RU2456703C1 - Lead frame for shf and ehf semiconductor device - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: in the lead frame for a SHF and EHF semiconductor device, consisting of several leads outer and inner ends, the thickness of the lead frame is equal to 1-30 mcm and the length of outer leads which come out of the semiconductor device chip is equal to 0.1-1.5 mm, points for connecting inner and outer ends of the leads, as well as crossing the sections of the leads are smooth. At least two flat leads have a tapered section, wherein the width of its narrow part W_H coincides with the size of the inner end, and the width of the wide part W_k and length l satisfy the condition: ΔL/ΔC=1.15±0.75, where: ΔL is the relative change in spurious inductance of the flat lead L in percentages to its maximum possible change when W_k changes from 0.03 to 1 mm; ΔC is the relative change in spurious capacitance of the flat lead C in percentages to its maximum possible change when W_k changes from 0.03 to 1 mm, wherein L=0.05+[0.66-0.04(W_k/W_H)]1, C=[0.008+0.0002fW_k/W_H)]1, W_H is greater than or equal to 0.03 mm, and W_k varies from 0.04 to 1 mm.

EFFECT: improved electrical characteristics owing to optimisation of the configuration of leads and reduced power loss of the SHF signal.

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Description

The invention relates to electronic equipment, namely, to the output frames for connecting crystals of microwave and EHF semiconductor devices to the topological drawing of microstrip boards of hybrid integrated circuits of the microwave and EHF range.

Known output frame for integrated circuits, which contains support strips and several conclusions, each of which has an outer and inner ends. The outer ends of the terminals are connected to the support strips, and the inner ends extend from the support strips to the center of the frame. In the center of the lead frame is a removable element, on the periphery of which there are several recesses. The inner ends of the findings are placed in the recesses of the removed element to prevent their displacement from one relative to another [1].

The disadvantage of this design is the need to manufacture a central removable element with recesses, the high complexity of manufacturing technology, the inconvenience of use for microwave and EHF ranges.

The closest technical solution is the output frame for the microwave and EHF semiconductor device, consisting of several terminals with external and internal ends, while the external ends are connected to the supporting strips of the external technological frame, and the internal ends have a configuration corresponding to the configuration of the contact pads of the crystal of the semiconductor device, and are intended for direct connection with them, the thickness of the output frame is 1-30 microns, and the length of the outer ends of the terminals extending beyond the limits of The height of the semiconductor device is 0.1-1.5 mm, the junctions of the internal and external ends of the terminals, as well as the transitions of the sections of the terminals are made smooth [2]. The frame design has improved electrical characteristics compared to the analogue, but insufficient, due to the configuration of the flat terminals and, as a result, high signal energy losses on the microwave.

The technical result of the invention is to improve electrical characteristics by optimizing the configuration of the terminals and, as a result, reducing signal power loss on the microwave.

The technical result is achieved in that in the output frame for the microwave and EHF semiconductor device, consisting of several terminals with external and internal ends, while the outer ends of the terminals are connected to the supporting strips of the external technological frame, and the inner ends have a configuration corresponding to the configuration of the contact pads of the crystal semiconductor device, and are designed for direct connection with them, the thickness of the output frame is 1-30 microns, and the length of the external terminals extending beyond the crista ulla of a semiconductor device is 0.1-1.5 mm, the joints of the inner and outer ends of the terminals, as well as the transitions of the sections of the terminals are smooth, at least two flat terminals have a wedge-shaped section, and the width of its narrow part Wn coincides with the size of the inner end, and the width of the wide part Wк and the length l satisfy the condition: ΔL / ΔC = 1.15 ± 0.75, where: ΔL is the relative change in the parasitic inductance of the flat terminal L in percent of its maximum possible change when Wk changes from 0.03 up to 1 mm; ΔC is the relative change in the parasitic capacitance of the flat terminal C as a percentage of its maximum possible change when Wc changes from 0.03 to 1 mm, while L = 0.05 + [0.66-0.04 (Wc / Wn)] 1 ; C = [0.008 + 0.0002 (Wk / Wn)] 1, Wn is greater than or equal to 0.03 mm, and Wk varies from 0.04 to 1 mm.

To facilitate the connection of the external ends of the terminals, it is possible to connect several internal ends of the terminals into one external using wedge-shaped sections.

The presence of at least one flat terminal of the wedge-shaped section allows to reduce its stray inductance L with a slight increase in stray capacitance C and, thus, to reduce the power loss of the transmitted microwave signal, and thus improve electrical characteristics.

The fulfillment of the condition ΔL / ΔC = 1.15 ± 0.75, where L = 0.05 + [0.66-0.04 (Wк / Wн)] 1 spurious inductance and C = [0.008 + 0.0002 (Wк / Wн)] 1 parasitic capacitance of the wedge-shaped section of the output can further reduce the loss of the transmitted signal, which means to improve the electrical characteristics of semiconductor devices and hybrid integrated circuits of the microwave and EHF ranges in which they are installed and used.

