JP2002103402A - Semiconductor resin sealing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve power saving and space saving. SOLUTION: A semiconductor resin sealing apparatus is equipped with an upper platen 1 and a lower base platen 3 fixed and arranged in an opposed state by a tie bar 2, the moving platen 4 provided between the upper platen 1 and the lower base platen 3 in an up and down movable manner, the upper hot plate 5 held to the undersurface of the upper platen 1, the lower hot plate 6 held to the upper surface of the moving platen 4, the upper and lower molds 7 and 8 respectively mounted on the upper and lower hot plates 5 and 6 in a freely detachable manner, a double toggle mechanism 9 for moving the moving platen 4 up and down to clamp a mold and the mold clampling force detection mechanism 10 provided in the vicinity of the tie bar on the side of the lower base platen. The output from the mold clampling force detection mechanism 10, immediately before the upper and lower molds 7 and 8 come into contact with each other during mold closing operation, is taken in very time and operationally controlled as an offset value at the time of detection of mold touch force and mold clamping force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor resin sealing device for resin sealing a semiconductor element on a lead frame.

[0002]

2. Description of the Related Art Conventionally, as a semiconductor resin sealing device for resin sealing a semiconductor element on a lead frame, FIG.
The following are known.

[0003] Reference numeral 1 in the figure denotes an upper platen for holding an upper hot platen, which will be described later. A movable platen 4 is provided between the upper platen 1 and the lower base platen 3 so as to be vertically movable along the tie bar 2. An upper hot platen 5 is held on the lower surface side of the upper platen 1, and a lower hot platen 6 is held on the upper surface side of the moving platen 4.

A pair of upper and lower dies 7 and 8 are detachably fitted to the upper and lower hot plates 5 and 6, respectively. Hereinafter, the upper mold 7 and the lower mold 8 are collectively called a mold. Between the moving platen 4 and the lower base platen 3, a double toggle mechanism 9 for vertically moving the moving platen 4 and clamping the upper mold 7 and the lower mold 8 is arranged. In the vicinity of the lower base platen 3 side of the tie bar 2, a mold clamping force detecting mechanism 10 is provided. The upper platen 1 is fixedly held by the tie bar 2 and the fixing nut 11 erected from the lower base platen 3.

A loader 1 for supplying a lead frame and a resin tablet onto a lower die 8 between the tie bar 2 and the hot plate in a dimensional relationship that does not interfere with the vertical movement of the lower hot plate 6.
2. An unloader (not shown) for taking out the molded product from the mold, and a guide rail 14 of a die cleaner 13 for cleaning the molded mold are provided. A transfer unit 15 for injecting resin into a mold is fixed to the lower surface of the moving platen 4. The double toggle mechanism 9 incorporates a driving force conversion mechanism 16 using a ball screw in the center of the lower base platen 3 and is connected to a mold clamping motor (hereinafter simply referred to as an electric motor) 18 by a belt transmission mechanism 17.

[0006]

By the way, in the conventional clamping force control of the semiconductor resin sealing device, the clamping force value from the clamping force detecting mechanism 10 provided on the tie bar 2 is always fed back to a predetermined value. The stop position of the electric motor 18 has been controlled in real time so that the mold clamping force value is output. The double toggle mechanism 9 is a mechanism in which the mold opening / closing operation and the mold clamping operation can be performed by one electric motor or an actuator in place of the electric motor. However, if the mold clamping force value is directly used as a control amount, the following problem occurs.

[0007] When the mold clamping operation is started and approaching the vicinity of a predetermined mold clamping force generation point, the speed and the position of the electric motor 18 are controlled based on the deviation between the current value of the mold clamping force and the required mold clamping force value. Although the control target is the amount of clamping force, the detection resolution of the clamping force detection mechanism 10 is much coarser than the resolution of the movement amount of the moving platen 4 via the electric motor 18 and the double toggle mechanism 9. Since the control value to the electric motor 18 includes the distortion of the double toggle mechanism 9 itself, it is difficult to put the mold clamping force and the rotation amount of the electric motor 18 in one formula in the entire region of the predetermined mold clamping force. However, in the vicinity of the required mold clamping force generation point, the electric motor 18 must finely adjust the control position so as to attain the required mold clamping force.

