JP2000292491A - Two branch transmission line and two branch driver circuit and semiconductor tester employing it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce useless oscillation waveform by providing means for connecting an waveform improving means between the receiving ends of first and second transmission lines. SOLUTION: A series termination resistor TR2 terminates a reflection wave returning from a third transmission line CB3 and has a characteristic impedance equal to that of the third transmission line CB3. The third transmission line CB3 is a coaxial cable having a characteristic impedance of 50 Ω. First and second transmission lines CB1, CB2 have same line length and connected, at one ends thereof, with the third transmission line CB3 through a double impedance. As an waveform improving means, a fourth transmission line CB4 having a characteristic impedance equal to that of the first transmission line CB1 is employed and connected between the receiving ends of the first and second transmission lines CB1, CB2. When the fourth transmission line CB4 is connected, a circulation path passing through paths LP1, LP2 and returning back to the two branch point is formed and both paths LP1, LP2 have a perfectly identical propagation delay.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention drives one transmission line from a drive end, and reduces unnecessary vibration waveforms in reception waveform signals at both reception ends of a transmission line that branches into two on the way. 2-branch transmission line from which a more faithful waveform signal can be obtained,
Two-branch driver circuit and semiconductor test apparatus using the same

[0002]

2. Description of the Related Art The prior art will be described below with reference to the principle diagram of a two-branch driver circuit used in the semiconductor test apparatus shown in FIG. Here, the two-branch driver circuit has a form in which the transmission line is branched into two in the middle of the transmission line. In addition, there are a parallel termination and a series termination as termination forms of the transmission line, but here, a case where the termination is performed in series by a resistor on the transmission end side. Since the semiconductor test apparatus is well-known and well-known in the art, the description of the configuration of the entire system is omitted. Further, the semiconductor test device has a large number of channels of the driver DR1. However, when simultaneously measuring a plurality of DUTs, a finite number of driver channels may not be enough. At this time, if a two-branch driver circuit is applied, the number of devices that can be simultaneously tested may be doubled.

[0003] The main components of FIG.
0, the driver DR1, the series terminating resistor TR2, and the third
It comprises a transmission line CB3, a first transmission line CB1, a second transmission line CB2, and two devices under test (DUT).

A pulse signal source 100 is a desired test pattern generation source for testing a DUT in a semiconductor test apparatus, and is generated by, for example, a pattern generator and a waveform shaper.

In a semiconductor test apparatus, a driver DR1 outputs a logic signal to a high level VIH voltage and a low level VIL.
A high-speed drive waveform signal converted into a predetermined amplitude voltage by a voltage is supplied to the series termination resistor TR2. The output end of this driver is called the drive end. The drive waveform signal is generated and output at a rising edge (leading edge) and a falling edge (trailing edge) at an edge defined at a predetermined timing by calibration in advance. Here, the waveforms at the first and second receiving ends, which are the IC pins of both DUTs, are faithful to the waveform of the driving waveform signal at the driving end.
It is required that the edge has a predetermined timing.
If the waveform is distorted or the edge timing is off,
It is not preferable because the measurement quality of the device is deteriorated and the timing measurement accuracy is deteriorated.

The series termination resistor TR2 is connected to the third transmission line CB
3 is a series terminating resistor for terminating the total reflection wave returning from the far end, and is inserted in series with the line. As the resistance value, for example, when the characteristic impedance of the third transmission line CB3 is 50Ω, a resistance value of 50Ω is used. However, since the driver DR1 itself has an internal resistance of about several Ω, a resistance value obtained by subtracting this internal resistance is used. Incidentally, in a semiconductor test apparatus, it is generally connected to the third transmission line CB3 via a performance board.

The third transmission line CB3 is, for example, a coaxial cable having a characteristic impedance of 50Ω and a length of several tens of cm.
In the semiconductor test apparatus, as is well known, the third transmission line CB3 is accommodated in a relay device (Hyfix) that interfaces between the performance board and the handler device or the prober device, and is put to practical use.

A first transmission line CB1 and a second transmission line CB2
Is a line having the same line length, and the third transmission line CB
A characteristic impedance value twice as large as the characteristic impedance value of 3, for example, when the characteristic impedance is 100Ω and 1
It is a coaxial cable or a microstrip line having a length of about 0 cm. One ends of the first transmission line CB1 and the second transmission line CB2 are connected to the third transmission line CB3. Needless to say, the connection is properly performed so that the characteristic impedance at this connection point does not cause discontinuity.