The narrowing of the width of the narrow part of the wedge Wн of the wedge-shaped portion of the flat output is explained by the fact that the contact area of the microwave and EHF semiconductor devices (transistors and monolithic semiconductor integrated circuits) is usually performed with a minimum size of 30 × 30 μm.

The limitation of the width of the wide part of the wedge Wk of the wedge-shaped portion of the flat output from above is explained by the fact that the width of the fifty-ohm microstrip asymmetric line of the hybrid integrated circuit board running on a dielectric substrate is approximately equal to the thickness of the substrate, and the usual thickness of the dielectric substrate does not exceed 1 mm. The limitation of the width of the wide part of the wedge Wk of the wedge-shaped portion of the flat output from the bottom is explained by the fact that a smaller expansion practically does not give the effect of improving electrical characteristics.

The invention is illustrated by drawings.

Figure 1 presents a fragment of the proposed output frame of the microwave and EHF semiconductor device, where:

- flat terminal 1;

- the outer end of pin 2;

- the inner end of terminal 3;

- supporting strips of the external technological frame 4;

- contact area 5;

- crystal semiconductor device 6;

- part of the outer ends of the conclusions, extending beyond the crystal of the semiconductor device 7;

- a wedge-shaped section of a flat terminal with a length of 1 8;

- the narrow part of the wedge-shaped section with a width of Wn 9;

- a wide part of the wedge-shaped section with a width of Wk 10;

- the place of trimming of the external technological frame 11.

Figure 2 presents graphs of the relationship ΔL / ΔC on the width Wk of the flat beam output of the output frame, where:

^___ at Wн = 0.05 mm, 1 = 0.5 mm;

- ^. - with Wн = 0.05 mm, 1 = 1 mm;

---- at Wn = 0.1 mm, 1 = 0.5 mm.

Figure 3 presents the equivalent planar output of the output frame, where Z is the wave resistance of the input and output; L _equiv. equivalent inductance; C _equiv equivalent capacity.

Figure 4 is a graph of the relationship ΔL / ΔC versus the width Wк of the beam output of the output frame at Wн = 0.03 mm.

Figure 5 is a graph of the relationship ΔL / ΔC versus the width Wк of the beam output of the output frame at Wн = 0.3 mm.

Example.

The output frame of the microwave and EHF semiconductor device, for example, field effect transistor 3P976A - 5 (AEYAR.432140.207TU). The 3P976A-5 field-effect transistor crystal has three drain contact pads 5 and three gate contact pads 5. The output frame consists of two conclusions 1, the drain and the gate, the inner ends 3 of which are connected to the contact pads 5, the two outer ends 2 are connected to the support strips 4 of the external technological frame 11. The inner ends 3 of the output 1 have a configuration corresponding to the configuration of the contact pads of the crystals. The size of the contact pad 5 of the transistor crystal is 50 × 50 μm. The dimensions of the inner end 3 of the output 45 × 45 μm, which provides a gap of 2.5 μm and facilitates their combination.

The thickness of the output frame is 8 microns. The material from which the frame is made - galvanically deposited gold provides good conductivity, weldability with contact pads 5 having a metallization structure of Ti 0.02 μm (sprayed) - Pd 0.2 μm (sprayed) - Au 3 μm (galvanically deposited).

The inner ends of 3 conclusions 1 are connected by thermosonic welding with the contact pads 5 of the crystal of the semiconductor device 6. The width of the outer end 2 of terminal 1 corresponds to a width of 0.5 mm of a film conductor of a fifty-ohm microstrip asymmetric line on a 0.5 mm thick polycore substrate of the board. The length of the outer ends of 2 conclusions 1, extending beyond the crystal 6, is 0.9 mm The joints of the inner ends 3 and the outer ends 2 of the terminals 1, as well as the transitions of the sections of the terminals 1 are made smooth. The conclusions 1 have wedge-shaped sections 8. The width of the narrow part of the wedge Wн of the wedge-shaped section 8 of the output delivers 45 μm, and the width of the wide part of the wedge Wc of the wedge-shaped section 8 of the output 1 is 0.5 mm, respectively. The length of the wedge-shaped section 1 is 1 mm. The ratio ΔL / ΔC is 0.78.

Using computer simulation and a two-dimensional electromagnetic modeling program [3] and comparing the stray inductances and capacitances of the wedge-shaped and rectangular sections of the terminals, as well as by calculating the S-parameters of the transistors taking into account the stray inductances and capacitances, it was found that replacing the rectangular sections of the flat terminal with wedge-shaped ones reduces the influence of parasitic parameters by about 10%.

