JP2002334962A - Method for manufacturing lead frame - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a lead frame, by which a lead frame with the small variation in a lead width and a lead spacing and superior precision in shape can be manufactured by etching method. SOLUTION: The method for manufacturing a lead frame, in which a resist is provided on a work 11, a pattern of a lead frame is drawn directly on the resist to form a resist mask and the work having the formed resist mask is etched to form a lead pattern, has steps of measuring the thickness of the work 11 for determining the thickness deviation between the measured plate thickness and a nominal plate thickness of the work 11, and applying the thickness deviation to the relation between the predetermined deviation of plate thickness and the spacing of the resist mask, to adjust the spacing of the resist mask and conduct etching.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of manufacturing a lead frame for a semiconductor device by an etching method.

[0002]

2. Description of the Related Art Conventionally, as a semiconductor device becomes multifunctional and miniaturized, a lead frame has been increased in the number of pins and both the lead width and the lead pitch have tended to be miniaturized. Such lead frames are often manufactured by an etching method.
In the manufacture of a lead frame by an etching method, first, a resist film is attached to a plate to be processed, and the resist film is exposed to light through a pattern mask that has been prepared in advance, and is then developed on the plate to be processed. A resist mask is formed. Then, by immersing the work plate on which the resist mask is formed in an etchant, or by spraying the etchant on the work plate on which the resist mask is formed, a portion of the work plate on which the resist mask is not formed. To form a lead frame. However, this method has a problem that a pattern mask must be manufactured each time the pattern of the lead frame changes. For this reason, there has been proposed a method of forming a resist mask by directly drawing a pattern of a lead frame on a resist film attached to a work plate, and etching the resist film. This method has the advantage that, even if the pattern is changed, it is not necessary to manufacture a new pattern mask each time, and the lead frame can be manufactured quickly even if the change occurs.

[0003]

However, in a multi-pin lead frame manufactured by a conventional method, a defective lead shape in which the lead width or lead interval largely deviates from a design value, or a stable lead width or lead interval is required. The problem of variation in the lead shape, which does not occur, is likely to occur. In particular, when the thickness of the plate to be processed fluctuates, the etchability of the etching changes, and the lead width and the lead interval fluctuate greatly. For this reason, at the tip of the inner lead in which both the lead width and the lead interval are miniaturized, the influence of the variation in the lead width and the lead interval is large, causing a problem that a desired wire bonding portion is not formed in the lead frame. I have. The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a lead frame manufacturing method capable of manufacturing a lead frame having a small variation in lead width and lead interval and having excellent shape accuracy by an etching method. I do.

[0004]

According to the first aspect of the present invention, there is provided a method for manufacturing a lead frame, comprising: providing a resist on a work plate; and forming a resist mask by directly drawing a pattern of the lead frame on the resist. Then, in a method for manufacturing a lead frame in which a lead pattern is formed by etching the work plate on which the resist mask is formed, a thickness of the work plate is measured, and the measured value of the plate thickness and the work thickness are measured. A thickness deviation from a nominal thickness of the plate is obtained, and the thickness deviation is applied to a predetermined relationship between the thickness deviation and the resist mask interval to adjust the resist mask interval to perform etching.

[0005] As shown in FIG. 4, if the thickness of the plate to be processed changes while the etching time for forming the lead pattern is the same, insufficient etching may occur at the thickened portion, The lead interval is narrow and the lead width is wide. On the other hand, in a portion where the plate thickness is reduced, the etching proceeds sufficiently, the lead interval is wide, and the lead width is narrow.
For this reason, the lead frame formed by etching due to a change in the plate thickness of the plate to be processed has a problem of a defective shape or a non-uniform shape. Therefore, in order to obtain a predetermined lead width and a predetermined lead interval, it is necessary to narrow the resist mask interval when the plate thickness of the workpiece increases, and to widen the resist mask interval when the plate thickness decreases. For this reason, a resist mask interval capable of obtaining a lead width and a lead interval substantially matching the design value is obtained with respect to a change in the plate thickness of the target plate, and based on the result, the plate of the target plate is determined. If the relationship between the thickness and the resist mask interval is quantitatively determined, the lead width and the lead interval that substantially match the design values can be adjusted by adjusting the resist mask interval when the thickness of the workpiece changes. It can be maintained. In the manufacture of a lead frame, the lead interval is uniquely determined if the lead width is determined. Therefore, it is possible to manage the lead interval fluctuation by managing the lead width fluctuation. Become.

