JP2009148987A - Release force measuring device and release force measuring method - Google Patents

Abstract

A release force measuring apparatus and a release force measuring method capable of accurately measuring a release force are provided.
A first mold 11 having a first through-hole 11a, a first rod 12 inserted into the first through-hole 11a and sliding through the first through-hole 11a, a second through-hole 13a, A recess 13b that surrounds the two through-holes 13a and has an opening larger than the first through-hole 11a, the first mold 11 and the recess 13b face each other, and the first through-hole 11a and the second through-hole 13a are coaxial. And a second mold 13 that is superimposed on the first mold 11 so as to face each other, and a bowl-shaped first component 14 that fits into the recess 13b on one end face, and is inserted into the second through hole 13a. A second rod 15 that slides in the second through-hole 13a, an elastic body 16 that supports the second rod 15, and a distance detection means 17 that obtains the distance between the second mold 13 and the first component 14, It comprises.
[Selection] Figure 1

Description

  The present invention relates to a release force measuring device and a release force measuring method.

  In the process of sealing a semiconductor chip placed on a lead frame with a mold using a mold, high adhesion is required between the lead frame and the molded resin. A high mold releasability is required between the formed resin.

If the releasability between the mold and the molded resin is low, a stress due to warpage is generated in the molded resin when the molded resin is taken out from the mold.
When the stress due to warpage becomes excessive, there is a problem that the characteristics of the semiconductor chip sealed with resin are affected and the semiconductor chip is damaged.
Furthermore, when the stress due to warpage exceeds the elastic limit of the molded resin, the molded resin itself may be damaged.

  Therefore, it is required to accurately evaluate the mold release force between the mold and the molded resin, optimize the surface condition of the mold, molding conditions of the resin, etc., and maintain it appropriately. Yes.

  Conventionally, in order to measure the mold release force between the mold and the molded resin, it was embedded in the bottom of the lower mold, and was installed under the ejector pin to push up the molded resin A release force measuring device using a load sensor is known (for example, see Patent Document 1).

The mold release force measuring device disclosed in Patent Document 1 includes an ejector rod that penetrates the movable plate, extends into the movable mold, and has its tip abutting the ejector plate, and a plurality of ejector pins provided on the ejector plate. And a spring that is attached to the ejector pin and biases the ejector pin in a direction in which the ejector pin is pulled from the mold.
When the ejector rod is moved forward to press the ejector plate, the ejector plate moves forward against the force of the spring. As a result, the ejector pin protrudes into the mold, and the molded product is protruded.

  However, in the mold release force measuring device disclosed in Patent Document 1, when the resin is molded, the resin enters the gap between the ejector pin and the ejector pin hole, and when the resin is released, the ejector pin slides. There is a problem that resistance increases.

As a result, an error occurs in the measurement, and there is a problem that an accurate release force cannot be measured. Since the resin that has entered the gap accumulates without being released, there is a problem that measurement errors accumulate when measurement is repeated.
Furthermore, the ejector pin cannot withstand the increased sliding resistance, which may cause damage to the release force measuring device.
JP 2002-144383 A

  The present invention provides a release force measuring device and a release force measuring method capable of measuring an accurate release force.

  A mold release force measuring apparatus according to an aspect of the present invention includes a first mold having a first through hole, a first rod that is inserted into the first through hole and slides through the first through hole, and a second rod. A through-hole and a recess surrounding the second through-hole and having an opening larger than the first through-hole, the first mold and the recess facing each other, and the first through-hole and the second through-hole A second mold that is superimposed on the first mold so that the hole is coaxially opposed to the first mold, and a bowl-shaped first part that fits into the recess on one end surface, and the second through hole A second rod that is inserted and slides through the second through hole, an elastic body that supports the second rod, and a distance detection means that determines a distance between the second mold and the first component. It is characterized by having.

  In the mold release force measuring method according to one aspect of the present invention, a first rod that slides through the first through hole is inserted into a first mold having the first through hole, and a tablet shape is inserted into the first through hole. And a second mold that has a second through hole, a second mold surrounding the second through hole and having a larger recess than the first through hole. A first rod having a first part, supported by an elastic body and sliding through the second through hole is inserted, and the second mold is overlapped with the first mold, and the first part Sealing the first through-hole, pressing the tablet-shaped resin with the first rod and compressing the resin, and moving the first mold relative to each other and compressing the resin Determining the distance that the first part has moved before the first part is separated from the first part; and And a spring constant of the elastic body, is characterized by comprising the steps of: obtaining a release force between the first component and the compression molded resin.

