TWI720544B - Manufacturing method of semiconductor device - Google Patents

Abstract

The method of manufacturing a semiconductor device includes a step of putting a glass material into a metal container 100 containing a first metal and a second metal, or putting a second metal and a glass material into the metal container 100 containing the first metal; During the period, by melting the glass material in the metal container 100 at the first heating temperature to generate the metal-containing glass component 100 containing the first metal or the second metal; and The step of placing the metal-containing glass component on the semiconductor layer.

Description

Manufacturing method of semiconductor device

The present invention relates to a method of manufacturing a semiconductor device using a glass material and a semiconductor device having a glass film.

In the past, attempts have been made to introduce life time killers for semiconductor devices. For example, in Japanese Patent Laid-Open No. 62-73730, after exposing the surface of each area (1), (2), and (3), a heavy metal thin film with a thickness of 500 to 1000 Å is deposited on the surface, and the temperature is 800 _{Heat treatment in an N 2} environment at ~1000°C for 60 to 120 minutes to diffuse the life inhibitor-containing substance into the substrate. Due to the diffusion of the lifetime inhibitor, the impurity level of the heavy metal in the crystal lattice position or the position between the crystal lattices in silicon becomes the recombination center. During operation, the recombination center moves between the regions. The electrons or holes in between are captured to shorten the switching time of the transistor.

However, in the use of this vapor deposition method, it is difficult to accurately 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 will be a lifetime when heavy metals are added. The temperature dependence of the chromophore becomes larger, and its control is an extremely difficult problem.

In order to solve this problem, Japanese Patent Laid-Open No. 2-51235 proposes a method of introducing a lifetime inhibitor, which is characterized by mixing heavy metal elements in polycrystalline silicon particles. After the powder, the powder adheres to the surface of the silicon substrate, and heat treatment is applied to diffuse heavy metals into the silicon substrate.

However, in this conventional method, compared with a semiconductor device that does not control the lifetime, the number of processes will increase and the manufacturing cost will also increase.

In addition, when trr (reverse recovery time) is controlled in units of μs, electron beam irradiation or the like is required. However, when electron beam irradiation or the like is used, it is necessary to introduce an expensive device.

In view of the above-mentioned problems, an object of the present invention is to provide a semiconductor device manufacturing method capable of controlling trr in units of μs without increasing the number of processes, and a semiconductor device manufactured by the manufacturing method.

[Concept One]

The method of manufacturing a semiconductor device according to the present invention is characterized by including: putting a glass material into a metal container containing a first metal and a second metal, or putting the first metal and a glass material into a metal container containing the second metal Process; a process of generating a metal-containing glass component containing the first metal or the second metal by melting the glass material in the metal container at the first heating temperature during the first period; And the step of arranging the metal-containing glass component on the semiconductor layer.

[Concept two]

In the manufacturing method of the semiconductor device according to the first concept of the present invention, the glass material is melted in the metal container at the first heating temperature during the first period, so that the metal-containing glass component contains The first metal and the second metal.

[Concept Three]

In the manufacturing method of the semiconductor device related to the concept 1 or the concept 2 of the present invention, the first heating temperature is higher than the melting point of the first metal and lower than the melting point of the second metal.

[Concept Four]

In the method of manufacturing a semiconductor device according to any one of Concept 1 to Concept 3 of the present invention, the metal container contains the first metal and the second metal, and in the metal container, the first metal It accounts for 3% to 10% by weight, and the second metal accounts for 90% to 97% by weight.

[Concept 5]

In the method for manufacturing a semiconductor device according to any one of Concept 1 to Concept 4 of the present invention, the first metal is gold and the second metal is platinum.

[Concept Six]

In the method for manufacturing a semiconductor device according to any one of Concept 1 to Concept 5 of the present invention, _{the content of SiO 2} of the glass material is in the range of 49.5 mol% to 64.3 mol%, and the content of _{Al 2} O _{3 is in the range of 49.5 mol% to 64.3 mol%.} Within the range of 3.7mol%~14.8mol%, _{the content of B 2} O ₃ is within the range of 8.4mol%~17.9mol%, the content of ZnO is within the range of 3.9mol%~14.2mol%, the content of alkaline earth metal oxides In the range of 7.4 mol% to 12.9 mol%, the first period is 1 to 3 hours, and the first heating temperature is above 1350°C and below 1700°C.

