JP4595694B2 - Manufacturing method of semiconductor device - Google Patents

Description

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

In order to improve electrical connection reliability, a semiconductor device using a resin core bump in which a conductive layer is formed on a resin protrusion as an external terminal has been developed. According to this, after the resin protrusion is formed on the semiconductor substrate, a conductive layer extending from the electrode pad to the resin protrusion is formed. In general, in the step of forming a conductive layer, Ar reverse sputtering is performed to remove an oxide layer on the electrode pad. However, when Ar reverse sputtering is performed, the carbonization of the surface of the resin protrusion proceeds, and as a result, the insulation resistance of the resin is lowered and migration may be caused. Further, in the case of the structure described above, the conductive layer is formed so as to pass over the resin protrusion having a three-dimensional shape, so that it is required to prevent peeling or disconnection of the conductive layer.
JP-A-2-272737

  An object of the present invention is to improve conductive adhesion and prevent migration.

(1) A method of manufacturing a semiconductor device according to the present invention includes:
(A) forming a resin layer having a stepped shape at least on the electrode pad side by performing a plurality of patterning steps above a semiconductor substrate having an electrode pad and a passivation film;
(B) a step of forming a resin protrusion by curing the resin layer;
(C) forming a conductive layer electrically connected to the electrode pad and passing above the resin protrusion;
including.

  According to the present invention, since the resin layer is formed stepwise, the rising of the resin protrusion after curing can be made gentle. Thereby, peeling of a conductive layer and prevention of a disconnection can be aimed at, and the improvement of the adhesiveness can be aimed at.

  In the present invention, B is provided above a specific A when B is provided directly on A, and when B is provided on A via the other, Shall be included. The same applies to the following inventions.

(2) In this method of manufacturing a semiconductor device,
In the step (a),
The resin layer may be formed such that the side opposite to the electrode pad side is stepped.

(3) In this method of manufacturing a semiconductor device,
In the step (a),
Patterning a first resin portion above the semiconductor substrate;
The second resin portion may be patterned and formed above the first resin portion so that the upper surface of the first resin portion is exposed all around.

(4) In this method of manufacturing a semiconductor device,
The resin material of the first resin portion may have higher wettability with respect to the passivation film than the resin material of the second resin portion.

  According to this, since the wettability of the first resin portion in the lower layer is high, it is easy to form the rising of the resin protrusion gently.

(5) In this method of manufacturing a semiconductor device,
In the step (c),
Before forming the conductive layer, with the Ar gas, the oxide film is removed from the surface of the electrode pad, and carbonization of the surface of the resin protrusion is advanced,
After forming the conductive layer, the resin protrusion may be partially removed using the conductive layer as a mask.

  According to this, even if the carbonization of the resin protrusion proceeds by Ar gas and the carbonized layer (or plasma polymerization layer) is formed, the rising of the resin protrusion is gently formed, so that the resin protrusion is carbonized. It can be easily removed without leaving a layer or the like. In particular, the carbonized layer or the like tends to remain at the base portion of the resin protrusion, but according to the present invention, the carbonized layer or the like remaining at the base portion of the resin protrusion can be easily removed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Method for manufacturing semiconductor device)
1 to 13 are views for explaining a method of manufacturing a semiconductor device according to an embodiment of the present invention.

  (1) First, as shown in FIGS. 1 and 2, a semiconductor substrate 10 is prepared. The semiconductor substrate 10 is, for example, a semiconductor wafer (see FIG. 1). In that case, the semiconductor substrate 10 has a plurality of chip regions 12 to be semiconductor chips, and an integrated circuit 14 is formed in each chip region 12. That is, when the semiconductor substrate 10 is divided into a plurality of semiconductor chips, each semiconductor chip has an individual integrated circuit 14. The integrated circuit 14 includes at least an active element such as a transistor. The chip region 12 has, for example, a rectangular shape (for example, a rectangle) in plan view. A plurality of electrode pads (for example, aluminum pads) 16 are formed in each chip region 12. The plurality of electrode pads 16 may be arranged along two opposing sides (for example, two sides on the long side) or four sides of the chip region 12. In that case, one or more rows of electrode pads 16 are arranged on each side. When the electrode pads 16 are arranged at the end portions of the chip region 12, the integrated circuit 14 may be formed in a central portion surrounded by the plurality of electrode pads 16. Alternatively, the electrode pad 16 may be formed in a region overlapping the integrated circuit 14 in plan view. The electrode pad 16 is electrically connected to the integrated circuit 14 by internal wiring (not shown).

