Semiconductor device manufacturing method and semiconductor device

Abstract

A method for manufacturing a semiconductor device comprises: a step of placing a glass material into a metal container 100 containing a first metal and a second metal, or placing a second metal and a glass material into a metal container 100 containing a first metal; a step of melting the glass material in the metal container 100 at a first heating temperature during a first period to generate a metal-containing glass component 100 containing the first metal or containing the second metal; and a step of placing the metal-containing glass component on a semiconductor layer.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a semiconductor device using a glass material and a semiconductor device having a glass film. Background Art

[0002] In the past, attempts have been made to introduce life time killers for semiconductor devices. For example, in Japanese Patent Publication No. 62-73730, after the surface of each region (1), (2), (3) is exposed, a film with a thickness of The heavy metal film is heat treated in an N2 environment at a temperature of 800 to 1000°C for 60 to 120 minutes to diffuse the substance containing the lifetime inhibitor into the substrate. Due to the diffusion of the lifetime inhibitor, the impurity energy level of the heavy metal dissolved in the lattice position or between the lattices in silicon becomes a recombination center. During operation, the electrons or holes moving between the regions are captured at the recombination center, thereby shortening the switching time of the transistor.

[0003] However, in this evaporation method, it is difficult to correctly control the amount of heavy metal added, and the diffusion coefficient of heavy metals is as fast as 10 －7 ~10 －8 cm / sec, so there is a problem that the temperature dependence of the lifetime becomes larger when heavy metals are added, and its control is extremely difficult.

[0004] In order to solve this problem, a method for introducing a lifetime inhibitor is proposed in Japanese Patent Application No. 2-51235, which is characterized by: after mixing heavy metal elements in a powder composed of polycrystalline silicon particles, the powder is adhered to the surface of a silicon substrate, and the heavy metal is diffused into the silicon substrate by applying heat treatment.

[0005] However, in this conventional method, the number of steps increases and the manufacturing cost also rises compared to a semiconductor device whose lifetime is not controlled.

[0006] Furthermore, when trr (reverse recovery time) is controlled in units of μs, electron beam irradiation or the like must be used. However, when electron beam irradiation or the like is used, it is necessary to introduce an expensive device.

[0007] In view of the above problems, an object of the present invention is to provide a method for manufacturing a semiconductor device capable of controlling trr in units of μs without increasing the number of steps, and a semiconductor device manufactured by the manufacturing method. Summary of the invention

[0008]

Concept 1

[0009] The method for manufacturing a semiconductor device according to the present invention is characterized by comprising:

[0010] A step of placing a glass material into a metal container containing a first metal and a second metal, or placing a first metal and a glass material into a metal container containing a second metal;

[0011] A step of melting the glass material in the metal container at a first heating temperature during a first period to generate a metallic glass component containing the first metal or the second metal; and

[0012] The step of placing the metallic glass component on the semiconductor layer.

[0013]

Concept 2

[0014] In a method for manufacturing a semiconductor device according to a first aspect of the present invention,

[0015] The glass material is melted in the metal container at a first heating temperature during a first period, so that the first metal and the second metal are contained in the metal-containing glass component.

[0016]

Concept 3

[0017] In the method for manufacturing a semiconductor device according to concept 1 or concept 2 of the present invention,

[0018] The first heating temperature is higher than a melting point of the first metal and lower than a melting point of the second metal.

[0019]

Concept 4

[0020] In the method for manufacturing a semiconductor device according to any one of the first to third concepts of the present invention,

[0021] The metal container contains the first metal and the second metal,

[0022] In the metal container, the first metal accounts for 3% to 10% by weight, and the second metal accounts for 90% to 97% by weight.

[0023]

Concept 5

[0024] In the method for manufacturing a semiconductor device according to any one of Concepts 1 to 4 of the present invention,

[0025] The first metal is gold and the second metal is platinum.

