Multi-chip Module

Abstract

A multi-chip optical module (2) obtained by packaging a plurality of IC chips (201A, 201B, 201C) mounted on a single substrate (101) includes: a lid component (203) that forms a housing space (S) for the plurality of IC chips (201A, 201B, 201C) together with the substrate (101) and has protrusions (111, 112, 113) protruding toward the IC chips (201A, 201B, 201C); and an adhesive layer (104A, 104B, 104C) that is formed between the protrusion (111, 112, 113) and the IC chip (201A, 201B, 201C). The protruding lengths of the protrusions (111, 112, 113) differ according to the height of the protrusions (111, 112, 113) with respect to the substrate (101).

Description

[Technical Field]

[0001] The present disclosure relates to multi-chip modules. [Background technology]

[0002] With the increasing demand for communications, further increases in the capacity of communication networks are being considered. In particular, there is a growing demand for higher capacity in optical communications. Furthermore, there is a strong demand for miniaturization of optical modules used in optical communications in order to improve the bit rate per unit volume of communications equipment and reduce power consumption. Multi-chip modules, in which multiple types of ICs (Integrated Circuits) and optical chips are mounted on a single chip substrate, are effective in miniaturizing optical modules. Such multi-chip modules are described, for example, in Patent Document 1. The optical integrated circuit type optical device described in Patent Document 1 is configured by housing a planar substrate optical integrated circuit and an electric circuit in a single package. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-223742 Summary of the Invention

[0004] However, it is known that IC chips, such as optical chips, generate heat during operation. When multiple IC chips are integrated on a single substrate, the heat density of the module increases, resulting in a rise in temperature during operation. Since an increase in module temperature can impair the reliability of the IC chips, there is a demand for improving this heat dissipation. Here, we will explain heat dissipation from IC chips.

[0005] FIG. 1 is a cross-sectional view of a known multi-chip optical module 1. The multi-chip optical module 1 includes a substrate 11, IC chips 21A, 21B, and 21C mounted on one surface (mounting surface) of the substrate 11, and a lid component 13 that houses the IC chips 21A, 21B, and 21C together with the substrate 11. The IC chips 21A, 21B, and 21C are mounted using bumps 22, and external terminals 12 are formed on the back surface of the substrate 11 opposite the mounting surface. In the multi-chip optical module 1, the integrated IC chips 21A, 21B, and 21C have different heights. Each of the IC chips 21A, 21B, and 21C is connected to the metal lid component 13 by a thermally conductive adhesive. With this configuration, the IC chips 21A, 21B, and 21C are thermally and mechanically connected to the lid component 13.

[0006] The top surface 13a of the lid component 13 has a uniform thickness. The heights of the IC chips 21A, 21B, and 21C are such that the IC chip 21A is the shortest, followed by the IC chip 21B and the IC chip 21C. Therefore, the thickness h1 of the adhesive layer 14 on the IC chip 21A is the thickest, followed by the thickness h2 of the adhesive layer 14 on the IC chip 21B and the thickness h3 of the adhesive layer 14 on the IC chip 21B. It is known that thermally conductive adhesives have high thermal resistance, making it difficult for them to dissipate heat as their thickness increases. In the example shown in FIG. 1, heat dissipation is most difficult in the adhesive layer 14 on the IC chip 21A, resulting in a rise in temperature and a loss of overall reliability for the multi-chip optical module 1.

[0007] One aspect of the present invention has been made in consideration of the above points, and relates to a multi-chip module that integrates a plurality of chip components of different heights, which has high heat dissipation properties, suppresses temperature increases, and improves reliability.

[0008] In order to achieve the above object, one aspect of the present invention provides a multi-chip module in which a plurality of chip components mounted on a single substrate are packaged, the multi-chip module comprising a lid component which, together with the substrate, forms a housing space for housing the plurality of chip components and has protruding portions protruding toward each of the chip components; and a first adhesive layer formed between the protruding portions and the chip components, the adhesive Agent and a first adhesive layer that fixes the chip component and the lid component to each other, and the protruding length of the protrusion increases as the height of the chip component relative to the substrate decreases.

