JP2020027885A - Method of manufacturing semiconductor element - Google Patents

Abstract

To provide a method of manufacturing a semiconductor element capable of suppressing a metal film from being adhered to one surface side of a wafer in a case where metal evaporation is performed to the other surface of the wafer whose one surface is temporarily fixed to a support member to form an individualization groove, compared with a case where the metal evaporation is performed without making the wafer incline.SOLUTION: A method of manufacturing a semiconductor element includes the following steps of: preparing a wafer 10 on whose front face a plurality of semiconductor elements are formed; fixing the wafer to a support member 16 while making the front face contacted; forming a division groove 15 on the wafer to divide the wafer into a plurality of individualized wafers 20 each including some of the plurality of semiconductor elements; and making the wafer incline to a direction of movement of an evaporation material 25 and evaporating a metal film on a rear face of the wafer in a state where the inclination direction of the inclination and an extension direction of the division groove 15 are not accorded with each other.SELECTED DRAWING: Figure 2

Description

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

  Patent Document 1 discloses a process in which a wafer having an element region formed on its surface is prepared and a groove is formed so as to surround the element region, and a step of attaching a rigid support to the surface of the wafer via an adhesive layer. And a process of thinning the wafer from the back surface to the groove and separating it into chips, a process of performing back surface processing with heat treatment with the chip attached to the support, and dissolving the adhesive layer and separating the chips respectively And a method of manufacturing a semiconductor device, wherein the adhesive layer is applied so as to enter the groove. In the method of manufacturing a semiconductor device disclosed in Patent Literature 1, metal deposition is performed on the back surface in a state of being divided into individual chips. Therefore, the electrode material is deposited not only on the back surface of the chip but also on the groove between the chips.

JP 2008-227284 A

  The present invention relates to a case where one side is temporarily fixed to a support member and a metal vapor deposition is performed on the other side of a wafer in which grooves for individualization are formed, compared with a case where the metal vapor deposition is performed without tilting the wafer. Accordingly, it is an object of the present invention to provide a method for manufacturing a semiconductor element in which a metal film is suppressed from adhering to one surface side.

  In order to achieve the above object, a method of manufacturing a semiconductor device according to a first aspect includes a step of preparing a wafer having a plurality of semiconductor elements formed on a front surface, and contacting the front surface. Fixing the wafer to a support member, forming a dividing groove in the wafer, dividing the wafer into a plurality of individual wafers each including a part of the plurality of semiconductor elements, and Inclining with respect to the traveling direction, and depositing a metal film on the back surface of the wafer in a state where the inclination direction of the inclination does not coincide with the extending direction of the dividing groove.

  The method for manufacturing a semiconductor element according to a second aspect is the method for manufacturing a semiconductor element according to the first aspect, wherein the step of depositing the metal film includes setting the angle between the inclined direction and the extending direction to other than 0 degree and 180 degrees. Is the step of depositing the metal film.

  The method for manufacturing a semiconductor element according to a third aspect is the method for manufacturing a semiconductor element according to the second aspect, wherein the step of depositing the metal film is performed by setting an angle between the inclined direction and the extending direction to 45 degrees or 135 degrees. This is a step of depositing the metal film.

  The method for manufacturing a semiconductor element according to a fourth aspect is the method for manufacturing a semiconductor element according to the first aspect, wherein the step of depositing the metal film is such that the deposition material divides an angle between the inclined direction and the extending direction. This is a step of depositing the metal film at an angle that does not reach the support member through the groove.

  The method for manufacturing a semiconductor element according to a fifth aspect is the method for manufacturing a semiconductor element according to the fourth aspect, wherein the step of depositing the metal film is such that the deposition material divides an angle between the inclined direction and the extending direction. This is a step of depositing the metal film at an angle that does not reach the front surface after passing through the groove.

  The method for manufacturing a semiconductor element according to a sixth aspect is the method for manufacturing a semiconductor element according to the first aspect, wherein the step of depositing the metal film includes changing an angle between the inclined direction and the extending direction to a traveling direction of the deposition material. Is a step of depositing the metal film at an angle such that a straight line indicating does not intersect with the surface of the support member exposed from the division groove via the division groove.

