JPH07130795A - Semiconductor element connecting method and apparatus therefor - Google Patents

Abstract

PURPOSE:To eliminate the positional discrepancy between a semiconductor element and a board, by making the temperature of the board to be connected with the semiconductor element and the temperature of a pressing device equal substantially to each other after the temperature of the board is increased up to a constant value not lower than the hardening starting temperature of an anisotropic conduction bonding sheet, and by pressing downward the semiconductor element with the pressing device during a predetermined time. CONSTITUTION:A stage 1 is electrically energized to heat a terminal 11 of a liquid crystal panel. When an anisotropic conductive bonding sheet higher than 150 deg.C in curing temperature is used, the current flowing through the stage 1 is so adjusted that the terminal temperature of the liquid crystal panel is maintained 160 deg.C after it is heated to that temperature. A pressing device 2 which is preheated to 160 deg.C is moved downward, and a TCP 10 is pressed downward by the pressing device 2, and further, this pressing-downward is continued about 30 seconds until a bonding agent is hardened in the state wherein conductive particles present in the anisotropic conduction bonding sheet are deformed by the pressure of the pressing device 2. Thereby, the temperature difference between the liquid crystal panel and the pressing device 2 is eliminated, and in its turn, the positional discrepancy between the liquid crystal panel and a board can be eliminated essentially when they are thermocompression-bonded to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for mounting a semiconductor element on a substrate, and more particularly to a semiconductor element connecting method and a connecting device which can obtain high accuracy.

[0002]

2. Description of the Related Art The technique of connecting a semiconductor element to a substrate using an anisotropic conductive adhesive sheet has been widely used in recent years because the connection of narrow-pitch electrodes can be easily obtained only by applying heat and pressure. . In particular, the connection of the driving LSI to the liquid crystal panel in the liquid crystal display device is a connection between the transparent electrodes and the dissimilar materials such as metal. Therefore, there is a method of thermocompression bonding the tape carrier to which the LSI is bonded using an anisotropic conductive adhesive sheet. It is common. Next, a method of connecting the liquid crystal panel and the driving LSI will be described.

A drive LSI is a so-called tape carrier package (hereinafter referred to as "T-carrier package") in which a semiconductor chip is bonded to a copper foil lead formed on a film tape such as polyimide.
The shape of (abbreviated as CP) is used. Next, as shown in FIG. 13, after the anisotropic conductive adhesive sheet 22 is temporarily fixed on the terminals 21 of the liquid crystal panel 20, the terminals of the TCP 23 and the liquid crystal panel terminals are aligned, and the anisotropic conductive adhesive sheet is adhered. Use the sex to temporarily fix it. Since a plurality of TCPs are usually connected to one side of the liquid crystal panel, this process is repeated for each TCP. Since it takes a certain amount of time to cure the anisotropic conductive adhesive sheet, the production amount per hour is increased. Therefore, the thermocompression bonding process is not performed for each TCP, and at least one side of the TCP is subjected to the thermocompression bonding process at the same time. This is to do it. Next, as shown in FIG. 14, the liquid crystal panel 20 is placed on the stage 24, and the TCP23 terminal is pressed by the high-temperature pressurizing device 25 to apply pressure and heat to the anisotropic conductive adhesive sheet, so that the anisotropic conductive film is anisotropically conductive. The conductive adhesive in the conductive adhesive sheet is sandwiched between the electrodes of the liquid crystal panel and the TCP to cure the adhesive and obtain a stable connection.

[0004]

By the way, recently, in the liquid crystal panel, the display pixel density is rapidly increasing, and along with that, the pitch of the connecting electrode terminals with the driving LSI is becoming narrower. In particular, as the pixel density is tripled due to the colorization of the display, the electrode terminal pitch is reduced to one third, and the demand for the connection position accuracy between the liquid crystal panel terminal and the TCP terminal is significantly increased.

However, in the above-mentioned conventional method, the liquid crystal panel 20 is arranged on the stage 24 and the temperature of the TCP terminal is pressed by the high temperature pressurizing device 25 so that the liquid crystal panel 20 and the TCP 23 of the driving LSI are connected accurately. It was found that a theoretical positional deviation occurs in the process of curing the adhesive in the directional conductive adhesive sheet 22. This displacement mechanism will be described with reference to the drawings.