[0026]

Concept 6

[0027] In the method for manufacturing a semiconductor device according to any one of the first to fifth concepts of the present invention,

[0028] The glass material has a SiO2 content in the range of 49.5 mol% to 64.3 mol%, an Al2O3 content in the range of 3.7 mol% to 14.8 mol%, a B2O3 content in the range of 8.4 mol% to 17.9 mol%, a ZnO content in the range of 3.9 mol% to 14.2 mol%, and an alkaline earth metal oxide content in the range of 7.4 mol% to 12.9 mol%,

[0029] The first period is 1 to 3 hours,

[0030] The first heating temperature is greater than 1350° C. and less than 1700° C.

[0031]

Concept 7

[0032] The semiconductor device according to the present invention is characterized by comprising:

[0033] a semiconductor layer; and

[0034] A glass film is provided on the semiconductor layer,

[0035] wherein the semiconductor layer contains dispersed gold,

[0036] The semiconductor layer is life-controlled by gold diffused from the glass film.

[0037] Effects of the Invention

[0038] According to the present invention, it is possible to provide a method for manufacturing a semiconductor device capable of controlling trr in units of μs without increasing the number of steps, and a semiconductor device manufactured by the manufacturing method. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a cross-sectional view of a semiconductor device used in the first embodiment of the present invention.

[0040] Figure 2 It is a cross-sectional view showing the manufacturing process of the semiconductor device used in the first embodiment of the present invention.

[0041] Figure 3 It is displayed from Figure 2 A cross-sectional view showing a process of manufacturing a semiconductor device during the process.

[0042] Figure 4 It is displayed from Figure 3 A cross-sectional view showing a process of manufacturing a semiconductor device during the process.

[0043] Figure 5 It is displayed from Figure 4 A cross-sectional view showing a process of manufacturing a semiconductor device during the process.

[0044] Figure 6 1 is a cross-sectional view showing a metal container and a metallic glass component used in each embodiment of the present invention.

[0045] Figure 7 It is a graph showing the relationship between heating time and heating temperature and trr. DETAILED DESCRIPTION

[0046] First embodiment

[0047] The semiconductor device of this embodiment has a PN junction of a diode, a thyristor, or the like. Figure 1 As shown, there is a first conductive type semiconductor substrate 11 composed of a first conductive type, a first conductive type semiconductor layer 12 composed of a first conductive type and having a lower dopant concentration of the first conductive type than the first conductive type semiconductor substrate 11 and disposed on the first conductive type semiconductor substrate 11, and a second conductive type semiconductor layer 13 disposed on the first conductive type semiconductor layer 12. The first conductive type is, for example, an n-type, and the second conductive type is, for example, a p-type. However, it is not limited thereto, and the first conductive type may be a p-type, and the second conductive type may be an n-type.

[0048] A silicon substrate, a silicon carbide substrate, a gallium nitride substrate, or the like can be used as the first conductive type semiconductor substrate 11, and its dopant concentration is, for example, 1×10 19 cm －3 ~1×10 20 cm －3 The first conductive semiconductor layer 12 is formed on the first conductive semiconductor substrate 11 by, for example, epitaxial growth. The dopant concentration in the first conductive semiconductor layer 12 is, for example, 5×10 15 cm －3 ~1×10 17 cm －3 The thickness of the first conductive semiconductor substrate 11 is, for example, 180 μm, and the thickness of the first conductive semiconductor layer 12 is, for example, 50 μm. The second conductive semiconductor layer 13 can be formed by implanting, for example, a p-type dopant (for example, boron) into the first conductive semiconductor layer 12. The dopant concentration in the second conductive semiconductor layer 13 is, for example, 1×10 16 cm －3 ~1×10 19 cm －3 , the thickness is, for example, 8 μm.

