JP6375586B2 - Manufacturing method of semiconductor device - Google Patents

Description

  The present invention relates to a method for manufacturing a semiconductor device.

  In a semiconductor device, in order to prevent deterioration from the semiconductor surface, a passivation film is provided to improve reliability. Therefore, a passivation film is generally formed on the outermost surface of a semiconductor device as a final process of semiconductor manufacturing. The passivation film can isolate and protect the semiconductor device from the external environment, and can mechanically and chemically protect the surface of the semiconductor device. Further, in order to enhance the passivation effect, a film made of an oxide and an organic film such as polyimide are combined.

For example, in Patent Document 1 and Patent Document 2, an oxide film (SiO ₂ ) film and a polyimide film are used in combination as a surface protective layer (passivation film) of a semiconductor device. A polyimide film is excellent in thermal and chemical properties as a protective film, has a low dielectric constant (usually 3.2 to 3.4), is rich in elongation characteristics, and is excellent in thermal expansion coefficient. Therefore, in addition to being used alone as a passivation film, a method of combining with an oxide film has been applied in various fields related to electronics.

  Usually, a plurality of semiconductor devices are formed on a single substrate in order to improve production efficiency. As described above, when an organic film such as polyimide is formed as a passivation film on a plurality of semiconductor devices formed on the substrate, it is generally formed on the entire substrate by spin coating or the like. This is because each semiconductor device is very small, and it is common sense that it is impossible to form a passivation film for each semiconductor device.

However, when an organic passivation film is applied to the substrate by spin coating or the like, there is a problem that the thickness of the passivation film on the periphery of the substrate becomes thick due to surface tension. If the thickness of the passivation film is increased in part, there arises a problem that the dicing blade is worn in a dicing process for dividing a plurality of semiconductor devices.
For this reason, an edge rinse is generally performed around the substrate after applying an organic passivation film by spin coating or the like. At this time, the edge rinse is carried out by adjusting the rinse liquid so as to hit a position of about several hundred μm from the outer peripheral edge of the substrate, rotating the substrate in this state, and performing edge rinse over the periphery of the substrate. .

JP 2002-203851 A JP-A-8-293492

  However, in the case of a substrate on which orientation flat (orientation flat: OF) is formed, the rinsing liquid does not reach the orientation flat portion by the above-described edge rinsing method, and the passivation film on the orientation flat portion cannot be removed. Since the organic passivation film remaining on the orientation flat portion is thick, there is a problem that the dicing blade is worn. Further, when the wear becomes severe, there is a problem that the frequency of replacement of the dicing blade is increased and the cost and productivity are remarkably deteriorated. The orientation flat portion is a region having a width of about several hundred μm from the outer peripheral edge of the orientation flat portion substrate.

  On the other hand, it is conceivable to design the system so that the discharge port of the rinse liquid is movable and the rinse liquid flows along the periphery of the substrate. However, in this case, it is necessary to move the discharge port of the rinse liquid in accordance with the arc portion of the substrate and the linear portion of the orientation flat. As described above, in order to drive the rinse outlet in a complicated manner, a drive control facility is required, which is expensive. Conversely, when the discharge port is fixed and the substrate is driven so as to correspond to the orientation flat, it is necessary to control the rotation of the substrate, which is costly.

It is also conceivable to reduce damage to the dicing blade by reducing the dicing speed. However, if the dicing speed is lowered, the throughput is lowered and the production efficiency is remarkably deteriorated.
Further, it is conceivable to remove a region where the organic passivation film remains and deposits by cutting and removing one row of semiconductor devices formed along the orientation flat among the plurality of formed semiconductor devices. However, in this method, semiconductor devices that should originally be usable are removed at the same time, resulting in a decrease in yield.