  A passivation film (protective film) 18 is formed on the surface of the semiconductor substrate 10 (formation surface of the integrated circuit 14). The passivation film 18 may be formed of either an inorganic system or an organic system. For example, the passivation film 18 may be formed of at least one layer of a silicon oxide film and a silicon nitride film. In the passivation film 18, an opening 19 that opens the electrode pad 16 is formed. At least a part (for example, only the central part) of the electrode pad 16 is exposed by the opening 19. In many cases, an oxide layer 17 is formed on the electrode pad 16. The oxide layer 17 is formed by natural oxidation, for example, and covers the surface of the electrode pad 16.

  (2) Next, as shown in FIGS. 3 to 8, the resin layer 40 is formed by performing a plurality of patterning steps. In the example shown in the present embodiment, the resin layer 40 including the first and second resin portions 20 and 30 is formed.

  First, as shown in FIGS. 3 to 5, the first resin portion 20 is formed on the semiconductor substrate 10 (specifically, on the passivation film 18). The first resin portion 20 can be formed in a region different from the electrode pad 16 in plan view. Although the planar shape of the 1st resin part 20 is not limited, For example, it can form in the linear form which has a predetermined | prescribed width | variety. In that case, the semiconductor substrate 10 can be formed so as to extend (for example, in parallel) along the boundary (for example, the long side direction) of the chip region 12.

  Specifically, first, as shown in FIG. 3, a photosensitive first resin material 20a is applied onto the semiconductor substrate 10 by, for example, a spin coating method. Thereafter, as shown in FIG. 4, a mask 22 having an opening 24 is disposed on the semiconductor substrate 10, and exposure is performed by irradiating light energy 26. In the case where a negative type in which the solubility of the developer is reduced in the irradiated portion of the light energy 26 is used as the first resin material 20a, the resin can be left only in the region exposed from the opening 24 of the mask 22. . Or, conversely, when a positive type in which the solubility of the developer increases in the irradiated portion of the light energy 26 is used as the first resin material 20a, the resin is left only in the region covered with the mask 22. Can do. Thereafter, by performing a developing process, the first resin portion 20 can be patterned into a predetermined shape as shown in FIG.

  Here, examples of the resin material of the first resin portion 20 include elastic resin materials such as polyimide resin, acrylic resin, phenol resin, epoxy resin, silicone resin, and modified polyimide resin. The first resin portion 20 can be, for example, polyimide, polybenzoxazole, benzocyclobutene, epoxy, or the like, which is an aromatic compound of an organic compound having a benzene ring and a ring in which it is condensed.

  Next, as shown in FIGS. 6-8, the 2nd resin part 30 is formed. Specifically, first, as shown in FIG. 6, a photosensitive second resin material 30a is applied onto the semiconductor substrate 10 by, for example, a spin coating method. Thereafter, as shown in FIG. 7, a mask 22 having an opening 24 is disposed on the semiconductor substrate 10, and exposure is performed by irradiating light energy 36. In the case where a negative type in which the solubility of the developer is reduced in the irradiated portion of the light energy 36 is used as the second resin material 30a, the resin can be left only in the region exposed from the opening 24 of the mask 22. . Or conversely, when a positive type in which the solubility of the developer increases in the irradiated portion of the light energy 36 is used as the second resin material 30a, the resin is left only in the region covered with the mask 22. Can do. Thereafter, by performing a developing step, the second resin portion 30 can be patterned into a predetermined shape as shown in FIG.

  The second resin part 30 can be formed in contact with the first resin part 20. In the example shown in FIG. 8, the second resin portion 30 is formed on the first resin portion 20. In that case, you may form the 2nd resin part 30 so that the upper surface of the 1st resin part 20 may be exposed to the perimeter. Thereby, the whole periphery of the resin layer 40 can be formed in step shape. The thicknesses of the first and second resin parts 20 and 30 (the thickness of the resin material to be applied before patterning) may be substantially the same, and the first resin part 20 in the lower layer is thicker. Alternatively, the upper second resin portion 30 may be thicker. The thickness of each resin part can be appropriately adjusted according to the shape of the resin protrusion 41 after curing.

  Here, as the resin material of the second resin portion 30, the contents described in the first resin portion 20 described above can be applied. For example, the first and second resin parts 20 and 30 may be the same resin after curing. Further, even if the resin material of the lower first resin portion 20 in contact with the passivation film 18 has higher wettability (lower viscosity) with respect to the passivation film 18 than the resin material of the second resin portion 30. Good. Thereby, the rising of the resin protrusion 41 after curing is easily formed. In addition, the wettability of the resin material can be appropriately adjusted by adjusting the contained additive and the like.

