CN103022026B - Multi-chip module and manufacturing method thereof - Google Patents

Abstract

The invention provides a multi-chip module and a manufacturing method thereof. The multi-chip module includes: the high-voltage component chip is provided with at least one power switch; the low-voltage control chip is coupled with the high-voltage element chip through a metal wire; the single chip seat is used for fixing the high-voltage element chip and the low-voltage control chip thereon; and a plurality of leads coupled to the single die pad through the extension portion of the die pad or the metal wire.

Description

Multi-chip module and manufacturing method thereof

technical field

The invention relates to a multi-chip module and a manufacturing method thereof, in particular to a multi-chip module in which a high-voltage component chip and a low-voltage control chip are fixed on the same chip holder and a manufacturing method thereof.

Background technique

FIG. 1 shows a typical power supply circuit, wherein the low-voltage control chip 14 in the multi-chip module 10 operates the high-voltage element chip 12 according to the flyback feedback signal FB and the current sensing signal CS. A power switch to convert the input voltage Vin to the output voltage Vout.

Please refer to FIG. 2A , which shows a prior art arrangement of the multi-chip module 10 . As shown in the figure, the multi-chip module 10 includes a high voltage element chip 12 and a low voltage control chip 14 . Wherein, the high-voltage component chip 12 is fixed on a dedicated chip holder 11 ; and the low-voltage control chip 14 is fixed on another dedicated chip holder 13 . Generally speaking, the manufacturing process of high-voltage components and low-voltage components is different, and the cost of manufacturing separately is lower than manufacturing on the same substrate at the same time. Therefore, it is very common to manufacture high-voltage component chips 12 and low-voltage control chips 14 separately; If it is a vertical component, the surface of the substrate has a potential. Therefore, the high-voltage component chip 12 and the low-voltage control chip 14 should not be fixed on the same chip holder at the same time, so as not to affect each other or even cause a short circuit. The specific implementation method is shown in Figure 2A As shown, the high-voltage element chip 12 and the low-voltage control chip 14 are fixed on different chip holders 11 and 13 and packaged in the same module. The advantage of this prior art is that it integrates the high-voltage component chip 12 and the low-voltage control chip 14 into a single package, and avoids mutual interference of chip signals.

FIG. 2B shows a cross-sectional view of tangent line AA in FIG. 2A. As shown in the figure, the separate chip holder 11 and the chip holder 13 are respectively fixed with a high-voltage element chip 12 and a low-voltage control chip 14 , and the chips are connected to each other by metal wires 15 to transmit signals. The disadvantage of this prior art is that the chip is fixed on a single dedicated chip pad, so the area of each chip pad is smaller than that of the shared chip pad, so that the heat dissipation efficiency is relatively poor. In addition, the temperature sensor (not shown) in the low-voltage control chip 14 cannot sense the temperature of the high-voltage element chip 12 (or has poor sensing accuracy), so as to activate overtemperature protection (OTP) when the temperature is too high. The prior art described above can be found, for example, in US Patent Application No. 2007/0200537.

3A-3C show another prior art multi-chip module 20 arrangement. Compared with the aforementioned prior art, this prior art integrates the high voltage element and the low voltage element into a single (monolithic) chip 22 . As shown in FIG. 3A , the chip holder 21 fixes a single chip 22 thereon. In this way, compared with the aforementioned prior art, the chip holder 21 has separate chip holders 11 and 13, and the heat dissipation area of the prior art is smaller. Larger, with better cooling effect. FIG. 3B shows the top view of the single chip 22 in simplified diagrams. As shown in the figure, the high voltage element 221 and the low voltage element 222 are integrated in the single chip 22 . FIG. 3C shows a cross-sectional view of tangent line AA in FIG. 2A. However, the disadvantage of this prior art is that the high-voltage components and low-voltage components need to be manufactured on the same substrate at the same time, and the manufacturing cost is high; in addition, the high-voltage components and low-voltage components are on the same substrate, which is prone to the noise problem of signal interaction. Such as crosstalk (crosstalk) and other issues.

