TW201637106A - Mask for emplacement of conductive ball and manufacturing method thereof - Google Patents

Abstract

The present invention provides a mask for emplacement of conductive ball, which is a mask for emplacement of conductive ball to form a bump on a substrate or wafer. The overall thickness of mask is fixed, the mask has a spacer, and is formed of plural planar and linear design patterns. It has excellent drug tolerance and mechanical strength without damaging a workpiece easily. Thin plates made of resins such as Polyimide are applied as the member to form the spacer. The spacer having a specific pattern is formed by ultraviolet light, and then the spacer is attached onto a metal mask made by electrolytic plating. Or, the spacer can be processed at the state that the metal mask is attached with a thin resin plate.

Description

Conductive ball fixing mask and manufacturing method thereof

The present invention relates to a mask for placing an electrically conductive ball on an electrode on a workpiece such as a substrate or wafer.

In a semiconductor manufacturing process, when a flip chip package is used or a bump electrode is formed on a germanium wafer, an electrode disposed on a workpiece such as a substrate or a germanium wafer in a predetermined pattern is generally used. A conductive ball made of a conductive metal is subjected to a reflow process to melt the solder and then adhered to the electrode (for example, refer to Patent Document 1).

Here, a metal mask of a stencil having a fine opening formed in a thin metal plate is used as a jig for fixing a conductive ball. This opening is formed in accordance with a pattern corresponding to the electrode on the workpiece, and when the metal mask is appropriately disposed with respect to the workpiece, it is set so that the conductive ball can be appropriately placed on the electrode.

In this project, the flux is applied to the electrodes in advance. This is to remove the oxide film of the electrode during the reflow process to improve the wettability of the electrode, and to adhere the molten solder well, or to prevent the conductive ball from moving from the fixed position.

However, the opposing surface of the workpiece with respect to the metal mask (hereinafter referred to as "fixed surface") is in contact with the surface on which the electrode on the workpiece is placed (hereinafter, "fixed surface"), in order to avoid assistance The flux adheres to the fixed surface and stains the metal mask by using a predetermined thickness of the spacer on the fixed surface of the metal mask to separate the hand from the fixed surface by a certain distance. Segment (for example, refer to Patent Document 2).

A metal having the same material as that of the metal mask is used as the material of the spacer, and a method of integrally forming it by electrolytic plating or the like is generally used. However, since the metal spacer is relatively hard, it is easy to damage the fixed surface of the workpiece. For this reason, a method of forming a spacer portion with a relatively soft resin such as a photoresist to protect the surface to be fixed is known (for example, see Patent Document 3).

Here, if the thickness of the spacer varies, since the spacer does not come into contact with the workpiece, there is a generation of a gap, and since the conductive ball rolls into the gap and dissolves during the reflow, the adjacent electrodes are caused to each other. Short circuit. Therefore, the interval between the fixed surface and the fixed surface is made constant, and in order to properly position the conductive ball, the thickness of the entire metal mask needs to have a certain thickness. In addition, in the use of the metal mask, in order to avoid breakage of the spacer, it is required to have excellent mechanical strength, and it is necessary to be resistant in order to avoid dissolution by the flux of the flux or the metal mask.

In the case where a metal spacer is formed by electrolytic plating, a pattern forming process such as a photosensitive dry film or a liquid resist, or an electroforming process or a photoresist film peeling is performed by photolithography. Engineering such as engineering is more complicated. Further, if the design pattern becomes fine, since the current density is concentrated due to the dense photoresist, the precipitation of the plating becomes unstable due to the difference in position, resulting in a problem that the variation in the thickness of the spacer becomes large. Further, in the case of forming a resin, similarly, since the patterning process of the photoresist by the photolithography method is necessary by the photoresist coating process, the engineering is complicated, and it is difficult to apply the coating according to a certain thickness, and the mechanical strength. Or the resistance is not enough.