  As a modification, the first and second resin portions 20 and 30 described above may be formed by a droplet discharge method (for example, an ink jet method). According to this, the resin material can be directly discharged only to a necessary region. In particular, according to the ink jet method, ink (resin material) can be provided economically without waste by applying a technique that has been put to practical use for an ink jet printer.

  The resin layer 40 formed in this way is formed in a staircase shape at least on the electrode pad 16 side (the bottom on the semiconductor substrate 10 side is wide) by the first and second resin portions 20 and 30. The stepped shape includes not only a case where a plurality of surfaces are connected with corners but also a case where a plurality of surfaces are connected with smooth curved surfaces. In the example shown in FIG. 8, the resin layer 40 has a stepped shape not only on the electrode pad 16 side but also on the opposite side. The resin layer 40 is formed in a step shape in a cross-sectional view perpendicular to the semiconductor substrate 10.

  (3) Next, as shown in FIG. 9, the resin protrusion 41 is formed by curing the resin layer 40. Specifically, by heating the resin layer 40, the resin is melted and then cured and contracted. The resin protrusion 41 having a curved surface can be formed by the curing process. The cross section of the resin protrusion 41 has, for example, a substantially semicircular shape, and the stepped portion before curing is formed with an inclined surface that rises gently. The rising angle (angle formed by the tangent of the inclined surface near the rising edge and the surface of the passivation film 18) θ is at least θ <90 ° (optimally θ≈0 °). In addition, the rising of the resin protrusion 41 is formed to be curved so as to form a concave shape in the outward direction (obliquely upward direction). As described above, when the entire circumference of the resin layer 40 has a stepped shape, the rising can be formed with a gently inclined surface on the entire circumference of the resin protrusion 41. Thereby, the below-mentioned conductive layer 50 can be extended on the resin protrusion 41 from every direction with high adhesiveness.

  (4) Next, as shown in FIGS. 10 to 12, a conductive layer 50 that is electrically connected to the electrode pad 16 and passes over the resin protrusion 41 is formed. 10 is a partial plan view after the conductive layer forming step, FIG. 11 is a sectional view taken along line XI-XI in FIG. 10, and FIG. 12 is a sectional view taken along line XII-XII in FIG.

  First, before forming the conductive layer 50, the oxide layer 17 on the electrode pad 16 is removed. The oxide layer 17 is, for example, grown by natural oxidation or grown by the above-described resin curing process. As a method for removing the oxide layer 17, for example, reverse sputtering of Ar gas can be applied. When reverse sputtering of Ar gas is performed on the entire surface of the semiconductor substrate 10, carbonization of the surface of the resin protrusion 41 proceeds. That is, a carbonized layer or a layer before reaching the carbonized layer (for example, a plasma polymerization layer) is formed on the surface of the resin protrusion 41. This embodiment is particularly useful when a carbonized layer or the like is formed in this way.

  The conductive layer 50 can be formed by forming a conductive foil by sputtering or vapor deposition and then patterning the conductive foil. The conductive layer 50 can be formed of, for example, a plurality of layers including a first layer (for example, a TiW layer) 52 serving as a base and a second layer (for example, an Au layer) 54 thereon. In that case, a conductive foil is formed by the first and second layers 52 and 54, the second layer 54 is patterned by etching (for example, wet etching) using the resist as a mask, and the patterned second layer 54 is masked. As an alternative, the first layer 52 may be patterned. The first layer 52 serving as a base can be used as a metal diffusion prevention, adhesion improvement or plating layer. As a modification, the first layer 52 as a base can be formed by sputtering or vapor deposition, and the second layer 54 thereon can be formed by electroless plating or electroplating. Thereby, the second layer 54 can be easily formed thick. Alternatively, the conductive layer 50 can be formed of a single layer (for example, an Au layer). The material of the conductive layer 50 is not limited to the above, and for example, Cu, Ni, Pd, Al, Cr, or the like can be used.

  The conductive layer 50 is a wiring layer that electrically connects the electrode pad 16 and the resin protrusion 41. The conductive layer 50 is formed so as to pass at least on the electrode pad 16, the passivation film 18, and the resin protrusion 41. In this embodiment, since the rising of the resin protrusion 41 is gently formed, the adhesion of the conductive layer 50 can be improved. Therefore, peeling of the conductive layer 50 and disconnection can be prevented. In the example shown in FIG. 11, the conductive layer 50 is formed so as to extend over the resin protrusion 41 and onto the passivation film 18 on the side opposite to the electrode pad 16. In other words, the conductive layer 50 is formed so as to branch from the resin protrusion 41 in a plurality of directions (for example, the electrode pad 16 side and the opposite side thereof) and reach the passivation film 18. Thereby, the further adhesive improvement with respect to the foundation | substrate of the conductive layer 50 can be aimed at. The conductive layer 50 has an electrical connection portion 56 formed on the resin protrusion 41.