  The method for manufacturing a semiconductor element according to a seventh aspect is the method for manufacturing a semiconductor element according to the sixth aspect, wherein the step of depositing the metal film includes changing an angle between the inclined direction and the extending direction to a direction in which the deposition material travels. Is a step of depositing the metal film at an angle at which the straight line indicating does not further intersect with the front surface exposed from the division groove via the division groove.

  The method for manufacturing a semiconductor element according to an eighth aspect is the method for manufacturing a semiconductor element according to any one of the first to seventh aspects, wherein the step of depositing the metal film is disposed around a central axis. A step of revolving the plurality of wafers around the central axis in the deposition material and depositing the metal film using a deposition apparatus that deposits a metal film.

  According to a ninth aspect of the present invention, in the method of the eighth aspect, the step of depositing the metal film includes rotating the plurality of wafers within a predetermined angle range to rotate the metal film. Is a step of vapor deposition.

  The method for manufacturing a semiconductor element according to a tenth aspect is the method for manufacturing a semiconductor element according to the eighth aspect, wherein the step of depositing the metal film is a step of depositing the metal film without rotating a plurality of wafers. It is.

  In a method of manufacturing a semiconductor device according to an eleventh aspect, in the method of manufacturing a semiconductor device according to any one of the first to tenth aspects, the step of depositing the metal film includes setting the tilt angle of the tilt to 10 degrees. The above is the step of depositing the metal film.

  According to the method of manufacturing a semiconductor device of the first aspect, when metal vapor deposition is performed on the back surface of a wafer in which the front surface is temporarily fixed to the support member and the groove for singulation is formed, the wafer is tilted. As compared with the case where metal deposition is performed without using a metal layer, a method of manufacturing a semiconductor element in which a metal film is suppressed from adhering to the front surface side is provided.

  According to the method for manufacturing a semiconductor element of the second aspect, the metal film can be attached to the front surface side as compared with the case where the angle between the inclined direction and the extending direction is 0 degree or 180 degrees. This has the effect of being suppressed.

  According to the semiconductor device manufacturing method of the third aspect, the metal film adheres to the front surface side as compared with the case where the angle between the inclined direction and the extending direction is an angle other than 45 degrees and 135 degrees. Is more effectively suppressed.

  According to the method of manufacturing a semiconductor device of the fourth aspect, the depth of the vapor deposition material penetrating into the dividing groove is smaller than the case where the angle between the inclined direction and the extending direction is set without considering the relationship with the support member. Is more reliably controlled.

  According to the method of manufacturing a semiconductor device of the fifth aspect, as compared with the case where the angle between the inclined direction and the extending direction is set without considering the relationship with the front surface of the wafer, the defect of the semiconductor device is reduced. This has the effect of suppressing occurrence.

  According to the method of manufacturing a semiconductor device of the sixth aspect, the inclination direction and the extension direction are determined without considering the relationship between the straight line indicating the direction of progress of the deposition material and the surface of the support member exposed from the division groove via the division groove. The effect that the depth of the vapor deposition material penetrating into the dividing groove is more reliably controlled as compared with the case where the angle formed by the angle is set.

  According to the method of manufacturing a semiconductor device of the seventh aspect, the inclination direction and the extension direction are determined without considering the relationship between the straight line indicating the traveling direction of the deposition material and the front surface exposed from the division groove via the division groove. In comparison with the case where the angle is set, there is an effect that occurrence of a defect in the semiconductor element is suppressed.

  According to the method for manufacturing a semiconductor device of the eighth aspect, in comparison with the case of using a vapor deposition apparatus in which a plurality of wafers are not revolved around a central axis in a vapor deposition material, in the deposition of a metal film on the back surface of a semiconductor wafer, This produces an effect that unevenness in vapor deposition is suppressed.

  According to the method for manufacturing a semiconductor device of the ninth aspect, unevenness in deposition is suppressed in the deposition of the metal film on the back surface of the semiconductor wafer, as compared with the case where the metal film is deposited without rotating a plurality of wafers at all. It has the effect of

  According to the method for manufacturing a semiconductor element of the tenth aspect, the depth of the vapor deposition material penetrating into the dividing grooves is smaller than in the case where a plurality of wafers are rotated and a metal film is vapor-deposited. Play.