FIG. 15A shows a liquid crystal panel 2 with a TCP 23.
It is in a state of being temporarily fixed by using the adhesive force of the anisotropic conductive adhesive sheet 22 after being aligned to 0. In this state, the positions of both the TCP electrode 26 and the liquid crystal panel electrode 27 are aligned, ignoring errors in material processing. Figure 15
(B) is the moment when the liquid crystal panel 20 is fixed on the stage 24 and the high-temperature pressing device 25 descends from above and comes into contact with the TCP 23. After that, the heat of the pressure device 25 is applied to the liquid crystal panel 2.
The liquid crystal panel 20 is gradually heated to 0, and the temperature of the pressure device 25 is lowered in a short time by heat conduction, but the amount of fall is small because heat is supplied from the heater. Figure 15
FIG. 15C shows a state after a lapse of a certain time from FIG. 15B, and the temperature of the liquid crystal panel 20 has changed due to thermal expansion. On the other hand, since the anisotropic conductive adhesive sheet 22 is softened and the friction coefficient between the TCP 23 and the liquid crystal panel 20 is lowered, slippage easily occurs between the two, and the TCP 23 does not follow the dimensional change of the liquid crystal panel 20. As shown in FIG. 15D, the thermosetting of the anisotropic conductive adhesive sheet 22 is completed after a certain period of time, and the liquid crystal panel 20 and the TCP 23 are removed from each other.
The positional relationship of (c) is fixed and the positional relationship between the two does not change even when the pressure device is raised and the liquid crystal panel 20 is cooled to room temperature. Both terminals 2 of TCP23 and liquid crystal panel 20
The position shift from the state of FIG. 15 (a) to the state of FIG. 15 (d) of Nos. 6 and 27 is not remarkable because the size scale is small in one TCP 23, but the amount of shift is proportional to the size scale of thermocompression bonding. A serious positional deviation occurs on the entire one side of the liquid crystal panel 20 to which a plurality of TCPs 23 are connected.

As a method of solving this, there is a method of crimping each TCP 23 one by one to reduce the displacement, but the crimping time is required to be 15 to 20 seconds per TCP, and a large number of TCs are required.
A large-sized liquid crystal panel using P is not practical because the process time increases.

In view of the problems of the conventional semiconductor element connecting method, an object of the present invention is to provide a semiconductor element connecting method and apparatus having a short process time and high positional accuracy. is there.

[0009]

According to the present invention, there is provided a step of disposing a semiconductor element on a substrate to be connected via an anisotropic conductive adhesive sheet and a substrate to be connected on a variable temperature stage whose temperature can be changed. After arranging, the temperature of the variable temperature stage is raised to heat the substrate to be connected, and after the temperature of the substrate to be connected reaches a certain value higher than the curing start temperature of the anisotropic conductive adhesive sheet, the temperature of the substrate to be connected is reached. And a step of pressurizing the semiconductor element for a predetermined time with a pressurizing device having substantially the same temperature.

Further, the present invention comprises an installation stage for installing a substrate to be connected, on which semiconductor elements are arranged, with an anisotropic conductive adhesive sheet, having a heating and cooling mechanism,
It is a semiconductor element connecting device provided with a pressurizing device controlled to a predetermined temperature for connecting to a semiconductor element by heating and pressurizing a substrate to be connected.

[0011]

In the method of the present invention, the substrate to which the semiconductor element is temporarily fixed is placed on the variable temperature stage via the anisotropic conductive adhesive sheet, and then the temperature of the stage is raised. As a result, the substrate to be connected is heated and its temperature rises, causing thermal expansion. However, the semiconductor element is deformed following the thermal expansion of the substrate because it is not constrained except for the temporary fixing force to the substrate to be connected. When the temperature of the substrate to be connected reaches the curing start temperature of the anisotropic conductive adhesive sheet or higher, the semiconductor elements are pressed by a pressurizing device that has approximately the same temperature, and the anisotropic conductive adhesive sheet is crushed to a prescribed thickness and then electrically Get a physical connection. In this step, since the temperature of the substrate to be connected and the temperature of the pressurizing device are almost the same, the dimensional change of the substrate does not occur. Next, when the curing of the anisotropic conductive adhesive sheet is completed, the pressurization is terminated and the substrate to be connected is gradually returned to room temperature, but since the anisotropic conductive adhesive sheet has already been cured, the The positional deviation between the semiconductor element and the substrate due to heat shrinkage does not occur.

Further, in the apparatus of the present invention, since the installation stage has a heating and cooling mechanism, the substrate is quickly heated, and the cooling mechanism promptly returns to the state before mounting the substrate to be connected to the next substrate. The semiconductor elements can be connected without delay.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a side view of a semiconductor element connecting device according to an embodiment of the present invention.

In the stage 1 on which the substrate to be connected is placed, the panel supporting surface 7 is heated in a short time by passing a current in the direction of the arrow as shown in FIG. It has a structure that allows the temperature to be lowered in time. As a material forming the stage 1, an Invar material having a very small coefficient of thermal expansion is used to suppress a shape change due to a temperature change.

As shown in FIG. 3, the pressurizing device 2 has a structure in which a cylindrical heater 8 is embedded in a metal block, and the temperature is detected by a temperature sensor 9, and the heater current is controlled to keep the metal block constant. Keeping at temperature. As shown in FIG. 1, the entire pressurizing device can be moved up and down by an air cylinder 4 to pressurize the terminal portion of the substrate to be connected placed on the stage 1.