  As described above, there is no proposal for a method for manufacturing a semiconductor device that can easily and inexpensively remove an organic passivation film formed on a semiconductor device over the entire circumference of the substrate on which the orientation flat is formed. The fact was not. Therefore, there has been a strong demand for a method of manufacturing a semiconductor device that suppresses the wear of the dicing blade due to the positive photosensitive film (passivation film) remaining in the orientation flat portion.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a method of manufacturing a semiconductor device that can easily and inexpensively remove a passivation film over the entire circumference of a substrate on which an orientation flat is formed. To do.

As a result of intensive studies, the present inventors have found that the positive photosensitive film formed on the orientation flat part can be partially exposed and removed at the same time as the part subjected to pattern exposure during development, thereby completing the present invention.
That is, the present invention provides the following means in order to solve the above problems.

(1) A method of manufacturing a semiconductor device of the present invention includes a step of forming a semiconductor device on a substrate on which an orientation flat is formed, a step of forming a positive photosensitive film so as to cover the semiconductor device, and a periphery of the substrate Edge rinsing, pattern exposing a positive photosensitive film formed on the pad electrode of the semiconductor device, partially exposing a depositing portion of the positive photosensitive member accumulated in the orientation flat portion of the substrate, Developing and curing the positive photosensitive film.

(2) In the semiconductor device manufacturing method described in (1), an exposure focus may be set on the deposition portion.

(3) In the method of manufacturing a semiconductor device described in either (1) or (2), the partial exposure may be performed with a mask aligner.

(4) In the method for manufacturing a semiconductor device described in either (1) or (2), the partial exposure may be performed with a stepper.

  The method for manufacturing a semiconductor device of the present invention includes a step of partially exposing a depositing portion of a positive photosensitive member accumulated in an orientation flat portion of a substrate. By partially exposing the depositing portion of the positive photosensitive film accumulated in the orientation flat portion of the substrate, the depositing portion of the positive photosensitive film can be easily and inexpensively removed at the same time as the pattern exposure at the time of development.

  In the method of manufacturing a semiconductor device according to the present invention, the exposure focus may be adjusted to the deposited portion of the positive photosensitive film accumulated in the orientation flat portion of the substrate in the partial exposure. The deposited portion of the positive photoconductor is about twice as thick as other flattened positive photoconductor films (flat portions). Therefore, in the partial exposure, the positive photoconductor film can be sufficiently exposed by focusing the exposure focus on the positive photoconductor accumulation portion accumulated in the orientation flat portion of the substrate, and the positive photosensitivity layer completely accumulated in the orientation flat portion by development. The body can be removed.

In the method for manufacturing a semiconductor device of the present invention, partial exposure may be performed with a mask aligner.
The orientation flat portion is linear and does not have a particularly complicated shape. For this reason, by using a mask aligner that shields the portion other than the orientation flat portion, the positive photosensitive member accumulated in the orientation flat portion can be exposed at once.

  In the method for manufacturing a semiconductor device of the present invention, partial exposure may be performed with a stepper. The pattern exposure process, which is a pre-process of partial exposure, is generally performed with a stepper. By using a stepper for the partial exposure process, it is not necessary to change the apparatus for each process, and the production efficiency can be increased. Further, when partially exposing the orientation flat portion, a light shielding mask is not necessary. Therefore, it is possible to expose the positive photosensitive member accumulated in the orientation flat portion at a low cost without requiring an expensive mask.

It is a plane schematic diagram of the board | substrate with which the orientation flat was formed. The cross-sectional schematic diagram of a Schottky barrier diode is shown. It is the cross-sectional schematic diagram which expanded the orientation flat edge part of the Schottky barrier diode formed in the most orientation flat side after positive photoconductor film application | coating. It is the top view which showed typically the process of carrying out the edge rinse of the circumference | surroundings of a board | substrate. It is the schematic diagram which illustrated the pattern exposure process typically. It is the figure which showed the partial exposure by a stepper typically. It is the figure which showed typically the partial exposure by a mask aligner. 2 is a plan photograph of an orientation flat portion in the case of Example 1. FIG. 6 is a plane photograph of an orientation flat portion in the case of Example 3. FIG. 3 is a plane photograph of an orientation flat portion in the case of Comparative Example 1.