  According to the method of manufacturing a semiconductor device of the eleventh aspect, the metal film can be attached to the front surface side of the semiconductor wafer as compared with the case where the metal film is deposited by setting the inclination angle to less than 10 degrees. This has the effect of being suppressed.

FIG. 7 is a cross-sectional view showing an example of the manufacturing process of the semiconductor element according to the embodiment. (A) is a top view which shows the individual wafer arrange | positioned at the grind frame (tape frame for grinding) which concerns on embodiment, (b) is sectional drawing which shows the vapor deposition process which concerns on embodiment. (A) is a cross-sectional view showing a vapor deposition process when the tilt angle is 0 degrees, (b) is a cross-sectional view showing a vapor deposition process when the tilt angle is 30 degrees, and (c) is a tilt angle of the semiconductor wafer and a vapor deposition material. 6 is a graph showing a relationship between the depth of penetration and the depth of penetration.

  Hereinafter, an embodiment for carrying out the present invention will be described in detail with reference to FIGS.

  With reference to FIG. 1, a method for manufacturing a semiconductor device according to the present embodiment will be described.

  First, as shown in FIG. 1A, a semiconductor wafer 10 having an element pattern 12 formed on a semiconductor substrate 11 is prepared.

Next, as shown in FIG. 1B, the semiconductor wafer 10 is mounted on a dicing (division) member. The dicing member includes a dicing tape 13 and a dicing frame 14, and has a structure in which the dicing tape 13 is attached to the ring-shaped dicing frame 14.
The mounting of the semiconductor wafer 10 is performed by attaching the back surface of the semiconductor wafer 10 to a dicing tape. Note that the thickness of the semiconductor wafer 10 at this time is about 500 μm as an example.

Next, half dicing for dividing the semiconductor wafer 10 into individual wafers 20 is performed.
As will be described later, the individual wafer 20 is obtained by dividing the semiconductor wafer 10 into a plurality of pieces to facilitate handling of the semiconductor wafer 10. The half dicing is performed by forming a groove 15 from the front (element) surface side of the semiconductor wafer 10 as shown in FIG. The depth of the groove 15 is, for example, a depth obtained by adding about 20 μm to the thickness of the final semiconductor wafer 10. Note that the final thickness of the semiconductor wafer 10 in the present embodiment is about 120 μm as an example.

Next, as shown in FIG. 1D, transfer to the grind member of the semiconductor wafer 10 is performed.
Grinding refers to back grinding for making the thickness of the semiconductor wafer 10 the final thickness. As shown in FIG. 1D, the grind member has a configuration in which a grind tape 16 is adhered to a grind frame 17 which is a ring-shaped frame. The transfer to the grind member is performed by embedding the front surface of the semiconductor wafer 10 in the grind tape 16.

  Next, as shown in FIG. 1E, the back surface is ground (ground) to divide the semiconductor wafer 10 into individual wafers 20. Although the number of divisions of the individual wafer 20 is not limited, in the present embodiment, it is divided into four. This back grinding is performed using, for example, a grindstone.

  Next, as shown in FIG. 1F, a back electrode 18 is deposited. The details of the deposition of the back electrode 18 will be described later.

Next, as shown in FIG. 1 (g), each individual wafer 20 is mounted on a dicing member.
Dicing in this step is dicing for further dividing the individual wafer 20 into the semiconductor elements 21. The dicing member includes a ring-shaped dicing frame 23 and a dicing tape 22, and the dicing tape 22 is attached to the dicing frame 23. This step is performed for the number of individual wafers 20. The notation “× N” in FIG. 1G represents the number of individual wafers 20, and N = 4 in the present embodiment.

Next, as shown in FIG. 1H, a groove 19 is formed and full dicing is performed. Full dicing refers to dividing the individual wafer 20 into individual semiconductor elements 21 (singulation).
Dicing is performed using, for example, a dicing blade or the like.

  Next, as shown in FIG. 1I, an appearance inspection of the semiconductor element 21 is performed. The appearance inspection is performed by, for example, image processing using the camera 24. Thereafter, the dicing tape 22 is peeled off from the back surface of the semiconductor element 21 and separated into individual semiconductor elements 21.