In view of this, the present invention aims at the deficiencies of the above-mentioned prior art, and proposes a multi-chip module and its manufacturing method in which the high-voltage component chip and the low-voltage control chip are fixed on the same chip seat, which can improve the problem of chip heat dissipation, and does not need to increase manufacturing cost.

Contents of the invention

One of the objectives of the present invention is to overcome the deficiencies and defects of the prior art and propose a multi-chip module.

Another object of the present invention is to provide a method for manufacturing a multi-chip module.

In order to achieve the above object, from one point of view, the present invention provides a multi-chip module, comprising: a high-voltage component chip, which has at least one power switch; a low-voltage control chip, which is coupled to the high-voltage component chip through a metal wire. a single chip seat, used to fix the high voltage element chip and the low voltage control chip on it; and a plurality of pins, coupled with the single chip seat through an extension of the chip seat or metal wires.

In one embodiment, the high-voltage device chip preferably includes: a lateral metal oxide semiconductor field effect transistor (MOSFET) power switch; and a lateral depletion-type start-up switch.

In the multi-chip module, the high-voltage element chip may further include a thermal diode for sensing temperature.

In another embodiment, the lateral depletion start switch preferably has a lateral depletion MOSFET or a lateral depletion junction field effect transistor (junction field effect transistor, JFET).

In another implementation mode, the power switch has a first current inflow terminal, a first control terminal, and a first current outflow terminal, through the operation of the first control terminal, a switch current is controlled to flow into the first A current inflow terminal, and flows out from the first current outflow terminal; the high voltage component chip further includes a sampling transistor, used to sample the switching current, which includes: a second current inflow terminal, included in the first current inflow terminal ; a second control terminal, included in the first control terminal; and a second current outflow terminal, isolated from the first current outflow terminal, and generating a sampling current proportional to the switch current.

From another point of view, the present invention also provides a method for manufacturing a multi-chip module, including: providing a high-voltage element chip having at least one power switch; coupling the high-voltage element chip to a low-voltage control chip through metal wires; The high-voltage component chip and the low-voltage control chip are fixed on a single chip holder; and the single chip holder is coupled to a plurality of pins through an extension part or a metal wire of the chip holder.

The following will be described in detail through specific embodiments, so that it is easier to understand the purpose, technical content, characteristics and effects of the present invention.

Description of drawings

Figure 1 shows a typical power supply circuit;

2A-2B show a prior art arrangement of the multi-chip module 10;

3A-3C show another prior art multi-chip module 20 arrangement;

4A-4B show a first embodiment of the present invention;

5A-5C show a second embodiment of the present invention.

Explanation of symbols in the figure

10, 20, 30, 40 multi-chip modules

11, 13, 15, 21, 31 chip socket

12, 16, 32, 42 high voltage component chips

14, 34, 44 low voltage control chip

15, 35 metal wire

22 single chip

221 high voltage components

222 low voltage components

37 pins

39 extension

CS current sense signal

Drain drain

DriftRegion drift area

FB feedback signal

Gate grid

R resistance

S1 power switch

S2 sampling transistor

Source1, Source2 source

Vin input voltage

Vout output voltage

Detailed ways

Please refer to FIGS. 4A and 4B , which show the first embodiment of the present invention. The multi-chip module 30 includes a high-voltage element chip 32 having at least one power switch, a low-voltage control chip 34 , a single chip holder 31 and multiple pins 37 . As shown in FIG. 4A , the low voltage control chip 34 is coupled to the high voltage element chip 32 through a metal wire 35 . Moreover, both the high-voltage component chip 32 and the low-voltage control chip 34 are fixed on a single chip holder 31 , as shown in FIG. 4B , which is a cross-sectional view taken along line CC in FIG. 4A . In addition, the plurality of pins 37 are coupled to the high-voltage element chip 32 and the low-voltage control chip 34 on the single chip holder 31 through the extension portion 39 of the chip holder 31 or the metal wire 35 .

