JP2013222786A - Semiconductor substrate, method for manufacturing semiconductor substrate, and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a semiconductor substrate improved in adhesion between a substrate and a land, in a semiconductor substrate including a land; a method for manufacturing the semiconductor substrate; and electronic equipment.SOLUTION: A semiconductor substrate 1 comprises: a substrate 10; a through hole 16 penetrating through from one principal surface of the substrate 10 toward the other principal surface; and a land 20 including an end part 24 exposed from the principal surface and an axis part formed continuously from the end part 24 in the through hole 16. In a cross section of the end part in the direction along the principal surface, a cross section close to the principal surface is larger than a cross section apart from the principal surface.

Description

  The present invention relates to a semiconductor substrate provided with lands, a method for manufacturing the semiconductor substrate, and an electronic apparatus.

  Conventionally, there is a technique for three-dimensionally stacking semiconductor chips in order to mount the semiconductor chips at high density. In this technique, semiconductor chips are stacked and each semiconductor chip is connected by wiring. The semiconductor chip has, for example, electrodes formed on the front surface and the back surface thereof, and a through hole penetrating the front surface and the back surface of the semiconductor chip. The through hole is filled with a land as a through electrode, and the front and back electrodes are electrically connected through the land. Then, when semiconductor chips having such an electrode structure are stacked, the electrodes formed on the back surface of one semiconductor chip are connected to the electrodes formed on the surface of another semiconductor chip, thereby connecting the wires between the semiconductor chips. can do. Various techniques have been proposed to improve the quality of such semiconductor chips and to reduce the size.

  For example, as a technique for facilitating alignment at the time of stacking semiconductor chips, Patent Document 1 discloses that an opening hole is provided in a semiconductor chip, the opening hole is filled with a conductive member, and the upper surface of the conductive member is recessed. It is described that a terminal is provided.

  In addition, in order to reduce the thickness of the wiring board, Patent Document 2 describes that the first plating conductor layer is attached so that only the inner wall of the through hole provided in the insulating plate has a through hole coaxial with the through hole. By narrowing the space in the through hole, the second plated conductor layer is then deposited in the through holes remaining in the first plated conductor layer and on the upper and lower surfaces of the insulating plate for the core. And filling the through holes of the plated conductor layer and forming wiring conductors on the upper and lower surfaces of the insulating plate for the core.

JP 2004-207317 A JP2011-216519A

  As a procedure for forming a land on a substrate by electroplating, first, a through hole is formed in the thickness direction of the substrate, and an insulating film and a metal film are formed on one main surface of the substrate and the inner wall of the through hole. Further, a plating resist having an opening in a region where the through hole is formed is formed on one main surface of the substrate. Then, using the metal film as an electrode, lands are formed on the inner wall and the opening of the through hole by electroplating. FIG. 7 is a schematic cross-sectional view of the substrate when two lands are formed on the substrate in this way. Next, the plating resist is peeled off, and the metal film exposed by the peeling is removed by etching.

  In the step of removing the metal film, not only the metal exposed on the surface but also the metal film existing between the land and the substrate may be side-etched. FIG. 8 is a schematic cross-sectional view of the contact portion between the land and the substrate when the metal film existing between the land and the substrate is side-etched. FIG. 9 is a photograph of a cross section of a land and a metal film showing a state where the metal film is actually side-etched. As shown in these drawings, when the metal film existing between the land and the substrate is side-etched, the contact area between the land and the substrate decreases, and the adhesion between the land and the substrate also decreases. As a result, the land is easily detached from the substrate. FIG. 10 is a photograph showing a state in which such a land is detached from the through hole of the substrate. Thus, if the land is easily detached from the substrate, it is difficult to ensure sufficient reliability of the quality of the semiconductor substrate.

Furthermore, in recent years, semiconductor chips have been miniaturized and integrated, and when a plurality of lands are arranged on a substrate, the pitch between the lands tends to be narrowed.
However, if the pitch between lands is narrowed, there is a possibility of short-circuiting between adjacent lands during wiring. When the cross-sectional shape of the land is reduced to prevent this short circuit, the contact area between the land and the substrate is further reduced, and the land is easily detached from the substrate.

  The present invention has been made to solve the above problems, and the present invention provides a semiconductor substrate having improved land adhesion to a semiconductor substrate having lands, a method of manufacturing the same, and an electronic apparatus. The purpose is to do.