  In the above description of the method for manufacturing a semiconductor device, only steps deeply related to the present invention are shown, and some of the steps are omitted. For example, after the deposition of the back electrode 18 in FIG. 1F, a heat treatment step for ensuring the ohmic property of the back electrode 18 and an electrical inspection step of the semiconductor element 21 included in the individual wafer 20 may be included. .

Here, a large-diameter and thin semiconductor wafer, particularly a compound semiconductor wafer, is likely to be broken during the manufacturing process (process), and may be divided in advance into a size that can be easily transported.
Further, in the step of performing a metal vapor deposition process on a semiconductor wafer divided on a tape, if the semiconductor wafer is kept in a horizontal state, the vapor deposition material passes between division grooves (also referred to as "streets") to form an element pattern. May cause device failure by adhering near the front surface of a damaged semiconductor wafer, or the metal film adhered to the tape surface may fall on the element pattern when the tape is subsequently peeled off, causing a failure. It is assumed that

  In the above-described method of manufacturing a semiconductor device according to the present embodiment, as shown in FIG. 1E, the device surface is fixed to the grind tape 16 and divided into individual wafers 20, and then, as shown in FIG. As shown in the figure, when the back electrode 18 is deposited, if the individual wafer 20 is subjected to the deposition process without tilting while keeping the individual wafer 20 perpendicular to the traveling direction of the deposition material, the deposition material passes through the dividing groove, and the element of the semiconductor element is removed. It may adhere to the surface and cause a defect of the semiconductor element. Alternatively, the vapor deposition material that has passed through the division grooves may adhere to the grind tape and drop on the element surface of the semiconductor element when the grind tape is peeled off, thereby causing a defect in the semiconductor element.

  Therefore, in the present embodiment, the semiconductor wafer is inclined with respect to the traveling direction of the deposition material, and the metal film is vapor-deposited on the back surface of the semiconductor wafer in a state where the inclination axis of the inclination does not coincide with the extending direction of the dividing groove. And Thus, when metal deposition is performed on the back surface of the wafer in which the element surface is temporarily fixed to the support member and grooves for singulation are formed, compared with the case where metal deposition is performed without tilting the wafer, An advantage is provided in that a method of manufacturing a semiconductor element in which a metal film is suppressed from adhering to the element surface side is provided.

  Hereinafter, the metal deposition process according to the present embodiment will be described in more detail with reference to FIGS.

FIG. 2A is a view of the state shown in FIG. 1E as viewed from the back surface side of the semiconductor wafer 10.
As shown in FIG. 2A, a semiconductor wafer 10 divided into four individual wafers 20 is mounted on a grind member including a grind tape 16 and a grind frame 17. FIG. 2B shows an arrangement state when performing the metal deposition shown in FIG. 1F on the individual wafers 20 mounted on the grinding members (the grinding tape 16 and the grinding frame 17). The mask 26 shown in FIG. 2B is a mask that covers a region other than the region of the semiconductor wafer 10 (individual wafer 20) to be subjected to metal deposition.

  As shown in FIG. 2B, in the metal vapor deposition step according to the present embodiment, the semiconductor wafer 10 is tilted about the point C by a predetermined tilt angle θ with respect to the traveling direction of the vapor deposition material 25. . Further, as shown in FIG. 2A, the inclination is made such that the direction of the inclination does not coincide with the extending direction of the groove 15. That is, assuming an A-A 'line (hereinafter referred to as an "inclination axis") that defines the center of the inclination, a direction passing through the point C and perpendicular to the paper surface coincides with the direction of the inclination axis A-A'. The angle between the reference groove 15 and the tilt axis AA ′ (hereinafter, “rotation angle φ”) is not particularly limited as long as it is other than 0 degree (180 degrees). In this case, 45 ° is particularly preferable because the vapor deposition material 25 is hard to equally enter the groove 15 in any direction.

  Next, the tilt angle θ will be described in more detail with reference to FIG. FIG. 3A shows the state of adhesion of the metal film to the semiconductor wafer 10 when the inclination angle θ is θ = 0 degrees, and FIG. 3B shows the state of the metal film when the inclination angle θ is 30 degrees. 10 shows the state of adhesion to 10 respectively. 3A and 3B, the rotation angle φ is set to a direction different from the extending direction of all the grooves 15.