The two DUTs are the same device. For example, the two DUTs are mounted on contact-specific IC sockets (contactors) in the handler device and used. The distance between the two DUTs differs depending on the system, but exists close to, for example, about 10 cm. Here, an IC pin end connected to one DUT is referred to as a first receiving end, and the other is referred to as a second receiving end. Further, at both receiving ends of the DUT, there are distributed capacities Cs1 and Cs2 of several picofarads including the input capacitance of the DUT itself and the distributed capacitance of the IC socket, respectively.

Next, the defective waveform will be described with reference to FIG. Here, in FIG. 4, the forward path from the two branch point to the first receiving end is PASS1f, the return path is PASS1r, the forward path from the two branch point to the second receiving end is PASS2f, and the return path is PASS1f.
Called ASS2r.

FIGS. 3A, 3B and 3C show waveform distortion at the receiving end. On the other hand, the reception waveform of FIG. 3C is a propagation delay amount Td from the bifurcation point of the transmission line in FIG.
1 and Td2 are examples of reception waveforms at both reception ends when the delay amounts are the same. In this case, the waveform is an ideal reception waveform, and there is no problem. That is, the waveform propagation at this time is almost totally reflected from both receiving ends, and returns to the two branch points with exactly the same phase and the same voltage. Therefore, both return signals are terminated as they are by the series terminating resistor TR2 via the third transmission line CB3, and the process ends.

On the other hand, the reception waveforms of FIGS. 3A and 3B show the propagation delay Td1 of the first transmission line CB1 and the propagation delay Td of the second transmission line CB2 from the two branch points to the receiving end in FIG.
2 is a case where the propagation delay amount is slightly different, and is an example of one vibration waveform (see FIG. 3A) and the other vibration waveform (see FIG. 3B) at both receiving ends at this time. The difference in the amount of propagation delay causes a difference in delay due to variations in soldering of cable terminals even if the cable is cut at the same cable length, or if the first transmission line CB1 and the second transmission line CB2 have the same propagation delay amount. However, due to the distributed capacitances of the contactors (IC sockets: contacts) and the like, and the different distributed capacitances Cs1 and Cs2 generated due to the devices (manufacturing lots, manufacturers, etc.) having different input capacities, the total of the forward path and the return path can be obtained. A similar vibration waveform is also generated when a difference occurs in the propagation delay time.

Here, the vibration waveform of FIG. 3 will be described. At the two-branch point, the drive waveform signal from the driver divides into two, reciprocates at both receiving ends, and is totally reflected back.
Since the waveform propagation at this time returns to the two branch points with a different phase relationship, the waveform propagation is terminated by the series terminating resistor TR2 via the third transmission line CB3 and the other transmission line (the first transmission line CB1, The signal propagates again to the second transmission line CB2). As a result of this repetition, a vibration waveform as shown in FIGS. 3A and 3B is generated. In this figure, the vibration amplitude (see FIG. 3D) is related to the phase difference and the slew rate of the waveform.
Further, the oscillation cycle (see FIG. 3E) is one outgoing path PASS1f.
And the time difference of the propagation delay between the return path PASS1r and the other forward path PASS2f and return path PASS2r.

By the way, in order to test a high-speed device operating at several hundred MHz or more in recent years, it is necessary to generate and apply a waveform with a much higher slew rate (for example, 0.2 nS / V). Accordingly, even a small phase difference results in a large vibration amplitude. In addition, since the pulse edge interval also approaches, the next edge comes before the vibration amplitude (see FIG. 3D) attenuates. For this reason, the waveform changes (see FIGS. 3F and 3G) under the influence of the vibration waveform of the leading edge / trailing edge of the immediately preceding pulse, despite being defined at the predetermined timing. As a result, there is a problem that the leading edge / trailing edge timing of the immediately following pulse changes as shown in FIGS. This is extremely unfavorable for a semiconductor test apparatus requiring timing accuracy. The occurrence of the above-mentioned vibration waveform makes it difficult to apply an appropriate predetermined test waveform to the DUT, particularly when testing a high-speed device, and is therefore extremely undesirable from the viewpoint of maintaining the performance of the device test.

[0015]

As described above, in the prior art, a high-speed pulse signal is transmitted through one transmission line, and is branched into two parts in the middle and supplied to two receiving terminals. Unnecessary vibration waveforms are likely to occur in the branch transmission line. This can result in a distorted waveform at the receiving end,
The timing accuracy of the edge of the waveform deteriorates. This is an undesirable and practical disadvantage. Therefore, the problem to be solved by the present invention is that a signal driven from the drive end of one transmission line is divided into two on the way, and unnecessary waveforms are received at the reception ends of the two branched transmission lines. An object of the present invention is to provide a two-branch transmission line and a two-branch driver circuit capable of reducing a vibration waveform and a semiconductor test apparatus using the same.