[Concept Seven]

The semiconductor device according to the present invention is characterized by comprising: a semiconductor layer; and a glass film provided on the semiconductor layer, wherein the semiconductor layer contains dispersed gold, and the semiconductor layer is diffused from the glass film. The gold comes to be controlled by life.

According to the present invention, it is possible to provide a semiconductor device manufacturing method capable of controlling trr in units of μs without increasing the number of processes, and a semiconductor device manufactured by the manufacturing method.

11: First conductivity type semiconductor substrate

12: The first conductivity type semiconductor layer

13: Second conductivity type semiconductor layer

20: first electrode

21: Aluminum silicide film

22: Nickel silicide film

23: Ni (nickel)-P film

30: second electrode

50: glass film

61: Insulating film

62: Insulating film

65: Countertop groove

70: opening

100: metal container

110: Metallic glass component

FIG. 1 is a cross-sectional view of a semiconductor device used in the first embodiment of the present invention.

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

3 is a cross-sectional view showing the process of the manufacturing process of the semiconductor device in which the process is performed from FIG. 2;

4 is a cross-sectional view showing the process of the manufacturing process of the semiconductor device in which the process is performed from FIG. 3;

FIG. 5 is a cross-sectional view showing the process of the manufacturing process of the semiconductor device in which the process is performed from FIG. 4;

Fig. 6 is a cross-sectional view showing a metal container and a metal-containing glass component used in each embodiment of the present invention.

Fig. 7 is a graph showing the relationship between heating time and heating temperature and trr.

The first embodiment

The semiconductor device of this embodiment has a PN junction such as a diode and a thyristor. For example, as shown in FIG. 1, a semiconductor device has: a first conductivity type semiconductor substrate 11 composed of a first conductivity type, and a first conductivity type semiconductor substrate 11 provided on the first conductivity type semiconductor substrate 11 has a higher dopant concentration than the first conductivity type. The semiconductor substrate 11 has a thinner first conductivity type semiconductor layer 12 composed of a first conductivity type, and a second conductivity type semiconductor layer 13 provided on the first conductivity type semiconductor layer 12. Among them, the first conductivity type is, for example, n-type, and the second conductivity type is, for example, p-type. However, it may not be limited to this, the first conductivity type may be p-type, and the second conductivity type may be n-type.

A silicon substrate, a silicon carbide substrate, a gallium nitride substrate, etc. can be used as the first conductivity type semiconductor substrate 11, and the dopant concentration thereof is, for example, 1×10 ¹⁹ cm ^-3 to 1×10 ²⁰ cm ^-3 . The first conductivity type semiconductor layer 12 is formed on the first conductivity type semiconductor substrate 11, for example, by epitaxial growth, and the dopant concentration in the first conductivity type semiconductor layer 12 is, for example, 5×10 ¹⁵ cm ^-3 to 1×10 ¹⁷ cm ^-3 . The thickness of the first conductivity type semiconductor substrate 11 is, for example, 180 μm, and the thickness of the first conductivity type semiconductor layer 12 is, for example, 50 μm. The second conductive type semiconductor layer 13 can be formed by implanting, for example, p-type dopants (for example, boron) on the first conductive type semiconductor layer 12, and the dopant concentration in the second conductive type semiconductor layer 13 is, for example, 1×10. ^{From 16} cm ^-3 to 1×10 ¹⁹ cm ^-3 , the thickness is, for example, 8 μm.

The first electrode 20 is provided on the front surface of the second conductive type semiconductor layer 13, and the second electrode 30 is provided on the back surface of the first conductive type 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 has, for example, an aluminum silicide film 21, a nickel silicide film 22, and a Ni (nickel)-P film 23. The second electrode 30 has a nickel film, and the nickel film has a silicide film.

A glass film 50 as a passivation film is provided around the first electrode 20. This semiconductor device is manufactured according to the following method.

A substrate is prepared. The substrate has: a first conductivity type semiconductor substrate 11 composed of a first conductivity type, provided on the first conductivity type semiconductor substrate 11 and having a higher dopant concentration of the first conductivity type than the first conductivity type semiconductor substrate 11 A thinner first conductivity type semiconductor layer 12 composed of a first conductivity type, and a second conductivity type semiconductor layer 13 provided on the first conductivity type semiconductor layer 12 (refer to FIG. 2).

_{Next, an insulating film 61 made of SiO 2} or the like is formed on the second conductivity type semiconductor layer 13 (refer to FIG. 2 ). _{In addition, an insulating film 62 made of SiO 2} or the like is formed on the back surface of the first conductive type semiconductor substrate 11 (refer to FIG. 2 ).

