JP3434704B2 - Conductive element array sheet manufacturing equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive element array sheet for forming bumps on electrodes of a semiconductor element or a circuit board in a semiconductor package, for example, and a manufacturing apparatus therefor.

[0002]

2. Description of the Related Art In a conventional semiconductor package, for example, a semiconductor element is sealed with a resin or the like, and a lead frame, which is a metal plate-shaped external terminal, extends outward from the side surface of the sealing resin. It is electrically connected to the corresponding electrode of the circuit board. A semiconductor package using such a lead frame becomes larger with an increase in the number of external terminals, and thus cannot meet the demand for downsizing. Therefore, in recent years, in place of the lead frame, a BGA (Ball Grid Array) method has been proposed in which protruding electrodes, that is, bumps, are formed on the bottom surface of the sealing resin as external terminals by soldering,
We are responding to the demand for an increase in the number of external terminals and miniaturization. Further, a flip chip method has also been proposed in which bumps are formed on a circuit board and a semiconductor element, respectively, and the bumps are associated with each other and soldered, so that the semiconductor element is directly bonded to the circuit board, that is, mounted.

Such a bump is obtained by arranging conductive elements such as solder balls on a large number of electrodes provided on the surface of a semiconductor element, and heating and fusing these conductive elements to the electrodes. . In order to arrange the conductive elements on the electrodes, for example, the conductive elements previously arranged on another substrate are transferred to the electrodes of the semiconductor element, or the semiconductor element is covered with a mask having holes corresponding to the electrode patterns. Then, the conductive element that is sown from above is inserted into each hole by a brush or the like, that is, squeezed.

[0004]

However, the arrangement of the conductive elements as described above has the following problems. When the elements are arranged by transfer as in the former case, the conductive elements may be displaced or dropped at the time of transfer, and if the transfer substrate has a warp or deformation, the transfer may not be performed accurately. Further, the conductive element is pressed by the pressure applied to the substrate, and thereby transferred from the substrate to the semiconductor element, so that the deformation of the conductive element is unavoidable. An uneven height of the conductive element from the surface of the semiconductor element may result in the conductive element not adhering to the circuit board. For this reason, after the semiconductor package is manufactured, a step of inspecting whether all the electrodes of the semiconductor element are connected to the corresponding electrodes of the circuit board and a step of repairing the electrode with a poor connection are required,
The problem is poor production efficiency.

When the masks having holes are arranged like the latter, the conductive elements are prevented from being displaced, dropped and deformed as in the former, but the step of squeezing the semiconductor element and the conductive elements are A process for surely checking whether all the holes have been filled is necessary, and in this case also, there is a problem that production efficiency is poor.

The present invention has been made in view of the above circumstances, and by using the conductive element array sheet, the conductive elements can be easily and highly accurately arrayed on the electrodes of the semiconductor element or the circuit board to improve the productivity of the semiconductor package. Is to improve.

[0007]

SUMMARY OF THE INVENTION Conductive element array of the present invention.
The sheet manufacturing apparatus uses conductive elements according to a predetermined pattern.
Aligning means for arranging the transfer plate on one side of the transfer plate and the thermoplastic
A system for manufacturing a sheet with an insulating layer composed mainly of resin.
Of the transfer plate and one side of the insulating layer.
Face the surface on which the element is provided and face the transfer plate of the insulating layer.
Surface or the surface opposite to the surface facing the transfer plate.
Conductive by heating and pressurizing from one side even if not
And pressurizing means for closely fixing a part of the elastic element to the insulating layer
Characterized in that it comprises a.