[0049] A first electrode 20 is provided on the front surface of the second conductive semiconductor layer 13, and a second electrode 30 is provided on the back surface of the first conductive semiconductor substrate 11. The first electrode 20 is, for example, an anode electrode, and the second electrode 30 is, for example, a cathode electrode. The first electrode 20 includes, for example, an aluminum silicide film 21, a nickel silicide film 22, and a Ni (nickel)-P film 23. The second electrode 30 includes a nickel film, and the nickel film includes a silicide film.

[0050] A glass film 50 as a passivation film is provided around the first electrode 20. This semiconductor device is manufactured by the following method.

[0051] A substrate is prepared, the substrate comprising: a first conductive type semiconductor substrate 11 composed of a first conductive type, a first conductive type semiconductor layer 12 composed of the first conductive type and disposed on the first conductive type semiconductor substrate 11 and having a lower first conductive type dopant concentration than the first conductive type semiconductor substrate 11, and a second conductive type semiconductor layer 13 disposed on the first conductive type semiconductor layer 12 (see Figure 2 ).

[0052] Next, an insulating film 61 made of SiO2 or the like is formed on the second conductive semiconductor layer 13 (see Figure 2 ). In addition, an insulating film 62 made of SiO2 or the like is formed on the back surface of the first conductive semiconductor substrate 11 (see Figure 2 ).

[0053] Then, if Figure 3 As shown in FIG. 1 , the formed insulating film 61 is used as a mask to perform etching to form the mesa trench 65. As the etching in this embodiment, dry etching, wet etching, or the like can be used.

[0054] Then, if Figure 4 As shown, a protective film (passivation film) is formed through the glass film 50 so as to cover the formed mesa groove 65 and the insulating film 61 .

[0055] Then, if Figure 5 As shown in FIG. 1 , the opening 70 is formed on the formed insulating film 61 and the glass film 50 by etching.

[0056] Furthermore, a first electrode 20 is formed on the opening on the front side, and a second electrode 30 is formed on the back side (see Figure 1 ).

[0057] Next, an example of a method for producing the glass film 50 used in the present embodiment will be described.

[0058] When manufacturing the glass film 50 according to the present embodiment, in a metal container 100 (see Figure 6) as a raw material for making glass (glass material adding step). The metal container 100 is, for example, a metal crucible. The first metal is gold (Au), and the second metal is platinum (Pt). In the metal container 100, the first metal accounts for 3% to 10% by weight, and the second metal accounts for 90% to 97% by weight. As the first metal, rhodium (Rh) may also be used in addition to gold. The metal container 100 may contain a metal other than the first metal and the second metal, may be composed of an alloy of three components, namely, the first metal, the second metal and the third metal, or may be composed of an alloy of four or more components.

[0059] For example, the SiO2 content of the glass material is in the range of 49.5 mol% to 64.3 mol%, the Al2O3 content is in the range of 3.7 mol% to 14.8 mol%, the B2O3 content is in the range of 8.4 mol% to 17.9 mol%, the ZnO content is in the range of 3.9 mol% to 14.2 mol%, and the alkaline earth metal oxide content is in the range of 7.4 mol% to 12.9 mol%.

[0060] Subsequently, the glass material is melted in the metal container 100 at the first heating temperature during the first period (melting step). By melting the glass material in the metal container 100 in this way, a metal-containing glass component 110 containing the first metal, the second metal, or both the first metal and the second metal is generated in the glass component. The first heating temperature is higher than the melting point of the first metal and lower than the melting point of the second metal. The first period is, for example, 1 to 3 hours, and the first heating temperature is, for example, not less than 1350°C and not more than 1700°C. In addition, the melting point of gold is 1064°C, and the melting point of platinum is 1768°C.