Furthermore, as described in Patent Document 3, the spacer has a pillar shape. In the case of the shape of the protrusion, it is more likely to be broken, or when the fixed surface of the metal mask is washed, the cleaning tool such as the waste cloth is easily hooked to the pillar, and it is not easy to wipe.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 11-243274

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2005-101242

Patent Document 3: Japanese Patent No. 4664146

An object of the present invention is to provide a conductive ball fixing mask which is formed by all the thicknesses of the mask, has a spacer, and is formed in a functional design pattern such as a surface or a line, and is resistant to machinery and machinery. It is excellent in strength and does not easily damage the workpiece, and is easy to be cleaned by a mask.

In order to achieve the above object, the invention of claim 1 is a conductive ball fixing mask for positioning a conductive ball on an electrode arranged on a predetermined surface of a workpiece in a predetermined pattern, and is characterized in that: a flat mask formed in an in-plane according to a pattern corresponding to the electrode, having an opening through which a conductive ball can be inserted; and a film-like thin plate having a resin The layer is composed of a polyamidene which is a heat-resistant resin and a spacer which is formed by cutting a thin plate into a lattice pattern, a line shape, a surface shape or a combination of these. Inside, wherein the resin layer faces the surface side, in order to avoid The spacer is prevented from blocking the opening, and the mask and the sheet are adhered by a heat/pressure hardening type adhesive sheet made of epoxy resin.

The invention described in claim 2 is a method for manufacturing a conductive ball fixing mask for positioning a conductive ball on an electrode arranged on a predetermined surface of a workpiece in a predetermined pattern, characterized by comprising: a mask In the manufacturing process, a pattern corresponding to the electrode is formed in the surface by any one of an electrolytic plating method, a laser processing method, or an etching method, and has a mask that can be inserted through an opening of the size of the conductive ball. a film-forming sheet having a resin layer composed of a polyacrylamide which is a heat-resistant resistant resin, which is lattice-shaped, linear, planar or a certain design pattern of these combinations is cut to remove a unnecessary portion of the sheet to form a spacer; in a bonding process, the resin layer is oriented toward the surface side, in order to prevent the spacer from blocking the opening, the sheet, A heat/pressure hardening type adhesive sheet composed of an epoxy resin is peelably attached to the surface of the mask; and an adhesive works to adhere the mask to the sheet with a predetermined heat or pressure.

The invention of claim 3 is a method for manufacturing a conductive ball fixing mask for positioning a conductive ball on an electrode arranged on a predetermined surface of a workpiece in a predetermined pattern, which comprises: a mask In the manufacturing process, a pattern corresponding to the electrode is formed in the surface by any one of an electrolytic plating method, a laser processing method, or an etching method, and has a mask that can be inserted through an opening of the size of the conductive ball. a film-like sheet having a resin layer composed of a polyacrylamide which is a heat-resistant resistant resin, the resin layer being oriented toward the surface side, and an adhesive sheet made of epoxy resin may be used. Peelingly adhering to the surface of the mask; a spacer forming process, using an ultraviolet laser in the plane of the thin plate, in order to avoid cutting the mask, adjusting the processing conditions to an appropriate value, and The sheet is in the form of a lattice, a line, a face, or a group of these a certain design pattern cut to remove a unnecessary portion of the sheet to form a spacer; and an adhesive process to adhere the mask to the sheet with a predetermined heat or pressure, wherein the spacer is formed as Will not block the opening.

The invention of claim 4, wherein the conductive ball fixing mask according to claim 1 or the conductive ball fixing mask according to claim 2 is characterized in that the mask is attached After the bonding work with the thin plate, the ultraviolet laser is used before the adhesion of the mask to the thin plate, and in order to avoid cutting the mask, the processing conditions are adjusted to an appropriate value, and the thin plate is cut. Break to process air gullies or air holes.

According to the invention of claim 1, since the thin plate having a uniform thickness is used as the material of the spacer, the thickness of the spacer passing through the entire mask can be maintained within a certain range, and the spacer can be prevented because it is in close contact with the workpiece. The conductive balls roll into the gap between the two, thereby reducing the occurrence of defects.

According to the invention of claim 2, by using a polyimide having a high mechanical strength or high resistance as a resin layer of a thin plate as compared with a case of forming a metal, a spacer can be formed, and the workpiece is less likely to be damaged. The fixed surface is less soluble or damaged. Further, since it has high heat resistance, it can be appropriately cut by ultraviolet rays, and has an effect of reducing thermal deformation in the adhesion process between the thin plate and the mask.