  As shown in FIG. 3A, when the inclination angle θ is 0 degree, the direction of the groove 15 between the individual wafers 20 is parallel to the traveling direction of the deposition material 25. The vapor deposition material 25 penetrates through the groove 15 at the same time as the formation of the back electrode 18, and the metal film 27 adheres to the grind tape 16. In some cases, the metal film 27 diffuses in the lateral direction to reach the semiconductor element formed on the front surface of the individual wafer 20.

On the other hand, when the inclination angle θ is 30 degrees as shown in FIG. 3B, the direction of the groove 15 between the individual wafers 20 is not parallel to the traveling direction of the deposition material 25. Because of (intersecting), the vapor deposition material 25 hardly penetrates through the groove 15 while forming the back electrode 18, and the vapor deposition material 25 only attaches the metal film 27 to the wall surface near the opening end of the groove 15. ing.
That is, when the inclination angle is 30 degrees, the metal film 27 penetrates only from the opening end of the groove 15 along the wall surface of the groove 15 by the penetration depth d.

  FIG. 3C is a graph showing a result of simulating the relationship between the inclination angle θ (degree = deg) and the penetration depth d (μm). FIG. 3C simulates the case where the rotation angle φ is 45 ° and the width of the groove 15 is 10 μm and 15 μm. In addition, t shown in FIG. 3C is the thickness of the semiconductor wafer 10 (individual wafer 20), and is set to 120 μm as an example in the simulation. That is, in FIG. 3C, when the penetration depth d reaches the thickness t, the deposition material 25 reaches the grind tape 16 and the metal film 27 adheres to the grind tape.

  Referring to FIG. 3C, for example, when the width of the groove 15 is 10 μm, the penetration depth d is d = 37 μm when the inclination angle θ is θ = 30 degrees, and the penetration depth is d when the inclination angle θ is θ = 45 degrees. The length d is d = 21 μm. That is, the greater the inclination angle θ, the greater the angle between the depth direction of the groove 15 and the traveling direction of the vapor deposition material 25, so that the penetration depth d decreases. However, if the inclination angle θ is extremely large, it is considered that the film formation of the back electrode 18 may be affected. Therefore, the upper limit of the actual inclination angle θ may be set in consideration of the film formation state of the back electrode 18 and the like. .

  On the other hand, as the inclination angle θ decreases, the penetration depth d increases, but from FIG. 3C, if the inclination angle θ is 10 degrees or more, the penetration depth d becomes the substrate thickness t (120 μm in this example). It turns out that it does not reach. That is, it is understood that the inclination angle θ needs to satisfy θ ≧ 10 degrees. However, as is apparent from FIG. 3C, the lower limit of the inclination angle θ should be set according to the thickness t of the semiconductor wafer 10.

Next, a vapor deposition apparatus used in the method for manufacturing a semiconductor device according to the present embodiment will be described.
The vapor deposition apparatus according to the present embodiment has the following configuration. That is, an arrangement member for arranging a plurality of semiconductor wafers mounted on a dicing member includes a plurality of vapor deposition domes arranged around a central axis, and the vapor deposition dome on which a plurality of semiconductor wafers are arranged revolves around the central axis. It is possible. Further, the arrangement member itself is also rotatable, and each of the plurality of semiconductor wafers is also allowed to rotate with the rotation of the arrangement member. Then, a vapor deposition material is caused to fly on a vapor deposition dome on which a plurality of semiconductor wafers are arranged, thereby performing vapor deposition of a back electrode on the semiconductor wafer. In the vapor deposition apparatus having the above-described configuration, generally, the back electrode is uniformly formed by using both revolution and rotation.

  On the other hand, the vapor deposition apparatus according to the present embodiment is configured to perform revolving but not to rotate. This is because, in the present embodiment, the rotation angle φ is set so that the extending direction of the groove 15 does not coincide with the tilt axis (the line AA ′ in FIG. 2), and the vapor deposition material 25 enters the inside of the groove 15. However, when the arrangement member is rotated, the rotation angle φ changes, and at a specific timing of the rotation, the extending direction of the groove 15 and the tilt axis become parallel or nearly parallel, and the vapor deposition material is This is because the possibility of intrusion to the back increases (that is, the intrusion depth d shown in FIG. 3B increases). On the other hand, since the revolution has almost no influence on the rotation angle φ, it is executed as usual.