[0006] The thickness of a work plate used for a lead frame is controlled by rolling.
For example, it is distributed within a certain range centered on the nominal plate thickness (finished plate thickness control value during rolling). Therefore, in order to determine the quantitative relationship between the thickness of the plate to be processed and the resist mask interval,
Rather than using the absolute value of the thickness, it is possible to obtain a clear quantitative relationship to the variation in the thickness by using the thickness deviation, which is the difference between the measured value of the thickness and the nominal thickness. . For this reason,
It is preferable to measure the thickness of the plate to be used to determine the thickness deviation, and to determine the optimum resist mask interval from the quantitative relationship between the obtained thickness deviation and the resist mask interval. The present inventor has confirmed through experiments that the relationship between the thickness deviation and the resist mask interval is substantially linear. FIG. 5 schematically shows the relationship between the thickness deviation and the resist mask interval when the lead width substantially matches the lead width design value.

In the lead frame manufacturing method according to the first aspect of the present invention, the relationship between the thickness deviation and the resist mask interval is such that the lead width of the formed lead pattern is changed with respect to the variation of the thickness deviation. Preferably, it is determined from substantially matching the design value. An optimum resist mask interval can be successively determined with respect to the variation of the plate thickness deviation, and the etching can be performed under the condition that the lead width of the lead pattern always substantially matches the designed lead width.

According to a second aspect of the present invention, there is provided a method for manufacturing a lead frame, wherein a resist is provided on a plate to be processed, and a lead frame pattern is directly drawn on the resist to form a resist mask. In a method for manufacturing a lead frame, wherein a lead pattern is formed by etching a formed workpiece, a lead width of a predetermined portion of the formed lead pattern is measured, and a measured value of the lead width and the lead pattern are measured. Then, a lead width deviation from the lead width design value is obtained, and the resist mask interval corresponding to the lead width of the portion is adjusted according to the lead width deviation to perform etching.

In general, when a lead frame is manufactured by an etching method, even if etching conditions, for example, the type, concentration, and temperature of an etching solution are fixed, the lead width of an actually obtained lead pattern greatly differs from a designed value. It may be. This is because the change in the etching rate occurs due to the change in the material of the plate to be processed, and the resist mask interval also changes in each part as the lead width of the lead pattern changes in each part. Is considered to be a factor. For this reason, in order to make the lead width of the obtained lead pattern substantially equal to the design value, the lead width of the actually obtained lead pattern is measured, and the lead width between the lead width and the design value is determined. It is preferable to obtain the width deviation and reflect the result to the adjustment of the interval between the resist masks formed on the plate to be processed.

[0010] Here, the adjustment of the resist mask interval is particularly required due to the fluctuation of the lead width at the tip of the inner lead where the lead width is strictly required for wire bonding. Therefore, the range in which the resist mask interval needs to be adjusted is determined according to the value of the lead width deviation d. For example, when −5 μm <d <5 μm, the adjustment of the resist mask interval is unnecessary, and −10 μm <d ≦ −. 5 μm or 5
In the case of μm ≦ d <10 μm, it is only necessary to adjust the distance between the resist masks at the portion where the tip of the inner lead is formed.
Further, when d ≦ −10 μm or 10 μm ≦ d, all the resist mask intervals need to be adjusted. In a lead frame used for a semiconductor device requiring high speed, a predetermined lead width and a predetermined lead interval are required for all lead patterns such as outer leads other than inner leads. Therefore, in this case, the lead width deviation d
However, if, for example, d ≦ −5 μm or 5 μm ≦ d, it is necessary to adjust all the resist mask intervals.