[0009] According to the above-described embodiment, in a multi-chip module in which a plurality of chip components having different heights are integrated, heat dissipation is high, and temperature rise can be suppressed, thereby improving reliability. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view of a known multi-chip optical module; [Figure 2] 1 is a diagram showing a cross section of a multi-chip optical module according to a first embodiment. [Figure 3] FIG. 10 is a cross-sectional view of a multi-chip optical module according to a second embodiment. [Figure 4] FIG. 10 is a cross-sectional view of a multi-chip optical module according to a third embodiment. [Figure 5] FIG. 10 is a cross-sectional view of a multi-chip optical module according to a fourth embodiment. [Figure 6] FIG. 10 is a cross-sectional view of a multi-chip optical module according to a fifth embodiment. [Figure 7] FIG. 10 is a cross-sectional view of a multi-chip optical module according to a sixth embodiment. [Figure 8] FIG. 13 is a cross-sectional view of a multi-chip optical module according to a seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] The first to seventh embodiments of the present invention will be described below with reference to the drawings. In the drawings, like components are denoted by like reference numerals, and their description may be omitted. The drawings are intended to explain the configuration, technical concept, functions, effects, and positional relationships of each part of the first to seventh embodiments. Therefore, the drawings do not limit the specific shapes of the multi-chip modules of the first to seventh embodiments. The drawings are also not limited to accurately depicting the aspect ratios and dimensions of the multi-chip modules and chip components of the first to seventh embodiments. In the first to seventh embodiments, the multi-chip module is configured as a multi-chip optical module integrating IC chips of optical devices.

[0012] [First embodiment] FIG. 2 is a cross-sectional view illustrating a multi-chip optical module 2 according to a first embodiment. The multi-chip optical module 2 is configured by packaging multiple IC chips 201A, 201B, and 201C, which are chip components mounted on a single substrate 101. The cross-sectional view shows a cross section of the multi-chip optical module 2 cut in the direction in which the IC chips 201A, 201B, and 201C are arranged. The IC chips are mounted using bumps 202. The substrate 101 includes external terminals 102 for electrically connecting the IC chips 201A, 201B, and 201C to external devices. Hereinafter, in this specification, the up-down direction is determined so that the mounting surface 101a of the substrate 101 is lower than the IC chips 201A, 201B, and 201C, i.e., so that the IC chips 201A, 201B, and 201C are mounted on the mounting surface 101a. This up-down direction is determined regardless of the direction of gravity.

[0013] The optical devices, IC chips 201A, 201B, and 201C, are configured by integrating optical elements such as optical waveguides, optical modulators, and semiconductor lasers on a single crystal substrate such as silicon or compound semiconductor. The multi-chip optical module 2 includes a lid component 203 that, together with the substrate 101, forms a storage space S for storing the IC chips 201A, 201B, and 201C. The IC chips 201A, 201B, and 201C shown in FIG. 2 have different heights, with IC chip 201A being the shortest and IC chip 201C being the tallest. The storage space S need only be a space that contains the IC chips 201A, 201B, and 201C, and it is not necessary to seal the IC chips 201A, 201B, and 201C.

[0014] The lid component 203 also has protrusions 111, 112, and 113 that protrude toward the IC chips 201A, 201B, and 201C, respectively. The protrusion lengths of the protrusions 111, 112, and 113 vary depending on the heights of the IC chips 201A, 201B, and 201C relative to the substrate 101. The multi-chip optical module 2 also includes adhesive layers 104A, 104B, and 104C that are first adhesive layers formed between the protrusions 111, 112, and 113 and the IC chips 201A, 201B, and 201C.

[0015] The lid component 203 also has sidewalls 203b and 203d around the protrusions 111, 112, and 113. The sidewalls 203b and 203d form a continuous wall. The surface of sidewall 203b facing the substrate 101 is referred to as sidewall-facing surface 203c, and the surface of sidewall 203d facing the substrate 101 is referred to as sidewall-facing surface 203e. Furthermore, the upper surface of IC chip 201A facing the protrusion 111 is referred to as chip-facing surface 201Aa, the upper surface of IC chip 201B facing the protrusion 112 is referred to as chip-facing surface 201Ba, and the upper surface of IC chip 201C facing the protrusion 113 is referred to as chip-facing surface 201Ca.

[0016] The "height" of IC chips 201A, 201B, and 201C refers to the distance from mounting surface 101a to chip-facing surfaces 201Aa, 201Ba, and 201Ca of IC chips 201A, 201B, and 201C, with substrate 101 (mounting surface 101a) as the reference. However, the first embodiment is not limited to such a reference, and the heights of IC chips 201A, 201B, and 201C may be determined based on a common surface. The height of IC chip 201A, etc. is equal to the thickness of IC chip 201A, etc.