Hereinafter, a semiconductor device manufacturing method to which the present invention is applied will be described in detail with reference to the drawings as appropriate.
In the drawings used in the following description, in order to make the characteristics of the present invention easier to understand, the characteristic parts may be shown in an enlarged manner for the sake of convenience, and the dimensional ratios of the respective components are different from actual ones. Sometimes. In addition, the materials, dimensions, and the like exemplified in the following description are examples, and the present invention is not limited to them, and can be appropriately changed and implemented without changing the gist thereof.
As described above, an oxide film such as SiO ₂ or a nitride film such as Si ₃ N ₄ is also used as the passivation film, and may be used in combination with an organic film such as polyimide. In the following description, a structure using an SiO ₂ film as one of the passivation films is illustrated. Among these passivation films, the SiO ₂ film that is not an organic film is distinguished from a positive photosensitive film that is an organic film of interest in the present invention.

  A method of manufacturing a semiconductor device according to the present invention includes a step of forming a plurality of semiconductor devices on a substrate on which an orientation flat is formed, a step of forming a positive photosensitive film so as to cover the semiconductor device, and a periphery of the substrate. Edge rinsing, pattern exposure of a positive photosensitive film formed on the pad electrode of the semiconductor device, partial exposure of a positive photosensitive accumulation portion accumulated in the orientation flat portion of the substrate, Developing and curing the positive photosensitive film. Each semiconductor device is produced by dividing the substrate after development and curing.

[Semiconductor device formation process]
FIG. 1 is a schematic plan view of a substrate on which an orientation flat is formed. The substrate 1 is provided with a straight line portion called an orientation flat (orientation flat) 1a on the outer peripheral portion thereof. Moreover, the linear part called the 2nd orientation flat (index flat) 1b may be provided. The orientation flat 1a is provided so that the direction of the crystal axis can be seen. Further, the crystal orientation and front and back of the substrate 1 can be determined from the positional relationship with the second orientation flat 1b.
In recent years, a notch called a notch is also formed on a silicon substrate, but an SiC substrate having an orientation flat 1a is generally used.

A plurality of semiconductor devices are fabricated on the substrate 1. In Figure 1, each region surrounded by the vertical line 1L ₁ and horizontal 1L _2, to prepare a semiconductor device, along a vertical line 1L ₁ and horizontal line 1L _2, producing a plurality of semiconductor devices by cutting the substrate can do.
Here, the semiconductor device is not particularly limited, and a light-emitting diode element, a solar cell element, a transistor element, or the like can be manufactured. Hereinafter, a Schottky barrier diode (SBD) formed on a SiC substrate will be described as an example.

FIG. 2 is a schematic cross-sectional view of a Schottky barrier diode. The Schottky barrier diode 10 includes a substrate 1, an n-type SiC epitaxial layer 2 formed on one surface (surface) of the substrate 1, and a plurality of p-type impurity diffusion regions 3 formed in a surface layer of the n-type Si epitaxial layer 2. A plurality of p-type ohmic electrodes 4 formed on the surface of the p-type impurity diffusion region 3, and a surface of the n-type SiC epitaxial layer 2 so as to cover the plurality of p-type impurity diffusion regions 3 and the p-type ohmic electrode 4 A Schottky electrode 5 formed thereon and a surface pad electrode 6 formed on the Schottky electrode 5 are provided. Further, an n-type ohmic electrode 7 and a back-side pad electrode 8 formed so as to cover the n-type ohmic electrode 7 are formed on the back surface of the substrate 1.
The p-type impurity diffusion region 3 has a high-concentration p-type impurity diffusion region 3a and a low-concentration p-type impurity diffusion region surrounding the high-concentration p-type impurity diffusion region 3a depending on the doping amount (concentration) of the p-type impurity. It is comprised from the area | region 3b.