[0016]

First, in order to solve the above-mentioned problems, in the configuration of the present invention, the series termination resistor TR2
And a third transmission line CB3 having a predetermined characteristic impedance.
(Eg coaxial line or microstrip line)
And a first transmission line CB1 and a second transmission line CB2 having a characteristic impedance value twice as large as the characteristic impedance value of the third transmission line CB3, and one end of the series termination resistor TR2 is connected to one end of the third transmission line CB3. And the other end of the third transmission line CB3 is connected to the first transmission line CB1 and the second transmission line CB.
2 are connected to one end of each of the two lines, and are branched into two. The other end of the first transmission line CB1 (this is called a first reception end) and the other end of the second transmission line CB2 (this is called a second reception end). ), A high-speed drive waveform signal is applied from the other end of the series terminating resistor TR2 in the line (this is called a drive end),
In a two-branch transmission line, which is distributed and supplies a waveform signal of a predetermined quality to both ends of a first receiving end and a second receiving end,
A two-branch transmission line characterized by comprising constituent means for connecting the waveform improving means 10 between both ends of the reception ends of the transmission line CB1 and the second transmission line CB2 to improve the quality of the reception waveform at the reception end. . According to the above invention, the signal driven from the drive end of one transmission line is divided into two in the middle and
A two-branch transmission line capable of reducing unnecessary vibration waveforms in reception waveform signals at the receiving ends of both branched transmission lines can be realized.

Second, in order to solve the above problem, in the configuration of the present invention, a driver, a series termination resistor TR2, a third transmission line CB3 having a predetermined characteristic impedance, and a third
A first transmission line CB1 and a second transmission line CB2 each having a characteristic impedance value twice as large as the characteristic impedance value of the transmission line CB3, and the driver receives the input waveform signal and buffers the driving waveform signal in series termination. Resistance TR2
Of the third transmission line CB3 by the output impedance of the driver and the series termination resistor TR2.
The other end of the series termination resistor TR2 is connected to one end of the third transmission line CB3, and the other end of the third transmission line CB3 is connected to the first transmission line CB1.
And one end of both lines of the second transmission line CB2 and
The driver branches to the other end (first receiving end) of the first transmission line CB1 and the other end (second receiving end) of the second transmission line CB2, from the output end (driving end) of the driver to a high-speed driving waveform. In a two-branch driver circuit for generating and splitting a signal and transmitting a predetermined quality waveform signal to both ends of a first receiving end and a second receiving end, the other ends of the first transmission line CB1 and the second transmission line CB2 There is a two-branch driver circuit characterized by comprising a configuration means for connecting the waveform improving means 10 between both ends of the circuit to improve the quality of the received waveform at the receiving end.

FIG. 5 (b) shows a solution according to the present invention. One aspect of the waveform improving means 10 connected between the two receiving ends is a fourth transmission line CB4 (for example, a coaxial line or a microstrip line) having the same characteristic impedance as the characteristic impedance value of the first transmission line CB1. There is the aforementioned two-branch transmission line or the aforementioned two-branch driver circuit. Further, as one mode of the waveform improving means 10 connected between both receiving terminals, a resistance element which exhibits an impedance of a fraction (eg, 例 え ば or less) of the characteristic impedance value of the first transmission line CB1 is used. There is the above-described two-branch transmission line or the above-described two-branch driver circuit. In addition, as one mode of the waveform improving means 10 connected between the two receiving ends, a capacitive element exhibiting an impedance of a fraction (eg, １ ／ or less) of the characteristic impedance value of the first transmission line CB1 is used. The above-described two-branch transmission line or the above-mentioned two-branch transmission line
There is a branch driver circuit. FIG. 5 (c) shows a solution according to the present invention. As one mode of the waveform improving means 10 connected between both receiving ends, the first transmission line C
The fifth transmission line CB5 having the same characteristic impedance as B1
A two-branch transmission line or a two-branch driver circuit, characterized in that the capacitance element exhibits an impedance of a fraction (e.g., 1/5 or less) of the characteristic impedance value of the fifth transmission line CB5. There is. FIG. 5 (d) shows a solution according to the present invention. As one mode of the waveform improving means 10 connected between both receiving ends,
The fifth, which is the same as the characteristic impedance of the first transmission line CB1,
The above-described two-branch transmission line or the above-described two-branch transmission line, wherein the transmission line CB5 and the fifth transmission line CB5 are resistance elements each having an impedance of a fraction (e.g., 以下 or less) of the characteristic impedance value of the fifth transmission line CB5. There is a branch driver circuit. Further, as one mode of the waveform improving means 10 connected between the two receiving ends, a driving waveform signal branched at two branch points for a high frequency component is supplied to both the receiving ends and the waveform improving means 1.
0, wherein the transmission line is a transmission line that propagates through 0 and loops back to the two branch points.
There is a branch driver circuit.