Subsequently, as shown in FIG. 3, the formed insulating film 61 is used as a mask, and etching is performed to form a mesa trench 65. As the etching in this embodiment, dry etching, wet etching, or the like can be used.

Next, as shown in FIG. 4, a protective film (passivation film) is formed by the glass film 50 so as to cover the mesa trench 65 and the insulating film 61 after the formation.

Subsequently, as shown in FIG. 5, an opening 70 is formed on the insulating film 61 and the glass film 50 after formation by etching.

In addition, the first electrode 20 is formed on the opening on the front side, and the second electrode 30 is formed on the back side (see FIG. 1).

Next, an example of the manufacturing method of the glass film 50 used in this embodiment is demonstrated.

When manufacturing the glass film 50 according to the present embodiment, a glass material is put into the metal container 100 (see FIG. 6) containing the first metal and the second metal as a raw material for making glass (glass material input 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) can also be used in addition to gold. The metal container 100 may contain metals other than the first metal and the second metal, or may be composed of an alloy of the first metal, the second metal, and the third metal, or may be an alloy of four or more components. constitute.

For example, _{the content of SiO 2} in the glass material is in the range of 49.5 mol% to 64.3 mol%, _{the content of Al 2} O ₃ is in the range of 3.7 mol% to 14.8 mol%, and the content of B ₂ O ₃ is in the range of 8.4 mol%. In the range of 17.9 mol%, the content of ZnO is in the range of 3.9 mol% to 14.2 mol%, and the content of alkaline earth metal oxides is in the range of 7.4 mol% to 12.9 mol%.

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 two metals of 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, 1350°C or more and 1700°C or less. In addition, the melting point of gold is 1064°C and the melting point of platinum is 1768°C.

The glass film 50 is formed by disposing the metal-containing glass composition 110 prepared as described above on a semiconductor layer such as the second conductivity type semiconductor layer 13 (glass film forming process). Specifically, the melted metal-containing glass component 110 is cooled and pulverized into a particle size of several μm, and the pulverized metal-containing glass component 110 is disposed on the first conductive semiconductor substrate 11, the first conductive semiconductor After the layer 12 and the second conductive type semiconductor layer 13 are formed on the semiconductor layer, the metal-containing glass component 110 is melted (see FIG. 4). In FIG. 4, although the mesa trench 65 is provided up to the first conductivity type semiconductor substrate 11, this is only one example, and it can also be used in the first conductivity type semiconductor substrate 11 and the first conductivity type semiconductor substrate 11. The mesa trench 65 is provided on the layer 12 and the mesa trench 65 is not provided on the first conductivity type semiconductor substrate 11.

The glass film 50 in this embodiment contains a metal such as a first metal. Therefore, by providing such a glass film 50, it is possible to use the first conductivity type semiconductor layer 12 that affects trr control. A small amount of metal such as the first metal is dispersed in the semiconductor layer. In this way, according to the confirmation of the inventors of the present application, trr (reverse phase recovery time) in the semiconductor layer can be set to 5 μs or more and 15 μs or less, thereby enabling life control. In addition, the ideal situation of trr is above 5μs and below 11μs, and the more ideal situation is above 5μs and below 8μs. In addition, in the conventional form of adding heavy metals, since a large amount of heavy metals is added compared with the present embodiment, it is impossible to control trr in units of μs.

The experimental results are shown in Figure 7. In this experiment, the resistivity ρ=30Ω is used. cm wafers. As shown in Figure 7, when purely using Pt as the metal container 100, trr is about 22μs, when using a Pt-Au crucible containing gold in platinum (Au content is 5 wt%), trr can be reduced . Specifically, as shown in FIG. 7, after the glass material is melted in a Pt-Au crucible at a temperature of 1350°C for 5 hours, the glass composition (metal-containing glass component 110) is placed in the semiconductor layer. The trr in the semiconductor layer is about 15 μs. After the glass material was melted in the Pt-Au crucible at a temperature of 1450°C for 1 hour, the glass composition (metallic glass component 110) was placed in the semiconductor layer. At this time, the trr in the semiconductor layer was approximately 14μs. After the glass material was melted in the Pt-Au crucible at a temperature of 1450°C for 2 hours, the glass composition (the metallic glass component 110) was placed in the semiconductor layer, and the trr in the semiconductor layer was about 11μs. After melting the glass material in the Pt-Au crucible at a temperature of 1560°C for 1 hour, the glass composition (containing the metallic glass component 110) is placed in the semiconductor layer, and the trr in the semiconductor layer is about 8μs. After the glass material was melted in the Pt-Au crucible at a temperature of 1560°C for 2 hours, the glass composition (metallic glass component 110) was placed in the semiconductor layer, and the trr in the semiconductor layer was about 8μs. In addition, after the inventor’s confirmation, it can be considered that gold has easy integration The nature of the glass composition, therefore, compared to rhodium (Rh), using gold (Au) as the first metal is helpful to be able to easily control trr.