  ADVANTAGE OF THE INVENTION According to this invention, the mold release force measuring apparatus and mold release force measuring method which can measure exact mold release force are obtained.

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

  A release force measuring apparatus according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing a configuration of a release force measuring apparatus according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a main part of the release force measuring apparatus.

  As shown in FIG. 1, the release force measuring apparatus 10 of the present embodiment is inserted into a first mold 11 having a first through hole 11a and the first through hole 11a, and slides through the first through hole 11a. A first rod 12, a second through-hole 13a, and a recess 13b surrounding the second through-hole 13a and having an opening larger than the first through-hole 11a. The first mold 11 and the recess 13b are opposed to each other. The second mold 13 is superimposed on the first mold 11 so that the first through-hole 11a and the second through-hole 13a are coaxially opposed to each other, and the bowl-shaped second is fitted to the recess 13b on one end surface. The second rod 15 is inserted into the second through hole 13a and slides through the second through hole 13a, the elastic body 16 supports the second rod 15, and the second mold 13. Distance detecting means 17 for obtaining a distance from the first component 14.

Further, a second part 18 having a bowl shape is provided at the other end of the second rod 15 so as to sandwich the elastic body 16 between the second mold 13 and the second die 13.
On the second mold 13, a pedestal 19 having a support 19a and a top plate 19b supported by the support 19a is attached. A distance detection means 17 is attached to the top plate 19 b of the gantry 19.

  The first and second molds 11 and 13 are, for example, block-shaped stainless steel, and the surfaces on which the first and second molds 11 and 13 are overlapped are each finished flat.

  The first rod 12 is a cylindrical stainless steel material having a thermal expansion coefficient equal to that of the first mold 11 and a flat one end surface. Similarly, the second rod 15 is a cylindrical stainless steel material whose thermal expansion coefficient is equal to that of the second mold 13 and whose both end faces are flat.

  The first component 14 has a thermal expansion coefficient equal to that of the second mold 13 and is a plate-like stainless steel material. The first component 14 is detachably attached to one end surface of the second rod 15.

  The elastic body 16 is, for example, a coiled spring. By passing the second rod 15 through the air core of the coil, the elastic body 16 is disposed coaxially with the second rod 15 and is sandwiched between the second mold 13 and the bowl-shaped second component 18. . Thereby, the second rod 15 is supported by the elastic body 16.

  The length of the elastic body 16 and the spring constant are balanced with the weights of the second rod 15, the first component 14, and the second component 18, so that the first component 14 is in the recess 13 b of the second mold 13. It is set so as to be separated from the bottom surface and positioned below the second mold 13.

The distance detection means 17 is an eddy current displacement sensor, for example. When a high frequency current is passed through an excitation coil (not shown) of the distance detecting means 17, an eddy current corresponding to the distance from the distance detecting means 17 flows through the bowl-shaped second component 18 by electromagnetic induction.
Naturally, the amount of change in the distance between the second mold 13 and the second part 18 is equal to the amount of change in the distance between the second mold 13 and the first part 14.

  The strength of the eddy current can be determined by, for example, the power necessary to keep the high frequency current of the excitation coil constant. Therefore, the bowl-shaped second component 18 is limited to a low-resistance conductive material, and for example, a copper material is preferable.

  When the second mold 13 is overlapped with the first mold 11, first, the first component 14 comes into contact with the first mold 11, and the second rod 15 slides up the second through hole 13 a and rises. The first component 14 is fitted into the recess 13b.

  When the first mold 11 and the second mold 13 are overlapped and the first part 14 is pressed by the first rod 12, the first part 14 fitted in the recess 13b and the second mold 13 are the same. The depth of the recess 13b of the second mold 13 and the thickness of the first component 14 are set to be equal, for example, so as to be on the plane (the surface of the first mold 11).

  Thereby, the 1st metal mold | die 11 and the 1st component 14 contact | adhere, the 1st through-hole 11a is covered with the 1st component 14, the 1st through-hole 11a, the 1st rod 12, and the 1st component The space surrounded by 14 is sealed.

  A tablet-like resin (not shown) is put into the first through-hole, and the first rod 12 is slid and raised by the driving means 21 having the piston 20 that can be moved up and down by the motor M. By pressing, compression molding is performed.

  The first part and the resin are brought into close contact with each other by compression molding. When the first mold 11 is lowered, the first part 14 is pulled by the compression-molded resin, the second rod 15 slides and descends, and the elastic body 16 is compressed.