Since the toggle mechanism receives a large force, a slide bearing is generally used. Naturally, static friction resistance and dynamic friction resistance exist. Once in the stop state, the starting torque for performing the correction movement increases. When trying to control the mold clamping force in real time, this starting torque frequently occurs. At this time, the rotation speed of the electric motor 18 is substantially equal to zero, but the torque is always generated. Therefore, it is necessary to select a capacity of the electric motor 18 capable of generating the torque for a long time. Eventually, the capacity of the electric motor becomes large, and the space efficiency is deteriorated and the electric power is wastefully consumed in configuring the device.

Further, the clamping force detecting mechanism 10 generally uses a strain gauge attached thereto, but has a small amount of hysteresis. Although the output value is generated immediately after the load is applied, the output value is offset in a direction opposite to the addition after a lapse of time. This offset is also erroneously recognized as a control amount in the mold clamping force control, and the electric motor shifts to the mold clamping force correction operation and continues to generate torque.

If an offset occurs when a load is applied, the offset is not instantaneously released and remains even when the load is removed. Therefore, the zero of the detection mechanism is offset, and the true mold clamping force, that is, the control amount becomes unclear in the next mold clamping operation. In recent years, high productivity of the semiconductor resin sealing device has been advanced, and the ratio of the time during which the mold is clamped to the time during which the mold is not clamped has increased. In the past, the ratio was 3: 1, but in recent years it has become 6: 1 due to the configuration and high speed of the apparatus. In short, the time during which the load is applied is long, and the offset due to the hysteresis gradually progresses to a certain value as the molding process is repeated. The mold closing point immediately after the machine is stopped due to machine maintenance or mold cleaning or other factors, or when the mold clamping operation is not performed periodically, and the mold clamping reached when the machine has been running for a certain period of time. The point is different.

When the value of the mold clamping force is displayed, the displayed value itself always indicates a predetermined value. It is natural that the control is performed so as to have the value, but it can be understood that the actual mold clamping force is not the indicated value.

The present invention has been made in view of the above circumstances, and takes in the output from the mold clamping force detecting mechanism immediately before the upper mold and the lower mold come into contact with each other during the mold closing operation, and takes in the mold touch force each time. By using a configuration in which arithmetic control is performed as an offset value when detecting the mold clamping force, mold clamping control is performed with a motor having a necessary minimum capacity, thereby saving power and space. It is an object to provide a stop device.

[0013]

According to the present invention, there is provided an upper platen and a lower base platen fixedly arranged in an opposed state with tie bars up and down, and a movable member provided between the upper platen and the lower base platen so as to be vertically movable. A platen, an upper heating plate held on the lower surface side of the upper platen, a lower heating plate held on the upper surface side of the moving platen, and detachably fitted to the upper heating plate and the lower heating plate, respectively. A pair of upper and lower upper and lower molds, a double toggle mechanism provided between the moving platen and the lower base platen to move the moving platen up and down to clamp the mold, and a lower base platen of the tie bar And a mold clamping force detector immediately before the upper mold and the lower mold abut during the mold closing operation. The output from a semiconductor resin-sealing apparatus characterized by arithmetic control as an offset value in detecting a mold touch force and the clamping force is taken each time.

In the present invention, when the rotation stop position of the motor that generates the required mold clamping force is unknown, the operation is performed using the mold clamping force from the mold clamping force detection mechanism as a control amount, and the rotation stop position of the motor once ends. At the time of the mold clamping operation after being clarified, it is preferable to perform the mold clamping operation by controlling the positioning of the electric motor.

In the present invention, the mold touch force means a low-pressure mold clamping force at the time of performing a low-pressure mold clamping operation for protecting a mold in a stage before shifting to a mold clamping operation. In other words, the mold touch force is defined as the force used for the operation to prevent the foreign matter from entering the mold (upper mold, lower mold) if the mold clamping operation is performed suddenly and damages the mold. means. The operation principle is as follows. That is, the rotational position of the electric motor that generates the predetermined type touch force by the act of the mold touch detection operation is stored in advance, and a positive / negative tolerance is set to the rotational position. (Depending on the amount of rotation of the motor corresponding to the minimum detected thickness of the motor). Also, during operation, look at the output from the mold clamping force detection mechanism,
If the rotational position of the electric motor when the predetermined type touch force is generated is within the allowable range, it is determined that there is no foreign matter.
If it is out of the allowable range, the mold is opened immediately for a predetermined amount and abnormally stopped.