The Schottky barrier diode 10 is manufactured by the following procedure.
First, an n-type SiC epitaxial layer 2 is epitaxially grown on one surface of the substrate 1 using the CVD method or the like. Next, by ion-implanting a part of the n-type SiC epitaxial layer 2, the high-concentration p-type impurity diffusion region 3a and the low-concentration p-type impurity diffusion region 3b surrounding the high-concentration p-type impurity diffusion region 3a. And form. At this time, ion implantation only at a predetermined position can be realized by ion implantation through an oxide film having a predetermined shape formed by a resist pattern.
Next, a plurality of p-type ohmic electrodes 4 are formed side by side on the surface of the p-type impurity region 3. The p-type ohmic electrode 4 can be formed by sputtering through a resist pattern or the like. As the p-type ohmic electrode 4, Ti, Al, or a laminate thereof can be used.
Further, the Schottky electrode 5 and the surface pad electrode 6 are laminated by sputtering or vapor deposition so as to cover the plurality of p-type ohmic electrodes 4. At this time, lamination is performed only in a predetermined region using a resist pattern or the like. As the Schottky electrode 5, for example, Mo can be used, and as the surface pad electrode 6, for example, a stacked body of Ni, Ti, and Al films can be used.
The n-type ohmic electrode 7 is generally formed before the p-type ohmic electrode 4 is formed. Specifically, it can be formed by forming a Ni film on the back surface of the substrate 1 by, for example, sputtering or vapor deposition and performing heat treatment in an inert gas or vacuum atmosphere.
Further, the back pad electrode 8 can be formed by forming a metal layer made of Ag or the like by sputtering after forming a positive photosensitive film to be described later.

[SiO ₂ film forming step]
In addition to the positive photosensitive film, a passivation film 11 of an SiO ₂ film may be formed. The SiO ₂ film can be formed between the SiC epitaxial film and the positive photosensitive film so as to be in contact with the surface of the SiC epitaxial film. Since the SiO ₂ film has excellent moisture resistance, the passivation effect can be further enhanced in combination with the positive photosensitive film.
The SiO ₂ film can be formed by forming a mask by a known photoresist process, forming a SiO ₂ film by CVD, and removing the mask. The SiO ₂ film is provided so as to cover the surface of the SiC epitaxial layer. In FIG. 2, the thickness of the SiO ₂ film is the same as the total thickness of the p-type ohmic electrode and the surface pad electrode, but it may be thinner or thicker than the surface pad electrode. It is good also as a shape which covers a part of edge part of this.

[Positive photoconductor film forming process]
Next, a positive photosensitive film 20 is formed so as to cover the semiconductor device (Schottky barrier diode) 10.
The positive photosensitive film 20 can be applied to the entire surface of the substrate 1 using spin coating or the like. FIG. 3 is an enlarged cross-sectional schematic view of the orientation flat end of the Schottky barrier diode formed on the most orientation flat side after the positive photosensitive film is applied. In the figure, the right side is the orientation flat 1a side. A positive photosensitive member accumulates on the outer periphery of the substrate 1 due to surface tension. In particular, as shown in FIG. 3, since the orientation flat portion 1 c is formed with a straight portion in plan view, the positive photosensitive film 20 is less likely to flow out of the substrate 1 than the outer peripheral portion having other arcs. For this reason, the positive photosensitive member accumulates and the accumulation portion 20b is easily formed. The place other than the deposition part 20b is formed almost flat by spin coating, and becomes a flat part 20a.
The thickness of the deposition part 20b formed in the orientation flat part 1c is about twice as thick as the flat part 20a. For example, when the thickness of the flat portion of the positive photosensitive film is designed to be 8 to 9 μm and spin coating is performed, the positive photosensitive film is accumulated with a width of 0.8 mm from the outer peripheral edge of the substrate 1, and the height of the top portion is increased. It becomes about 16-18 μm. The thickness of the positive photosensitive film can be 4 to 12 μm, preferably 6 to 10 μm, and more preferably 7 to 9 μm.
Here, the “orientation flat portion” is a region having a width of several hundred μm from the outer peripheral edge of the substrate of the orientation flat portion, and means a region where a positive photosensitive member is accumulated and a deposition portion is formed. Further, the “deposition portion” means a region having a thickness of 1.5 times or more with respect to the film thickness at the central portion of the substrate.