In the method of manufacturing a lead frame according to a second aspect of the present invention, the adjustment of the resist mask interval is performed when the lead width deviation exceeds an allowable value. It is preferable to carry out the conditions under the same conditions. In advance, the conditions for adjusting the resist mask spacing with respect to variations in the lead width deviation are determined, so if the lead width deviation is calculated and the value exceeds the allowable value, the resist mask spacing can be adjusted immediately. Become.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention. Here, FIG. 1 is an explanatory view showing a schematic configuration of a lead frame manufacturing equipment to which the lead frame manufacturing method according to the first embodiment of the present invention is applied, and FIG. 2 is a lead manufactured by the same lead frame manufacturing method. FIG. 3 is an explanatory diagram of a frame design pattern, and FIG. 3 is an explanatory diagram showing a schematic configuration of a lead frame manufacturing facility to which a lead frame manufacturing method according to a second embodiment of the present invention is applied. As shown in FIG. 1, a lead frame manufacturing equipment 1 to which a method for manufacturing a lead frame according to a first embodiment of the present invention is applied.
Numeral 0 denotes a conveying means (not shown) of the workpiece plate 11, a thickness measuring means 12 for measuring the thickness of the workpiece board 11, and a
A cleaning machine 13 for cleaning the surface of the work 1
A resist sticking machine 14 for sticking a resist on the surface of 1;
A resist pattern drawing machine 15 for exposing the pattern of the lead frame to the resist affixed to the plate 11 to be processed, a developing machine 16 for developing the drawn resist to form a resist mask, and a processing machine on which the resist mask is formed An etching machine 17 for etching the plate 11; Hereinafter, these will be described in detail. FIG.
In the above description, the workpiece plate 11 is shown as being passed through in a state where the respective manufacturing means are stretched. However, a looper may be provided between the manufacturing means to pass through.

For the plate 11 to be processed, for example, a Cu alloy or a Fe-Ni alloy having a nominal thickness of 0.1 to 0.2 mm can be used. For the thickness measuring means 12, for example, a transmission type supersonic thickness gauge can be used. The washing machine 13 is provided with, for example, a water washing unit, an organic solvent washing unit, and an infrared drying unit. By passing the work plate 11 through the washing machine 13, dirt attached to the surface of the work plate 11 is removed. It is possible to increase the adhesive strength when the resist is removed and the resist is attached to the work plate 11. The resist pasting machine 14 pastes a resist on the surface of the processed plate 11 after cleaning, and may be a device generally used for resist pasting in the manufacture of a lead frame. In addition, as the developing device 16 and the etching device 17, devices generally used in the production of lead frames can be used.

The resist pattern drawing machine 15 includes a thickness deviation unit 18 for determining a thickness deviation, control means 19 for determining a resist mask interval from the thickness deviation, and a resist pattern based on the resist mask interval determined by the control means 19. Is provided directly on the resist. The sheet thickness deviation unit 18 calculates the sheet thickness based on the sheet thickness measurement value of the work sheet 11 input from the sheet thickness measuring means 12 and the nominal work thickness of the work sheet 11 transferred from a production management controller (not shown). Calculate the thickness deviation. The control means 19 is provided with a resist mask interval determining unit for determining a resist mask interval of the resist pattern, and a resist pattern control unit for performing photosensitive control so that a resist pattern is formed based on the determined resist mask interval. ing. In the resist mask interval determination unit, based on the lead pattern and the lead width design value transferred from the control device for production management,
1 even when the thickness of the lead pattern fluctuates, that is, when the thickness deviation fluctuates, the lead width of the formed lead pattern always substantially matches the lead width design value. The resist mask interval is determined in accordance with the value of the thickness deviation input from the thickness deviation device 18 so as to be within the range of ± 10 μm. The thickness deviation device 18 and the control means 19 can be configured using, for example, a personal computer. The photosensitive means 20 has a function of exposing the lead pattern at the resist mask interval determined by the control means 19, and irradiates light for exposing the resist, for example, a laser emitting unit 21 and the resist at the determined resist mask interval. The optical control unit 22 controls the optical path of the laser beam so that the light is exposed.

With the above configuration, the thickness of the work plate 11 being continuously conveyed is sequentially measured by the thickness measuring means 12, and the result is measured by the thickness deviation of the resist pattern drawing machine 15. The thickness deviation is obtained by inputting the thickness deviation to the predetermined relationship between the thickness deviation and the resist mask interval by the control means 19, and the thickness variation of the workpiece 11 is calculated from the thickness deviation. Then, the optimum resist mask interval is determined, and the lead pattern can be directly drawn by exposing the resist affixed to the processing target plate 11 by the exposure means 20. As a result, by developing and etching the processing target plate 11 on which the resist pattern is drawn, even if the thickness of the processing target plate 11 fluctuates on the way, the lead width of the lead pattern always formed becomes the lead width design value. Can be manufactured.