The third transmission line CB3, the first transmission line CB1, and the second transmission line CB2 are coaxial lines or microstrip lines. Also, the first
The connection target connected to the receiving end and the second receiving end is the above-described two-branch driver circuit which is a device under test (DUT) of a semiconductor test apparatus.

The two-branch transmission line includes an output terminal of a driver channel of a pin electronics circuit of a semiconductor test device and two DUs connected to the driver channel.
There is a semiconductor test apparatus characterized in that the semiconductor test apparatus is provided so as to be applied to distribution supply between the same IC pins corresponding to T. The semiconductor testing apparatus is characterized in that the waveform improving means 10 is connected between both contactors (contacts) corresponding to the same IC pin which makes electrical contact with two devices under test to be tested by the semiconductor testing apparatus. There is.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings together with embodiments.

FIG. 3 shows the principle of the two-branch transmission line of the present invention, FIG.
This will be described below with reference to a diagram for explaining the waveform distortion at the receiving end of FIG. 5 and three examples of the waveform improving means in FIG. still,
Elements corresponding to the conventional configuration are denoted by the same reference numerals.

First, the configuration of the present invention will be described. Figure 1 shows 2
The main components of the branch transmission line are a pulse signal source 100, a series termination resistor TR2, a third transmission line CB3, a first transmission line CB1, and a second transmission line CB.
2 and waveform improving means 10. At this time, an object is to transmit and supply a faithful waveform signal corresponding to the drive waveform signal to both ends of the first receiving end and the second receiving end. This is a configuration in which the waveform improving means 10 is added to the conventional configuration. The other components are the same as those in the related art and need not be described. Note that the distributed capacitance C is applied to the input of the device or device to be received at the first receiving end and the second receiving end, respectively.
Although it is assumed that s1 and Cs2 exist, a resistance component other than the distributed capacitance may be present as a load. However, the resistance value must be practically sufficiently larger than the characteristic impedance of the transmission line of 100Ω, for example, 10 KΩ or more.

The waveform improving means 10 includes a first transmission line CB1
And the waveform improving means 10 is connected between both ends of the receiving end of the second transmission line CB2. As a specific example of the waveform improving unit 10, a fourth transmission line CB4 having the same characteristic impedance as the characteristic impedance value of the first transmission line CB1, for example, 100Ω is used. In addition, there is no limitation on the amount of transmission delay of the fourth transmission line CB4, and it is only necessary that both receiving ends can be connected. Of course, the transmission line may be a coaxial cable or a microstrip line.

Next, waveform improvement by the above configuration will be described with reference to FIGS. Here, the first transmission line C
It is assumed that there is a difference in the amount of propagation delay between B1 and the second transmission line CB2. Also, as shown in FIG. 1, one loop path LP1 includes a first transmission line CB1, a fourth transmission line CB
4, the second transmission line CB2 is in the order of the path, and the other loop path LP2 is the second transmission line CB2, the fourth transmission line CB
4. The path is in the order of the first transmission line CB1.

In the present invention, by adding the fourth transmission line CB4, the light is reflected at both receiving ends and does not return to the two branch points as in the related art, but instead travels around the loop paths LP1 and LP2 to the two branch points. A return circuit is formed. What should be noted here is that both loop paths LP1, LP2
Are points passing through the same transmission line. Therefore, both of the loop paths LP1 and LP2 have exactly the same propagation delay. This means that even if there is a difference in the amount of propagation delay between the first transmission line CB1 and the second transmission line CB2,
When both of the drive waveform signals divided into two at the branch point make a round and return to the two branch points, both signals always return at the same timing. As a result, the unnecessary vibration waveforms shown in FIGS. 3A and 3B as in the related art are not generated, and in the present invention, the ideal waveform shown in FIG. 3C is obtained at both the first receiving end and the second receiving end. That is a special advantage. The connection point of the fourth transmission line CB4 is desirably an ideal circuit connection form connecting the end point of the first reception end and the end point of the second reception end, but is connected to a position several millimeters away from the end point. However, since the useless vibration waveform is extremely small, it can be implemented practically.