[0008]

[0009]

[0010]

[0011]

[0012]

[0013]

[0014]

[0015]

In the conductive element array sheet manufacturing apparatus,
The sheet manufacturing means may adhere a metal foil to one surface of the insulating layer of the sheet, in which case the heating and pressing means makes the surface of the insulating layer on which the metal foil is not provided face the conductive element, Heating and pressurization is performed from at least one surface side of the surface of the metal foil opposite to the surface in close contact with the insulating layer or the surface of the insulating layer on which the metal foil is not provided.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a conductive element array sheet and a conductive element array sheet manufacturing apparatus according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a sectional view of the conductive element array sheet of the first embodiment. The electrically conductive element array sheet 10 includes a sheet 12 made of an insulating layer containing a thermoplastic resin as a main component, and an electrically conductive element 14 closely fixed to the sheet 12. Each conductive element 14 is pressed onto the upper surface 12u of the sheet 12 from above, and about the lower half is embedded together with the deformation of the sheet 12. About the upper half of each conductive element 14 projects from the upper surface 12u of the sheet 12.

The thermoplastic resin is a polyimide modified by silicone (general term for organopolysiloxanes),
The sheet 12 is obtained by mixing an epoxy resin, which is a thermosetting resin, with this silicone-modified polyimide.

The thermoplastic resin is not limited to the silicone-modified polyimide, but other polyimide-based resins, polyamide-based resins, polyester-based resins, fluorine-based resins, silicone-based resins, acrylic-based resins, synthetic rubber-based resins, etc. Any resin may be used. Further, in the first embodiment, the epoxy resin, which is a thermosetting resin, is added to the thermoplastic resin, but the sheet 12 may be formed of only the thermoplastic resin.
Alternatively, in addition to the thermosetting resin, a colorant, an inorganic filler, and various coupling agents may be added if necessary.

The conductive element 14 may be, for example, 40% tin, 6 lead.
It is a solder ball consisting of 0%. A material having a melting point (corresponding to a eutectic point in the case of solder) of the conductive element 14 is higher than the glass transition temperature of the thermoplastic resin in the sheet 12 is selected. Thereby, the conductive element 1
The thermoplastic resin can be heat-softened and embedded in the sheet 12 without deforming 4.

The shape of the conductive element 14 is not limited to a ball shape, that is, a true sphere, but may be a polyhedron such as a cylinder.
The material of the conductive element 14 is not limited to solder, but may be a simple substance of metal such as gold, silver, copper or an alloy of these metals. Further, the polymer particles may be plated with metal, or the metal core may be plated, that is, the metal particles may be plated with another metal. The metal used for metal plating is mainly gold, but silver, copper, solder, and alloys thereof may be used for metal plating.

FIG. 2 is a block diagram showing a simplified structure of a conductive element array sheet manufacturing apparatus for manufacturing the conductive element array sheet shown in FIG. 3 to 5 are cross-sectional views schematically showing manufacturing steps in the conductive element array sheet manufacturing apparatus. The conductive element array sheet manufacturing apparatus is
A sheet manufacturing apparatus 22, a conductive element arraying apparatus 24, a heating / pressurizing apparatus 26, and a conveying apparatus 28 are provided.

In the sheet manufacturing apparatus 22, the liquid thermoplastic resin is added with other components as required, molded into a sheet having a predetermined thickness Th, and further cut into a predetermined size. This gives the sheet 12 (FIG. 3). The sheet 12 is conveyed from the sheet manufacturing apparatus 22 to the heating / pressurizing apparatus 26 by a conveyor 28 such as a belt conveyor.

On the other hand, in the conductive element array device 24,
Transfer plate 242 having recesses formed according to a predetermined pattern
The conductive elements 14 are arranged on top (FIG. 4). The transfer plate 242 is, for example, a metal plate, and a hemispherical recess 242a is formed by a laser or the like on one surface of the transfer plate 242, that is, the upper surface 242u. The transfer plate 242 is horizontally supported by the supporting means 244, and at this time, the upper surface 242u in which the concave portion 242a is formed is directed upward. The supporting means 244 can slightly vibrate the transfer plate 242.

The upper surface 24 of the transfer plate 242 held horizontally
2u has at least more conductive elements 14 than the number of recesses.
And then the transfer plate 242 is slightly vibrated.
As a result, the conductive element 14 on the upper surface 242u of the transfer plate 242 is positioned by being partially accommodated in the recess 242a, or rolls off the upper surface 242u. In this way, the conductive elements 14 are arranged corresponding to the positions of the recesses 242a. The transfer plate 242 on which the conductive elements 14 are arranged is transported to the heating / pressurizing device 26 by the transport device 28, similarly to the sheet 12.