Next, a method for manufacturing a lead frame according to the first embodiment of the present invention will be described in detail. The plate 11 to be processed is transferred to the lead frame manufacturing equipment 1 by the transport means.
When it is conveyed to zero, first, the thickness of the workpiece plate 11 is measured by the thickness measuring means 12. The plate 11 whose thickness has been measured is conveyed to the cleaning device 13 to remove dirt attached to the surface. Then, it is conveyed to the resist sticking machine 14 and the resist is stuck on the surface of the plate 11 to be processed.
The plate 11 to which the resist has been applied is conveyed to the photosensitive unit 20.

On the other hand, the measured value of the thickness measured by the thickness measuring means 12 is transferred to a thickness deviation device 18. Sheet thickness deviation device 18
In, the thickness deviation is calculated using the nominal thickness of the workpiece plate 11 transferred from the production management control device, and the result is transferred to the control means 19. Further, the lead pattern and the lead width design value are input from the production management control device to the control means 19, and the resist mask interval determination unit determines the resist mask interval from the lead width design value and the thickness deviation. The result is transferred to the resist pattern control unit,
In the resist pattern control unit, operation conditions of the optical control unit 22 of the photosensitive unit 20 for forming a pattern mask for forming a lead pattern having a lead width design value are calculated.

When a work plate detector (not shown) detects that the work plate 11 to which the resist has been applied has been conveyed to the photosensitive means 20, a detection signal is input to the control means 19, and the control means 19 The operation conditions obtained by the resist pattern control unit are output to the optical control unit 22 and a laser transmission control signal is output to the laser transmission unit 21. Therefore, the resist pattern can be exposed to the resist stuck on the surface of the workpiece 11 in synchronization with the transport of the workpiece 11. The processing target plate 11 having the resist exposed to the resist pattern is subsequently conveyed to the developing machine 16 and the resist is developed to form a resist mask on the processing target plate 11. The lead pattern can be formed on the workpiece 11 by transporting the workpiece 11 on which the resist mask is formed to the etching machine 17 for etching. FIG. 2 shows an example of a design pattern for a lead pattern to be formed. Here, 22a is the lead frame, 22b is the semiconductor chip mounting portion, 22c is the inner lead, 22d is the tip of the inner lead, 22d
e indicates an outer lead, respectively.

Next, as shown in FIG. 3, the lead frame manufacturing equipment 23 to which the method for manufacturing a lead frame according to the second embodiment of the present invention is applied comprises a conveying means (not shown) for the plate 11 to be processed, A washing machine 24 for cleaning the surface of the work plate 11, a resist pasting machine 25 for applying a resist to the surface of the work plate 11 after cleaning, and direct drawing of a lead frame pattern on the resist affixed to the work plate 11 A resist pattern drawing machine 26 for developing, a developing machine 27 for developing a drawn resist to form a resist mask, and an etching machine 28 for etching the workpiece plate 11 on which the resist mask is formed. Hereinafter, these will be described in detail, but a washing machine 24, a resist pasting machine 25, a developing machine 27 used in the lead frame manufacturing equipment 23,
Since the etching machine 28 can use substantially the same components as the lead frame manufacturing equipment 10, detailed description of the components will be omitted.