According to the invention of claim 3, a conductive ball fixing mask can be obtained, and the spacer is less likely to be damaged than the conventional pillar shape, and the mask can be easily washed.

According to the invention of claim 4, since the ultraviolet ray can cut the polyamine at a beautiful position, it is possible to form a spacer having a better dimensional accuracy or shape.

The above and other objects, features, and advantages of the present invention will become more apparent and understood.

1, 4, 7, 10, 13‧‧‧ Conductive ball fixing mask

2, 5, 8, 11, 14‧‧‧ metal mask (mask)

21, 51, 81, 111, 141‧‧

3, 6, 9, 12, 15‧‧‧ resin sheet (thin sheet)

31, 61, 91, 121, 151‧‧‧ spacers

32‧‧‧Air Ditch

Fig. 1 is a front view (a) and a side sectional view (b) showing a conductive ball fixing mask according to an embodiment of the present invention.

Fig. 2 is a front elevational view showing a mask according to an embodiment of the present invention.

Fig. 3 is a front elevational view showing a thin plate according to an embodiment of the present invention.

Fig. 4 is a front elevational view showing the middle of the production of the conductive ball fixing mask according to the embodiment of the present invention.

Fig. 5 is a flow chart showing the manufacture of a mask for a conductive ball according to an embodiment of the present invention.

Fig. 6 is a view showing a use state (cross-sectional view) of a conductive ball fixing mask according to an embodiment of the present invention.

Fig. 7 is a front elevational view showing a mask for a conductive ball according to another embodiment of the present invention.

Fig. 8 is a front elevational view showing a mask for a conductive ball according to another embodiment of the present invention.

Fig. 9 is a front elevational view showing a mask for a conductive ball according to another embodiment of the present invention.

Fig. 10 is a front elevational view showing a mask for a conductive ball according to another embodiment of the present invention.

Fig. 11 is a flow chart showing a manufacturing process of a mask according to another embodiment of the present invention by electrolytic plating.

Fig. 12 is a flow chart showing a manufacturing process of a mask according to another embodiment of the present invention by an etching method.

Figure 13 is a perspective view showing the mask of another embodiment of the present invention by laser processing. A flow chart for the project.

Fig. 1 is a front view (a) and a cross-sectional view (b) of the conductive ball fixing mask 1 of the embodiment. First, the conductive ball fixing mask 1 substantially includes a metal mask (mask) 2 and a resin sheet (thin sheet) 3, and the metal mask 2 and the resin sheet 3 are bonded together by an adhesive sheet (not shown). .

The metal mask 2 is made of a thin metal such as nickel or stainless steel. Generally, the thickness is 0.015 mm to 0.2 mm, and the outer shape is a quadrilateral (square or rectangular) having a side of 100 mm to 600 mm. Here, the method of manufacturing the metal mask 2 may be an electrolytic plating method, an etching method, a laser processing method, or the like as described later, but in the present embodiment, any of them may be used.

In the surface of the metal mask 2, in order to insert the conductive ball, an opening 21 having a through hole of φ0.01 mm to 1.00 mm is formed in plural in accordance with a predetermined pattern. Here, in order to allow the conductive ball to be smoothly inserted and the position to be set is not shifted, the diameter of the opening 21 is set to be 1 to 1.5 times the diameter of the conductive ball.

Next, the resin sheet 3 is a film having a thickness of 0.02 to 0.2 mm, and the outer dimension is equal to or larger than the entire area of the opening 21 covering the metal mask 2, and the outer dimension of the metal mask 2 is set to be small. Further, as the material of the resin sheet 3, polybenzamine which is excellent in chemical resistance and heat resistance and has high mechanical strength can be used.