The heating / pressurizing device 26 is provided with, for example, a plate-shaped heat block 262 capable of setting an arbitrary temperature, and a cooling table 264 that supports the member to be heated and sandwiches the member to be heated by the heat block 262. . Heat block 26
The surface of 2 is coated with Teflon, etc., so that the sheet 12 made of resin is heated by the heat block 26 when heated and pressed.
Adhesion to the surface of No. 2 is prevented. The positions of the heat block 262 and the cooling table 264 may be replaced with each other.

The transfer plate 242 is horizontally mounted at a predetermined position on the cooling table 264. The sheet 12 is reversed from the state of FIG. 3, that is, the upper surface 12u is the upper surface 24 of the transfer plate 242.
The sheet is conveyed above the transfer plate 242 while being directed downward so as to face 2a. The sheet 12 is a transfer plate 24.
After being positioned with respect to No. 2, they are stacked on the transfer plate 242.

The sheet 1 is heated by the heat block 262.
From above the sheet 2, the sheet 12 is pressed toward the transfer plate 242 (in the direction of the outlined arrow in the figure), and the sheet 12 is heated to soften the thermoplastic resin in the sheet 12 and thereby to reduce the conductivity. The element 14 is embedded in the sheet 12. Through the above steps, the conductive element array sheet 10 shown in FIG. 1 is obtained.

By heating under pressure of the heat block 262,
Since the conductive element 14 is firmly and closely fixed to the sheet 12, the position of the conductive element 14 loosely fitted on the transfer plate 242 is stable, and the arrangement position of the conductive elements 14 is maintained with high accuracy. . The heating temperature of the heat block 262 is higher than the glass transition temperature of the thermoplastic resin in the sheet 12 and is a temperature at which the conductive element 14 is not softened / deformed / altered, for example, from the eutectic point which is the melting point of solder. Set to low temperature. Therefore, since the sheet 12 is softened and deformed, the conductive element 14 is not deformed. Further, the amount of protrusion of each conductive element 14 from the upper surface 12u of the sheet 12 can be made substantially uniform.

Manufacturing of a semiconductor package using the conductive element array sheet 10 shown in FIG. 1 will be described with reference to FIGS. 6 and 7. FIG. 6 shows a conductive element array sheet 10
9 is a diagram schematically showing a step of transferring the conductive element 14 of FIG. 1 to the semiconductor element 50, and FIG.
4 is a diagram showing a semiconductor package in which a semiconductor element 50 and a circuit board 70 are connected via a connector 4.

First, the conductive element 14 of the conductive element array sheet 10 is transferred to the semiconductor element 50. The conductive element array sheet 10 is placed at a predetermined position on the cooling table 264, and the semiconductor element 50 is supported above it at a predetermined distance by a supporting means (not shown). An electrode 52 having a predetermined pattern is formed on the lower surface 50b of the semiconductor element 50. The conductive element array sheet 10 is formed by the above-described process, but at this time, the conductive elements 14 are arrayed at positions corresponding to the electrodes 52.

That is, the semiconductor element 50 is positioned with respect to the conductive element array sheet 10 by a camera (not shown) or the like, and at this time, each electrode 52 faces the corresponding conductive element 14. After the semiconductor element 50 is positioned, it is stacked on the conductive element array sheet 10.

The semiconductor element 50 is a conductive element array sheet 1
After the semiconductor element 50 is mounted on the heat block 2
It is heated and pressurized by 62. The heating may be performed by a known IR reflow device (the description of the structure is omitted). At this time, the heating temperature of the heat block 262 is set higher than the melting point of the conductive element 14. Therefore, the conductive element 14 is fused to the electrode 52 by heat and pressure. Also,
Since the heating temperature of the heat block 262 is higher than the glass transition temperature of the thermoplastic resin, even if the sheet 12 is warped or deformed at room temperature, it softens during heating and pressing. Therefore, the conductive elements 14 are substantially in the same plane at the time of transfer, and transfer is always performed accurately. After this heat and pressure treatment, the sheet 12 is removed by peeling it from the semiconductor element 50. That is, only the conductive element 14 is transferred to the semiconductor element 50.