As shown in FIGS. 12 and 13, after forming the conductive layer 50, the resin protrusion 41 may be partially removed using the conductive layer 50 as a mask. Thereby, for example, it is possible to improve the dischargeability of the adhesive during mounting. For example, when the resin protrusions 41 are formed in a straight line having a predetermined width and a plurality of electrical connection portions 56 are arranged at predetermined intervals in the length direction of the resin protrusions 41, adjacent electrical connection portions The portion exposed between 56 is etched and removed by an anisotropic etchant (for example, O ₂ plasma) 58. In that case, in order to prevent damage to the passivation film 18, etching can be performed so as to provide a resin residue 44 between the adjacent electrical connection portions 56. According to the present embodiment, since the rise of the resin protrusion 41 is gentle, an anisotropic etchant can easily enter the base portion of the resin protrusion 41, thereby forming the base portion of the resin protrusion 41. The carbonized layer and the like can be easily removed as compared with the conventional case. Therefore, migration due to the carbonized layer or the like can be prevented, and reliability can be improved.

  In this way, the semiconductor device 100 having a plurality of resin core bumps 60 can be manufactured. The resin core bump 60 is formed on one surface of the semiconductor substrate 10 (the surface on which the integrated circuit 14 is formed), and includes a resin protrusion 42 and an electrical connection portion 56 formed on the resin protrusion 42. According to this, since the resin protrusion 42 becomes a core and itself has elasticity, it is possible to improve the stress relaxation function and electrical connection reliability at the time of mounting. Note that the semiconductor device according to the present embodiment has a configuration that can be derived from the contents of the above-described method for manufacturing a semiconductor device.

(Electronics)
FIG. 14 is a diagram showing an electronic device according to an embodiment of the present invention. The electronic device (for example, display device) 1000 includes the semiconductor device 100. In the example shown in FIG. 14, the electronic device 1000 includes a semiconductor device 100, a first substrate 200 made of a resin film or the like, and a second substrate 300 made of glass or the like. The semiconductor device 100 is, for example, face-down mounted on the first substrate 200. Specifically, the wiring pattern formed on the first substrate 200 and the resin core bump 60 of the semiconductor device 100 are electrically connected. An insulating adhesive (not shown) (for example, NCF (Non Conductive Film) or NCP (Non Conductive Paste)) is provided between the semiconductor device 100 and the first substrate 200. Alternatively, the first substrate 200 can be omitted and the semiconductor device 100 can be mounted face down on the second substrate 300. Examples of the electronic device 1000 include a liquid crystal display, a plasma display, and an EL (Electrical Luminescence) display. Note that FIG. 15 shows a notebook personal computer as an example of an electronic apparatus according to an embodiment of the present invention, and FIG. 16 shows a mobile phone.

(First modification)
FIG. 17 is a diagram illustrating a method for manufacturing a semiconductor device according to a modification of the embodiment of the present invention. In this modification, the form of the resin protrusion 70 is different from that described above.

  The details described above can be applied to the details of the step of forming the resin layer before curing. However, in this modification, before the step of forming the conductive layer 50, a plurality of resin layers are formed so as to be spaced apart from each other so that any of the resin protrusions 70 are paired with each electrode pad 16. For example, after a plurality of resin layers are patterned and formed in a columnar shape, a plurality of resin protrusions 70 can be formed in a hemispherical shape by a curing process. The resin layer before curing can be formed so that the entire circumference forms a step shape.

  For example, the conductive layer 50 electrically connects any one electrode pad 16 and any one resin protrusion 70. In that case, the conductive layer 50 may be formed so as to cover only a part of one resin protrusion 70 or may be formed so as to cover the whole. In the former case, since the external force is released by exposing a part of the resin protrusion 70, it is possible to prevent cracks in the electrical connection portion 56 (conductive layer 50) during mounting.

  In this modified example, since the resin protrusions 70 are separately formed in advance, the step of partially removing the resin protrusions after forming the conductive layer 50 may be omitted as in the above-described example. it can.

(Second modification)
18 and 19 are diagrams illustrating a method for manufacturing a semiconductor device according to a modification of the embodiment of the present invention. Also in this modification, the form of the resin protrusion 141 is different from that described above.