When the repulsive force of the compressed elastic body 16 exceeds the adhesion between the first component 14 and the compression-molded resin, the first component 14 and the resin are pulled apart.
The maximum load at the moment when the first component 14 and the compression-molded resin are separated from each other is the mold release force between the first component 14 and the compression-molded resin.
The mold release force is obtained by the product of the distance moved until the first part 14 is separated and the spring constant of the elastic body 16.
Here, the release force referred to in the present specification means a so-called front release force that pulls the first component 14 and the compression-molded resin in a direction perpendicular to the contact surface.

FIG. 2 is a cross-sectional view showing the first component 14 detachably attached to one end surface of the second rod 15.
As shown in FIG. 2, the first component 14 has countersunk holes 30 and 31 in the center, and is fixed to the female screws 32 and 33 formed on one end surface of the second rod 15 by countersunk screws 34 and 35. Yes.

  A plurality of first parts 14a, 14b, and 14c having the same size and different materials and surface conditions are prepared in advance, and the relationship between the material and the surface condition and the release force is detailed by exchanging the first parts 14. It is possible to investigate.

  Next, a method for measuring the mold release force will be described in detail with reference to FIGS. FIGS. 3 to 6 are cross-sectional views sequentially showing the process of measuring the releasing force, and FIG. 7 is a view showing the output of the distance detecting means 17.

  First, as shown in FIG. 3, the first rod 12 is inserted into the first through hole 11a, and the tablet-like resin 40 is poured into the first through hole 11a.

  Next, as shown in FIG. 4, the second mold 13 is opposed to the first mold 11, the first mold 11 and the recess 13b face each other, and the first through hole 11a and the second through hole 13a are coaxial. Overlapping so as to face each other.

Next, while heating the tablet-like resin 40, the first rod 12 is slid and raised to press the tablet-like resin 40, and the inner wall of the first through hole 11 a and one end surface of the first rod 12. Then, the resin 41 that is compression-molded is obtained following the mold constituted by the first component 14.
At this time, the distance Lmin to the second component 18 is measured by the distance detection means 17. The distance Lmin is a position where the second rod 15 is pushed up to the highest point.

  Since the first component 14 is in close contact with the first mold 11 and the first through hole 11a is sealed by the first component 14, the melted tablet-like resin 40 is formed between the first mold 11 and the first component 14. There is no entry into the gap.

  Next, as shown in FIG. 5, while the first mold 11 is slid and lowered, the distance L to the second component 18 is monitored by the distance detecting means 17, and the second mold 13 and the first mold 11 are monitored. A distance L-Lmin from the component 14 is obtained.

The compression-molded resin 41 is held in the first mold 11 by the side surface adhesion force with the inner wall of the first through hole 11 a and the back surface adhesion force with the first rod 12.
Since the sum of the side surface adhesion force and the back surface adhesion force is larger than the front surface adhesion force with the first component 14, the first component 14 is pulled by the compression-molded resin 41, and the second rod 15 slides. And descend.

  As a result, the elastic body 16 is compressed and the repulsive force F = k (L−Lmin) is accumulated in the elastic body 16 according to the lowered distance. Here, k is a spring constant of the elastic body 16.

Next, as shown in FIG. 6, when the repulsive force F of the elastic body 16 exceeds the adhesion between the first component 14 and the compression-molded resin 41, the first component 14 and the compression-molded resin are used. 41 is pulled apart.
If the distance from the distance detection means 17 to the second part 18 at that time is Lmax, the distance between the second mold 13 and the first part 14 is represented by Lmax−Lmin.
Thereby, the release force F = k (Lmax−Lmin) between the first component 14 and the compression-molded resin 41 is obtained.

When the first component 14 and the compression-molded resin 41 are separated from each other, the second rod 15 slides up through the second through-hole 13a by the repulsive force F of the elastic body 16.
The second rod 15 stops at a position where the weight of the second rod 15, the first component 14, and the second component 18 and the repulsive force of the elastic body 16 are balanced while damped and oscillating. The distance from the distance detection means 17 to the 2nd component 18 at that time is set to L0.

FIG. 7 is a diagram showing the output of the distance detection means 17. As shown in FIG. 7, at time t <b> 0 to t <b> 1, the tablet-like resin 40 is charged, the second mold 13 is superimposed on the first mold 11, and the first rod 12 slides through the first through hole 11 a. And start rising. The output of the distance detection means 17 at this time is L0.
Next, at time t1, the tablet-like resin 40 comes into contact with the first component 14, and compression molding is started. The output of the distance detection means 17 at this time is Lmin.