[0061] The prepared metal-containing glass component 110 is placed on a semiconductor layer such as the second conductive type semiconductor layer 13, thereby forming the glass film 50 (glass film forming step). Specifically, the melted metal-containing glass component 110 is cooled and then crushed into particles with a diameter of several μm, and the crushed metal-containing glass component 110 is placed on a semiconductor layer such as the first conductive type semiconductor substrate 11, the first conductive type semiconductor layer 12, and the second conductive type semiconductor layer 13, and then the metal-containing glass component 110 is melted (see Figure 4 ).exist Figure 4 Although the form in which the mesa groove 65 is set up to the first conductive semiconductor substrate 11 is shown, this is only one example, and a form in which the mesa groove 65 is set on the first conductive semiconductor substrate 11 and the first conductive semiconductor layer 12, and the mesa groove 65 is not set on the first conductive semiconductor substrate 11 may also be adopted.

[0062] The glass film 50 in this embodiment contains a metal such as a first metal. Therefore, by providing such a glass film 50, a very small amount of a first metal or other metal can be dispersed in a semiconductor layer such as the first conductive semiconductor layer 12 that affects trr control. In this way, according to the confirmation of the inventor of the present application, the trr (reverse recovery time) in the semiconductor layer can be set to be greater than 5μs and less than 15μs, so that life control can be performed. In addition, the ideal trr is greater than 5μs and less than 11μs, and the more ideal trr is greater than 5μs and less than 8μs. Moreover, in the previous form of adding heavy metals, since a large amount of heavy metal is added compared to the present embodiment, it is impossible to control trr in units of μs.

[0063] The experimental results are Figure 7 In this experiment, a wafer with a resistivity of ρ = 30Ω㎝ was used. Figure 7 As shown in , when pure Pt is used as the metal container 100, trr is about 22 μs. When a Pt-Au crucible containing gold in platinum (Au content accounts for 5 weight %) is used, trr can be reduced. Specifically, Figure 7 As shown, after the glass material was melted at 1350°C in a Pt-Au crucible for 5 hours, the glass composition (including the metallic glass component 110) was set in the semiconductor layer, and the trr in the semiconductor layer was about 15μs. After the glass material was melted at 1450°C in a Pt-Au crucible for 1 hour, the glass composition (including the metallic glass component 110) was set in the semiconductor layer, and the trr in the semiconductor layer was about 14μs. After the glass material was melted at 1450°C in a Pt-Au crucible for 2 hours, the glass composition (including the metallic glass component 110) was set in the semiconductor layer, and the trr in the semiconductor layer was about 11μs. After the glass material was melted at 1560°C in a Pt-Au crucible for 1 hour, the glass composition (including the metallic glass component 110) was set in the semiconductor layer, and the trr in the semiconductor layer was about 8μs. After the glass material was melted at 1560°C in a Pt-Au crucible for 2 hours, the glass composition (including the metallic glass component 110) was placed in the semiconductor layer, and the trr in the semiconductor layer was about 8μs. In addition, after confirmation by the inventor, since gold is considered to be easily soluble in the glass composition, using gold (Au) as the first metal is helpful for easily controlling trr compared to rhodium (Rh).

[0064] "Effect"

[0065] Next, an example of the effect according to the present embodiment will be described. In addition, all the modes described in the "effect" can be adopted.

[0066] Glass has always been melted in a container such as a crucible. In this embodiment, since only glass is melted according to the conventional process, this embodiment is different from the form of adding heavy metals or performing electron beam irradiation, and trr can be controlled without increasing the number of processes. In addition, according to this embodiment, trr can be controlled in units of μs. Therefore, trr can be controlled in units of μs while preventing the manufacturing cost of semiconductor devices such as chips from increasing.

[0067] As a method of controlling trr in μs, specifically, by adjusting the temperature and time, it is possible to Figure 7 Therefore, the trr can be adjusted in an extremely simple manner by simply adjusting the temperature and time according to the desired trr in each semiconductor device. Figure 7 As shown, trr can be controlled more effectively by adjusting the temperature than by adjusting the time. Ideally, the temperature should be greater than or equal to 140

[0068] The heating is preferably performed at a temperature of 0°C, preferably at a temperature of 1500°C or higher, and more preferably at a temperature of 1550°C or higher.