  In the example shown in FIG. 18, the resin layer 140 is formed to have a stepped shape only on the electrode pad 16 side. In that case, the side opposite to the electrode pad 16 in the resin layer 140 is not stepped, and for example, a plane that rises vertically is formed by the first and second resin portions 120 and 130. Thereafter, as shown in FIG. 19, by curing the resin layer 140, it is possible to form the resin protrusion 141 having a gently rising edge on the electrode pad 16 side. According to this, since the conductive layer 50 can prevent peeling and disconnection at least between the electrode pad 16 and the resin protrusion 141, it is possible to prevent the occurrence of poor electrical connection.

(Other variations)
In the present embodiment, it is only necessary that the resin layer before curing has a stepped shape at least on the electrode pad 16 side, and the patterning pattern of the first and second resin portions is not limited to the above. For example, it is possible to form a staircase by first forming a thin resin portion by patterning on the electrode pad 16 side, and then forming a thick resin portion next to the thin resin portion and patterning it. is there.

  In the above-described example, an example in which the resin layer before curing is formed stepwise by two patterning steps is described. However, the present embodiment is not limited to this, and the patterning step is performed three or more times. You can also.

  The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same purposes and results). In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that achieves the same effect as the configuration described in the embodiment or a configuration that can achieve the same object. Further, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

It is a figure explaining the manufacturing method of the semiconductor device which concerns on this Embodiment. It is a figure explaining the manufacturing method of the semiconductor device which concerns on this Embodiment. It is a figure explaining the manufacturing method of the semiconductor device which concerns on this Embodiment. It is a figure explaining the manufacturing method of the semiconductor device which concerns on this Embodiment. It is a figure explaining the manufacturing method of the semiconductor device which concerns on this Embodiment. It is a figure explaining the manufacturing method of the semiconductor device which concerns on this Embodiment. It is a figure explaining the manufacturing method of the semiconductor device which concerns on this Embodiment. It is a figure explaining the manufacturing method of the semiconductor device which concerns on this Embodiment. It is a figure explaining the manufacturing method of the semiconductor device which concerns on this Embodiment. It is a figure explaining the manufacturing method of the semiconductor device which concerns on this Embodiment. It is the XI-XI sectional view taken on the line of FIG. It is the XII-XII sectional view taken on the line of FIG. It is a figure explaining the manufacturing method of the semiconductor device which concerns on this Embodiment. It is a figure which shows the electronic device which concerns on this Embodiment. It is a figure which shows the electronic device which concerns on this Embodiment. It is a figure which shows the electronic device which concerns on this Embodiment. It is a figure explaining the manufacturing method of the semiconductor device which concerns on the modification of this Embodiment. It is a figure explaining the manufacturing method of the semiconductor device which concerns on the modification of this Embodiment. It is a figure explaining the manufacturing method of the semiconductor device which concerns on the modification of this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Semiconductor substrate 16 ... Electrode pad 18 ... Passivation film 20 ... 1st resin part 30 ... 2nd resin part 40 ... Resin layer 41,42 ... Resin protrusion 50 ... Conductive layer 60 ... Resin core bump 70 ... Resin protrusion 100 ... Semiconductor device 140 ... resin layer 141 ... resin protrusion

Claims (4)

A resin layer that forms a first resin layer on the passivation film and a second resin layer on the first resin layer by performing a plurality of patterning steps on the surface of the semiconductor substrate having the electrode pad and the passivation film. Forming process ;
A resin protrusion forming step of forming a resin protrusion having a curved surface by curing the first resin layer and the second resin layer ;
A conductive layer forming step of forming a conductive layer electrically connected to the electrode pad and passing through the surface of the resin protrusion;
Have
The first resin layer is made of a first resin material, the second resin layer is made of a second resin material,
The first resin material has higher wettability with respect to the passivation film than the second resin material.
A method for manufacturing a semiconductor device. 2. The method of manufacturing a semiconductor device according to claim 1, wherein, in the resin layer forming step, the resin layer is formed so that the electrode pad side has a stepped shape. 3. In the resin layer forming step,
3. The semiconductor according to claim 1, wherein a second resin layer is formed on the first resin layer such that an upper surface of the first resin layer is exposed all around the first resin layer. 4. Device manufacturing method. In the resin layer forming step,
Before forming the conductive layer, with the Ar gas, the oxide film is removed from the surface of the electrode pad, and carbonization of the surface of the resin protrusion is advanced,
The method for manufacturing a semiconductor device according to claim 1, wherein after the formation of the conductive layer, the resin protrusion is partially removed using the conductive layer as a mask.

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