Next, at time t2, the first mold 11 starts to descend, and the first mold 11 and the second mold 13 are opened. The output of the distance detection means 17 at this time increases from Lmin to Lmax according to the falling time.
Next, at time t3, the first component 14 and the resin 41 are separated. The output of the distance detecting means 17 at this time returns to L0 while being damped and oscillated.

In this embodiment, since the resin 41 compression-molded by the first component 14 is drawn out instead of extruding the resin molded by the ejector pin, the first through-hole 11a and the first rod are compressed at the time of compression molding. The resin that has entered the gap with 12 does not affect the measurement of the release force.
Since the first mold 11 and the first part 14 are in close contact with each other with no gap, the resin does not enter the gap like sliding during compression molding.

FIG. 8 is a diagram showing the force applied to the contact surface between the first component 14 and the compression-molded resin 41 in comparison with the comparative example, where the solid line shows the present example and the broken line shows the comparative example. is there.
Here, the comparative example means that the elastic body 16 is not provided and the force that separates the first component 14 and the compression-molded resin 41 is measured by a load sensor. First, a comparative example will be described.

As shown in FIG. 8, in the comparative example, when the first mold 11 starts to be lowered, the load sensor has high rigidity, so that the first sensor 14 and the resin 41 that has been compression-molded are suddenly displaced by a slight displacement. The force acts on.
Therefore, due to non-uniformity of the force applied at the interface between the first component 14 and the compression-molded resin 41 and non-uniformity of the adhesion force, the measurement value varies, and the mold is released with good reproducibility. It is difficult to seek power.

On the other hand, in this embodiment, since the elastic body 16 has high stretchability, a force is gently applied to the interface between the first part 14 and the compression-molded resin 41, leading to a large displacement and compression molding with the first part 14. The released resin 41 is released.
Therefore, it is difficult for the measurement value to vary due to the nonuniformity of the force applied at the interface between the first component 14 and the compression molded resin 41 and the nonuniformity of the adhesion force, and the releasability with high reproducibility. Can be obtained.

  As described above, the release force measuring apparatus 10 according to the present embodiment is in close contact with the first mold 11 and seals the first through hole 11a, and the first component 14 is on one end surface. The elastic body 16 which supports the 2nd rod 15 attached so that attachment or detachment is possible, and the distance measurement means 17 which calculates | requires the distance of the 2nd metal mold | die 13 and the 1st component 14 are comprised.

Rather than extruding the resin 41 compression molded by the ejector pin, the resin 41 compressed by the first component 14 is pulled out, so that the gap between the first through hole 11a and the first rod 12 is compressed. The resin that has entered does not affect the measurement of the release force.
Since the first mold 11 and the first part 14 are in close contact with each other with no gap, the resin does not enter the gap like sliding during compression molding.

  Since the elastic body 16 gently applies a force to the interface between the first part 14 and the compression-molded resin 41 that are in close contact with each other, the measurement is caused by the non-uniformity of the force application and the non-uniformity of the adhesion force. Difficult to produce values. Therefore, a release force measuring device and a release force measuring method that can accurately measure the release force can be obtained.

  Since the elastic body 16 is a coiled spring, advantages such as high load measurement accuracy, heat resistance (compression molding temperature of 180 ° C. or higher), easy replacement, and low cost can be obtained.

  Here, the case where the second rod 15 is supported by the elastic body 16 sandwiched between the second mold 13 and the second component 18 with a coil-shaped spring has been described. May be hung from the mount 19 via an elastic body.

FIG. 9 is a view showing a main part of the mold release force measuring apparatus including the second rod 15 that is supported from the gantry 19 via an elastic body.
As shown in FIG. 9, the release force measuring device 50 is supported by elastic bodies 51, 52, 53 having one end fixed to the top plate 19 b of the gantry 19 and the other end fixed to the second component 18. A second rod 15 is provided.
The elastic bodies 51, 52, 53 are arranged in, for example, an equilateral triangle shape and support the second rod 15 at three points.

  According to this, since the load is applied to the elastic bodies 51, 52, 53 only in the extending direction, the elastic bodies 51, 52, 53 are not limited to springs, and rubber can be used. is there.