In this embodiment, the substrate to be connected is a glass substrate constituting a liquid crystal panel, and the semiconductor element to be connected is an LSI mounted with a tape carrier package (TCP).

First, as shown in FIG. 4, with the TCP 10 and the electrode pattern on the terminal 11 of the liquid crystal panel aligned, the both are temporarily adhered via the anisotropic conductive adhesive sheet 12.

Next, as shown in FIG. 5, the terminal 1 of the liquid crystal panel
1 is placed directly above the stage 1 of the connecting device. Next, a current is passed through the stage 1 to raise the temperature and heat the terminals 11 of the liquid crystal panel. In this embodiment, since the anisotropic conductive adhesive sheet 12 which starts curing at 150 ° C. or higher is used, when the terminal temperature of the liquid crystal panel reaches 160 ° C., the current passed through the stage 1 is adjusted so as to maintain 160 ° C. did.

Next, as shown in FIG. 6, the pressure device 2 which has been heated and kept at 160 ° C. in advance is lowered to press the TCP 10 from above so that the conductive particles in the anisotropic conductive adhesive sheet 12 are pressed. Pressing was continued for about 30 seconds until the adhesive was cured in the deformed state. Since the anisotropic conductive adhesive sheet 12 is rapidly cured when the curing start temperature is exceeded, the temperature rising rate of the liquid crystal panel terminals is made sufficiently fast, and at the same time when the set temperature (160 ° C. in this embodiment) is reached, pressure is applied. It is necessary to start.

Next, the current flowing to the stage 1 is stopped, the cooling air is started to be blown from the nozzles 3, and at the same time, the pressurizing device 2 is moved up. Then, the liquid crystal panel is taken out of the stage 1 and a series of connection work is completed. Regarding the timing of taking out the liquid crystal panel, since the anisotropic conductive adhesive sheet 12 has already been hardened and the TCP 10 has been firmly adhered to the terminal 11, there is no problem even if the liquid crystal panel is taken out of the stage at a terminal temperature of 160 ° C. Rather, in order to shorten the process time, take out the liquid crystal panel before the temperature drop of stage 1,
It is more effective to lower the temperature of the stage 1 during the next work of arranging the liquid crystal panel.

Next, another embodiment of the present invention will be described.

FIG. 7 is a side view of a semiconductor element connecting device according to another embodiment.

As shown in FIG. 8, the stage comprises a support member 13 for the substrate to be connected and a vertically movable heating block 14. The heating block 14 has a structure in which a cylindrical heater 17 is embedded in a metal block 16, and a temperature sensor 18
The temperature is detected and the heater current is controlled to keep the metal block at a constant temperature. The stage heats the support member 13 by bringing the heating block 14 close to or in close contact with the support member 13, and as a result, the support member 1
It is possible to raise the temperature of the substrate to be connected, which is arranged on the substrate 3. Further, after the heating block 14 is separated from the support member 13, the temperature of the support member 13 can be lowered in a short time by blowing low temperature air from the nozzle 3.
As described above, the structure in which the heating block 14 and the supporting member 13 are separated has an advantage that a member that requires complicated processing such as the current heating stage in the first embodiment is unnecessary.

As shown in FIG. 9, the pressurizing device 2 has a structure in which a cylindrical heater 8 is embedded in a metal block, and the temperature is detected by a temperature sensor 9 and the heater current is controlled to keep the metal block constant. Keeping at temperature. As shown in FIG. 7, the entire pressurizing device can be moved up and down by the air cylinder 4 to pressurize the terminals of the substrate to be connected placed on the supporting member 13.

Similar to the first embodiment, the substrate to be connected is a glass substrate which constitutes a liquid crystal panel, and the semiconductor element to be connected is a TCP-mounted LSI. Next, the connection method will be described.

First, as shown in FIG. 10, in a state where the TCP 10 and the electrode pattern on the terminal 11 of the liquid crystal panel are aligned, both of them are temporarily bonded together via the anisotropic conductive adhesive sheet 12.

Next, as shown in FIG. 11, the terminals 11 of the liquid crystal panel are arranged so as to come directly above the supporting member 13 of the stage of the connecting device. Next, the heating block 14 is raised and brought into close contact with the supporting member 13, and the terminals 11 of the liquid crystal panel are heated through the supporting member 13.