It is another object of the present invention to provide a semiconductor substrate, a manufacturing method thereof, and an electronic apparatus that can ensure a large contact area with a land substrate.
Another object of the present invention is to provide a semiconductor substrate, a method for manufacturing the same, and an electronic device that make it difficult for the land to be detached from the substrate.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.
Application Example 1 Substrate, a through-hole penetrating from one main surface of the substrate toward the other main surface, an end exposed from the main surface, and the through-hole continuously from the end A semiconductor substrate, wherein a cross-sectional area near the main surface is larger than a cross-sectional area far from the main surface in a cross section of the end portion in a direction along the main surface .

  According to the present invention, the cross-sectional area in the direction along the main surface of the substrate in the land is larger in cross-sectional area near the main surface than the cross-sectional area far from the main surface, so that the contact area between the land and the substrate Can be ensured greatly, the adhesion between the land and the substrate can be improved, and the land can be hardly separated from the substrate.

Application Example 2 The semiconductor substrate according to Application Example 1, wherein a TiW / Cu film is provided between the substrate and the land.
According to the present invention, when the land is formed on the TiW / Cu film by electroplating, the TiW / Cu film between the substrate and the land is side-etched in the etching process for removing the TiW / Cu film layer. However, the cross-sectional shape of the land in the direction along the main surface of the substrate is larger than the end of the cross-sectional area closer to the main surface than the cross-sectional area far from the main surface, so that the TiW / Cu film The contact area with the land can be increased, the adhesion between the land and the substrate can be improved, and the land can hardly be detached from the substrate.

Application Example 3 The semiconductor substrate according to Application Example 1 or 2, wherein the end portion has a trapezoidal shape and extends from the cross section far from the main surface toward the cross section close to the main surface.

  According to the present invention, the flared portion from the cross section far from the main surface toward the cross section close to the main surface is monotonous at a uniform angle from the cross section far from the main surface to the cross section close to the main surface. Compared to the inclination, the area of the cross section far from the main surface can be increased, and the mounting area can be secured when solder is mounted on the end of the cross section far from the main surface.

Application Example 4 A step of forming a through hole in the thickness direction of a substrate, a step of forming a TiW / Cu film on one main surface of the substrate and the surface of the through hole, and the one main surface of the substrate A plating resist forming step of forming a plating resist having a reverse tapered opening in which an opening area increases toward the main surface on the surface; and the through-hole and the opening by electroplating using the TiW / Cu film as an electrode A method of manufacturing a semiconductor substrate, comprising: a step of forming a land on a portion; a step of peeling the plating resist; and a step of removing the TiW / Cu film exposed by peeling of the plating resist. .

  According to the present invention, a plating resist having an opening with a reverse taper whose opening area increases as it approaches the main surface is formed on the one main surface of the substrate, and the TiW / Cu film is used as an electrode to In order to form lands in the through holes and the openings by plating, a cross-sectional area closer to the main surface than a cross-sectional area far from the main surface in the cross section of the end of the land in the direction along the main surface of the substrate. Even if the TiW / Cu film between the substrate and the land is side-etched in the step of removing the TiW / Cu film, the contact area between the land and the TiW / Cu film can be secured. Therefore, the adhesion between the land and the substrate can be improved, and the land can be hardly separated from the substrate.

Application Example 5 The plating resist is a photosensitive resin that is cured by ultraviolet rays, and in the plating resist forming step, the one main surface of the substrate is coated with an unexposed plating resist, and the ultraviolet rays are transmitted through a mask. The method of forming a semiconductor substrate according to application example 5, wherein the plating resist is irradiated, the periphery of the region where ultraviolet irradiation is blocked by the mask is exposed again with a predetermined exposure amount or less, and development processing is performed. .

  According to the present invention, the mask is exposed to a predetermined exposure amount or less so that the plating resist close to the substrate around the region where ultraviolet irradiation is blocked by the mask is not hardened, thereby approaching the main surface of the substrate. As a result, it is possible to form an inversely tapered opening having an opening area that increases.

[Application Example 6]
An electronic device including a semiconductor device,
An electronic apparatus, wherein the semiconductor device includes the semiconductor substrate according to any one of Application Examples 1 to 3.
According to the present invention, an electronic device with high quality and reliability can be provided.