"effect"

Hereinafter, an example of the effect according to the present embodiment will be described. In addition, all the forms described in "Effects" can be adopted.

Traditionally, glass has been melted in a vessel such as a crucible. In this embodiment, since only glass is melted according to the conventionally used process, this embodiment is different from the form of adding heavy metals or performing electron beam irradiation, and can control trr without increasing the number of processes. In addition, according to the present embodiment, trr can be controlled in units of μs. Therefore, it is possible to control trr in units of μs while preventing the increase in the manufacturing cost of semiconductor devices such as wafers.

As a method of controlling trr in units of μs, specifically, by adjusting temperature and time, it is possible to adjust trr in the semiconductor layer as shown in FIG. 7. Therefore, it is possible to adjust trr in an extremely simple method by adjusting the temperature and time according to the required trr in each semiconductor device. In addition, as shown in Fig. 7, by adjusting the temperature, trr can be controlled more effectively than adjusting the time. Ideally, heating is performed at a temperature greater than or equal to 1400°C, more ideally, heating is performed at a temperature greater than or equal to 1500°C, and more ideally, heating is performed at a temperature greater than or equal to 1550°C.

In addition, in recent years, in the PFC (Power Factor Correction) of the air conditioner, the partial switch method (simple PAM) has occupied the majority. In the simple PAM operation mode, the use of diode bridge as part of the switch is added, which requires improvement of the diode bridge trr characteristics. In addition, in semiconductor devices such as IGBTs that do not want to increase the forward loss but require a certain degree of switching speed, sometimes it is necessary to control trr in μs. In this regard, according to the present embodiment, it is not necessary to perform an additional process, and thus, it is possible to reduce the cost while being helpful for improving the trr characteristic in μs.

In the case of using conventional heavy metal diffusion, although trr can be controlled in units of ns, it is difficult to control it in units of μs. If electron beam irradiation is used, trr can be controlled in units of μs, but expensive equipment must be introduced. In this regard, according to the present embodiment, it is also explained that trr can be controlled in units of μs without introducing expensive equipment.

By setting the first heating temperature to be higher than the melting point of the first metal, the first metal, the second metal, or two metals of the first metal and the second metal can be contained in the glass composition. In addition, when the first metal and the second metal in the metal container 100 become an alloy, even if it is heated to a temperature higher than the melting point of the first metal, the first metal will not melt immediately. This can also be confirmed in Figure 7 by increasing the temperature to decrease trr. In other words, although the melting point of gold is 1064°C as mentioned above, by increasing the temperature to 1350°C→1450°C→1560°C, trr changes and the amount of metal contained in the glass material also changes, which proves By heating to a temperature higher than 1064°C, the gold will melt immediately and will not be contained in the glass composition.

In addition, the alloy ratio in the metal container 100 is also important. For example, in the metal container 100, if the first metal as gold accounts for 3 wt% to 10 wt%, and the second metal as platinum accounts for 90 wt% to 97 wt%, trr can be effectively adjusted. Once the amount of the first metal is less than 3% by weight, it becomes difficult to make the glass It will be difficult to adjust trr. On the other hand, if the amount of the first metal is more than 10% by weight, the strength of the metal container 100 will also become weak after the heating temperature is increased.

Second embodiment

Next, the second embodiment of the present invention will be described.

In the first embodiment, the metal container 100 containing the first metal and the second metal is used. In this embodiment, description is made using a form in which the first metal and the glass material are put into the metal container 100 containing the second metal. The rest is the same as the first embodiment, and the second embodiment can also adopt all the configurations adopted in the first embodiment.

An example of the manufacturing method of the glass film 50 used in this embodiment is demonstrated.

The first metal (usually gold) and the glass material are put into the metal container 100 made of the second metal (usually platinum).

Next, the glass material is melted in the metal container 100 at the first heating temperature in the first period (melting step). By melting the glass material in the metal container 100 in this way, the metal-containing glass component 110 containing the first metal is produced. 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 or more and 1700°C or less.