The resist pattern drawing machine 26 is, for example, a shape measuring means 29 for measuring a lead width of a predetermined portion with respect to a lead pattern formed by etching from a resist mask formed at a standard lead mask interval of a design pattern. A lead width deviation unit 30 for calculating a lead width deviation; a control unit 31 for determining a resist mask interval from the lead width deviation; and a resist pattern directly drawn on the resist based on the resist mask interval determined by the control unit 31. Photosensitive means 32 is provided. As the shape measuring means 29, for example, a television camera having a CCD element can be used. The lead width deviation device 30 calculates the lead width deviation based on the lead width measurement value of the lead pattern input from the shape measuring means 29 and the lead width design value of the lead pattern transferred from the production management controller (not shown). I do. The control means 31 is provided with a resist mask interval determining unit for determining a resist mask interval of the resist pattern, and a resist pattern control unit for performing a photosensitive control so that a resist pattern is formed based on the determined resist mask interval. ing. In the resist mask interval determination unit, the allowable value of the lead width deviation is determined in advance for each part of the resist pattern, and only when the lead width deviation exceeds the allowable value, the lead width becomes the lead width design value. The resist mask interval is determined so as to substantially match. The lead width deviation device 30 and the control means 31 can be configured using, for example, a personal computer. The photosensitive means 32 includes the control means 3
It has a function of exposing the lead pattern at the resist mask interval determined in step 1 and irradiating light to sensitize the resist, for example, a laser emitting unit 33 and a laser beam so that the resist is exposed at the determined resist mask interval An optical control unit 34 for controlling an optical path is provided.

Next, a method for manufacturing a lead frame according to the second embodiment of the present invention will be described in detail. The plate 11 to be processed is transferred to the lead frame manufacturing equipment 2 by the transfer means.
3, first, the work plate 11 is transferred to the cleaning device 24 to remove the dirt attached to the surface. Subsequently, the substrate 1 is conveyed to the resist attaching machine 25 to be processed 1
A resist is stuck on the surface of 1. The plate 11 to which the resist has been applied is conveyed to a resist pattern drawing machine 26. In the resist pattern drawing machine 26, the photosensitive means 32 is operated in accordance with an instruction from the control means 31 so that a lead pattern having a designed lead width is formed, and the resist pattern is exposed. The processing target plate 11 having the resist exposed to the resist pattern is subsequently conveyed to the developing machine 27, where the resist is developed to form a resist mask on the processing target plate 11. The processing target plate 11 on which the resist mask is formed is conveyed to the etching machine 28 and etched, and the lead pattern is changed to the processing target plate 1.
1 is formed. The work plate 11 on which the lead pattern has been formed is carried out of the etching machine 28 and
9 is used to measure the lead width of the part set in advance.
The measured lead width is input to the lead width deviation unit 30, and the lead width deviation is calculated based on the lead width design value of the corresponding part transferred from the control device for production management. The lead width deviation is input to the control means 31. Is done.

The lead width deviation input to the control means 31 is determined by the resist mask interval determination section. In the resist mask interval determination unit, the allowable value of the lead width deviation is determined in advance for each part of the resist pattern, and the part to be determined is determined according to the type of the lead pattern to be manufactured. Therefore, a comparison is made between the input lead width deviation and an allowable value determined at the determination site, for example, the tip of the inner lead. When the lead width deviation exceeds the allowable value, the lead width of the formed lead pattern substantially matches the designed lead width, for example, ± 10 μm with respect to the designed lead width.
The resist mask interval is calculated so as to fall within the range, and the resist mask interval is determined. In the resist pattern control unit, operation conditions of the optical control unit 34 of the photosensitive unit 32 are calculated so that a resist pattern is formed at the resist mask interval determined by the resist mask interval determination unit. When the operation conditions are determined, the control unit 31 outputs the operation conditions obtained by the resist pattern control unit to the optical control unit 34 and outputs a laser transmission control signal to the laser transmission unit 33. Therefore, the resist pattern with the corrected resist mask interval can be exposed to the resist affixed to the surface of the workpiece 11 in synchronization with the transport of the workpiece 11.

The embodiment of the present invention has been described above.
The present invention is not limited to this embodiment,
For example, the resist mask interval was adjusted each time for the variation of the thickness deviation.However, an allowable value of the thickness deviation was provided for each resist pattern to be formed, and only when the thickness deviation exceeded the allowable value, the resist mask was set. Adjustment of the mask interval may be performed. Although the lead width deviation determination site is the tip of the inner lead, in a lead frame used for a semiconductor device requiring high speed, the resist mask interval should be adjusted for the lead width of all the lead patterns. Can also.