[0017] As shown in FIG. 2, the protrusion lengths of the protrusions 111, 112, and 113 vary depending on the heights of the IC chips 201A, 201B, and 201C relative to the substrate 101. Here, the "protrusion length" refers to the length from a common reference position for the protrusions 111, 112, and 113 to the protrusion-facing surfaces 203aa, 203ab, and 203ac of the protrusions 111, 112, and 113 that face the IC chips 201A, 201B, and 201C. In the example shown in FIG. 2, the protrusion length is determined relative to the top surface 203f of the lid component 203. However, the first embodiment is not limited to this example. For example, the protrusion length may be determined relative to any of the inner surfaces of the lid component 203, or any of the protrusion-facing surfaces 203aa, 203ab, and 203ac.

[0018] 2, the protrusion length pa of the protrusion 111 on the IC chip 201A, which has the smallest height, is the longest, followed by the protrusion length pb of the protrusion 112 on the IC chip 201B, which has the next largest height, and the protrusion length pc of the protrusion 113 on the IC chip 201C, which has the longest height, is the shortest. The IC chip 201A is fixed to the lid component 203 by an adhesive layer 104A between the chip-facing surface 201Aa and the protrusion-facing surface 203aa. The IC chip 201B is fixed to the lid component 203 by an adhesive layer 104B between the chip-facing surface 201Ba and the protrusion-facing surface 203ab, and the IC chip 201C is fixed to the lid component 203 by an adhesive layer 104C between the chip-facing surface 201Ca and the protrusion-facing surface 203ac. With this configuration, regardless of the height of IC chips 201A, 201B, and 201C, adhesive layers 104A, 104B, and 104C can be made sufficiently thin, suppressing heat accumulation in the adhesive layers and preventing temperature rise in the IC chips. This prevents malfunctions and other problems caused by temperature rise in the IC chips, contributing to improving the reliability of the IC chips.

[0019] Furthermore, the first embodiment uses a lid component 203 that is at least partially made of a metal material. Examples of such lid components include those made of nickel-plated kovar, an alloy containing iron, nickel, and cobalt, and those made of a gold-tin alloy. Such lid components 203 have high thermal conductivity and heat dissipation properties, and can further enhance the effect of suppressing temperature increases in the IC chip.

[0020] [Second embodiment] 3 is a cross-sectional view illustrating a multi-chip optical module 3 according to a second embodiment. The multi-chip optical module 3 is a multi-optical module in which multiple IC chips 201A, 201B, and 201C mounted on a single substrate 101 are packaged. The multi-chip optical module 3 includes the substrate 101 and a lid component 303. The substrate 101 and the lid component 303 are stacked together to form a storage space S for the IC chips 201A, 201B, and 201C. The lid component 303 includes protrusions 121, 122, and 123 that protrude toward the IC chips 201A, 201B, and 201C, respectively. A protrusion-facing surface 303aa of the protrusion 121 faces the IC chip 201A, a protrusion-facing surface 303ab of the protrusion 122 faces the IC chip 201B, and a protrusion-facing surface 303ac of the protrusion 123 faces the IC chip 201C. A series of sidewalls 303b and 303d are provided around the IC chips 201A, 201B, and 201C. A sidewall-facing surface 303c of the sidewall 303b and a sidewall-facing surface 303e of the sidewall 303d face the substrate 101.

[0021] Of the protrusions 121, 122, and 123, protrusion 121 is disposed on IC chip 201A, protrusion 122 is disposed on IC chip 201B, and protrusion 123 is disposed on IC chip 201C. As in the first embodiment, the lengths of protrusions 122 and 123 correspond to the heights of IC chips 201B and 201C. That is, the length of protrusion 122 on IC chip 201B, which is relatively short, is relatively long, and the length of protrusion 123 on IC chip 201C, which is relatively tall, is relatively short.

[0022] In the second embodiment, the protrusions 121 and 122 have the same protrusion length and are integral. However, in the second embodiment, the integral protrusions 121 and 122 are distinguished, for example, by a boundary between an imaginary plane that passes between the IC chips 201A and 201B and is perpendicular to the substrate 101 and the lid component 303. On the other hand, the height of the IC chip 201A is lower than that of the IC chip 201B, and the distance between the chip facing surface 201Aa and the protrusion facing surface 303aa is wider than the distance between the chip facing surface 201Ba and the protrusion facing surface 303ab. In the second embodiment, the adhesive layers 104Aa and 104Ab between the IC chip 201A and the protrusion 121 include a spacer 301. The sum of the thickness of the adhesive layers 104Aa and 104Ab including the spacer 301 and the height (thickness) of the IC chip 201 is equal to the sum of the thicknesses of the IC chip 201B and the adhesive layer 104B.