[0069] In addition, in recent years, in the PFC (Power Factor Correction) part of the air conditioner, the partial switching method (simple PAM) occupies the majority. In the operation mode of the simple PAM, the use of the bridge diode as a partial switch has increased, which requires the improvement of the trr characteristics of the bridge diode. In addition, in semiconductor devices such as IGBTs that do not want to increase forward losses but only require a certain degree of switching speed, it is sometimes necessary to control the trr in μs. In this regard, according to this embodiment, there is no need to perform additional processes, which can help improve the trr characteristics in μs while suppressing costs.

[0070] When using the conventional heavy metal diffusion, although trr can be controlled in ns, it is difficult to control it in μs. If electron beam irradiation is used, trr can be controlled in μs, but expensive equipment needs to be introduced. In this regard, according to this embodiment, it is also helpful to control trr in μs without introducing expensive equipment.

[0071] By setting the first heating temperature higher than the melting point of the first metal, the glass component can contain the first metal, the second metal, or both the first metal and the second metal. In addition, when the first metal and the second metal in the metal container 100 form an alloy, the first metal will not melt immediately even if heated to a temperature higher than the melting point of the first metal. Figure 7 That is, although the melting point of gold is 1064°C as described above, by increasing the temperature from 1350°C to 1450°C to 1560°C, trr changes and the amount of metal contained in the glass material also changes, proving that gold is immediately melted and not contained in the glass component by heating to a temperature higher than 1064°C.

[0072] In addition, the alloy ratio in the metal container 100 is also important. For example, in the metal container 100, if the first metal, gold, accounts for 3% to 10% by weight and the second metal, platinum, accounts for 90% to 97% by weight, trr can be effectively adjusted. If the amount of the first metal is less than 3% by weight, it becomes difficult to include the metal in the glass component, and it becomes difficult to adjust trr. On the other hand, if the amount of the first metal exceeds 10% by weight, the strength of the metal container 100 will also be weakened after the heating temperature is increased.

[0073] Second embodiment

[0074] Next, a second embodiment of the present invention will be described.

[0075] In the first embodiment, a metal container 100 containing a first metal and a second metal is used. In this embodiment, a first metal and a glass material are put into a metal container 100 containing a second metal. Other aspects are the same as those of the first embodiment, and the second embodiment can also adopt all the configurations adopted in the first embodiment.

[0076] An example of a method for manufacturing the glass film 50 used in the present embodiment will be described.

[0077] A first metal (usually gold) and a glass material are placed in a metal container 100 made of a second metal (usually platinum).

[0078] Next, the glass material is melted in the metal container 100 at the first heating temperature during a first period (melting step). By melting the glass material in the metal container 100 in this way, a metal-containing glass component 110 containing the first metal is generated. The first heating temperature is higher than the melting point of the first metal and lower than the melting point of the second metal. The first period is, for example, 1 to 3 hours, and the first heating temperature is, for example, 1350° C. to 1700° C.

[0079] The prepared metal-containing glass component 110 is disposed on a semiconductor layer such as the second conductive type semiconductor layer 13, thereby forming a glass film 50 (glass film forming step). In this way, the glass film 50 of this embodiment is mixed with a metal such as the first metal. Therefore, by disposing such a glass film 50, the first metal can be dispersed in a semiconductor layer such as the first conductive type semiconductor layer 12 that affects trr control.

[0080] Based on the above, the inventors of the present application have confirmed that when the first metal is placed in the metal container 100 composed of the second metal, the metal container 100 may sometimes dissolve or have holes. Since the glass material will flow out once a hole is opened in the metal container 100, it is not suitable for mass production. In particular, since Pt has a high reactivity, it is easy to cause such a problem of dissolution or hole opening. In addition, when the second metal is Pt, it will become a very expensive metal container 100, so this problem of opening a hole in the metal container 100 is also unbearable in terms of cost. Therefore, from this point of view, the first embodiment is more helpful than the second embodiment.