In the calculations, the equivalent planar output circuit shown in Fig. 3 was used, the wave resistance of the input and output Z of which is 50 Ohm. The circuit consists of an input equivalent capacitance to earth C _equiv , an equivalent inductance L _equiv to pass and an output equivalent capacitance to earth C _equiv . The equivalent circuit allows you to take into account the stray inductances and capacitances introduced by these conclusions into the transistor circuit when calculating the parameters of the transistor. The calculations showed that it is possible to find the values of the parameters L _eq and C _{eq of the} equivalent circuit at which the S-parameters of the transistor in the frequency range 2-18 GHz practically coincide with the S-parameters of the transistor calculated by the two-dimensional electromagnetic simulation program.

The calculation of parasitic equivalent inductances and capacitances of flat beam terminals is presented in table 1 and 2.

Table 1. Wedge-shaped beam output of the output frame. Initial width 30 μm, final 300 μm beginning: width 300 μm, con. - 1 mm Length l, microns L _equiv , nH C _equiv , pF L _equiv , nH C _equiv , pF one hundred 0.106 0.0012 0.07 0.003 300 0.185 0.003 0.11 0.006 500 0.28 0.0044 0.15 0.009 700 0.38 0.006 0.2 0.013 900 0.483 0.008 0.25 0.016 1100 0.585 0.009 0.3 0.02 1300 0.687 0.01 0.34 0.023 1500 0.788 0.012 0.39 0.025

Table 2. Rectangular pin output width is 30 microns, width 300 mm Length l, microns L _equiv , nH C _equiv , pF L _equiv , nH C _equiv , pF one hundred 0.133 0.001 0.09 0.001 300 0.28 0.0018 0.14 0.004 500 0.44 0.0032 0.21 0.007 700 0.62 0.0045 0.29 0.01 900 0.77 0.006 0.35 0.013 1100 0.93 0.0075 0.43 0.016 1300 1.1 0.009 0.5 0.019 1500 1.26 0.01 0.57 0.022

An analysis of the results shows that:

- the use of a wedge-shaped flat beam output can significantly reduce the parasitic inductance of the output;

- parasitic output capacitance practically does not increase;

- the effectiveness of the wedge-shaped output increases with increasing length of the flat beam output.

Thus, the introduction of wedge-shaped sections allows you to minimize stray inductances and capacitances and thereby reduce the power loss of the transmitted signal, and therefore, improve electrical characteristics.

The device operates as follows. The output frame is connected by the inner ends of 3 flat terminals 1 to the contact pads 5 of the crystal 6 of the microwave field-effect transistor, and the outer ends of 2 terminals 1 to the microstrip line of the hybrid integrated circuit board. After trimming the technological frame, the conclusions of the output frame provide the supply of the microwave signal with minimal losses to the transistor and the removal of the processed (amplified) signal from the transistor to the output microstrip line with minimal losses.

The proposed design in comparison with the prototype improves electrical characteristics by reducing the energy loss of the microwave signal, which is associated with better coordination of the microstrip line and the outer ends of the conclusions of the frame and when the signal is transferred from the external ends of the conclusions to the output microstrip line, as well as reducing losses during the transition from the pads of the semiconductor device (transistor) to the microstrip lines by optimizing the shape of the terminal sections.

Information sources

1. US patent No. 4415917, MKI H01L 29/60, 23/48, NKI 357-70, publication 83.11.15, T. 1036, 3.

2. RF patent No. 2191492 for the invention, IPC ⁷ H05K 3/24, H01L 23/48, priority 04/17/2000, Output frame for microwave and EHF semiconductor devices. Iovdalsky V.A., Pchelin V.A.

3. Microwave Office / vss / AO 2006, http // www.appwave.com.

Claims (2)

1. The output frame for the microwave and EHF semiconductor device, consisting of several flat terminals with external and internal ends, while the outer ends of the terminals are connected to the supporting strips of the external technological frame, and the inner ends have a configuration corresponding to the configuration of the contact pads of the crystal of the semiconductor device and are intended for direct connection with them, the thickness of the output frame is 1-30 μm, and the length of the outer ends of the terminals extending beyond the semiconductor crystal is approximately pa is equal to 0.1-1.5 mm, the joints of the inner and outer ends of the terminals, as well as the transitions of the sections of the terminals are made smooth, characterized in that at least one flat terminal has a wedge-shaped portion, and the width of its narrow part Wn coincides with the size of the inner end, and the width of the wide part Wк and length 1 correspond to the condition: ΔL / ΔC = 1.15 ± 0.75,
where ΔL is the relative change in the parasitic inductance of the flat terminal L as a percentage of its maximum possible change when Wc changes from 0.03 to 1 mm;
ΔС is the relative change in the parasitic capacitance of the flat terminal C as a percentage of its maximum possible change when Wk changes from 0.03 to 1 mm, while
L = 0.05 + [0.66-0.04 (Wk / Wn)] 1,
C = [0.008 + 0.0002 (Wk / Wn)] 1,
Wн is greater than or equal to 0.03 mm, and Wк varies from 0.04 to 1 mm. 2. The output frame for the microwave and EHF semiconductor device according to claim 1, characterized in that several internal ends of the terminals are connected to one external using wedge-shaped sections of the terminals.

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