[0023] The spacer 301 may be formed from AlN or CuW. Because the spacer 301 has higher processing accuracy than the lid component 303, the thickness of the adhesive layers 104Aa and 104Ab can be adjusted with higher precision to reduce variations. That is, because the lid component 303 is manufactured by cutting the base material, the dimensional tolerance of the step of the protruding portion is approximately 100 μm. On the other hand, because the spacer 301 is manufactured by cutting and plating the base material, the dimensional tolerance can be reduced to approximately 20 μm. According to the second embodiment, the heights of the protruding portions 121 and 122 are made equal to eliminate any steps, and the thickness of the adhesive layers 104Aa and 104Ab on the IC chip 201A can be adjusted with high precision to minimize the thickness.

[0024] [Third embodiment] FIG. 4 is a cross-sectional view illustrating a multi-chip optical module 4 according to a third embodiment. The multi-chip optical module 4 includes a substrate 101 and a lid component 403. The lid component 403 includes protrusions 131, 132, and 133 that protrude toward the IC chips 201A, 201B, and 201C, respectively. A protrusion-facing surface 403aa of the protrusion 131 faces the IC chip 201A, a protrusion-facing surface 403ab of the protrusion 132 faces the IC chip 201B, and a protrusion-facing surface 403ac of the protrusion 133 faces the IC chip 201C. A series of sidewalls 403b and 403d are provided around the IC chips 201A, 201B, and 201C. A sidewall-facing surface 403c of the sidewall 403b and a sidewall-facing surface 403e of the sidewall 403d face the substrate 101.

[0025] In the third embodiment, there is no step between the protrusions 131 and 132, and they are integrated. A spacer 301 is disposed between the IC chip 201A and the protrusion-facing surface 403aa, and adhesive layers 104Aa and 104Ac are formed above and below the spacer 301. Furthermore, in the third embodiment, the area of ​​the protrusion-facing surface 403aa of the protrusion 131 is smaller than the area of ​​the chip-facing surface 201Aa, and the area of ​​the protrusion-facing surface 403ab of the protrusion 132 is smaller than the area of ​​the chip-facing surface 201Ba. This configuration allows the adhesive on the chip-facing surfaces 201Aa and 201Ba to overflow beyond the protrusions 131 and 132, respectively, to form adhesive layers 104Ac and 104D with fillets. Therefore, the third embodiment can prevent the adhesive from flowing toward the substrate 101. Furthermore, the adhesive strength between the lid component 403 and the IC chip 201A, etc., can be increased.

[0026] [Fourth embodiment] FIG. 5 is a cross-sectional view illustrating a multi-chip optical module 5 according to a fourth embodiment. The multi-chip optical module 5 includes a substrate 101 and a lid component 503. The lid component 503 includes protrusions 141, 142, and 143 that protrude toward the IC chips 201A, 201B, and 201C, respectively. A protrusion-facing surface 503aa of the protrusion 141 faces the IC chip 201A, a protrusion-facing surface 503ab of the protrusion 142 faces the IC chip 201B, and a protrusion-facing surface 503ac of the protrusion 143 faces the IC chip 201C. A series of sidewalls 503b and 503d are provided around the IC chips 201A, 201B, and 201C. A sidewall-facing surface 503c of the sidewall 503b and a sidewall-facing surface 503e of the sidewall 503d face the substrate 101. An adhesive layer 104Aa, a spacer 301, and an adhesive layer 104Ad are provided between the protrusion facing surface 503aa and the chip facing surface 201Aa.

[0027] The fourth embodiment differs from the first embodiment and the like in that the protruding portions 141 and 142 each have a step portion with a different protruding length. That is, as shown in FIG. 5, the protruding portion 141 has a protruding facing surface 503aa and a protruding facing surface 503ad, which has a shorter protruding length than the protruding facing surface 503aa. The protruding facing surfaces 503aa and 503ad form a step portion 504. The protruding portion 142 has a protruding facing surface 503ab and a protruding facing surface 503ae, which has a shorter protruding length than the protruding facing surface 503ab. The protruding facing surfaces 503ab and 503ae form a step portion 505. Furthermore, in the fourth embodiment, as in the third embodiment, the area of ​​the protruding facing surface 503aa is smaller than the area of ​​the chip-facing surface 201Aa, and the area of ​​the protruding facing surface 503ab is smaller than the area of ​​the chip-facing surface 201Ba.