It is a typical sectional view of a semiconductor substrate concerning an embodiment of the present invention. FIG. 2 is a schematic enlarged view of a portion where one main surface of a substrate and a land in FIG. 1 are in contact via a TiW / Cu film. It is process drawing of the manufacturing method of the semiconductor substrate which concerns on this embodiment. It is a figure corresponding to process 8 in the case of forming a plurality of lands in a substrate. It is a schematic perspective view which shows the personal computer with which the semiconductor substrate which concerns on this embodiment is mounted. It is a schematic perspective view which shows the mobile telephone with which the semiconductor substrate which concerns on this embodiment is mounted. It is a figure explaining the manufacturing process of the conventional semiconductor substrate. It is a typical enlarged view of the part in which the one main surface of a board | substrate and a land contact through a metal film in the conventional semiconductor substrate. It is the photograph of the cross section of the land and metal film which show a mode that the conventional metal film was side-etched. It is a photograph which shows the state which the conventional land separated from the through-hole of the board | substrate.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic cross-sectional view of a semiconductor substrate 1 according to an embodiment of the present invention.
As shown in the figure, the semiconductor substrate 1 includes a substrate 10, an insulating film 12, a TiW / Cu film 14, lands 20, and electrode pads 30. The substrate 10 is made of Si (silicon). The substrate 10 is provided with a through hole 16 penetrating in the thickness direction from one main surface of the substrate 10 to the other main surface. The through hole 16 has, for example, a cylindrical shape. The shape of the through hole 16 is not limited to a cylindrical shape, and may be other shapes such as a quadrangular prism shape. An insulating film 12 is formed on both main surfaces of the substrate 10 and the inner wall of the through hole 16. The insulating film 12 is made of, for example, SiO ₂ (silicon oxide).

  A land 20 is formed in the through hole 16 of the substrate 10. The land 20 includes an end portion 24 exposed from one main surface and a shaft portion 22 formed in the through hole 16 continuously from the end portion 24. The diameter of the end portion 24 is formed larger than that of the shaft portion 22, and the land 20 has a T-shaped side surface. The land 20 is formed of a metal such as Cu (copper). An electrode pad 30 is provided on the other main surface of the substrate 10 so as to cover the through hole 16. The electrode pad 30 is made of, for example, Al (aluminum). An electrode (not shown) of a component is connected to the end 24 of the land 20 via, for example, solder (not shown), and the land 20 serves as a through electrode that electrically connects the component and the electrode pad 30. Fulfill.

  A TiW / Cu film 14 is provided between the land 20 and the insulating film 12 and the electrode pad 30. This TiW / Cu film 14 is used when the land 20 is formed by electroplating. The TiW / Cu film 14 is formed with a TiW (titanium tungsten) film as a barrier layer, and a Cu film is formed thereon as a seed layer.

  The cross section along the main surface of the substrate 10 at the end 24 of the land 20 has a larger cross sectional area closer to the main surface than a cross sectional area far from the main surface. In the present embodiment, the end 24 has a trapezoidal shape and flares from a cross section far from the main surface of the substrate 10 toward a cross section close to the main surface.

  FIG. 2 is a schematic enlarged view of a portion where one main surface of the substrate 10 in FIG. 1 and the land 20 are in contact via the TiW / Cu film 14. As shown in the figure, there is a portion where the TiW / Cu film 14 does not exist between the substrate 10 and the land 20. In the portion where the TiW / Cu film 14 does not exist, after the land 20 is formed on the TiW / Cu film 14 by electroplating, the TiW / Cu film 14 where the land 20 is not formed is removed by etching. At this time, the TiW / Cu film 14 between the substrate 10 and the land 20 is side-etched. In this case, the contact area between the land 20 and the TiW / Cu film 14 (substrate 10) is smaller than when the TiW / Cu film 14 is entirely present between the substrate 10 and the land 20. However, in the present embodiment, the cross-sectional area in the direction along the main surface of the substrate 10 at the end 24 of the land 20 is larger in the cross-sectional area closer to the main surface than in the cross-sectional area far from the main surface. Therefore, even if there is a portion where the TiW / Cu film 14 does not exist between the substrate 10 and the land 20, the contact area between the land 20 and the TiW / Cu film 14 can be secured. 10 can be improved, and the land 20 can be hardly separated from the substrate 10.

  Further, the shape of the end portion 24 is a trapezoid, and the skirt spreads from the cross section far from the main surface of the substrate 10 toward the cross section close to the main surface, so that the cross section from the cross section far from the main surface becomes a cross section close to the main surface. Compared to the monotonic inclination at a uniform angle toward the main surface, the area of the end of the cross section far from the main surface can be increased, and when solder is mounted on the end of the cross section far from the main surface A sufficient solder mounting area can be secured.

  Note that, from the viewpoint of securing the contact area, the end 24 may be monotonously inclined at a uniform angle from a cross section far from the main surface of the substrate 10 toward a cross section close to the main surface.