  The positive photosensitive film is not particularly limited, but a film using polyimide, polybenzoxazole, or the like can be used. A positive polyimide film is preferable because it is common and easily available.

  The conditions for spin coating are preferably 2000 rpm to 2500 rpm when the viscosity is 2000 cP to 4000 cP. By setting this range, it is possible to suppress the thickness of the positive photosensitive member accumulated in the outer peripheral portion and the orientation flat portion.

Before forming the positive photosensitive film 20, it is preferable to dehydrate and bake the substrate 1 on which the semiconductor device is formed. This is because moisture causes deterioration of the semiconductor device and is preferably removed as much as possible. In particular, since the organic semiconductor layer and the like are significantly deteriorated by moisture, it is preferable to perform dehydration baking.
By performing dehydration baking, moisture remaining inside the semiconductor device can be removed, and by forming the positive photosensitive film 20 after dehydration baking, moisture from the external environment can also be blocked.

  The conditions for the dehydration baking are not particularly limited, but it is preferably performed at 100 ° C. to 200 ° C. for 30 seconds to 5 minutes. Moreover, it is more preferable to carry out at 130 to 170 degreeC for 30 second-2 minutes. Thereby, moisture can be removed without damaging the organic layer.

  Further, it is preferable to slightly bake after coating the positive photosensitive film 20. The baking is preferably performed at 100 ° C. to 150 ° C. for 1 second to 10 seconds. Since the positive photosensitive film 20 after coating has fluidity, the fluidity can be suppressed by slightly baking, and the controllability of the latter half process described later can be improved.

[Edge rinse process]
Next, edge rinsing is performed around the substrate 1. FIG. 4 is a plan view schematically showing the step of edge rinsing around the substrate. The edge rinse is performed in order to remove the positive photosensitive member accumulated on the outer peripheral portion in the coating process of the positive photosensitive member film 20 described above.
As shown in FIG. 4, a discharge port 30 for discharging a rinsing liquid is provided on the outer peripheral portion of the substrate 1, and the rinsing liquid is discharged from the discharge port 30 to a predetermined width from the outer peripheral end of the substrate 1. By rotating the substrate 1 in a state where the rinse liquid is discharged to a predetermined width from the outer peripheral end, the positive photosensitive member accumulated at the outer peripheral end of the substrate 1 can be removed.
Here, the “predetermined width” is a width that can cover the width of the portion where the positive photoconductor is accumulated and the film thickness is thick, and the film thickness of the positive photoconductor film is 1.5% with respect to the central portion of the substrate. A case where the thickness is twice or more is defined as “a state where the positive photosensitive member is accumulated”.

  At this time, the orientation flat 1 a and the second orientation flat 1 b exist inside the outer peripheral end of the substrate 1. Therefore, when all the positive photosensitive film 20 accumulated in the orientation flat portion 1c of the orientation flat 1a and the orientation flat portion 1d of the second orientation flat 1b is to be removed, the orientation flat portion 1c enters the inside from the end of the substrate at the center of the orientation flat 1a. It is necessary to discharge the rinsing liquid to the remaining area (since the first orientation flat is generally formed inside the second orientation flat). When the substrate 1 is rotated in such a configuration, the positive photosensitive film 20 that does not need to be removed in other regions (such as the outer peripheral edge of the arc) is removed. That is, a semiconductor device that can be used originally cannot be used, and the yield decreases.

  In order to maintain the yield, it is necessary to have a configuration in which the rinsing liquid is discharged to a predetermined width from the outer peripheral end. However, in this case, the rinse solution does not reach the orientation flat portion 1c, and the positive photosensitive film 20 on the orientation flat portion 1c cannot be removed. Therefore, in this invention, the polyimide film 20 of the said part can be easily removed by providing the partial exposure process mentioned later.