[0024]

According to the first and second embodiments of the present invention, the thickness of the work plate is measured, and the thickness deviation between the measured value of the work thickness and the nominal thickness of the work plate is determined. Since the thickness deviation is applied to a predetermined relation between the thickness deviation and the resist mask interval to adjust the resist mask interval and perform etching, it is possible to manufacture a lead frame having a lead pattern with excellent shape accuracy. it can. In particular, in the method for manufacturing a lead frame according to the second aspect, the setting condition of the resist mask interval at which the lead width of the lead pattern formed with respect to the variation of the thickness deviation becomes a predetermined value is obtained in advance. The optimum resist mask interval for the thickness deviation can be quickly determined, and the lead frame with high shape accuracy can be manufactured efficiently. It becomes possible.

In the method for manufacturing a lead frame according to the third and fourth aspects, the lead width of a predetermined portion of the formed lead pattern is measured, and the measured value of the lead width and the lead width design value of the lead pattern are measured. The lead width deviation is determined, and the resist mask interval corresponding to the lead width of the part is adjusted according to the lead width deviation to perform the etching. Therefore, the resist mask interval can be adjusted immediately, and a lead frame with high shape accuracy can be manufactured. be able to. In particular,
In the method for manufacturing a lead frame according to claim 4,
The adjustment of the resist mask interval is performed under the condition that the lead width substantially coincides with the design value of the lead width when the lead width deviation exceeds the allowable value. Is done,
It is possible to stably manufacture a lead frame having high shape accuracy.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration of a lead frame manufacturing facility to which a method for manufacturing a lead frame according to a first embodiment of the present invention is applied.

FIG. 2 is an explanatory diagram of a design pattern of a lead frame manufactured by the lead frame manufacturing method.

FIG. 3 is an explanatory diagram showing a schematic configuration of a lead frame manufacturing facility to which a method for manufacturing a lead frame according to a second embodiment of the present invention is applied.

FIG. 4 is an explanatory diagram showing a conceptual relationship between a plate thickness of a work plate and a side etching amount.

FIG. 5 is a schematic diagram showing a relationship between a thickness deviation and a resist mask interval when a lead width substantially matches a lead width design value.

[Explanation of symbols]

10: Lead frame manufacturing equipment, 11: Work plate, 1
2: plate thickness measuring means, 13: washing machine, 14: resist pasting machine, 15: resist pattern drawing machine, 16: developing machine, 1
7: etching machine, 18: plate thickness deviation device, 19: control means, 20: photosensitive means, 21: laser emitting section, 22: optical control section, 22a: lead frame, 22b: semiconductor chip mounting section, 22c: inner lead , 22d: tip of inner lead, 22e: outer lead, 23: lead frame manufacturing equipment, 24: cleaning machine, 25: resist attaching machine, 26: resist pattern drawing machine, 27: developing machine,
28: etching machine, 29: shape measuring means, 30: lead width deviation device, 31: control means, 32: photosensitive means, 33:
Laser transmitter, 34: Optical controller

Claims (4)

[Claims] 1. A resist is formed on a work plate, a lead frame pattern is directly drawn on the resist to form a resist mask, and the work plate on which the resist mask is formed is etched to form a lead pattern. In the method for manufacturing a lead frame, the thickness of the plate to be processed is measured, the thickness deviation between the measured value of the thickness and the nominal thickness of the plate to be processed is determined, and the thickness deviation is determined in advance. A method of manufacturing a lead frame, wherein the etching is performed by adjusting the resist mask interval by applying the relationship between the plate thickness deviation and the resist mask interval. 2. The lead frame manufacturing method according to claim 1, wherein the relationship between the thickness deviation and the resist mask interval is such that a lead width of the formed lead pattern is read with respect to the variation of the thickness deviation. A method for manufacturing a lead frame, wherein the method is determined based on substantially matching a width design value. 3. A resist is formed on a plate to be processed, a pattern of a lead frame is directly drawn on the resist to form a resist mask, and the plate on which the resist mask is formed is etched to form a lead pattern. In the lead frame manufacturing method, a lead width of a predetermined portion of a formed lead pattern is measured, and a lead width deviation between a measured value of the lead width and a lead width design value of the lead pattern is determined. A method of manufacturing a lead frame, comprising: adjusting a resist mask interval corresponding to a lead width of the portion according to a width deviation to perform etching. 4. The method of manufacturing a lead frame according to claim 3, wherein the adjustment of the resist mask interval is performed when the lead width deviation exceeds an allowable value. A method for manufacturing a lead frame, wherein the method is performed under conditions that match the conditions.