Next, in this embodiment, since the anisotropic conductive adhesive sheet 12 which starts curing at 150 ° C. or higher is used, when the terminal temperature of the liquid crystal panel reaches 160 ° C., as shown in FIG. The pressure device 2 heated to ℃ and kept warm is lowered to press the TCP 10 from above, and the conductive particles in the anisotropic conductive adhesive sheet 12 are heated under pressure for about 30 seconds until the adhesive cures. The pressure continued. When the pressure device 2 contacts the TCP 10, there is no need to heat the substrate any more, and the heating block 14 descends and the supporting member 13
Be more separated. Since the anisotropic conductive adhesive sheet 12 is rapidly cured when the curing start temperature is exceeded, the temperature rising rate of the liquid crystal panel terminals is made sufficiently fast, and at the same time when the set temperature (160 ° C. in this embodiment) is reached, pressure is applied. It is necessary to start.

Next, after the set time, the pressurizing device 2 rises, the liquid crystal panel is taken out, and a series of connection work is completed. Also,
In preparation for the next substrate connecting operation, cooling air is blown to the support member 13 of the stage to cool it to a constant temperature. This is because if the temperature of the substrate to be connected is not constant at the start of each work, the rise rate of the substrate temperature may change and the connection state may vary, and the work time is not constant, which adversely affects production control. Is.

The present invention can be widely applied not only to the liquid crystal panel but also to a connecting method using an anisotropic conductive adhesive sheet, and a very high positional accuracy can be easily obtained.

Needless to say, the variable temperature stage of the present invention is not limited to the one disclosed in the above embodiment.

[0033]

As is apparent from the above description,
INDUSTRIAL APPLICABILITY The semiconductor element connecting method and the semiconductor element connecting apparatus of the present invention are thermocompression bonding methods that use an anisotropic conductive adhesive sheet, but eliminate the temperature difference between the substrate to be connected and the pressurizing device, and in principle thermocompression bonding occurs. The present invention fundamentally eliminates the positional deviation at the time, and makes it possible to manufacture a color liquid crystal panel or the like having a high display pixel density which requires highly accurate connection.

[Brief description of drawings]

FIG. 1 is a side view of a semiconductor element connecting device according to an embodiment of the present invention.

FIG. 2 is a side view of a stage of the same semiconductor device connecting apparatus as above.

FIG. 3 is a side view of the heating device of the semiconductor element connecting device of the same as above.

FIG. 4 is a sectional view of the same liquid crystal panel as above.

FIG. 5 is a side view showing one state of the semiconductor element connecting process of the same.

FIG. 6 is a side view showing a state of a semiconductor element connecting process of the same as above.

FIG. 7 is a side view of a semiconductor element connecting device according to another embodiment of the present invention.

FIG. 8 is a side view of a stage of the same semiconductor element connecting device as above.

FIG. 9 is a side view of the heating device for the semiconductor element connecting device of the same as above.

FIG. 10 is a sectional view of the same liquid crystal panel as above.

FIG. 11 is a side view showing a state of a semiconductor element connecting step of the same as above.

FIG. 12 is a side view showing one state of the same semiconductor device connecting step.

FIG. 13 is a perspective view of a liquid crystal panel in a conventional example.

FIG. 14 is a side view of the thermocompression bonding process as above.

FIG. 15 (a) is a plan view of the liquid crystal panel of the same as above, and FIG.
Is a plan view of the same liquid crystal panel, (c) is a plan view of the same liquid crystal panel, and (d) is a plan view of the same liquid crystal panel.

[Explanation of symbols]

1 Stage 2 Pressurizer 3
Nozzle 4 Air cylinder 5 Foundation frame 6
Panel support base 7 Panel support surface 8 Cylindrical heater 9
Temperature sensor 10 TCP 11 Liquid crystal panel terminal 12
Anisotropically conductive adhesive sheet 13 Support member 14 Heating block 15
Air cylinder 16 Metal block 17 Cylindrical heater 18
Temperature sensor 20 Liquid crystal panel 21 Terminal 22
Anisotropically conductive adhesive sheet 23 TCP 24 Stage 25
Pressure device 26 TCP electrode 27 Liquid crystal panel electrode

Claims (2)

[Claims] 1. A step of arranging a semiconductor element on a substrate to be connected via an anisotropic conductive adhesive sheet, and arranging the substrate to be connected on a variable temperature stage whose temperature can be changed, and then changing the temperature. A step of heating the stage to raise the temperature of the substrate to be connected, and after the temperature of the substrate to be connected reaches a constant value equal to or higher than the curing start temperature of the anisotropic conductive adhesive sheet, the temperature of the substrate to be connected is substantially A method of connecting a semiconductor element, comprising: pressing and heating the substrate to be connected and / or the semiconductor element for a predetermined time with a pressurizing device at the same temperature. 2. An installation stage for installing a substrate to be connected, which has a semiconductor element arranged thereon through an anisotropic conductive adhesive sheet, having a heating and cooling mechanism, and the substrate to be connected and / or the semiconductor element. A semiconductor element connection device comprising: a pressurizing device that pressurizes and heats and is controlled to a predetermined temperature.