In the present invention, when the first mold clamping operation is performed, if the base table is not prepared, the mold clamping motor is set to a predetermined mold clamping force based on the mold clamping force from the mold clamping force detecting function. And the relationship between the clamping force and the position of the motor during the clamping operation is created in the base table and the temporary table, and the position of the clamping motor with respect to the required clamping force described in the temporary table in the next clamping operation. To control the position of the mold clamping motor. Since the mold clamping motor is controlled by the position control, once the position is controlled at the mold clamping point, a large amount of torque is not required to hold the clamp motor, and power consumption during mold clamping can be suppressed. In addition, during the mold clamping operation, the moment of inertia of the mold clamping motor and other components can be used, and the lack of motor driving force in the initial part of the mold clamping (sufficient boost factor) peculiar to the double toggle mechanism can be compensated. It is possible to use a motor having a large capacity, which saves space in the device configuration.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to FIG. However, the same members as those in FIG. 5 will be described with the same reference numerals. (Embodiment) Reference numeral 1 in the drawing denotes an upper platen for holding an upper heating plate, which will be described later. A movable platen 4 is provided between the upper platen 1 and the lower base platen 3 so as to be vertically movable along the tie bar 2. An upper hot platen 5 is held on the lower surface side of the upper platen 1, and a lower hot platen 6 is held on the upper surface side of the moving platen 4.

The upper heating plate 5 and the lower heating plate 6 are removably fitted with a pair of upper and lower molds 7 and 8 respectively. Between the moving platen 4 and the lower base platen 3, a double toggle mechanism 9 for vertically moving the moving platen 4 and clamping the upper mold 7 and the lower mold 8 is arranged. In the vicinity of the lower base platen 3 side of the tie bar 2, a mold clamping force detecting mechanism 10 is provided. The upper platen 1 is fixedly held by the tie bar 2 and the fixing nut 11 erected from the lower base platen 3.

A loader 1 that supplies a lead frame and a resin tablet onto a lower die 8 between the tie bar 2 and the hot plate in a dimensional relationship that does not interfere with the vertical movement of the lower hot plate 6.
2. An unloader (not shown) for taking out the molded product from the mold, and a guide rail 14 of a die cleaner 13 for cleaning the molded mold are provided. A transfer unit 15 for injecting resin into a mold is fixed to the lower surface of the moving platen 4. The double toggle mechanism 9 incorporates a driving force conversion mechanism 16 using a ball screw at the center of the lower base platen 3 and is connected to an electric motor 18 by a belt transmission mechanism 17.

Reference numeral 20 denotes control means electrically connected to the mold clamping force detecting mechanism 10 and the electric motor 18, respectively. The control means 20 controls the electric motor 18, and the value of the clamping force detecting mechanism 10 is output to the control means 20.

Next, the operation and effect of the semiconductor resin sealing device having the above-described configuration will be described. When operating the device,
The required clamping force required for molding and the management value in terms of product quality for the required clamping force are set in the control means 20 by an input device (not shown) in advance.

As shown in FIGS. 2 to 4, the control means 20 stores a table for storing an offset value 21 used for the current mold clamping operation, a mold clamping force detection value 22 at the mold clamping operation completion point, and Current table 24 having a table for storing the motor rotation stop position 23 (feed amount)
And a temporary table 25 for storing the same values as in the previous clamping operation, a base table 26 serving as a reference for the two tables, an output from the clamping force detecting mechanism 10 and a position detector of the electric motor 18. And a control device (not shown) for controlling the operation of the electric motor 18.

The mold clamping operation will be described. After the lead frame and the resin are set on the mold by the loader 12, the lower mold 8 moves up together with the movable platen 4. Immediately before the upper mold 7 and the lower mold 8 come into contact with each other when the lower mold 8 moves up, the control means 20 takes in the output from the mold clamping force detecting mechanism 10 and stores it as an offset value 21 in the current table 24. . This offset value 21 is added to the value from the mold clamping force detection mechanism 10 in a series of mold clamping operations thereafter,
It is treated as a mold clamping force correction value.

Before the mold is clamped, a mold touch detection operation is performed. Here, the mold touch detection operation is an operation for detecting whether or not foreign matter has entered the mold. When a predetermined mold touch force is reached, the rotation stop position of the electric motor 18 registered before that and the current electric motor Whether the rotation stop position of the motor 18 exceeds a certain range, or the previously registered motor 11
8, when the predetermined die touch force is reached before reaching the rotation stop position, and the rotation stop position of the electric motor 18 at that time exceeds a predetermined range as compared with the registered position, it is determined to be abnormal. Is then shifted to a mold clamping operation (detailed description and illustration are omitted).