  In the above-described embodiment, the land 20 has a T-shaped side surface and has been described as penetrating through the through hole 16 of the substrate 10 to serve as a through electrode. The head 24 as the land may be disposed on a substrate on which the through hole 16 is not provided.

Next, a method for manufacturing the semiconductor substrate 1 having the above configuration will be described with reference to FIG.
(Process 1: Board preparation)
First, the other main surface of the substrate 10 is covered with an insulating film 12, and an electrode pad 30 is provided on the insulating film 12.

(Process 2: Support substrate bonding)
Next, after the support substrate 40 is attached to the surface of the insulating film 12 on which the electrode pads 30 are provided with an adhesive 50 to increase the strength, the substrate 10 is thinned to a desired thickness.

(Step 3: Etching the substrate)
Next, a resist 60 in which an opening is patterned in a region where the through hole 16 is to be formed is formed on one main surface of the substrate 10.

  Next, the substrate 10 exposed in the opening of the resist 60 is etched until the insulating film 12 on the other main surface is exposed. By this etching, a through hole 16 is formed in the substrate 10. When the etching is completed, the resist 60 is peeled off.

(Process 4: Insulating film removal 1)
Next, the insulating film 12 exposed by forming the through hole 16 is removed by etching, and further, the insulating film 12 is completely removed by ashing to expose the electrode pad 30.

(Step 5: Insulating film formation)
Next, the insulating film 12 is formed on one main surface of the substrate 10, the inner wall of the through hole 16, and the electrode pad 30.

(Step 6: Insulating film removal 2)
Next, in Step 5, the insulating film 12 formed on the electrode pad 30 is removed.
Specifically, the resist 62 is patterned so as to provide an opening in the through hole 16 portion of one main surface of the substrate 10, and the insulating film 12 on the electrode pad 30 is removed by etching. When the etching is completed, the resist 62 is peeled off. Next, the insulating film 12 on the electrode pad 30 is completely removed by ashing.

(Step 7: Sputtering)
Next, the TiW / Cu film 14 is formed on one main surface of the substrate 10, the inner wall of the through hole 16, and the electrode pad 30 by sputtering.

(Process 8: Plating)
Next, in order to form the land 20, the plating resist 64 is patterned on one main surface of the substrate 10.
Specifically, a photosensitive resin that is cured by ultraviolet rays is used as the plating resist 64, and the unexposed plating resist 64 is applied to the entire main surface of the substrate 10 by spin coating.

  Next, a mask (not shown) is disposed on the plating resist 64 at a position facing the electrode pad 30 (through hole 16), and the mask is disposed by irradiating the plating resist 64 with ultraviolet light transmitted through the mask. A portion of the plating resist 64 that is not exposed is exposed. Next, the periphery of the region where ultraviolet irradiation is blocked by the mask is exposed again with a predetermined exposure amount or less, and development processing is performed. In the development process, the sufficiently exposed portion of the plating resist 64 is cured and does not dissolve in the developer. On the other hand, on the main surface of the substrate 10 around the mask where the amount of exposure was small because the ultraviolet irradiation was blocked by the mask and the portion that was not exposed to the mask and the periphery of the mask was exposed at a predetermined exposure amount or less. The close part dissolves in the developer. As a result, a reverse-tapered opening 66 is formed in the plating resist 64, the opening area of which increases as it approaches the main surface of the substrate 10.

  In addition, by increasing the film thickness of the plating resist 64, the exposure amount of the portion near the main surface of the substrate 10 around the region where ultraviolet irradiation is blocked by the mask is adjusted so that the plating resist 64 does not cure, You may make it form the opening part 66 of a reverse taper which an opening area becomes large as it approaches the main surface of the board | substrate 10. As shown in FIG.

  Next, Cu electroplating is performed using the TiW / Cu film 14 as an electrode, and the shaft portion 22 and the end portion 24 of the land 20 are formed in the through hole 16 of the substrate 10 and the opening 66 of the plating resist 64, respectively. Due to the shape of the opening 66 of the plating resist 64, the cross section in the direction along one main surface of the substrate 10 at the end 24 of the land 20 has a cross sectional area closer to the main surface than the cross sectional area far from the main surface. growing.

(Step 9: Metal film removal)
Next, the plating resist 64 is stripped with a stripping solution.
At this time, as shown in FIG. 4, when a plurality of lands 20 are formed on the substrate 10, even if the pitch between the plurality of lands 20 is narrow, the plating resist 64 is smaller than the portion closer to the substrate 10. Since the cross-sectional area of the part far from is larger, the peeling solution can be sufficiently spread over the plating resist 64, and the plating resist 64 can be easily peeled off.