A known flip chip mounter (not shown) is used as a device for connecting the semiconductor element 50 to the circuit board 70 through the conductive element 14. The flip chip mounter positions the semiconductor element 50 having the conductive element 14 on the circuit board 70, and then the electrode 52 of the semiconductor element 50 and the electrode 72 of the circuit board 70 are connected via the conductive element 14.

The lower surface 50b of the semiconductor element with conductive element 50 is a surface 70 of the circuit board 70 on which the electrodes 72 are formed.
The semiconductor element 50 is positioned with respect to the circuit board 70 so that the electrode 52 is opposed to u and the corresponding electrode 72 is aligned with the electrode 72, and then the semiconductor element 50 is stacked on the circuit board 70. The electrodes 72 of the circuit board 70 are formed corresponding to the electrode pattern of the semiconductor element 50. Then, as shown in FIG.
The semiconductor element 50 is heated and pressed by the heat block 262 toward the circuit board 70, or is heated by the IR reflow device, so that the conductive element 14 is fused to the electrode 72. A heat block may be provided instead of the cooling table 264, and pressure heating may be performed from both upper and lower sides.

By the above processing, the semiconductor package shown in FIG. 7 is obtained. The electrode 52 of the semiconductor element 50 and the electrode 72 of the circuit board 70 are connected by the conductive element 14, that is, soldered. The conductive element 14 serves as a bump between the semiconductor element 50 and the circuit board 70 in the semiconductor package.

As described above, in the first embodiment, the conductive element 14 is adhered and fixed to the sheet 12 containing the thermoplastic resin in accordance with the predetermined pattern. Therefore, when the conductive element 14 is transferred to the semiconductor element 50. The conductive element will not be displaced or fall. Further, even if the sheet 12 is warped or deformed at room temperature, it is softened by heat during transfer, so that transfer is always performed accurately. As described above, according to the first embodiment, it is possible to obtain the conductive element array sheet that enables the bump formation of the semiconductor package to be performed easily and highly accurately.

A second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, the conductive element array sheet 110 includes the lower surface 112 of the sheet 112.
The configuration and the manufacturing process are the same as those of the first embodiment except that the metal foil 116 is provided on b, and the description of the same configuration and the manufacturing process is omitted. The configuration similar to the conductive element array sheet 10 is shown by adding 100 to the reference numeral.

In the sheet manufacturing apparatus, a thermoplastic resin solution is applied to one surface of the metal foil 116 and then dried, whereby a sheet 112 with the metal foil is obtained. A known bar coater, doctor blade, spin coating or the like is used as a device for applying the solution of the thermoplastic resin to the metal foil. A description of these devices will be omitted.

As the metal foil 116, for example, copper foil, nickel foil, stainless steel foil, titanium foil, aluminum foil is used. In the sheet 112, the metal foil 11 is formed on the insulating resin layer.
By closely adhering 6, the expansion and contraction of the insulating resin during heating and cooling is reduced, and the sheet 112 is reinforced.

As shown in FIG. 9, in the heating / pressurizing device, the sheet 112 is placed on the transfer plate 242 so that the metal foil 116 faces the heat block 262, and is heated and pressed. In this case, since the metal foil 116 is in contact with the heat block 262, it is not necessary to provide the heat block 262 with a structure for preventing adhesion of the thermoplastic resin such as Teflon coat. The heat block 262 is attached to the transfer plate 24.
2 is provided on the lower surface side and pressure heating is performed downward, that is, the transfer plate 242.
It may be performed from the side of the insulating resin layer facing the.

Also in the second embodiment, since the conductive element 114 is closely fixed to the sheet 112, displacement and drop of the conductive element at the time of transferring the conductive element 114 to the semiconductor element can be prevented. Further, even if the sheet 112 is warped or deformed at room temperature, it is softened by heat during transfer, so that transfer is always performed accurately. Therefore, similarly to the first embodiment, the bumps of the semiconductor package can be easily and highly accurately formed by the conductive element array sheet of the second embodiment. Furthermore, by providing the metal foil 116, the strength of the sheet 112 is improved and deformation due to expansion and contraction is reduced.