[0081] Third embodiment

[0082] Next, a third embodiment of the present invention will be described.

[0083] In this embodiment, the first metal and the glass material are placed in a metal container 100 containing the first metal and the second metal. The rest is the same as the first embodiment, and the third embodiment can also adopt all the configurations adopted in the first embodiment.

[0084] An example of a method for manufacturing the glass film 50 used in the present embodiment will be described.

[0085] A first metal (usually gold) and a glass material are placed in a metal container 100 composed of a first metal (usually gold) and a second metal (usually platinum).

[0086] Next, the glass material is melted in the metal container 100 at the first heating temperature during a first period (melting step). By melting the glass material in the metal container 100 in this way, a metal-containing glass component 110 containing the first metal, the second metal, or both the first metal and the second metal is generated. The first heating temperature is higher than the melting point of the first metal and lower than the melting point of the second metal. The first period is, for example, 1 to 3 hours, and the first heating temperature is, for example, 1350° C. to 1700° C.

[0087] The prepared metal-containing glass component 110 is disposed on a semiconductor layer such as the second conductive type semiconductor layer 13, thereby forming a glass film 50 (glass film forming step). In this way, the glass film 50 of this embodiment is mixed with a metal such as the first metal. Therefore, by disposing such a glass film 50, a metal such as the first metal can be dispersed in a semiconductor layer such as the first conductive type semiconductor layer 12 that affects trr control.

[0088] The first metal contained in the glass material means that the first metal gradually disappears from the metal container 100. In this embodiment, the first metal that has been reduced is replenished, and this can be adopted, for example, when the glass material is melted by using the metal container 100 after using it for more than a predetermined number of times. On the other hand, as described in the second embodiment, once the first metal is put into the metal container 100, a hole is opened in the metal container 100, so the amount of the first metal added to the metal container 100 is extremely small.

[0089] The above-described embodiments and the disclosed drawings are merely examples for illustrating the invention described in the claims, and the invention described in the claims is not limited by the above-described embodiments or the disclosed drawings. In addition, the claims initially described in the application are merely examples, and the claims can be appropriately modified based on the description of the specification, drawings, etc.

[0090] Explanation of symbols

[0091] 100 Metal Container

[0092] 110 Metallic glass components

Claims

1. A method for manufacturing a semiconductor device, characterized in that: include: A step of placing a glass material into a metal container containing a first metal and a second metal, or placing a first metal and a glass material into a metal container containing a second metal; A step of melting the glass material in the metal container at a first heating temperature during a first period to generate a metallic glass component containing the first metal or the second metal; as well as The step of placing the metallic glass component on the semiconductor layer, The first heating temperature is higher than the melting point of the first metal and lower than the melting point of the second metal, The first metal is gold and the second metal is platinum.

2. The method for manufacturing a semiconductor device according to claim 1, wherein: in, During a first period, the glass material is melted in the metal container at a first heating temperature, so that the first metal and the second metal are contained in the metal-containing glass component.

3. The method for manufacturing a semiconductor device according to claim 1, wherein: in, The metal container contains the first metal and the second metal, In the metal container, the first metal accounts for 3% to 10% by weight, and the second metal accounts for 90% to 97% by weight.

4. The method for manufacturing a semiconductor device according to claim 1, wherein: in, In the glass material, the content of SiO2 is in the range of 49.5mol% to 64.3mol%, the content of Al2O3 is in the range of 3.7mol% to 14.8mol%, the content of B2O3 is in the range of 8.4mol% to 17.9mol%, the content of ZnO is in the range of 3.9mol% to 14.2mol%, and the content of oxides of alkaline earth metals is in the range of 7.4mol% to 12.9mol%. The first period is 1 to 3 hours, The first heating temperature is greater than 1350° C. and less than 1700° C.

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