  Next, the TiW / Cu film 14 exposed by the removal of the plating resist 64 is removed by etching. At this time, even if the TiW / Cu film 14 between the land 20 and the insulating film 12 is eroded by side etching, the cross-sectional area close to the substrate 10 at the end 24 of the land 20 is increased. The contact area with the TiW / Cu film 14 can be maintained, and the land 20 is difficult to separate from the substrate 10.

(Process 10: support substrate peeling)
Next, the support substrate 40 and the adhesive 50 are peeled from the substrate 10. Thus, the semiconductor substrate 1 is completed.

  As described above, the cross section of the end portion 24 of the land 20 in the direction along the main surface of the substrate 10 is larger in cross section near the main surface than the cross sectional area far from the main surface. The contact area with 10 can be increased. Therefore, the adhesion of the land 20 to the substrate 10 can be improved, and the land 20 can be hardly separated from the substrate 10. Further, even if the diameter of the land 20 is reduced for size reduction, a structure that is difficult to be detached from the substrate 10 can be obtained.

  Further, since the plating resist 64 has a larger cross-sectional area at the end portion farther from the substrate 10 than at the end portion close to the substrate 10, even when the pitch between the lands 20 is narrow when the plurality of lands 20 are provided, the manufacturing process is performed. When the plating resist 64 is peeled off, the plating resist 64 can be easily peeled off by sufficiently spreading the stripping solution over the plating resist 64.

  Further, the end portion 24 of the land 10 is trapezoidal, and is widened from the cross section far from the main surface of the substrate 10 toward the cross section close to the main surface, so that it is far from the main surface of the land 20. The area of the end portion of the cross section can be increased and the pitch between the end portions 24 can be widened, so that the stripping solution can easily penetrate and the plating resist 64 can be easily stripped.

  Next, an embodiment of an electronic device on which a semiconductor device including a semiconductor substrate is mounted will be described with reference to FIGS. FIG. 5 is a schematic perspective view showing a personal computer, and FIG. 6 is a schematic perspective view showing a mobile phone. As an example of an electronic device on which a semiconductor device including the semiconductor substrate 1 is mounted, a personal computer 300 illustrated in FIG. 5 and a mobile phone 400 illustrated in FIG. 6 can be given. By mounting the semiconductor device including the semiconductor substrate 1 on these electronic devices, the reliability of the quality of the electronic devices can be ensured.

DESCRIPTION OF SYMBOLS 1 ...... Semiconductor substrate, 10 ...... Board | substrate, 12 ...... Insulating film, 14 ...... TiW / Cu film, 16 ...... Through-hole, 20 ...... Land, 22 ...... Shaft part, 24 ......... End, 30 ......... Electrode pad, 40 ......... Support substrate, 50 ......... Adhesive, 60 ......... Resist, 62 ......... Resist, 64 ...... Plating resist, 66 ......... Aperture.

Claims (6)

A substrate,
A through hole penetrating from one main surface of the substrate toward the other main surface;
An end exposed from the main surface and a land formed in the through hole continuously from the end;
A semiconductor substrate characterized in that, in a cross section of the end portion in a direction along the main surface, a cross-sectional area close to the main surface is larger than a cross-sectional area far from the main surface.   The semiconductor substrate according to claim 1, wherein a TiW / Cu film is provided between the substrate and the land.   3. The semiconductor substrate according to claim 1, wherein the end portion has a trapezoidal shape and extends from a cross section far from the main surface toward a cross section close to the main surface. Forming a through hole in the thickness direction of the substrate;
Forming a TiW / Cu film on one main surface of the substrate and the surface of the through hole;
A plating resist forming step of forming a plating resist having an opening portion having an inverse taper on the one main surface of the substrate, the opening area of which increases as it approaches the main surface;
Using the TiW / Cu film as an electrode, forming a land in the through hole and the opening by electroplating;
Removing the plating resist;
Removing the TiW / Cu film exposed by peeling of the plating resist;
A method for manufacturing a semiconductor substrate, comprising: The plating resist is a photosensitive resin that is cured by ultraviolet rays,
In the plating resist forming step, the one main surface of the substrate is coated with an unexposed plating resist, and the plating resist is irradiated with ultraviolet light that is transmitted through a mask.
5. The method of forming a semiconductor substrate according to claim 4, wherein the periphery of the region where ultraviolet irradiation is blocked by the mask is exposed again with a predetermined exposure amount or less, and development processing is performed. An electronic device including a semiconductor device,
An electronic apparatus comprising the semiconductor substrate according to any one of claims 1 to 3.