  The rinse liquid is not particularly limited as long as it can dissolve the positive photosensitive film 20, but thinner or the like can be used.

[Pre-baking process]
The applied positive photosensitive film is pre-baked before the step before pattern exposure. The pre-baking conditions are preferably performed at a temperature of 100 ° C. to 150 ° C. for 5 minutes to 20 minutes. By performing pre-baking, the positive photoreceptor after application is sufficiently solidified. Further, by carrying out within the above condition range, the solvent remaining in the positive photosensitive member can be evaporated to make the film dense.

[Pattern exposure process]
Next, the positive photosensitive film formed on the pad electrode of the semiconductor device is subjected to pattern exposure. The removal of the positive photosensitive film 20 formed on the pad electrode (surface pad electrode) 6 of the semiconductor device 10 is performed in order to connect the wiring to the semiconductor device 10. If this process is not performed, it does not function as a semiconductor device, so it is an essential process.
FIG. 5 is a schematic view schematically showing the pattern exposure process. As shown in FIG. 5, pattern exposure is performed on the positive photosensitive film 20 formed on the pad electrode (surface pad electrode) 6. The pattern exposure can be performed using an exposure mask in which a light shielding portion is formed. In addition, a plurality of semiconductor devices 10 formed on the substrate 1 can be subjected to pattern exposure on a predetermined region over the entire surface of the substrate 1 by performing shots for each semiconductor device 10 using a stepper. At this time, the exposure focus is set to the surface of the flat portion of the positive photosensitive film opposite to the substrate 1. Generally, Cr or the like is used for the light shielding portion.

In the pattern exposure step, it is preferable to simultaneously expose the positive photosensitive film 20 on the scribe line between the semiconductor devices. The scribe line corresponds to the vertical line 1L ₁ and the horizontal line 1L ₂ in FIG. By performing pattern exposure on this portion as well, the positive photosensitive film 20 on the scribe line can be removed in a development process described later. By removing the positive photosensitive film in this portion, it is possible to suppress damage to the dicing blade during dicing.

[Partial exposure process]
Next, the positive photosensitive member accumulation portion accumulated in the orientation flat portion of the substrate 1 is partially exposed. The partial exposure may be performed using a mask aligner, or may be performed using a blank mask with a stepper.

First, the case where it is performed by a stepper will be described. FIG. 6 is a diagram schematically showing partial exposure by a stepper. The light is collected by the lens 41 through the blank mask 40 and irradiated onto the substrate 1. The condensed light is applied to the orientation flat portions 1c and 1d in FIG. Therefore, the orientation flat portions 1c and 1d can be partially exposed.
At this time, if a stepper is used, a shot can be made for each predetermined region, so that only the orientation flat portions 1c and 1d can be shot. That is, an expensive light-shielding mask is not required, and the positive photoreceptor film accumulated in the orientation flat portion can be partially exposed at a low cost. Moreover, since the pattern exposure process of the process before partial exposure is generally performed by a stepper, the partial exposure process also uses a stepper, so that it is not necessary to change the apparatus for each process. Furthermore, since partial exposure can be performed only by removing the exposure mask in the pattern exposure process, the process can be simplified.

  Next, a case where a mask aligner is used will be described. FIG. 7 is a diagram schematically showing partial exposure by a mask aligner. Since the mask aligner does not use a lens or the like, the irradiated light is directly exposed on the substrate 1. Therefore, when the exposure mask 50 in which the light shielding part 51 is formed is used, only a part where the light shielding part 51 is not formed is exposed. Therefore, partial exposure can be performed at a time by forming the light-shielding portion 51 so that only the orientation flat portions 1c and 1d are exposed. The orientation flat portions 1c and 1d are linear and do not have a particularly complicated shape. The design of the light shielding part 51 can be very simple. Therefore, by using the mask aligner, it is possible to expose the positive photosensitive member accumulated in the orientation flat portion at once very easily.