  Although the case where the first component 14 is detachably attached to the second rod 15 by the countersunk screws 34 and 35 has been described, as shown in FIG. 10, the female screw 60 is provided on one end surface of the second rod 15. It may be formed and detachably attached with the male screw 61 formed on the first component 14. According to this, since the countersunk screws 34 and 35 are not exposed on the surface of the 1st component 14, there exists an advantage that adhesiveness with the resin 41 by which compression molding was carried out is stabilized more.

Although the case where the elastic body 16 is a coil-shaped spring has been described, a dish-shaped spring may be used. A plate-shaped spring is suitable for generating a large load in a narrow space compared to a coil-shaped spring.
The attachment method is the same as in FIG. 1. By passing the second rod 15 through a through hole formed in the center of the dish-shaped spring, the dish-shaped spring is arranged coaxially with the second rod 15. It is sandwiched between the two molds 13 and the bowl-shaped second part 18. Thereby, the 2nd rod 15 is supported by a plate-shaped spring.

  The case where the distance detecting means 17 is an eddy current type displacement sensor has been described. However, as long as the distance can be continuously measured and the measured value can be recorded (stored), other types of displacement sensors such as a static sensor can be used. A capacitive displacement sensor, an optical displacement sensor, or the like may be used.

Sectional drawing which shows the structure of the mold release force measuring apparatus which concerns on the Example of this invention. Sectional drawing which shows the principal part of the mold release force measuring apparatus which concerns on the Example of this invention. Sectional drawing which shows the mold release force measuring method which concerns on the Example of this invention in order of a process. Sectional drawing which shows the mold release force measuring method which concerns on the Example of this invention in order of a process. Sectional drawing which shows the mold release force measuring method which concerns on the Example of this invention in order of a process. Sectional drawing which shows the mold release force measuring method which concerns on the Example of this invention in order of a process. The figure which shows the output of the distance detection means of the mold release force measuring apparatus which concerns on the Example of this invention. The figure which shows the relationship between the displacement and mold release force which concern on the Example of this invention in contrast with a comparative example, and a solid line is a figure which shows a present Example, and a broken line is a figure which shows a comparative example. Sectional drawing which shows the principal part of another mold release force measuring apparatus which concerns on the Example of this invention. Sectional drawing which shows the principal part of another mold release force measuring apparatus which concerns on the Example of this invention.

Explanation of symbols

10, 50 Release force measuring device 11a First through hole 11 First mold 12 First rod 13a Second through hole 13b Recess 13 Second mold 14, 14a-14f First component 15 Second rod 16, 51, 52, 53 Elastic body 17 Distance detection means 18 Second part 19 Base 19a Post 19b Top plate 20 Piston 21 Drive means 30, 31 Countersunk holes 32, 33, 60 Female thread 34, 35 Countersunk screw 40, 41 Resin 61 Male thread

Claims (5)

A first mold having a first through hole;
A first rod that is inserted into the first through hole and slides through the first through hole;
A second through hole, and a recess surrounding the second through hole and having an opening larger than the first through hole, the first mold and the recess facing each other, and the first through hole and the first A second mold that is superimposed on the first mold so that the two through holes are coaxially opposed to each other;
A first rod having a hook-shaped first part that fits into the recess on one end surface, and a second rod that is inserted into the second through hole and slides through the second through hole;
An elastic body that supports the second rod;
Distance detecting means for determining a distance between the second mold and the first part;
A release force measuring apparatus comprising:   The said elastic body is a spring, It is pinched | interposed between the said 2nd metal mold | die and the hook-shaped 2nd part formed in the other end part of the said 2nd rod. Release force measuring device.   When the second mold is overlaid on the first mold and the first part is pressed with the first rod, the first part fitted into the recess and the second mold are on the same plane. The release force measuring device according to claim 1, wherein   4. The plurality of first parts having different materials and surface states are provided, and the first parts are detachably attached to one end face of the second rod. Release force measuring device. Inserting a first rod that slides through the first through-hole into a first mold having the first through-hole, and charging a tablet-like resin into the first through-hole;
A second mold surrounding the second through hole and the second through hole and having a recess larger than the first through hole has a hook-shaped first part that fits into the recess on one end surface, and is elastic A second rod that is supported by the body and slides through the second through hole is inserted, the second mold is overlaid on the first mold, and the first through hole is sealed with the first component. And a process of
Pressing the tablet-like resin with the first rod and compressing it;
A step of relatively moving the first mold and obtaining a distance moved by the first part before the compression molded resin and the first part are separated;
Obtaining a release force between the compression molded resin and the first component from the moving distance and the spring constant of the elastic body;
The mold release force measuring method characterized by comprising.

Images