Here, the value to be calculated as the mold touch force is obtained by subtracting the offset value 21 from the output from the mold clamping force detection mechanism 10. As a result, a true mold touch force can always be obtained even if the zero point of the mold clamping detection mechanism 10 is offset. The process proceeds to the next mold clamping operation only when there is no abnormality in the mold touch detection. The control method of the mold closing operation changes depending on whether data in the base table 26 exists or not.

First, control in the case where there is no data in the base table 26 will be described with reference to FIG. However, in FIG. 2, (A), (B), and (C) show the states of the current table 24, the temporary table 25, and the base table 26, respectively, immediately after taking in the offset value, immediately after closing the mold, and after updating the table. The required mold clamping force 30 is 600 kN, and the management value 31 for product quality is 20 kN (the same applies to FIGS. 3 and 4 described later).
Further, in FIG. 2, “& h80D355” indicates a numerical value representing the rotation amount of the electric motor in hexadecimal. Here, the origin position is determined to be "&h80000000", and "& h
“h80D355” is a position rotated by “& hD355” (54101 pulses in decimal notation) to the + side. Assuming 2000 pulses / REV for one rotation of the motor,
It means the position rotated by 27.0505.

If there is no data in the base table 26, the target clamping force 27 is calculated when the offset value 21 is fetched. Here, the target mold clamping force 27 is
This is a mold clamping force corresponding to the required mold clamping force 30 for actual control, and is a mold clamping force taking into account the offset value 21. Next, a mold clamping operation is performed on the electric motor 18 until the target mold clamping force 27 is reached. The control is switched to the position control based on the rotation stop position 23 (feed amount) of the electric motor 18 when the target clamping force 27 is reached, and the rotation stop position 28 of the electric motor is recorded on the base table 26. Thereafter, the position control, that is, the control position of the electric motor 18 is not corrected even if the output from the mold clamping force detection mechanism 10 changes by a small amount until the molding is completed. As a result, the electric motor 18 generates a large torque only for an instantaneous time in the control process near the target mold clamping force reaching point, and after switching to the position control, it is possible to suppress the generation of only the minimum torque necessary for stopping. .

Once created, the base table 26 is not reset until a reason such as a product change, a mold change, a set temperature change, a mold touch reference change, or the like occurs. After the base table is created, the same value (motor rotation stop position) 29 is also recorded in the temporary table 25.

Next, a case where the base table 26 has been created will be described with reference to FIG. However,
In FIG. 3, (A) and (B) show the current table 24 immediately after taking in the offset value and the current table 24 immediately after completion of the mold clamping operation, respectively.
This shows the state of the temporary table 25 and the base table 26.

The mold clamping operation is performed by the positioning control based on the rotation stop position 29 of the electric motor 18 recorded in the temporary table 25. Immediately after the mold clamping operation (positioning operation) is completed, the mold clamping force detection value 22 and the motor positioning stop position 2
3 is recorded in the current table 24. The positioning control is the simplest method of controlling the electric motor 18, and it is easy to control the motor 18 to a predetermined rotation stop position. The torque generated from the electric motor 18 is only the starting torque at the start of mold clamping, the driving torque during mold clamping, and the deceleration torque at the time of stopping. Once the stop point enters the positioning range, the servo lock is performed.

The servo lock operation is a control for changing the torque in accordance with the deviation from the target position and keeping the torque within the positioning range. Since the pulse resolution on the motor 18 side is much larger than the clamping force resolution of the mold clamping point and many components are provided from the motor 18 to the mold clamping point, the motor 1
The position correction within the positioning range of No. 8 is insensitive to the mold clamping force. This can be performed without requiring a large amount of torque for the electric motor 18, and power consumption during mold clamping, that is, during servo lock, can be extremely reduced.

Next, the process of creating a table when correcting the position where the motor 18 stops rotating will be described with reference to FIG. However, in FIG. 4, (A) and (B) show the states of the current table 24, the temporary table 25, and the base table 26 immediately after taking in the offset value and immediately after completing the mold closing operation, respectively.

The mold clamping force detected value 22 recorded in the current table 24 is compared with the required mold clamping force 30 recorded in the base table 26 in consideration of the offset value 21. When a predetermined difference occurs, the calculated difference is detected. The motor 1 in which a predetermined number of pulses according to the difference is recorded in the temporary table 25
8 is added to the rotation stop position 29 and recorded. The “predetermined difference” is one of the management values 31 for product quality input in advance.
/ 2 or less, and the predetermined number of pulses is determined by calculating the motor feed amount corresponding to the mold clamping force difference by using a calculation formula of the double toggle mechanism 9. If the difference is equal to or greater than the control value 31 for product quality, the apparatus is stopped after the completion of the molding process, and the fact is displayed on a screen or the like to notify the apparatus operator. At the same time, the data in the base table 26 and the data in the temporary table 25 are reset.