Next, another specific example of the waveform improving means 10 will be described with reference to FIG. FIG. 5A shows the waveform improving means 10.
FIG. 5B is an equivalent circuit corresponding to FIG. As described above, the first transmission line CB1
It has been found that the drive waveform signal distributed to and the second transmission line CB2 should return once. In the configuration example of FIG. 5C, the capacitor C that can pass high frequency components
1 is inserted in the middle of the fifth transmission line CB5 or at an arbitrary point on the line in series. This means that the DC component and the low frequency component can be ignored from the viewpoint of the vibration waveform, and the waveform does not deteriorate. That is, it suffices that a high-frequency component corresponding to the slew rate of the leading edge or the trailing edge of the waveform can pass through the circuit in a loopable manner. Therefore, if desired, a predetermined capacitance value corresponding to the slew rate of the edge, for example, 1000
Picofarads may be inserted in series. Also in this case, since the same amplitude waveform returns to the two branch points at the same timing, no useless vibration waveform is generated, so that it is practically applicable without any trouble.

In the configuration example shown in FIG. 5C, a transmission line having a resistance value enough to allow the distributed drive waveform signal to make a single pass, for example, a characteristic impedance of 100Ω, for example, 1 /
In this embodiment, a resistance of 5 or less and 10 Ω or less is inserted in the middle of the fifth transmission line CB5 or at an arbitrary point in the line. Also in this case, since the same amplitude waveform returns to the two branch points at the same timing, no useless vibration waveform is generated, so that it is practically applicable without any trouble.

If desired, the waveform improving means 10 may be a series connection of the capacitor C1 of FIG. 5C and the resistor R1 of FIG. 5D.

In FIG. 5 (b, c, d), if the two receiving ends are close to each other by about several cm and the waveforms are deteriorated to a practically applicable level at the two receiving ends, it is possible to reduce The connection may be made using a single wire instead of the five transmission lines CB5.

As a specific application example of the above-described two-branch transmission line, as shown in FIG. 2, there is an example of application to a driver channel provided in a pin electronics circuit of a semiconductor test device. That is, the output terminal of the driver DR1 of the pin electronics circuit and the output terminal 2 connected to this output terminal.
There is a two-branch transmission line that distributes and supplies between the corresponding identical IC pins of one DUT to the contactor of the handler device or the prober device via a performance board or a HIFIX. As described above, by applying the present invention, the waveform of the driver DR1 can be faithfully applied as it is to the IC pins of the DUT. As a result, a great advantage that a device test can be performed with excellent waveform quality can be obtained. As a result, improvement of the measurement quality of the device by the semiconductor test apparatus and further improvement of the timing measurement accuracy can be realized.

[0032]

According to the present invention, the following effects can be obtained from the above description. As described above, according to the present invention, the configuration including the means for connecting the waveform improving means between both ends of the reception ends of the first transmission line CB1 and the second transmission line CB2 is provided. When both of the divided drive waveform signals make a round and return to the two branch points, the two signals always return at the same timing,
The influence of the difference in the amount of propagation delay between the first transmission line CB1 and the second transmission line CB2 is eliminated. As a result, a special advantage is obtained in that unnecessary vibration waveforms are eliminated and the waveforms can be supplied to both receiving ends with good waveform quality and timing edges. Further, when the present invention is applied to a driver channel of a pin electronics circuit of a semiconductor test apparatus, it is possible to improve the measurement quality of the semiconductor test apparatus device and further improve the timing measurement accuracy. Therefore, the technical effect of the present invention is great, and the industrial economic effect is also great.

[Brief description of the drawings]

FIG. 1 is a principle diagram of a two-branch transmission line according to the present invention.

FIG. 2 is a principle diagram of a two-branch driver circuit according to the present invention.

FIG. 3 is a view for explaining waveform distortion at a receiving end according to the present invention.

FIG. 4 is a principle diagram of a conventional two-branch driver circuit used in a semiconductor test apparatus.

FIG. 5 shows three examples of waveform improving means according to the present invention.