A lattice-shaped spacer 31 is formed in the surface of the resin sheet 3 by ultraviolet processing. The spacer 31 can cut the resin sheet into a square shape in a predetermined design pattern, and is formed in a lattice shape that can expose the opening 21 of the metal mask 2. The width of the spacer 31 is set to 0.01 to 20.0 mm so as not to impair the mechanical strength. The design pattern of the spacer 31 is a shape When the resin sheet 3 is appropriately overlapped with the metal mask 2, the spacers 31 may be disposed at intervals of the openings 21, or may be disposed at intervals of the aggregates (cells) of the openings 21, and may not block the openings. 21 design and size.

In the light source of the ultraviolet processing method, an ultraviolet laser can be used, and a flame retardant resin such as polyamine can be cut beautifully in the shape of the non-destructive cut portion.

Further, around the spacer 31 of the resin sheet 3, the air grooves 32 are formed in a lattice shape. This is to make the conductive ball fixing mask 1 in close contact with the workpiece, and to release the air between the workpiece and the spacer 31 to the outer groove. Similarly to the spacer 31, it can be processed by ultraviolet laser.

Further, an epoxy resin having excellent chemical resistance can be used by laminating the adhesive sheet of the metal mask 2 and the resin sheet 3. Adhesive sheet is hardened by heat or pressure to exert adhesion.

Next, a method of manufacturing the conductive ball fixing mask 1 of the present embodiment will be described with reference to the flowchart of FIG.

First, the production of the metal mask 2 is performed (step S1). In the present embodiment, the metal mask 2 can be electrolytically plated in consideration of a manufacturing method that has never existed. (On a plating substrate made of a flat plate of a conductive metal such as stainless steel, photolithography is used to measure sensitivity. A photoresist film such as a dry film or a liquid resist, after forming an opening pattern, is subjected to electrolytic nickel plating using an amine sulfonic acid bath or a sulfuric acid bath (watt bath) on a plating substrate, and laser processing Method (exposure by laser irradiation, metal (mainly stainless steel) plate for metal mask material), etching method (by photolithography, image formation of an opening pattern on a stainless steel substrate, by Etching is performed to form an opening). The simple flow of each production project is described in the 11th to 13th drawings.

Next, the processing of the resin sheet 3 is performed by ultraviolet laser processing to form an interval. The partition 31 (step S2). The spacer 31 is formed in a lattice shape by cutting a rectangular piece from the resin sheet 3 according to a predetermined design pattern. In addition, the order of steps S1 and S2 can also be reversed.

Next, the metal mask 2 produced in the step S1 and the resin sheet 3 produced in the step S2 are aligned and bonded in order to prevent the spacer 31 from blocking the opening 21 (step S3). Here, the metal mask 2 and the resin sheet 3 do not need to be adhered, but are detachably fixed by the adhesion of the adhesive sheet or the heat-resistant tape.

Next, the processing of the air groove 32 is performed by ultraviolet laser processing (step S4). In order to surround the four rectangular cut portions formed in step S2, the slits are cut into three slits in the vertical and horizontal directions, and the spacers 31 are formed by being separated by the air grooves 32, respectively. At this time, in order to prevent the metal mask 2 from being cut, the processing conditions of the ultraviolet laser are modulated to appropriate values. Further, in the ultraviolet laser processing, in order to perform the next step S4, the peeling can be easily performed, and the blank portion is integrally processed as much as possible (in the present embodiment, the lattice portions are all connected together).

The lattice-shaped blank portion generated in step S4 is peeled off (step S5).

The metal mask 2 and the resin sheet 3 are adhered by predetermined heat or pressure (step S6).

Next, a fixing step of the conductive ball for the conductive ball fixing mask 1 of the present embodiment will be described with reference to Fig. 6 .

The conductive ball was placed in a mask 1 and stretched over a stencil frame formed of a stainless steel frame 100 and a polyester mesh plate 101 to perform plate making.

The plated conductive ball is fixed to the mask 1, and a predetermined position of the workpiece 102 on which the electrode 103 is coated with a flux (not shown) is provided.

The conductive ball 104 is cast to the opposite side of the workpiece 102 of the conductive ball fixing mask 1, and is placed on the electrode 103 of the workpiece 102 through the opening 21.