[0028] According to the fourth embodiment, the adhesive overflows from the protrusion 141 and flows into the step 504, forming an adhesive layer 104Ad having a fillet. The adhesive between the chip-facing surface 201Ba and the protrusion-facing surface 503ab of the IC chip 201B overflows from the protrusion 142 and flows into the step 505, forming an adhesive layer 104E having a fillet. This prevents the adhesive from moving toward the substrate 101, and also increases the adhesive strength between the lid component 503 and the IC chip 201A, etc.

[0029] [Fifth embodiment] FIG. 6 is a cross-sectional view illustrating a multi-chip optical module 6 according to a fifth embodiment. The multi-chip optical module 6 includes a substrate 101 and a lid component 603. The lid component 603 includes protrusions 151, 152, and 153 that protrude toward the IC chips 201A, 201B, and 201C, respectively. A protrusion-facing surface 603aa of the protrusion 151 faces the IC chip 201A, a protrusion-facing surface 603ab of the protrusion 152 faces the IC chip 201B, and a protrusion-facing surface 603ac of the protrusion 153 faces the IC chip 201C. A series of sidewalls 603b and 603d are provided around the IC chips 201A, 201B, and 201C. A sidewall-facing surface 603c of the sidewall 603b and a sidewall-facing surface 603e of the sidewall 603d face the substrate 101. An adhesive layer 104Aa, a spacer 301, and an adhesive layer 104Ab are provided between the protrusion facing surface 603aa and the chip facing surface 201Aa.

[0030] The fifth embodiment differs from the first embodiment and others in that an adhesive layer 601 is also formed between the sidewall portions 603b and 603d and the substrate 101, i.e., the substrate 101 and the lid component 603 are bonded together. The adhesive layer 601 corresponds to the second adhesive layer in the fifth embodiment. According to the fifth embodiment, it is possible to compensate for the decrease in adhesive strength caused by thinning the adhesive layers 104Aa and 104Ab in consideration of heat dissipation function. The sidewall facing surfaces 603c and 603e are closer to the substrate 101 than the protrusion facing surfaces 603aa, 603ab, and 603ac. Therefore, the gap between the lid component 603 and the substrate 101 is relatively narrow, and the thickness of the adhesive layer 601 can be set to a thickness that compensates for the adhesive strength without raising the temperature around the IC chip.

[0031] [Sixth embodiment] FIG. 7 is a cross-sectional view illustrating a multi-chip optical module 7 according to a sixth embodiment. The multi-chip optical module 7 includes a substrate 101 and a lid component 703. The lid component 703 includes protrusions 161, 162, and 163 that protrude toward the IC chips 201A, 201B, and 201C, respectively. A protrusion-facing surface 703aa of the protrusion 161 faces the IC chip 201A, a protrusion-facing surface 703ab of the protrusion 162 faces the IC chip 201B, and a protrusion-facing surface 703ac of the protrusion 163 faces the IC chip 201C. A series of sidewalls 703b and 703d are provided around the IC chips 201A, 201B, and 201C. Sidewall-facing surfaces 703ca and 703cb of the sidewall 703b and a sidewall-facing surface 703e of the sidewall 703d face the substrate 101.

[0032] In the sixth embodiment, at least a portion of each of the sidewalls 703b and 703d has a step 704 that varies in distance from the substrate 101. The step 704 is formed so that the side farther from the protrusions 161 is farther from the substrate 101 than the side closer to the protrusions 161. That is, the step 704 is formed by a sidewall-facing surface 703cb that is farther from the substrate 101 and a sidewall-facing surface 703ca that is closer to the substrate 101 than the sidewall-facing surface 703cb. That is, the sidewall-facing surface 703cb of the sidewall 703b of the lid component 703 is farther from the substrate 101 on the outside of the lid component 703. The adhesive that bonds the substrate 101 and the lid component 703 penetrates the step 704 and forms a fillet. According to the sixth embodiment, the state of the adhesive layer 701 at the step 704 can be observed from the outside, facilitating visual inspection.