[Explanation of symbols]

 C1 Capacitor Cs1, Cs2 Distributed capacitance DR1 Driver R1 Resistance CB1 First transmission line CB2 Second transmission line TR2 Series termination resistor CB3 Third transmission line CB4 Fourth transmission line CB5 Fifth transmission line 10 Waveform improving means 100 Pulse signal source

Claims (12)

[Claims] 1. A series termination resistor, a third transmission line having a predetermined characteristic impedance, a first transmission line and a second transmission line having a characteristic impedance value twice as large as the characteristic impedance value of the third transmission line. And one end of the series termination resistor is connected to one end of a third transmission line, and the other end of the third transmission line is connected to one end of both lines of the first transmission line and the second transmission line. Branch, and the other end of the first transmission line (this is connected to the first
With respect to the other end of the second transmission line (referred to as a second receiving end) and the other end (referred to as a driving end) of the series terminating resistor in the line, high-speed driving is performed. A two-branch transmission line that applies a waveform signal and splits and supplies a waveform signal of a predetermined quality to both ends of the first reception end and the second reception end; the first transmission line and the second transmission line 2. A two-branch transmission line characterized by comprising a configuration means for connecting a waveform improving means between both ends of the receiving end to improve the quality of a received waveform at the receiving end. 2. A driver, a series termination resistor, a third transmission line having a predetermined characteristic impedance, and a first transmission line and a second transmission line having a characteristic impedance value twice as large as the characteristic impedance value of the third transmission line. A driver for receiving the input waveform signal and supplying a buffered drive waveform signal to one end of the series terminating resistor and supplying the driving waveform signal to the third transmission line by an output impedance of the driver and the series terminating resistor. The other end of the series terminating resistor is connected to one end of a third transmission line, and the other end of the third transmission line is connected to the first transmission line and the second transmission line.
Each of the two ends of the transmission line is connected to one end of the transmission line to branch into two, and the other end of the first transmission line (first reception end) and the other end of the second transmission line (second reception end) A two-branch driver circuit for generating a high-speed driving waveform signal from an output end (driving end) of a driver, dividing the signal into two, and transmitting a predetermined quality waveform signal to both ends of the first receiving end and the second receiving end. A two-branch driver circuit comprising: means for connecting a waveform improving means between both ends of the other end of the first transmission line and the other end of the second transmission line to improve the quality of a received waveform at a receiving end. . 3. The two-branch according to claim 1, wherein the waveform improving means connected between both receiving ends is a fourth transmission line having the same characteristic impedance as the characteristic impedance value of the first transmission line. The transmission line or the two-branch driver circuit according to claim 2. 4. The waveform improving means connected between both receiving ends is a resistance element having an impedance of a fraction of the characteristic impedance value of the first transmission line or less. The two-branch transmission line according to claim 1, or the two-branch driver circuit according to claim 2. 5. The waveform improving means connected between both receiving ends is a capacitive element having an impedance of a fraction of the characteristic impedance value of the first transmission line or less. The two-branch transmission line according to claim 1, or the two-branch driver circuit according to claim 2. 6. A waveform improving means connected between both receiving ends, the fifth improving means having the same characteristic impedance as the first transmission line.
3. The two-branch transmission line according to claim 1, wherein the transmission line is a capacitive element exhibiting an impedance of a fraction of the characteristic impedance of the fifth transmission line or less. Branch driver circuit. 7. A waveform improving means connected between both receiving ends, the fifth improving means having the same characteristic impedance as the first transmission line.
3. The two-branch transmission line according to claim 1, wherein the transmission line and the fifth transmission line are resistance elements each having an impedance of a fraction of the characteristic impedance of the fifth transmission line or less. Branch driver circuit. 8. A waveform improving means connected between both receiving ends, wherein the drive waveform signal branched at two branch points for the high frequency component is transmitted through both the receiving ends and the waveform improving means. 3. The two-branch transmission line according to claim 1, wherein the transmission line is a transmission line that loops back to the two-branch point. 9. The two-branch transmission line according to claim 1, wherein the third transmission line, the first transmission line, and the second transmission line are coaxial lines or microstrip lines. Driver circuit. 10. A device under test (DUT) of a semiconductor test apparatus connected to the first receiving end and the second receiving end.
The two-branch driver circuit according to claim 2, wherein 11. A two-branch transmission line includes an output terminal of a driver channel of a pin electronics circuit of a semiconductor test device and two DUTs connected to the driver channel.
A semiconductor test apparatus, which is provided to be applied to distribution supply between the corresponding same IC pins. 12. The waveform improving means is connected between two contactors (contacts) corresponding to the same IC pin which makes electrical contact with two devices under test to be tested by a semiconductor test apparatus. 12. The semiconductor test apparatus according to item 11.