In order to make the high-voltage element chip 32 and the low-voltage control chip 34 be fixed on a single chip seat 31, and to avoid the substrate surface of the vertical high-voltage element and the substrate surface of the low-voltage control chip as described in the prior art have different potentials; The high-voltage device chip 32 of the embodiment may include, but is not limited to: a lateral metal oxide semiconductor field effect transistor (MOSFET) power switch; and/or a lateral depletion-type start-up switch. Because the horizontal high-voltage element is different from the vertical high-voltage element, its substrate surface has the same potential (grounded) as the substrate surface of the low-voltage control chip, so it can be fixed on the same chip holder 31 .

Wherein, the high-voltage element chip 32 may include, but is not limited to, thermal diodes (thermal diodes), which can be used to sense temperature, and then control the high-voltage element to further prevent the chip from overheating.

In addition, the above-mentioned lateral depletion start-up switch is, for example but not limited to, a lateral depletion type MOSFET or a lateral depletion type junction field effect transistor (JFET), which is used to operate in the circuit start-up process.

5A-5C show a second embodiment of the present invention. As shown in FIG. 5A , the multi-chip module 40 includes a high-voltage element chip 42 and a low-voltage control chip 44 . In this embodiment, the high voltage device chip 42 includes, for example, a power switch S1 and a sampling transistor S2 , and the sampling transistor S2 is used to sense the current of the power switch S1 . The current inflow terminal of the sampling transistor S2 is coupled to the current inflow terminal of the power switch S1. The control terminal of the sampling transistor S2 and the control terminal of the power switch S1 are both coupled to the control pin Gate of the low voltage control chip 44 . The current output end of the sampling transistor S2 is coupled to one end of the resistor R, and the other end of the resistor R is coupled to the ground. (In the case of NMOS, the current inflow terminal is the drain, the control terminal is the gate, and the current outflow terminal is the source; in the case of PMOS or bicarrier junction transistors, it is the corresponding terminal, which is the same technical field. Those with ordinary knowledge are well known.) Through this sampling method, the power loss of sensing the power switch current can be reduced, the efficiency can be improved, and the sampling accuracy can be improved. In addition, please refer to FIG. 5B , which shows a mechanism of sensing the current of the power switch S1 through the sampling transistor S2 to achieve an overcurrent protection (OCP) mechanism, and the current sensing CS pin of the low voltage control chip 44 can be further omitted. As shown in FIG. 5B , the source of the sampling transistor S2 is coupled to a comparator circuit, compared with a set value, and generates an over-current protection signal OCP to achieve an over-current protection mechanism, thereby omitting the low-voltage control chip 44. Current sense CS pin to improve integration and reduce manufacturing cost.

FIG. 5C shows a top view of the sampling transistor S2 and the power switch S1. As shown in FIG. 5C , the power switch S1 includes a drain Drain, a drift region, a gate Gate, and a source Source1 . In practice, it can be considered that the source Source1 is divided into a small section as the source Source2 of the sampling transistor S2, and the drain Drain, the drift region, and the gate Gate are shared with the power switch S1, that is, The drain Drain (current inflow terminal) and gate Gate (control terminal) of the power switch S1 also serve as or include the drain Drain (current inflow terminal) and gate Gate (control terminal) of the sampling transistor S2 respectively, and the sampling transistor S2 The source Source2 (current outflow end) of the power switch S1 is isolated from the source Source1 (current outflow end) of the power switch S1, but the sampling transistor S2 and the power switch S1 are integrated into a single component to save the component area and simplify the component manufacturing process. In this way, the switching current of the power switch S1 can be deduced according to the size ratio of the source Source2 and the source Source1, and the sensed source Source2 voltage or current signal, which can be used as the current sensing signal CS or directly used for Carry out overcurrent protection mechanism.