  Further, in the partial exposure, it is preferable to focus the exposure on the positive photosensitive member deposition portion 20b (see FIG. 3) accumulated in the orientation flat portion 1c of the substrate 1. It is more preferable to focus on the top portion 20c of the deposition portion 20b. The deposited portion 20b is about twice as thick as the positive photosensitive film of the other flat portion 20a. Therefore, when the focal point is adjusted to the same height as the pattern exposure (the surface of the flat portion 20a opposite to the substrate 1), the positive photosensitive member of the deposition portion 20b cannot be sufficiently exposed. By focusing the exposure on the deposition portion 20b accumulated in the orientation flat portion 1c of the substrate 1, the positive photoreceptor film 20 can be sufficiently exposed, and the positive photoreceptor film 20 completely accumulated in the orientation flat portion 1c is removed by development. can do. Here, the “top portion” means a position farthest from the substrate 1 in the deposition portion 20b, and when a flat surface is formed on the top portion 20c of the deposition portion 20b, any position of the flat surface is used. Good.

[Development and curing process]
The positive photosensitive film exposed as described above is developed and cured. By performing development, it is possible to remove a portion exposed by pattern exposure and partial exposure of the positive photosensitive film. It is preferable to rinse with pure water after development. The semiconductor device after rinsing with pure water is more preferably blow-dried. By rinsing with pure water, impurities that did not flow down with the developer can be removed. Further, by removing moisture by blow drying, the positive photosensitive film can be uniformly heated in the curing process.
Further, the positive photosensitive film is cured completely by curing the developed positive photosensitive film. By this step, the influence of the semiconductor device from the external environment can be suppressed.

  In the development and curing steps, the same development and curing conditions as those for normal positive photosensitive film can be used. For example, AZ300MF (manufactured by Clariant) can be used as a developing solution, and a treatment such as heating at 140 ° C. for 30 minutes and then heating at 350 ° C. for 60 minutes can be performed.

[Dicing process]
Finally, a plurality of semiconductor devices are divided by dicing. The dicing of each semiconductor device can be performed by a commonly used method, while cooling with pure water and removing cutting waste while rotating the dicing blade at a high speed.

  In the present invention, the positive photosensitive member accumulated on the orientation flat portion 1c is removed by partial exposure and development. Therefore, it is possible to suppress the dicing blade from being damaged by wear. Further, since the wear of the dicing blade is suppressed, the dicing speed can be increased and the production efficiency can be increased.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Can be modified or changed.

[Example 1]
A Schottky diode semiconductor device was fabricated on a 4-inch substrate. Next, the 4-inch substrate on which this Schottky diode was fabricated was dehydrated and baked at 150 ° C. for 1 minute on a hot plate. A positive polyimide (manufactured by Toray Industries, Inc.) was applied as a positive photosensitive member by spin coating onto a dehydrated and baked 4-inch substrate. The spin coating was performed at 2200 rpm for 40 seconds and then at 3000 rpm for 1 second. The substrate on which the positive polyimide film was formed by this spin coating was heated with a hot plate at 120 ° C. for 5 seconds, and then edge rinse was performed.

  In the edge rinse, the rinse liquid was discharged to a width of 0.8 mm from the outer periphery (portion having an arc) of the 4-inch substrate. The rinsing liquid is a glycol solvent manufactured by Tokyo Ohka Kogyo Co., Ltd., with the product name “OK73 thinner” (Propylene / glycol / mono / methyl / ether / 70% propylene / glycol / mono / methyl / ether) Using. The substrate after the edge rinse was pre-baked on a hot plate at 120 ° C. for 10 minutes.

Next, the surface pad electrode portion was subjected to pattern exposure by a stepper using a mask having a light shielding portion formed of chrome. The pattern exposure conditions were such that the integrated exposure for one shot was 750 mJ / cm ² . Then, only the deposit part of the positive polyimide film deposited on the orientation flat part of the substrate was partially exposed by a stepper using a blank mask. The partial exposure conditions were 5 shots with an integrated exposure amount per shot of 1499.5 mJ / cm ² . The focus was set to -8 μm (the distance between the substrate and the lens was 8 μm apart) with respect to the focus at the time of pattern exposure so that the top of the positive polyimide accumulated in the orientation flat portion was focused.