If there is no problem, the motor 18 recorded in the temporary table 25 in the next mold clamping operation is used.
The same positioning control as described above is performed using the rotation stop position 29. After the occurrence of the problem, since the data of the base table 26 has been reset, the mold clamping operation is performed by a control method for detecting the mold clamping force and the motor rotation stop position.

Also, when the required mold clamping force 30 is changed, when the type is changed, when the mold is changed, when the mold temperature setting is changed, and the mold touch reference position is changed. Automatically reset in case.

According to the above embodiment, the mold clamping force is treated as a control amount only when the rotation stop position of the motor 18 for generating the mold clamping force is not determined, and thereafter, the motor 18 is clamped by the position control. Since the control is performed, the power consumption of the electric motor 18 during mold clamping can be suppressed, whereby the capacity of the electric motor 18 can be reduced, leading to space saving. Also, since the mold clamping force uses an offset value immediately before the mold abuts, even if there is hysteresis in the mold clamping force detection mechanism 10, the detected mold clamping force is a relative difference. That is, it is a relative distortion. Further, the relationship between the strain value and the mold clamping force does not change unless the apparatus configuration is changed, and the actual operation, that is, the actual mold clamping force in the mold clamping operation shows an accurate value, which is a problem for the equipment operator. Can be displayed accurately.

[0037]

As described in detail above, according to the present invention,
A configuration in which the output from the mold clamping force detection mechanism immediately before the upper mold and the lower mold contact during the mold closing operation is taken in each time and arithmetically controlled as an offset value when the mold touch force and the mold clamping force are detected. Accordingly, by performing mold clamping control with a motor having a necessary minimum capacity, a semiconductor resin sealing device capable of saving power and space can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a semiconductor resin sealing device showing one embodiment of the present invention.

FIG. 2 is a data creation progress diagram when a base table is not created.

FIG. 3 is a data creation progress diagram when a base table has been created.

FIG. 4 is a diagram showing a process of creating a table when correcting a motor rotation stop position.

FIG. 5 is an explanatory view of a conventional semiconductor resin sealing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Upper platen, 2 ... Tie bar, 3 ... Lower base platen, 4 ... Moving platen, 5 ... Upper hot platen, 6 ... Lower hot platen, 7 ... Upper die, 8 ... Lower die, 9 ... Tablugging mechanism, 10 ... mold clamping force detection mechanism, 11 ... fixed nut, 12 ... loader, 13 ... die cleaner, 14 ... guide rail, 15 ... transfer unit, 16 ... drive conversion mechanism, 17 ... belt transmission mechanism, 18 ... motor.

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 4F202 AD02 AH37 AP01 AP04 AR01 AR04 CA11 CB17 CL09 CL22 CL34 CL42 4F206 AD02 AH37 AP017 AP047 AR017 AR047 JA07 JB17 JL02 JM02 JN31 JP13 JP17 JQ06 JQ83 JQ88 JT05 JT01 JT01 BA015F

Claims (2)

[Claims] 1. An upper platen and a lower base platen fixedly arranged in a vertically opposed manner with a tie bar, a movable platen provided between the upper platen and the lower base platen so as to be vertically movable, and a lower surface of the upper platen Upper platen held on the upper side, a lower platen held on the upper side of the moving platen, and a pair of upper and lower upper and lower dies detachably fitted to the upper platen and the lower platen, respectively. A mold, provided between the moving platen and the lower base platen,
A semiconductor resin sealing device comprising: a double toggle mechanism for moving the movable platen up and down to clamp the mold; and a mold clamping force detecting mechanism provided near a lower base platen side of the tie bar. The output from the mold clamping force detection mechanism immediately before the upper mold and the lower mold in contact with each other is calculated and controlled as an offset value when the mold touch force and the mold clamping force are detected each time. Semiconductor resin sealing device. 2. When the rotation stop position of the electric motor that generates the required mold clamping force is unknown, the operation is performed using the mold clamping force from the mold clamping force detection mechanism as a control amount, and the rotation stop position of the motor once is clearly determined. 2. The semiconductor resin sealing device according to claim 1, wherein when the mold clamping operation is performed, the mold clamping operation is performed by positioning control of the electric motor.