[0044]

EXAMPLES The present invention will be described below with reference to examples. Tables 1, 2, and 3 shown below show the configurations of the sheet, transfer plate, and conductive element used in Examples 1 to 3, respectively.

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

[Table 3]

Example 1 The example sheet 1 shown in Table 1 was used as a sheet, the transfer plate 1 shown in Table 2 was used as a conductive element, and the example element 1 shown in Table 3 was used as a conductive element. A conductive element array sheet was manufactured. Resin A used in Example Sheet 1 has a glass transition temperature of 145
It is a mixed resin of a thermoplastic silicone-modified polyimide resin at ℃ and an epoxy resin. From the resin A solution, Example sheet 1 having a thickness of 100 μm was obtained. By etching, one surface of the metal plate has a diameter of 200 μm and a depth of 50.
The recesses of μm are formed in a grid pattern at intervals of 500 μm,
Thereby, the transfer plate 1 was obtained.

Example Element 1 has a diameter of 150 formed from solder (tin 40%, lead 60%) having a eutectic point of 183 ° C.
A μm solder ball (manufactured by Senju Metal Industry Co., Ltd.) was used. This Example element 1 was sown on the transfer plate 1, and the Example element 1 was arranged in each recess by vibration.

The transfer plate 1 on which the example elements 1 were arranged was placed on the cooling plate, and the example sheet 1 was superposed thereon.
The example element 1 was tightly fixed to the example sheet 1 by being heated and pressed by the heat block. The heating temperature of the heat block was 160 ° C., and the pressing pressure was 1 to 5 kgf per 121 solder balls.

Observation with a microscope and a known non-contact measuring device confirmed that about 60% of the diameter of Example element 1 in the thickness direction of Example sheet 1 was tightly fixed in Example sheet 1. .

Example 2 Example sheet 2 shown in Table 1,
The transfer plate 2 shown in Table 2 and the example element 2 shown in Table 3 were used to produce a conductive element array sheet. Resin B used in Example sheet 2 has a glass transition temperature of 12
Only the thermoplastic silicone-modified polyimide resin at 0 ° C. is used, and the metal foil C is a stainless steel foil having a thickness of 50 μm. A solution of resin B was applied to this metal foil C and dried to obtain Example sheet 2 having a thermoplastic resin layer thickness of 75 μm. The transfer plate 2 and the example element 2 are the same as the transfer plate 1 and the example element 1, respectively, and the description thereof is omitted here.

The transfer of Example Element 2 onto Example Sheet 2 was carried out in the same manner as in Example 1. However,
A heat block was provided below the transfer plate 2 instead of the cooling table, and the example sheet 2 and the transfer plate 2 were sandwiched between two heat blocks and heated and pressed.

By the same measurement as in Example 1, the Example element 2 was closely fixed in the Example sheet 2, and about 40% of the diameter of the Example element 2 in the thickness direction of the Example sheet 2 was about the Example sheet. It was confirmed that it was embedded in 2.

Example 3 A conductive element array sheet was produced using Example sheet 3 (Table 1), transfer plate 3 (Table 2), and Example element 3 (Table 2). The example sheet 3 has the same material and thickness as the example sheet 2. The transfer plate 3 has a diameter of 180 μm and a depth of 5 on one surface of the metal plate.
It is obtained by forming a cylindrical recess of 0 μm. The example element 3 has a cylindrical shape with a diameter of 150 μm and a height of 100 μm, was arranged on the transfer plate 3 and transferred to the example sheet 3 in the same manner as in the example 2.

By the same measurement as in Examples 1 and 2, the Example element 3 was closely fixed in the Example sheet 3, and the height of the Example element 3 was about 4 in the thickness direction of the Example sheet 3.
It was confirmed that about 50% was embedded in Example sheet 3.