The present invention has been described above with reference to preferred embodiments, but the above description is only for those skilled in the art to easily understand the content of the present invention, and is not intended to limit the scope of rights of the present invention. Under the same spirit of the present invention, various equivalent changes can be conceived by those skilled in the art. For example, the power switch S1 can be a PMOS or NMOS transistor; in the circuits shown in each embodiment, components that do not affect the main meaning of the signal can be inserted, such as other switches; and for example, the positive and negative inputs of the comparator or error amplifier can be interchanged , it only needs to correspond to the signal processing method of the correction circuit; another example, the multi-chip module of the present invention can be applied to various power supply circuits, such as power factor correction (PFC) circuits, flyback power factor correction circuits, or half bridges Circuits and the like are not limited to the flyback circuits shown in the respective figures. All of these can be deduced according to the teaching of the present invention, therefore, the scope of the present invention should cover the above and all other equivalent changes.

Claims (10)

1. A multi-chip module, characterized in that, comprising: A high-voltage component chip, which has at least one power switch; A low-voltage control chip, which is coupled to the high-voltage element chip through metal wires; a single chip holder for fixing the high voltage element chip and the low voltage control chip thereon; and a plurality of pins coupled to the single chip holder through an extension of the chip holder or metal wires; Wherein, the high-voltage element chip includes a horizontal high-voltage element and does not include a vertical high-voltage element. The horizontal high-voltage element has a first substrate surface, and the low-voltage control chip has a second substrate surface. The first substrate surface and the first substrate surface The surface of the second substrate is used to electrically connect to the ground potential; Wherein, the high pressure is higher than the low pressure. 2. The multi-chip module as claimed in claim 1, wherein the high voltage element chip comprises: a lateral MOSFET power switch; and A transverse air-suppression type start switch. 3. The multi-chip module as claimed in claim 2, wherein the high voltage element chip further comprises a thermal diode for sensing temperature. 4. The multi-chip module as claimed in claim 2, wherein the lateral depletion type enable switch has a lateral depletion type MOSFET or a lateral depletion type junction field effect transistor. 5. The multi-chip module as claimed in claim 1, wherein, the power switch has a first current inflow terminal, a first control terminal, and a first current outflow terminal, through the operation of the first control terminal, a The switch current flows into the first current inflow terminal and flows out from the first current outflow terminal; the high voltage element chip further includes a sampling transistor for sampling the switch current, which includes: the first current inflow terminal; the first control terminal; and A second current outflow end is isolated from the first current outflow end, and generates a sampling current with a ratio to the switch current, wherein the sampling transistor and the power switch are integrated into a single element. 6. A method for manufacturing a multi-chip module, comprising: providing a high-voltage element chip having at least one power switch; coupling the high-voltage element chip to a low-voltage control chip through metal wires; fixing the high-voltage element chip and the low-voltage control chip on a single chip holder; and coupling the single die holder to the plurality of pins through an extension of the die holder or metal wires; Wherein, the high-voltage element chip includes a horizontal high-voltage element and does not include a vertical high-voltage element. The horizontal high-voltage element has a first substrate surface, and the low-voltage control chip has a second substrate surface. The first substrate surface and the first substrate surface The surface of the second substrate is used to electrically connect to the ground potential; Wherein, the high pressure is higher than the low pressure. 7. The method of manufacturing a multi-chip module as claimed in claim 6, wherein the high voltage component chip comprises: a lateral MOSFET power switch; and A transverse air-suppression type start switch. 8. The manufacturing method of the multi-chip module as claimed in claim 7, wherein the high voltage element chip further comprises a thermal diode for sensing temperature. 9. The manufacturing method of a multi-chip module as claimed in claim 7, wherein the lateral depletion type enable switch has a lateral depletion type MOSFET or a lateral depletion type junction field effect transistor. 10. The manufacturing method of a multi-chip module as claimed in claim 6, wherein the power switch has a first current inflow terminal, a first control terminal, and a first current outflow terminal, through the operation of the first control terminal, A switch current is controlled to flow into the first current inflow end and flow out from the first current outflow end; the high voltage element chip further includes a sampling transistor for sampling the switch current, which includes: the first current inflow terminal; the first control terminal; and A second current outflow end is isolated from the first current outflow end, and generates a sampling current with a ratio to the switch current, wherein the sampling transistor and the power switch are integrated into a single element.