The glass film 50 is formed by disposing the prepared metal-containing glass composition 110 on a semiconductor layer such as the second conductive type semiconductor layer 13 (glass film forming process). In this way, the glass film 50 of the present embodiment is mixed with metals such as the first metal. Therefore, by setting this The glass film 50 can disperse the first metal in a semiconductor layer such as the first conductivity type semiconductor layer 12 that affects trr control.

Based on the above, the inventor of the present application confirmed that when the first metal is put in the metal container 100 made of the second metal, the metal container 100 may dissolve or open 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 high reactivity, it is easy to cause such elution or open pores. In addition, when the second metal is Pt, it becomes a very expensive metal container 100. Therefore, the problem of opening holes in the metal container 100 is also unbearable for cost. Therefore, from this point of view, the first embodiment is more explanatory than the second embodiment.

The third embodiment

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

In this embodiment, description is made using a form in which the first metal and the glass material are put into the 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.

An example of the manufacturing method of the glass film 50 used in this embodiment is demonstrated.

A first metal (usually gold) and a glass material are put into a metal container 100 made of a first metal (usually gold) and a second metal (usually platinum).

Next, the glass material is melted in the metal container 100 at the first heating temperature in the first period (melting step). By melting the glass material in the metal container 100 in this way, To generate a metal-containing glass component 110 containing the first metal, the second metal, or the two metals of the first metal and the second metal. 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 or more and 1700°C or less.

The glass film 50 is formed by disposing the prepared metal-containing glass composition 110 on a semiconductor layer such as the second conductive type semiconductor layer 13 (glass film forming process). In this way, the glass film 50 of the present embodiment is mixed with metals such as the first metal. Therefore, by providing such a glass film 50, it is possible to disperse metals such as the first metal in a semiconductor layer such as the first conductivity type semiconductor layer 12 that affects trr control.

The inclusion of the first metal in the glass material means that the first metal gradually disappears from the metal container 100. In the present embodiment, there is a meaning to supplement such a reduced first metal, and it can be adopted when, for example, the metal container 100 is used more than a predetermined number of times to melt the glass material. On the other hand, as explained in the second embodiment, once the first metal is put into the metal container 100, holes are opened in the metal container 100, so the amount of the first metal added to the metal container 100 It is very small.

The above-described embodiments and the disclosed drawings are merely examples for explaining the invention described in the claims, and the inventions described in the claims are not limited by the above-described embodiments or the disclosed drawings. In addition, the claims described at the beginning of the application are only examples, and the description of the claims can be appropriately changed based on descriptions in the specification, drawings, and the like.

11: First conductivity type semiconductor substrate

12: The first conductivity type semiconductor layer

13: Second conductivity type semiconductor layer

20: first electrode

21: Aluminum silicide film

22: Nickel silicide film

23: Ni (nickel)-P film

30: second electrode

50: glass film

61: Insulating film

62: Insulating film

65: Countertop groove

Claims (6)

A method of manufacturing a semiconductor device includes: putting a glass material into a metal container containing a first metal and a second metal, or putting the first metal and the glass into the metal container containing the second metal Material process; in the first period, the glass material is melted in the metal container at the first heating temperature to generate a metal-containing glass component containing the first metal or the second metal The process; and the process of providing the metal-containing glass component on the semiconductor layer. The method of manufacturing a semiconductor device according to claim 1, wherein in the first period, the glass material is melted in the metal container at the first heating temperature, so that the metal-containing The glass component contains the first metal and the second metal. The method of manufacturing a semiconductor device according to claim 1, wherein 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 method of manufacturing a semiconductor device according to claim 1, wherein 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. The method of manufacturing a semiconductor device according to claim 1, wherein the first metal is gold and the second metal is platinum. The method of manufacturing a semiconductor device according to claim 1, wherein, in the glass material, _{the content of SiO 2} is in the range of 49.5 mol% to 64.3 mol%, and _{the content of Al 2} O ₃ is in the range of 3.7 mol% to 14.8 mol%. In the range of mol%, _{the content of B 2} O ₃ is in the range of 8.4 mol% to 17.9 mol%, the content of ZnO is in the range of 3.9 mol% to 14.2 mol%, and the content of alkaline earth metal oxides is in the range of 7.4 mol%. Within the range of 12.9 mol%, the first period is 1 to 3 hours, and the first heating temperature is above 1350°C and below 1700°C.

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