Example 4 A semiconductor package was manufactured using the conductive element array sheet, semiconductor element and circuit board obtained in Example 1. However, the recesses of the transfer plate were not formed in a grid pattern, but were formed corresponding to the electrode pattern of the semiconductor element. The electrodes of the circuit board were also formed corresponding to the electrode pattern of the semiconductor element. A conductive element array sheet was placed on the cooling plate, a semiconductor element was placed thereon, and heated under pressure. At this time, the conductive element on the recess was opposed to the electrode of the corresponding semiconductor element. The sheet was removed after heating and pressing. All the conductive elements were transferred to the electrodes of the semiconductor device, which resulted in bumps of the semiconductor device.

The semiconductor element with a conductive element obtained as described above was mounted on a circuit board using a known flip chip mounter, and a semiconductor package was manufactured by this.

In this semiconductor package, it was confirmed by a known inspection method that all the electrodes of the semiconductor element were electrically connected to the corresponding electrodes of the circuit board.

As described above, it was confirmed that the conductive element adhered well to the sheet in any of Examples 1 to 3. The shape of the conductive element may be a sphere or a cylinder.
However, in this case, the shape of the concave portion of the transfer plate corresponds,
That is, it is preferably a hemisphere or a cylinder. Further, in Example 4, when the conductive element array sheet obtained in Example 1 was used, bump formation of the semiconductor package could be performed easily and with high accuracy.

[0061]

According to the conductive element array sheet of the present invention, the bumps of the semiconductor element and the circuit board can be formed easily and with high accuracy, and the productivity of the semiconductor package is improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing a conductive element array sheet according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a conductive element array sheet manufacturing apparatus.

FIG. 3 is a cross-sectional view showing a sheet.

FIG. 4 is a view showing a transfer plate on which conductive elements are arranged.

FIG. 5 is a diagram schematically showing a step of transferring a conductive element to a sheet.

FIG. 6 is a diagram schematically showing a step of transferring a conductive element to a semiconductor element.

FIG. 7 is a diagram schematically showing a step of transferring a semiconductor element with a conductive element onto a circuit board.

FIG. 8 is a sectional view showing a conductive element array sheet according to a second embodiment of the present invention.

FIG. 9 is a diagram schematically showing a step of transferring a conductive element to a sheet.

[Explanation of symbols]

10 Conductive element array sheet 12 sheets 14 Conductive element 22 Sheet manufacturing equipment 24 Conductive element arrangement device 26 Heating and pressurizing device 50 Semiconductor element 52, 72 electrodes 70 circuit board 242 Transfer plate 244 holding means 262 heat block 264 cooling table

─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Nobuaki Takahashi 5-7-1 Shiba, Minato-ku, Tokyo NEC Electric Co., Ltd. (72) Naoji Senba 5-7-1 Shiba, Minato-ku, Tokyo NEC (56) References JP-A-5-74846 (JP, A) JP-A-8-309522 (JP, A) JP-A-9-64521 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 23/12 H01L 21/60 H05K 3/34

Claims (2)

(57) [Claims] 1. Rolling conductive elements according to a predetermined pattern.
A sheet having an arranging means arranged on one surface of the copying plate and an insulating layer containing a thermoplastic resin as a main component is manufactured.
And a conductive element of the transfer plate is provided on one surface of the insulating layer.
The transfer surface of the insulating layer and the transfer plate of the insulating layer.
Surface or the surface opposite to the surface facing the transfer plate
Heating and pressurizing from at least one side of
Adheres and fixes a part of the conductive element to the insulating layer
And a heating and pressurizing means for controlling the conductivity.
Element array sheet manufacturing equipment. 2. The sheet manufacturing means is provided in front of the sheet.
The metal foil is adhered to one surface of the insulating layer, and the heating and pressurizing means is provided on the metal foil of the insulating layer.
The front side of the metal foil with the side not facing the conductive element.
The surface opposite to the surface that adheres to the insulation layer or the insulation
At least one of the layers of the layer without the metal foil
Claim that heat and pressure are applied from one surface side
Item 1. The electroconductive element array sheet manufacturing apparatus according to Item 1.