According to the conductive ball fixing mask 1 of the present embodiment, since the resin thin plate 3 having a uniform thickness is used as the material of the spacer 31, the thickness of the spacer 31 through the entire mask can be maintained within a certain range, and the spacer Since the contact with the workpiece 102 is good, the conductive ball 104 can be prevented from rolling into the gap, so that occurrence of defects can be reduced.

Further, in comparison with the case where the metal is formed, a spacer 31 can be formed by using the polyimide or the high-resistance polyamine in the resin sheet 3, and the fixed surface of the workpiece 102 is less likely to be damaged. And it is less soluble or damaged during use. Further, since it has high heat resistance, it can be appropriately cut by ultraviolet rays, and has an effect of reducing thermal deformation in the adhesion process of the resin sheet 3 and the metal mask 2.

Further, a conductive ball fixing mask 1 can be obtained, and the spacer 31 is less likely to be damaged than the conventional pillar shape, and the metal mask 2 can be easily washed.

Further, since the ultraviolet ray can cut the polyamine at a beautiful position, the spacer 31 having a better dimensional accuracy or shape can be formed.

Further, since the air can be released from the air groove 32, the spacer 31 can be easily adhered to the workpiece 102.

Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to the above-described embodiments, and may be extended to other forms as seen from the above.

For example, the spacer 31 can take various forms as shown in Figs. 7 to 10 . Here, the same configurations as those of the embodiment are not particularly described, and the description thereof will be omitted.

First, as shown in Fig. 7, the conductive ball is fixed by the mask 4, and the spacer 61 may have The spacer 31 is also in the form of a lattice, but the air groove 32 is not provided. In this case, the works of paragraphs 0034 and 0035 are not required.

Further, in the conductive ball fixing mask 7 of Fig. 8, the spacers 91 are linear, and since the respective wires are separated from the outer frame portion of the resin thin plate 9, as in the above embodiment, it is impossible to perform the independent of the metal mask. 8 pairs of spacers 91 are processed, and then processed from the back. Therefore, after the resin sheet 9 is bonded to the metal mask 8, the spacer 91 is processed by ultraviolet laser.

In this case, since the spacer 91 has a linear shape, it is easier to wipe than the case of the lattice shape, and it becomes easier to wash.

Further, according to this method, the conductive ball fixing mask 7 can be manufactured by a simpler method without performing the alignment of the metal mask 8 and the resin sheet 9 as in the embodiment.

Further, as the conductive ball fixing mask 10 shown in FIG. 9, for example, when the workpiece 102 is a wafer and the pattern of the opening 111 is circular, a shape like the spacer 121 may be formed; In the conductive ball fixing mask 13 shown in FIG. 10, when the pattern of the opening 141 is special, the spacer 151 having a linear shape and a planar shape may be formed as in the spacer 151.

Further, the method of manufacturing the metal masks 2, 5, 8, 11, 14 (hereinafter referred to as "metal mask 2" or the like) may be a machining method such as a drill or an end mill. Further, in the case of electroplating, it is not limited to electrolytic nickel plating, and electroless plating may be used. In this case, according to the characteristics of the electroless plating, in addition to the thickness uniformity of the metal mask, the plating film having high hardness and excellent durability can be obtained as compared with the electrolytic plating method.

Furthermore, in the above-described embodiment, the resin sheets 3, 6, 9, 12, and 15 (hereinafter referred to as "resin sheet 3 or the like") are a single layer structure of polyamidene, but are not limited thereto, and may be used. It is a multilayer structure of polyamine and metal. In this case, when the conductive ball is fixed to the workpiece 102 by the mask 1 or the like when it is attached to the metal mask 2 or the like, the polyimide can be brought into contact with the workpiece 102 (polyimide) Fitted toward the surface).

Further, the resin sheet 3 or the like does not necessarily need to use a single thickness, and a plurality of thicknesses may be used, and the thickness of the spacer 31 or the like may be partially changed. In this manner, the conductive ball fixing mask 1 in which the thickness of the spacer 31 or the like varies depending on the portion can be manufactured, and even if the workpiece 102 has a step, the spacer 31 or the like can be appropriately combined with the workpiece 102. Close contact.