  The substrate after pattern exposure and partial exposure was developed using AZ300MF (manufactured by Clariant) as a developer. The developer was poured three times, and then rinsed with pure water. The substrate after rinsing with pure water was blown with nitrogen. Finally, the positive polyimide film was heated at 140 ° C. for 30 minutes and then cured at 350 ° C. for 60 minutes.

[Example 2]
Example 2 differs from Example 1 only in that partial exposure was performed with a mask aligner. The exposure conditions at this time were an irradiation of only once with an integrated exposure amount of 7500 mJ / cm ² .

[Example 3]
The third embodiment is different from the first embodiment in that the focal position is not changed during partial exposure. That is, the partial exposure process was performed with the same focus as that of the pattern exposure process.

[Comparative Example 1]
Comparative Example 1 is different from Example 1 in that the partial exposure process is not performed.

8 is a plane photograph of the orientation flat portion in the case of Example 1, FIG. 9 is a plan photograph of the orientation flat portion in the case of Example 3, and FIG. 10 is a plan view of the orientation flat portion in the case of Comparative Example 1. It is a photograph. 9 and 10, a region surrounded by a broken line is a scribe line of the orientation flat portion. In FIG. 8, it can be seen that the positive polyimide in the orientation flat portion is completely removed. On the other hand, in FIG. 9, a part of the positive polyimide film remains on the scribe line as a residual, but in FIG. 10, compared to the case of Comparative Example 1 in FIG. It can be seen that the positive polyimide film is thin.
In the case of Example 2, a photograph similar to that in Example 1 (FIG. 8) was obtained (not shown).

1 ... substrate, 1a ... orientation flat, 1b ... second orientation flat, 1c, 1d ... orientation flat portion, 1L 1 _... vertical line, 1L 2 _... horizontal lines, 2 ... n-type SiC epitaxial layer, 3 ... p-type impurity diffusion regions, 4 ... p-type ohmic electrode, 5 ... Schottky electrode, 6 ... surface pad electrode, 7 ... n-type ohmic electrode, 8 ... backside pad electrode, 10 ... semiconductor device (Schottky barrier diode), 20 ... positive photosensitive film, 11 ... SiO2 film, 20a ... flat part, 20b ... deposition part, 20c ... top part, 30 ... discharge port, 40 ... blank mask, 41 ... lens, 50 ... exposure mask, 51 ... light shielding mask

Claims (6)

Forming a semiconductor device on the substrate on which the orientation flat portion is formed;
Forming a polyimide positive photosensitive film to be a passivation film so as to cover the semiconductor device;
Edge rinsing around the substrate;
Pattern exposing a positive photosensitive film formed on the pad electrode of the semiconductor device;
A step of partially exposing the depositing portion of the positive photosensitive member accumulated in the orientation flat portion of the substrate;
A method of manufacturing a semiconductor device, comprising: developing and curing the positive photosensitive film.     The method of manufacturing a semiconductor device according to claim 1, wherein, in the partial exposure, the deposition focus is adjusted to an exposure focus.   3. The method of manufacturing a semiconductor device according to claim 1, wherein the partial exposure is performed with a mask aligner.   The method of manufacturing a semiconductor device according to claim 1, wherein the partial exposure is performed by a stepper. 5. The method of manufacturing a semiconductor device according to claim 1, wherein in the step of forming the positive photosensitive film, a thickness of a flat portion of the positive photosensitive film is set to 4 to 12 μm. The semiconductor device has a SiO 2 at a position below the positive photosensitive body to be partially exposed. ₂ The manufacturing method of the semiconductor device as described in any one of Claim 1 to 5 provided with a film | membrane.