  By configuring the vapor deposition apparatus as described above, in the method for manufacturing a semiconductor element according to the present embodiment, a metal film such as a back electrode is uniformly formed and a metal film adheres to the element surface. More effectively suppressed.

  Here, in the vapor deposition apparatus according to the present embodiment, a configuration that does not rotate is described as an example. However, the configuration is not limited to this, and is limited in consideration of an allowable penetration depth d of the metal film 27 and the like. You may make it rotate a semiconductor wafer in an angle range.

  In the above-described embodiment, the process of depositing the back electrode has been described by way of example. However, the present invention is not limited to this, and the semiconductor wafer having one surface fixed to the support member and formed with a dividing groove (ie, a plurality of The present invention can be applied to any vapor deposition process as long as the process deposits a metal film on the other surface of the individual wafer. In addition, the surface to be vapor-deposited is not limited to the back surface, and may be a front surface. Further, the vapor-deposition material is not limited to metal, and may be another material.

Reference Signs List 10 semiconductor wafer 11 semiconductor substrate 12 element pattern 13 dicing tape 14 dicing frame 15 groove 16 grind tape 17 grind frame 18 back electrode 19 groove 20 individual wafer 21 semiconductor element 22 dicing tape 23 dicing frame 24 camera 25 evaporation material 26 mask 27 metal Film C Point d Penetration depth t Thickness θ Tilt angle φ Rotation angle

Claims (11)

A step of preparing a wafer having a plurality of semiconductor elements formed on the front surface,
Fixing the wafer to a support member by contacting the front surface,
Forming a dividing groove in the wafer, and dividing the wafer into a plurality of individual wafers each including a part of the plurality of semiconductor elements;
Tilting the wafer with respect to the direction of travel of the deposition material, and depositing a metal film on the back surface of the wafer in a state in which the tilt direction of the tilt does not match the extending direction of the division groove. Manufacturing method. The method of manufacturing a semiconductor device according to claim 1, wherein the step of depositing the metal film is a step of depositing the metal film at an angle between the inclination direction and the stretching direction other than 0 ° and 180 °. . The method of manufacturing a semiconductor device according to claim 2, wherein the step of depositing the metal film is a step of depositing the metal film with an angle between the tilt direction and the extension direction being 45 degrees or 135 degrees. The step of depositing the metal film is a step of depositing the metal film by setting an angle between the inclined direction and the extending direction to an angle at which the deposition material does not pass through the dividing groove and reach the support member. Item 2. A method for manufacturing a semiconductor device according to item 1. The step of depositing the metal film is a step of depositing the metal film by setting an angle between the inclined direction and the extending direction to an angle at which the deposition material passes through the division groove and does not reach the front surface. The method for manufacturing a semiconductor device according to claim 4. In the step of depositing the metal film, a straight line indicating an advancing direction of the deposition material at an angle between the inclined direction and the extending direction intersects a surface of the support member exposed from the division groove through the division groove. The method for manufacturing a semiconductor device according to claim 1, wherein the step of depositing the metal film is performed at an angle not to be performed. The step of depositing the metal film, the front surface exposed from the dividing groove through a straight line indicating an advancing direction of the deposition material at an angle between the inclined direction and the extending direction, and further, The method of manufacturing a semiconductor device according to claim 6, wherein the metal film is deposited at an angle that does not intersect. The step of depositing the metal film, the plurality of wafers disposed around a central axis is revolved around the central axis in the deposition material, the metal film is deposited using a deposition apparatus that deposits a metal film. The method of manufacturing a semiconductor device according to claim 1, wherein the method is a step of vapor deposition. The method of manufacturing a semiconductor device according to claim 8, wherein the step of depositing the metal film is a step of rotating the plurality of wafers within a predetermined angle range to deposit the metal film. The method of manufacturing a semiconductor device according to claim 8, wherein the step of depositing the metal film is a step of depositing the metal film without rotating a plurality of the wafers. The method of manufacturing a semiconductor device according to claim 1, wherein the step of depositing the metal film is a step of depositing the metal film with the inclination angle of the inclination being 10 degrees or more.