Further, in the outer frame portion of the resin sheet 3 or the like, by appropriately providing an air hole for releasing air, when attached to the metal mask 2 or the like, bubbles are not entrained to form air bubbles, and the resin sheet 3 can be made good. The ground is attached to the metal cover 2 and the like.

Further, the processing of the spacers 31, 61, 91, 121, and 151 (hereinafter referred to as "spacer 31") is not limited to the ultraviolet ray if the resin can be cut by a predetermined design pattern by irradiation with ultraviolet rays. Shoot. For example, the aperture (hole plate) in which the design pattern of the spacer 31 or the like is opened is adhered to the resin sheet 3 or the like, and the spacer 31 or the like can be formed even by a method of irradiating ultraviolet rays.

While the invention has been described above by way of a preferred embodiment, it is not intended to limit the invention, and it is intended to be within the scope of the invention. . Therefore, the scope of the invention is defined by the scope of the appended claims.

1‧‧‧Conducting ball fixing mask

2‧‧‧Metal mask (mask)

3‧‧‧Resin sheet (thin sheet)

31‧‧‧ spacers

32‧‧‧Air Ditch

Claims (4)

A conductive ball fixing mask for positioning a conductive ball on an electrode arranged on a predetermined surface of a workpiece according to a predetermined pattern, comprising: a metal flat mask, the mask is adapted to a pattern corresponding to the electrode is formed in the surface, having an opening that can be inserted through the size of the conductive ball; and a film-like thin plate having a resin layer made of a polyamidamide which is a heat resistant resin And the spacer is formed in a plane by cutting a thin plate into a predetermined design pattern of a grid shape, a line shape, a surface shape or a combination of these, wherein the resin layer faces the surface side, in order to avoid The spacer blocks the opening, and the mask and the sheet are adhered by a heat/pressure hardening type adhesive sheet made of epoxy resin. A manufacturing method for a conductive ball fixing mask for placing a conductive ball on an electrode arranged on a predetermined surface of a workpiece according to a predetermined pattern, comprising: a mask manufacturing process, by electrolytic plating, laser a method of processing or etching, wherein a pattern corresponding to the electrode is formed in the surface, having a mask that can be inserted through an opening of a size of the conductive ball; a spacer forming process will have a film-like thin plate of a resin layer composed of a polyacrylamide of a heat-resistant resistant resin, which is cut by a certain design pattern in a lattice shape, a line shape, a surface shape or a combination of these using an ultraviolet laser. Forming a spacer to remove unnecessary portions of the sheet; in a bonding process, the resin layer faces the surface side, and in order to prevent the spacer from blocking the opening, the sheet is made of epoxy/heat/pressure a hardened adhesive sheet removably attached to the surface of the mask; An adhesive project adheres the mask to the sheet with a predetermined heat or pressure. A manufacturing method for a conductive ball fixing mask for placing a conductive ball on an electrode arranged on a predetermined surface of a workpiece according to a predetermined pattern, comprising: a mask manufacturing process, by electrolytic plating, laser Any one of a processing method or an etching method, wherein a pattern corresponding to the electrode is formed in a plane, and has a mask that can be inserted through an opening of a size of the conductive ball; A film-like thin plate of a resin layer composed of a polyacrylamide of a heat-resistant resistant resin, the resin layer is oriented toward the surface side, and the heat/pressure hardening type adhesive sheet composed of an epoxy resin is peelably bonded To the surface of the mask; a spacer forming process, using an ultraviolet laser in the plane of the thin plate, in order to avoid cutting the mask, adjusting the processing condition to an appropriate value, and aligning the thin plate a grid pattern, a line shape, a surface shape, or a combination of these design patterns cut to remove a unnecessary portion of the sheet to form a spacer; and an adhesive process to adhere the mask with a predetermined heat or pressure The sheet Wherein the spacer is formed so as not to block the opening. A manufacturing method for a conductive ball fixing mask, which is a method for manufacturing a conductive ball fixing mask according to claim 2 or a conductive ball fixing mask according to item 3, After the mask is bonded to the thin plate, the ultraviolet laser is used before the adhesion between the mask and the thin plate, and the processing condition is adjusted to an appropriate value in order to avoid cutting the mask. The sheet is cut to process air grooves or air holes.