[0033] [Seventh embodiment] FIG. 8 is a cross-sectional view illustrating a multi-chip optical module 8 according to a seventh embodiment. The multi-chip optical module 8 includes a substrate 101 and a lid component 803. The lid component 803 includes protrusions 171, 172, and 173 that protrude toward the IC chips 201A, 201B, and 201C, respectively. A protrusion-facing surface 803aa of the protrusion 171 faces the IC chip 201A, a protrusion-facing surface 803ab of the protrusion 172 faces the IC chip 201B, and a protrusion-facing surface 803ac of the protrusion 173 faces the IC chip 201C. A series of sidewalls 803b and 803d are provided around the IC chips 201A, 201B, and 201C. Sidewall-facing surfaces 803ca and 803b of the sidewall 803b face the substrate 101.

[0034] The side wall 803d has a step 805 formed by lower surfaces 803ea and 803eb. An adhesive is applied between the step 805 and the substrate 101, and an adhesive layer 801 is further formed between the mounting surface 101a and lower surface 803eb of the substrate 101, as well as between the side surface 101b of the substrate 101 and the side wall 803ea. According to the seventh embodiment, the adhesive layer thickness can be reduced while increasing the adhesive area for bonding the lid component 803 and the substrate 101, thereby increasing the strength of the package of the multi-chip optical module. [Explanation of symbols]

[0035] 1,2,3,4,5,6,7,8 Multi-chip optical module 101 Substrate 101a Mounting surface 101b Side 102 External terminal 104A,104B,104C,104D,104Aa,104Ab,104Ac,104Ad,104Ae,601,701,801 Adhesive layer 111,112,113,121,122,123,131,132,133, 141,142,143,151,152,153,161,162,163,171,172,173 Projection 201A, 201B, 201C IC chip 201Aa, 201Ba, 201Ca Chip facing surface 202 Bump 203,303,403,503,603,703,803 Lid parts 203aa,203ab,203ac,303aa,303ab,303ac,403aa,403ab,403ac,503aa,503ab,503ac,503ad,503ae,603aa,603ab,603ac,703ab,703ac,803aa,803ab Protruding opposing surface 203b,203d,303b,303d,403b,403d,503b,503d,603b,603d,703b,703d,803b,803d,803ea Side wall part 203c, 203e, 303c, 303e, 403c, 403e, 503c, 503e, 603c, 603e, 703c, 703e, 703ca, 703cb, 803c Sidewall facing surfaces 203F Above 301 スペーサ 504,505,704,805 Step Difference Department 803ea, 803eb below S containment space

Claims

1. A multi-chip module in which a plurality of chip components mounted on a single substrate are packaged, a lid component which, together with the substrate, forms an accommodating space for accommodating the plurality of chip components and has protruding portions which protrude toward each of the chip components; a first adhesive layer formed between the protrusion and the chip component, the first adhesive layer fixing the chip component and the lid component to each other; A multi-chip module, wherein the protruding length of the protruding portion is longer as the height of the chip component relative to the substrate is lower.

2. 2. The multi-chip module of claim 1, wherein the first adhesive layer between at least one of the chip components and the protrusion includes a spacer, and the sum of the thickness of the first adhesive layer including the spacer and the chip component is equal to the sum of the thickness of another one of the chip components and the first adhesive layer between the other one of the chip components and the protrusion.

3. 3. The multi-chip module according to claim 1, wherein an area of ​​a protrusion-facing surface of said protrusion facing said chip component is smaller than an area of ​​a chip-facing surface of said chip component facing said protrusion.

4. 2. The multi-chip module according to claim 1, wherein a protruding surface of said protruding portion facing said chip component has a stepped portion with said protruding length varying.

5. 2. The multi-chip module of claim 1, wherein the lid component has a sidewall portion disposed around the protrusion, the sidewall portion having a sidewall-facing surface facing the substrate, the sidewall-facing surface being closer to the substrate than a protrusion-facing surface of the protrusion facing the substrate, and a second adhesive layer being formed between the sidewall-facing surface and at least a portion of the substrate.

6. 6. The multi-chip module according to claim 5, wherein the second adhesive layer is further formed between the side surface of the substrate and the side wall portion.

7. 6. The multi-chip module according to claim 5, wherein at least a portion of the sidewall opposing surface has a step portion that varies in distance from the substrate, and the step portion is formed so as to be farther from the substrate on a side of the sidewall opposing surface farther from the protrusion than on a side closer to the protrusion.

8. 2. The multi-chip module according to claim 1, wherein at least a portion of said lid component is made of metal.

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