. The film is formed with a thickness of 300 nm (FIG. 13J), and the opening 12 is covered. Thus, the structure shown in FIG. 12 is manufactured.

It is sectional drawing which shows the structure of the principal part of the semiconductor device which concerns on the reference form 1 of this invention. It is a circuit diagram which shows the structure of the resistance detection circuit part with which the semiconductor device of the reference form 1 and 2 of this invention is provided in common. (A) thru | or (k) are process flowcharts which show the process of manufacturing the said semiconductor device. It is sectional drawing which shows the structure of the principal part of the other semiconductor device which concerns on the reference form 1 of this invention. (A) thru | or (l) are process flowcharts which show the process of manufacturing the said semiconductor device. It is sectional drawing which shows the structure of the principal part of the semiconductor device which concerns on the reference form 2 of this invention. (A) thru | or (j) are process flowcharts which show the process of manufacturing the said semiconductor device. It is sectional drawing which shows the structure of the principal part of the other semiconductor device which concerns on the reference form 2 of this invention. (A) thru | or (j) are process flowcharts which show the process of manufacturing the said semiconductor device. It is sectional drawing which shows the structure of the principal part of the semiconductor device which concerns on embodiment of this invention. (A) thru | or (l) are process flowcharts which show the process of manufacturing the said semiconductor device. It is sectional drawing which shows the structure of the principal part of the other semiconductor device which concerns on embodiment of this invention. (A) thru | or (j) are process flowcharts which show the process of manufacturing the said semiconductor device. It is sectional drawing which shows the structure of the principal part of the conventional semiconductor device. It is sectional drawing which shows the structure of the principal part of the other conventional semiconductor device. It is sectional drawing which shows the structure of the principal part of other conventional semiconductor devices.

Explanation of symbols

1 Semiconductor substrate 1a Circuit main part (circuit component)
1b Resistance detection circuit (resistance detection circuit)
2 Wiring (main unit wiring)
3 connection portion 4 insulating protective film 4i, 4k protective film (first insulating protective film)
4j, 4l protective film (second insulating protective film)
5 Light-shielding film 6 Corrosion-resistant light-shielding film (corrosion-resistant light-shielding film)
7 Aluminum oxide film (coating film)
8 Light shielding upper wiring (resistance wiring, first wiring part)
9 Resistance detection upper wiring (resistance wiring, second wiring part)
10 Resistance detection and shading upper wiring (resistance wiring)
11 Upper wiring 12 Opening

Claims (6)

In a semiconductor device having a structure in which a circuit component formed on a semiconductor substrate and a main body wiring arranged on the semiconductor substrate are connected,
A light-shielding film provided to cover the main part of the circuit configuration part,
A coating film that is laminated so as to completely cover the light-shielding film and is formed of a film material having corrosion resistance;
An insulating protective film having a first insulating protective film having an opening opening on the main body wiring and a second insulating protective film for sealing the opening;
The light shielding film is formed so as to cover a part of the main body wiring, and the opening is opened in a portion of the main body wiring that is not covered with the light shielding film ,
The semiconductor device according to claim 1, wherein the second insulating protective film is also formed on the coating film . In a semiconductor device having a structure in which a circuit component formed on a semiconductor substrate and a main body wiring arranged on the semiconductor substrate are connected,
A light-shielding film laminated so as to cover the main part of the circuit component and having corrosion resistance;
An insulating protective film having a first insulating protective film having an opening opening on the main body wiring and a second insulating protective film for sealing the opening;
The light shielding film is formed so as to cover a part of the main body wiring, and the opening is opened in a portion of the main body wiring that is not covered with the light shielding film ,
The semiconductor device, wherein the second insulating protective film is also formed on the light shielding film .   The semiconductor device according to claim 1, wherein the coating film is made of aluminum oxide.   4. The semiconductor device according to claim 3, wherein the aluminum oxide is dyed.   3. The semiconductor device according to claim 1, wherein a surface of the insulating protective film is planarized.   The semiconductor device according to claim 1, wherein the light shielding film is made of tantalum or niobium.

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